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fonttosfnt.16962
0007-use-more-properties-according-to-XLFD.patch
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File 0007-use-more-properties-according-to-XLFD.patch of Package fonttosfnt.16962
From 5aabd5e0caba5ff6d71a1e05f2917ed20f5c0899 Mon Sep 17 00:00:00 2001 From: Christopher Zimmermann <madroach@gmerlin.de> Date: Tue, 7 Jul 2020 21:02:56 +0200 Subject: [PATCH 07/14] use more properties according to XLFD --- fonttosfnt.h | 23 +- read.c | 37 +- struct.c | 125 ++- util.c | 13 + write.c | 49 +- xlfd.txt | 2970 ++++++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 3146 insertions(+), 71 deletions(-) create mode 100644 xlfd.txt diff --git a/fonttosfnt.h b/fonttosfnt.h index 202ab5a..a05e036 100644 --- a/fonttosfnt.h +++ b/fonttosfnt.h @@ -86,6 +86,22 @@ typedef struct _FontNameEntry { char *value; } FontNameEntryRec, *FontNameEntryPtr; +typedef struct _Metrics { + int height; + int maxX; + int minX; + int maxY; + int minY; + int xHeight; + int capHeight; + int maxAwidth; + int awidth; + int ascent; + int descent; + int underlinePosition; + int underlineThickness; +} MetricsRec, *MetricsPtr; + typedef struct _Font { int numNames; struct _FontNameEntry *names; @@ -93,8 +109,8 @@ typedef struct _Font { int weight; /* as in the OS/2 table */ int width; /* as in the OS/2 table */ int italicAngle; /* degrees c-clockwise from the vertical */ - int underlinePosition; - int underlineThickness; + MetricsRec pxMetrics; + MetricsRec metrics; unsigned foundry; struct _Strike *strikes; } FontRec, *FontPtr; @@ -153,7 +169,7 @@ int findCode(CmapPtr, int); BitmapPtr strikeBitmapIndex(StrikePtr, CmapPtr, int); void strikeMetrics(StrikePtr, int*, int*, int*, int*, int*); int glyphMetrics(FontPtr, int, int*, int*, int*, int*, int*); -void fontMetrics(FontPtr, int*, int*, int*, int*, int*); +void fontMetrics(FontPtr, MetricsPtr); int maxIndex(CmapPtr); int readFile(char *filename, FontPtr); @@ -173,6 +189,7 @@ int macTime(int *, unsigned *); unsigned faceFoundry(FT_Face); char *faceEncoding(FT_Face); int faceFlags(FT_Face); +int faceIntProp(FT_Face, const char *); int faceWeight(FT_Face); int faceWidth(FT_Face); int faceItalicAngle(FT_Face); diff --git a/read.c b/read.c index a22ce41..db79a59 100644 --- a/read.c +++ b/read.c @@ -258,30 +258,6 @@ readFile(char *filename, FontPtr font) i++; #endif font->numNames = i; - - font->flags = faceFlags(face) | (symbol ? FACE_SYMBOL : 0); - font->weight = faceWeight(face); - font->width = faceWidth(face); - font->foundry = faceFoundry(face); - font->italicAngle = faceItalicAngle(face); - - rc = FT_Get_BDF_Property(face, "UNDERLINE_POSITION", &prop); - if(rc == 0 && prop.type == BDF_PROPERTY_TYPE_INTEGER) - font->underlinePosition = - (double)prop.u.integer / face->available_sizes[0].height * - TWO_SIXTEENTH; - else - font->underlinePosition = - - 1.5 / face->available_sizes[0].height * TWO_SIXTEENTH; - - rc = FT_Get_BDF_Property(face, "UNDERLINE_THICKNESS", &prop); - if(rc == 0 && prop.type == BDF_PROPERTY_TYPE_INTEGER) - font->underlineThickness = - (double)prop.u.integer / face->available_sizes[0].height * - TWO_SIXTEENTH; - else - font->underlineThickness = - 1.0 / face->available_sizes[0].height * TWO_SIXTEENTH; } if(face->num_fixed_sizes == 0) { @@ -304,6 +280,19 @@ readFile(char *filename, FontPtr font) return -1; } + font->flags = faceFlags(face) | (symbol ? FACE_SYMBOL : 0); + font->weight = faceWeight(face); + font->width = faceWidth(face); + font->foundry = faceFoundry(face); + font->italicAngle = faceItalicAngle(face); + font->pxMetrics.height = face->available_sizes[0].height; + font->pxMetrics.xHeight = faceIntProp(face, "X_HEIGHT"); + font->pxMetrics.capHeight = faceIntProp(face, "CAP_HEIGHT"); + font->pxMetrics.ascent = faceIntProp(face, "FONT_ASCENT"); + font->pxMetrics.descent = faceIntProp(face, "FONT_DESCENT"); + font->pxMetrics.underlinePosition = faceIntProp(face, "UNDERLINE_POSITION"); + font->pxMetrics.underlineThickness = faceIntProp(face, "UNDERLINE_THICKNESS"); + for(int i = 0; i < face->num_fixed_sizes; i++) { if(verbose_flag) fprintf(stderr, "size %d: %dx%d\n", diff --git a/struct.c b/struct.c index bcb07ba..1c14931 100644 --- a/struct.c +++ b/struct.c @@ -42,8 +42,32 @@ makeFont(void) font->weight = 500; font->width = 5; font->italicAngle = 0; - font->underlinePosition = - TWO_SIXTEENTH; - font->underlineThickness = TWO_SIXTEENTH; + font->pxMetrics.height = UNDEF; + font->pxMetrics.maxX = UNDEF; + font->pxMetrics.minX = UNDEF; + font->pxMetrics.maxY = UNDEF; + font->pxMetrics.minY = UNDEF; + font->pxMetrics.xHeight = UNDEF; + font->pxMetrics.capHeight = UNDEF; + font->pxMetrics.maxAwidth = UNDEF; + font->pxMetrics.awidth = UNDEF; + font->pxMetrics.ascent = UNDEF; + font->pxMetrics.descent = UNDEF; + font->pxMetrics.underlinePosition = UNDEF; + font->pxMetrics.underlineThickness = UNDEF; + font->metrics.height = UNDEF; + font->metrics.maxX = UNDEF; + font->metrics.minX = UNDEF; + font->metrics.maxY = UNDEF; + font->metrics.minY = UNDEF; + font->metrics.xHeight = UNDEF; + font->metrics.capHeight = UNDEF; + font->metrics.maxAwidth = UNDEF; + font->metrics.awidth = UNDEF; + font->metrics.ascent = UNDEF; + font->metrics.descent = UNDEF; + font->metrics.underlinePosition = UNDEF; + font->metrics.underlineThickness = UNDEF; font->foundry = makeName("UNKN"); font->strikes = NULL; return font; @@ -480,31 +504,90 @@ glyphMetrics(FontPtr font, int code, } void -fontMetrics(FontPtr font, - int *max_awidth_return, - int *min_x_return, int *min_y_return, - int *max_x_return, int *max_y_return) +fontMetrics(FontPtr font, MetricsPtr metrics) { int i, rc; - int max_awidth = 0; - int min_x = 10000 * 65536, min_y = 10000 * 65536; - int max_x = -10000 * 65536, max_y = -10000 * 65536; + double sumAwidth = 0; + unsigned count = 0; + + metrics->height = UNDEF /* TODO */; + metrics->maxAwidth = 0; + metrics->maxX = -10000 * TWO_SIXTEENTH; + metrics->maxY = -10000 * TWO_SIXTEENTH; + metrics->minX = 10000 * TWO_SIXTEENTH; + metrics->minY = 10000 * TWO_SIXTEENTH; + metrics->ascent = UNDEF; + metrics->descent = UNDEF; + metrics->underlinePosition = UNDEF; + metrics->underlineThickness = UNDEF; + for(i = 0; i < FONT_CODES; i++) { int awidth, x0, y0, x1, y1; rc = glyphMetrics(font, i, &awidth, &x0, &y0, &x1, &y1); if(rc < 0) continue; - if(awidth > max_awidth) - max_awidth = awidth; - if(x0 < min_x) min_x = x0; - if(y0 < min_y) min_y = y0; - if(x1 > max_x) max_x = x1; - if(y1 > max_y) max_y = y1; + + if(awidth > metrics->maxAwidth) metrics->maxAwidth = awidth; + if(x0 < metrics->minX) metrics->minX = x0; + if(y0 < metrics->minY) metrics->minY = y0; + if(x1 > metrics->maxX) metrics->maxX = x1; + if(y1 > metrics->maxY) metrics->maxY = y1; + + if(awidth > 0) { + sumAwidth += awidth; + count++; + } } - if(max_awidth_return) *max_awidth_return = max_awidth; - if(min_x_return) *min_x_return = min_x; - if(min_y_return) *min_y_return = min_y; - if(max_x_return) *max_x_return = max_x; - if(max_y_return) *max_y_return = max_y; -} + if (count) metrics->awidth = sumAwidth / count; + + if(font->pxMetrics.ascent == UNDEF) + metrics->ascent = metrics->maxY; + else + metrics->ascent = + font->pxMetrics.ascent + * TWO_SIXTEENTH / font->pxMetrics.height; + + if(font->pxMetrics.descent == UNDEF) + metrics->descent = metrics->minY; + else + metrics->descent = + font->pxMetrics.descent + * TWO_SIXTEENTH / font->pxMetrics.height; + + if(font->pxMetrics.capHeight == UNDEF) + /* TODO get ascent of letter 'X' - how to do lookups of ascii codes ? */ + metrics->capHeight = metrics->ascent; + else + metrics->capHeight = + font->pxMetrics.capHeight + * TWO_SIXTEENTH / font->pxMetrics.height; + + if(font->pxMetrics.xHeight == UNDEF) + /* TODO get ascent of letter 'x' - how to do lookups of ascii codes ? */ + metrics->xHeight = metrics->ascent * 2 / 3; + else + metrics->xHeight = + font->pxMetrics.xHeight + * TWO_SIXTEENTH / font->pxMetrics.height; + + if(font->pxMetrics.underlinePosition == UNDEF) + metrics->underlinePosition = - metrics->descent * 2; + else + metrics->underlinePosition = + font->pxMetrics.underlinePosition + * TWO_SIXTEENTH / font->pxMetrics.height; + + if(font->pxMetrics.underlineThickness == UNDEF) + /* TODO: this could be refined according to + * X Logical Font Description Conventions (xlfd.txt) + * by also considering the font weight. */ + /* make sure thickness is at least one pixel. */ + metrics->underlineThickness = + TWO_SIXTEENTH + / (font->pxMetrics.height < 9 ? font->pxMetrics.height : 9); + else + metrics->underlineThickness = + font->pxMetrics.underlineThickness + * TWO_SIXTEENTH / font->pxMetrics.height; +} diff --git a/util.c b/util.c index 594302a..1d61cca 100644 --- a/util.c +++ b/util.c @@ -395,6 +395,19 @@ faceFlags(FT_Face face) return flags; } +int +faceIntProp(FT_Face face, const char *name) +{ + int rc; + BDF_PropertyRec prop; + + rc = FT_Get_BDF_Property(face, name, &prop); + if(rc == 0 && prop.type == BDF_PROPERTY_TYPE_INTEGER) + return prop.u.integer; + else + return UNDEF; +} + char * faceEncoding(FT_Face face) { diff --git a/write.c b/write.c index 64b38b6..8f54625 100644 --- a/write.c +++ b/write.c @@ -61,7 +61,6 @@ static int writemaxp(FILE*, FontPtr); static int writename(FILE*, FontPtr); static int writepost(FILE*, FontPtr); -int max_awidth, min_x, min_y, max_x, max_y; static CmapPtr current_cmap = NULL; static int numglyphs, nummetrics; static int write_error_occurred, read_error_occurred; @@ -219,7 +218,7 @@ writeFile(char *filename, FontPtr font) int offset[15], length[15]; StrikePtr strike; - fontMetrics(font, &max_awidth, &min_x, &min_y, &max_x, &max_y); + fontMetrics(font, &font->metrics); out = fopen(filename, "wb+"); if(out == NULL) @@ -451,10 +450,12 @@ writehead(FILE* out, FontPtr font) writeLONG(out, time_hi); /* modified */ writeULONG(out, time_lo); - writeUSHORT(out, FONT_UNITS_FLOOR(min_x)); - writeUSHORT(out, FONT_UNITS_FLOOR(min_y)); - writeUSHORT(out, FONT_UNITS_CEIL(max_x)); - writeUSHORT(out, FONT_UNITS_CEIL(max_y)); + /* bounding box for all glyphs */ + writeUSHORT(out, FONT_UNITS_FLOOR(font->metrics.minX)); + writeUSHORT(out, FONT_UNITS_FLOOR(font->metrics.minY)); + writeUSHORT(out, FONT_UNITS_CEIL(font->metrics.maxX)); + writeUSHORT(out, FONT_UNITS_CEIL(font->metrics.maxY)); + writeUSHORT(out, font->flags); /* macStyle */ writeUSHORT(out, 1); /* lowestRecPPEM */ writeSHORT(out, 0); /* fontDirectionHint */ @@ -849,13 +850,15 @@ writehhea(FILE* out, FontPtr font) degreesToFraction(font->italicAngle, &num, &den); writeULONG(out, 0x00010000); /* version */ - writeSHORT(out, FONT_UNITS_CEIL(max_y)); /* ascender */ - writeSHORT(out, FONT_UNITS_FLOOR(min_y)); /* descender */ + writeSHORT(out, FONT_UNITS_CEIL(font->metrics.ascent)); /* ascender */ + writeSHORT(out, 0-FONT_UNITS_CEIL(font->metrics.descent)); /* descender */ writeSHORT(out, 0); /* lineGap */ - writeUSHORT(out, FONT_UNITS(max_awidth)); /* advanceWidthMax */ - writeSHORT(out, FONT_UNITS_FLOOR(min_x)); /* minLeftSideBearing */ - writeSHORT(out, FONT_UNITS_FLOOR(min_x)); /* minRightSideBearing */ - writeSHORT(out, FONT_UNITS_CEIL(max_x)); /* xMaxExtent */ + writeUSHORT(out, FONT_UNITS(font->metrics.maxAwidth)); /* advanceWidthMax */ + /* TODO: the next three are not calculated according to spec, are they ? + * https://docs.microsoft.com/en-us/typography/opentype/spec/hhea */ + writeSHORT(out, FONT_UNITS_FLOOR(font->metrics.minX)); /* minLeftSideBearing */ + writeSHORT(out, FONT_UNITS_FLOOR(font->metrics.minX)); /* minRightSideBearing */ + writeSHORT(out, FONT_UNITS_CEIL(font->metrics.maxX)); /* xMaxExtent */ writeSHORT(out, den); /* caretSlopeRise */ writeSHORT(out, num); /* caretSlopeRun */ writeSHORT(out, 0); /* reserved */ @@ -974,8 +977,8 @@ writepost(FILE* out, FontPtr font) writeULONG(out, 0x00030000); /* FormatType */ writeULONG(out, font->italicAngle); /* italicAngle */ - writeSHORT(out, FONT_UNITS(font->underlinePosition)); - writeSHORT(out, FONT_UNITS(font->underlineThickness)); + writeSHORT(out, FONT_UNITS(font->metrics.underlinePosition)); + writeSHORT(out, FONT_UNITS(font->metrics.underlineThickness)); writeULONG(out, fixed_pitch); /* isFixedPitch */ writeULONG(out, 0); /* minMemType42 */ writeULONG(out, 0); /* maxMemType42 */ @@ -990,7 +993,7 @@ writeOS2(FILE* out, FontPtr font) int i; writeUSHORT(out, 0x0001); - writeSHORT(out, FONT_UNITS(max_awidth / 2)); /* xAvgCharWidth; */ + writeSHORT(out, FONT_UNITS(font->metrics.awidth)); /* xAvgCharWidth; */ writeUSHORT(out, font->weight); /* usWeightClass; */ writeUSHORT(out, font->width); /* usWidthClass; */ writeSHORT(out, 0); /* fsType; */ @@ -1002,7 +1005,7 @@ writeOS2(FILE* out, FontPtr font) writeSHORT(out, UNITS_PER_EM / 5); /* ySuperscriptYSize; */ writeSHORT(out, 0); /* ySuperscriptXOffset; */ writeSHORT(out, UNITS_PER_EM / 5); /* ySuperscriptYOffset; */ - writeSHORT(out, FONT_UNITS(font->underlineThickness)); + writeSHORT(out, FONT_UNITS(font->metrics.underlineThickness)); /* yStrikeoutSize; */ writeSHORT(out, UNITS_PER_EM / 4); /* yStrikeoutPosition; */ writeSHORT(out, 0); /* sFamilyClass; */ @@ -1020,11 +1023,11 @@ writeOS2(FILE* out, FontPtr font) writeUSHORT(out, i); /* fsSelection; */ writeUSHORT(out, 0x20); /* usFirstCharIndex; */ writeUSHORT(out, 0xFFFD); /* usLastCharIndex; */ - writeUSHORT(out, FONT_UNITS_CEIL(max_y)); /* sTypoAscender; */ - writeUSHORT(out, FONT_UNITS_FLOOR(min_y)); /* sTypoDescender; */ + writeUSHORT(out, FONT_UNITS_CEIL(font->metrics.ascent)); /* sTypoAscender; */ + writeUSHORT(out, FONT_UNITS_FLOOR(font->metrics.descent)); /* sTypoDescender; */ writeUSHORT(out, 0); /* sTypoLineGap; */ - writeUSHORT(out, FONT_UNITS_CEIL(max_y)); /* usWinAscent; */ - writeUSHORT(out, -FONT_UNITS_FLOOR(min_y)); /* usWinDescent; */ + writeUSHORT(out, FONT_UNITS_CEIL(font->metrics.maxY)); /* usWinAscent; */ + writeUSHORT(out, -FONT_UNITS_FLOOR(font->metrics.minY)); /* usWinDescent; */ writeULONG(out, 3); /* ulCodePageRange1; */ writeULONG(out, 0); /* ulCodePageRange2; */ return 0; @@ -1064,11 +1067,11 @@ writePCLT(FILE* out, FontPtr font) writeULONG(out, 0x00010000); /* version */ writeULONG(out, 0); /* FontNumber */ - writeUSHORT(out, FONT_UNITS(max_awidth)); /* pitch */ - writeUSHORT(out, FONT_UNITS(max_y)); /* xHeight */ + writeUSHORT(out, FONT_UNITS(font->metrics.maxAwidth)); /* pitch */ + writeUSHORT(out, FONT_UNITS(font->metrics.xHeight)); /* xHeight */ writeUSHORT(out, style); /* style */ writeUSHORT(out, 6 << 12); /* TypeFamily */ - writeUSHORT(out, FONT_UNITS(max_y)); /* CapHeight */ + writeUSHORT(out, FONT_UNITS(font->metrics.xHeight)); /* CapHeight */ writeUSHORT(out, 0); /* SymbolSet */ writeCHARs(out, name, 16); /* TypeFace */ writeBYTEs(out, charComplement, 8); /* CharacterComplement */ diff --git a/xlfd.txt b/xlfd.txt new file mode 100644 index 0000000..03840e0 --- /dev/null +++ b/xlfd.txt @@ -0,0 +1,2970 @@ + + + + + + + + + + + + + + + + X Logical Font Description Conventions + + Version 1.5 + + X Consortium Standard + + X Version 11, Release 6.4 + + + + + + + Jim Flowers + Digital Equipment Corporation + + + + + + + Version 1.5 edited by Stephen Gildea + X Consortium, Inc. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +X Window System is a trademark of X Consortium, Inc. + +Helvetica and Times are registered trademarks of Linotype Company. + +ITC Avant Garde Gothic is a registered trademark of International Type- +face Corporation. + +Times Roman is a registered trademark of Monotype Corporation. + +Bitstream Amerigo is a registered trademark of Bitstream Inc. + +Stone is a registered trademark of Adobe Systems Inc. + +Copyright (C) 1988, 1994 X Consortium + +Permission is hereby granted, free of charge, to any person obtaining a +copy of this software and associated documentation files (the "Soft- +ware"), to deal in the Software without restriction, including without +limitation the rights to use, copy, modify, merge, publish, distribute, +sublicense, and/or sell copies of the Software, and to permit persons to +whom the Software is furnished to do so, subject to the following condi- +tions: + +The above copyright notice and this permission notice shall be included +in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS +OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL- +ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT +SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABIL- +ITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS +IN THE SOFTWARE. + +Except as contained in this notice, the name of the X Consortium shall +not be used in advertising or otherwise to promote the sale, use or +other dealings in this Software without prior written authorization from +the X Consortium. + +Copyright (C) 1988, 1989 Digital Equipment Corporation, Maynard MA. All +rights reserved. + +Permission to use, copy, modify, and distribute this documentation for +any purpose and without fee is hereby granted, provided that the above + + + + + + + + + + + + +copyright notice and this permission notice appear in all copies. Digi- +tal Equipment Corporation makes no representations about the suitability +for any purpose of the information in this document. This documentation +is provided as is without express or implied warranty. + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +1. Introduction + +It is a requirement that X client applications must be portable across +server implementations, with very different file systems, naming conven- +tions, and font libraries. However, font access requests, as defined by +the X Window System Protocol, neither specify server-independent conven- +tions for font names nor provide adequate font properties for logically +describing typographic fonts. + +X clients must be able to dynamically determine the fonts available on +any given server so that understandable information can be presented to +the user or so that intelligent font fallbacks can be chosen. It is +desirable for the most common queries to be accomplished without the +overhead of opening each font and inspecting font properties, by means +of simple ListFonts requests. For example, if a user selected a Hel- +vetica typeface family, a client application should be able to query the +server for all Helvetica fonts and present only those setwidths, +weights, slants, point sizes, and character sets available for that fam- +ily. + +This document gives a standard logical font description (hereafter +referred to as XLFD) and the conventions to be used in the core protocol +so that clients can query and access screen type libraries in a consis- +tent manner across all X servers. In addition to completely specifying +a given font by means of its FontName, the XLFD also provides for a +standard set of key FontProperties that describe the font in more +detail. + +The XLFD provides an adequate set of typographic font properties, such +as CAP_HEIGHT, X_HEIGHT, and RELATIVE_SETWIDTH, for publishing and other +applications to do intelligent font matching or substitution when han- +dling documents created on some foreign server that use potentially +unknown fonts. In addition, this information is required by certain +clients to position subscripts automatically and determine small capital +heights, recommended leading, word-space values, and so on. + +2. Requirements and Goals + +The XLFD meets the short-term and long-term goals to have a standard +logical font description that: + +o Provides unique, descriptive font names that support simple pattern + matching + +o Supports multiple font vendors, arbitrary character sets, and + encodings + +o Supports naming and instancing of scalable and polymorphic fonts + +o Supports transformations and subsetting of fonts + +o Is independent of X server and operating or file system implementa- + tions + + + + + 1 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +o Supports arbitrarily complex font matching or substitution + +o Is extensible + +2.1. Provide Unique and Descriptive Font Names + +It should be possible to have font names that are long enough and +descriptive enough to have a reasonable probability of being unique +without inventing a new registration organization. Resolution and size- +dependent font masters, multivendor font libraries, and so on must be +anticipated and handled by the font name alone. + +The name itself should be structured to be amenable to simple pattern +matching and parsing, thus allowing X clients to restrict font queries +to some subset of all possible fonts in the server. + +2.2. Support Multiple Font Vendors and Character Sets + +The font name and properties should distinguish between fonts that were +supplied by different font vendors but that possibly share the same +name. We anticipate a highly competitive font market where users will +be able to buy fonts from many sources according to their particular +requirements. + +A number of font vendors deliver each font with all glyphs designed for +that font, where charset mappings are defined by encoding vectors. Some +server implementations may force these mappings to proprietary or stan- +dard charsets statically in the font data. Others may desire to perform +the mapping dynamically in the server. Provisions must be made in the +font name that allows a font request to specify or identify specific +charset mappings in server environments where multiple charsets are sup- +ported. + +2.3. Support Scalable and Polymorphic Fonts + +If a font source can be scaled to an arbitrary size or varied in other +ways, it should be possible for an application to determine that fact +from the font name, and the application should be able to construct a +font name for any specific instance. + +2.4. Support Transformations and Subsetting of Fonts + +Arbitrary two-dimensional linear transformations of fonts should be able +to be requested by applications. Since such transformed fonts may be +used for special effects requiring a few characters from each of many +differently transformed fonts, it should be possible to request only a +few characters from a font for efficiency. + +2.5. Be Independent of X Server and Operating or File System Implemen- +tations + +X client applications that require a particular font should be able to +use the descriptive name without knowledge of the file system or other +repository in use by the server. However, it should be possible for + + + + 2 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +servers to translate a given font name into a file name syntax that it +knows how to deal with, without compromising the uniqueness of the font +name. This algorithm should be reversible (exactly how this translation +is done is implementation dependent). + +2.6. Support Arbitrarily Complex Font Matching and Substitution + +In addition to the font name, the XLFD should define a standard list of +descriptive font properties, with agreed-upon fallbacks for all fonts. +This allows client applications to derive font-specific formatting or +display data and to perform font matching or substitution when asked to +handle potentially unknown fonts, as required. + +2.7. Be Extensible + +The XLFD must be extensible so that new and/or private descriptive font +properties can be added to conforming fonts without making existing X +client or server implementations obsolete. + +3. X Logical Font Description + +XLFD is divided into two basic components: the FontName, which gives all +font information needed to uniquely identify a font in X protocol +requests (for example, OpenFont, ListFonts, and so on) and a variable +list of optional FontProperties, which describe a font in more detail. + +The FontName is used in font queries and is returned as data in certain +X protocol requests. It is also specified as the data value for the +FONT item in the X Consortium Character Bitmap Distribution Format Stan- +dard (BDF V2.1). + +The FontProperties are supplied on a font-by-font basis and are returned +as data in certain X protocol requests as part of the XFontStruct data +structure. The names and associated data values for each of the Font- +Properties may also appear as items of the STARTPROPERTIES...ENDPROPER- +TIES list in the BDF V2.1 specification. + +3.1. FontName + +Each FontName is logically composed of two strings: a FontNameRegistry +prefix that is followed by a FontNameSuffix. The FontName uses the ISO +8859-1 encoding. The FontNameRegistry is an x-registered-name (a name +that has been registered with the X Consortium) that identifies the reg- +istration authority that owns the specified FontNameSuffix syntax and +semantics. + +All font names that conform to this specification are to use a Font- +NameRegistry prefix, which is defined to be the string "-" (HYPHEN). +All FontNameRegistry prefixes of the form: +version-, where the speci- +fied version indicates some future XLFD specification, are reserved by +the X Consortium for future extensions to XLFD font names. If required, +extensions to the current XLFD font name shall be constructed by append- +ing new fields to the current structure, each delimited by the existing +field delimiter. The availability of other FontNameRegistry prefixes or + + + + 3 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +fonts that support other registries is server implementation dependent. + +In the X protocol specification, the FontName is required to be a +string; hence, numeric field values are represented in the name as +string equivalents. All FontNameSuffix fields are also defined as Font- +Properties; numeric property values are represented as signed or +unsigned integers, as appropriate. + +3.1.1. FontName Syntax + +The FontName is a structured, parsable string (of type STRING8) whose +Backus-Naur Form syntax description is as follows: + + FontName ::= XFontNameRegistry XFontNameSuffix | + PrivFontNameRegistry PrivFontNameSuf- + fix + XFontNameRegistry ::= XFNDelim | XFNExtPrefix Version XFN- + Delim + XFontNameSuffix ::= FOUNDRY XFNDelim FAMILY_NAME XFNDelim + WEIGHT_NAME XFNDelim SLANT XFNDelim + SETWIDTH_NAME XFNDelim ADD_ + STYLE_NAME XFNDelim PIXEL_SIZE XFNDe- + lim POINT_SIZE XFNDelim RESOLUTION_X + XFNDelim RESOLUTION_Y XFNDelim SPAC- + ING XFNDelim AVERAGE_WIDTH XFNDelim + CHARSET_REGISTRY XFNDelim + CHARSET_ENCODING + Version ::= STRING8 - the XLFD version that + defines an extension to the font name + syntax (for example, "1.4") + XFNExtPrefix ::= OCTET - "+" (PLUS) + XFNDelim ::= OCTET - "-" (HYPHEN) + PrivFontNameRegistry STRING8 - other than those strings + ::= reserved by XLFD +PrivFontNameSuffix ::= STRING8 + + +Field values are constructed as strings of ISO 8859-1 graphic charac- +ters, excluding the following: + +o "-" (HYPHEN), the XLFD font name delimiter character + +o "?" (QUESTION MARK) and "*" (ASTERISK), the X protocol font name + wildcard characters + +o "," (COMMA), used by Xlib to separate XLFD font names in a font + set. + +o """ (QUOTATION MARK), used by some commercial products to quote a + font name. + +Alphabetic case distinctions are allowed but are for human readability +concerns only. Conforming X servers will perform matching on font name +query or open requests independent of case. The entire font name string + + + + 4 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +must have no more than 255 characters. It is recommended that clients +construct font name query patterns by explicitly including all field +delimiters to avoid unexpected results. Note that SPACE is a valid +character of a FontName field; for example, the string "ITC Avant Garde +Gothic" might be a FAMILY_NAME. + +3.1.2. FontName Field Definitions + +This section discusses the FontName: + +o FOUNDRY field + +o FAMILY_NAME field + +o WEIGHT_NAME field + +o SLANT field + +o SETWIDTH_NAME field + +o ADD_STYLE_NAME field + +o PIXEL_SIZE field + +o POINT_SIZE field + +o RESOLUTION_X and RESOLUTION_Y fields + +o SPACING field + +o AVERAGE_WIDTH field + +o CHARSET_REGISTRY and CHARSET_ENCODING fields + +3.1.2.1. FOUNDRY Field + +FOUNDRY is an x-registered-name, the name or identifier of the digital +type foundry that digitized and supplied the font data, or if different, +the identifier of the organization that last modified the font shape or +metric information. + +The reason this distinction is necessary is that a given font design may +be licensed from one source (for example, ITC) but digitized and sold by +any number of different type suppliers. Each digital version of the +original design, in general, will be somewhat different in metrics and +shape from the idealized original font data, because each font foundry, +for better or for worse, has its own standards and practices for tweak- +ing a typeface for a particular generation of output technologies or has +its own perception of market needs. + +It is up to the type supplier to register with the X Consortium a suit- +able name for this FontName field according to the registration proce- +dures defined by the Consortium. + + + + + 5 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +The X Consortium shall define procedures for registering foundry and +other names and shall maintain and publish, as part of its public dis- +tribution, a registry of such registered names for use in XLFD font +names and properties. + + +3.1.2.2. FAMILY_NAME Field + +FAMILY_NAME is a string that identifies the range or family of typeface +designs that are all variations of one basic typographic style. This +must be spelled out in full, with words separated by spaces, as +required. This name must be human-understandable and suitable for pre- +sentation to a font user to identify the typeface family. + +It is up to the type supplier to supply and maintain a suitable string +for this field and font property, to secure the proper legal title to a +given name, and to guard against the infringement of other's copyrights +or trademarks. By convention, FAMILY_NAME is not translated. FAM- +ILY_NAME may include an indication of design ownership if considered a +valid part of the typeface family name. + +The following are examples of FAMILY_NAME: + +o Helvetica + +o ITC Avant Garde Gothic + +o Times + +o Times Roman + +o Bitstream Amerigo + +o Stone + +3.1.2.3. WEIGHT_NAME Field + +WEIGHT_NAME is a string that identifies the font's typographic weight, +that is, the nominal blackness of the font, according to the FOUNDRY's +judgment. This name must be human-understandable and suitable for pre- +sentation to a font user. The value "0" is used to indicate a polymor- +phic font (see section 6). + +The interpretation of this field is somewhat problematic because the +typographic judgment of weight has traditionally depended on the overall +design of the typeface family in question; that is, it is possible that +the DemiBold weight of one font could be almost equivalent in typo- +graphic feel to a Bold font from another family. + +WEIGHT_NAME is captured as an arbitrary string because it is an impor- +tant part of a font's complete human-understandable name. However, it +should not be used for font matching or substitution. For this purpose, +X client applications should use the weight-related font properties +(RELATIVE_WEIGHT and WEIGHT) that give the coded relative weight and the + + + + 6 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +calculated weight, respectively. + +3.1.2.4. SLANT Field + +SLANT is a code-string that indicates the overall posture of the type- +face design used in the font. The encoding is as follows: + +--------------------------------------------------------------------------- +Code English Translation Description +--------------------------------------------------------------------------- +"R" Roman Upright design +"I" Italic Italic design, slanted clockwise from the + vertical +"O" Oblique Obliqued upright design, slanted clockwise + from the vertical +"RI" Reverse Italic Italic design, slanted counterclockwise + from the vertical +"RO" Reverse Oblique Obliqued upright design, slanted counter- + clockwise from the vertical +"OT" Other Other +numeric Polymorphic See section 6 on polymorphic font support. +--------------------------------------------------------------------------- + + +The SLANT codes are for programming convenience only and usually are +converted into their equivalent human-understandable form before being +presented to a user. + +3.1.2.5. SETWIDTH_NAME Field + +SETWIDTH_NAME is a string that gives the font's typographic proportion- +ate width, that is, the nominal width per horizontal unit of the font, +according to the FOUNDRY's judgment. The value "0" is used to indicate +a polymorphic font (see section 6). + +As with WEIGHT_NAME, the interpretation of this field or font property +is somewhat problematic, because the designer's judgment of setwidth has +traditionally depended on the overall design of the typeface family in +question. For purposes of font matching or substitution, X client +applications should either use the RELATIVE_SETWIDTH font property that +gives the relative coded proportionate width or calculate the propor- +tionate width. + +The following are examples of SETWIDTH_NAME: + +o Normal + +o Condensed + +o Narrow + +o Double Wide + + + + + + 7 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +3.1.2.6. ADD_STYLE_NAME Field + +ADD_STYLE_NAME is a string that identifies additional typographic style +information that is not captured by other fields but is needed to iden- +tify the particular font. The character "[" anywhere in the field is +used to indicate a polymorphic font (see section 6). + +ADD_STYLE_NAME is not a typeface classification field and is only used +for uniqueness. Its use, as such, is not limited to typographic style +distinctions. + +The following are examples of ADD_STYLE_NAME: + +o Serif + +o Sans Serif + +o Informal + +o Decorated + +3.1.2.7. PIXEL_SIZE Field + +PIXEL_SIZE gives the body size of the font at a particular POINT_SIZE +and RESOLUTION_Y. PIXEL_SIZE is either an integer-string or a string +beginning with "[". A string beginning with "[" represents a matrix +(see section 4). PIXEL_SIZE usually incorporates additional vertical +spacing that is considered part of the font design. (Note, however, +that this value is not necessarily equivalent to the height of the font +bounding box.) Zero is used to indicate a scalable font (see section +5). + +PIXEL_SIZE usually is used by X client applications that need to query +fonts according to device-dependent size, regardless of the point size +or vertical resolution for which the font was designed. + +3.1.2.8. POINT_SIZE Field + +POINT_SIZE gives the body size for which the font was designed. +POINT_SIZE is either an integer-string or a string beginning with "[". +A string beginning with "[" represents a matrix (see section 4). This +field usually incorporates additional vertical spacing that is consid- +ered part of the font design. (Note, however, that POINT_SIZE is not +necessarily equivalent to the height of the font bounding box.) +POINT_SIZE is expressed in decipoints (where points are as defined in +the X protocol or 72.27 points equal 1 inch). Zero is used to indicate +a scalable font (see section 5). + +POINT_SIZE and RESOLUTION_Y are used by X clients to query fonts accord- +ing to device-independent size to maintain constant text size on the +display regardless of the PIXEL_SIZE used for the font. + + + + + + + 8 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +3.1.2.9. RESOLUTION_X and RESOLUTION_Y Fields + +RESOLUTION_X and RESOLUTION_Y are unsigned integer-strings that give the +horizontal and vertical resolution, measured in pixels or dots per inch +(dpi), for which the font was designed. Zero is used to indicate a +scalable font (see section 5). Horizontal and vertical values are +required because a separate bitmap font must be designed for displays +with very different aspect ratios (for example, 1:1, 4:3, 2:1, and so +on). + +The separation of pixel or point size and resolution is necessary +because X allows for servers with very different video characteristics +(for example, horizontal and vertical resolution, screen and pixel size, +pixel shape, and so on) to potentially access the same font library. +The font name, for example, must differentiate between a 14-point font +designed for 75 dpi (body size of about 14 pixels) or a 14-point font +designed for 150 dpi (body size of about 28 pixels). Further, in +servers that implement some or all fonts as continuously scaled and +scan-converted outlines, POINT_SIZE and RESOLUTION_Y will help the +server to differentiate between potentially separate font masters for +text, title, and display sizes or for other typographic considerations. + +3.1.2.10. SPACING Field + +SPACING is a code-string that indicates the escapement class of the +font, that is, monospace (fixed pitch), proportional (variable pitch), +or charcell (a special monospaced font that conforms to the traditional +data-processing character cell font model). The encoding is as follows: + +------------------------------------------------------------------ +Code English Translation Description +------------------------------------------------------------------ +"P" Proportional A font whose logical character + widths vary for each glyph. Note + that no other restrictions are + placed on the metrics of a propor- + tional font. +"M" Monospaced A font whose logical character + widths are constant (that is, every + glyph in the font has the same log- + ical width). No other restrictions + are placed on the metrics of a + monospaced font. + + + + + + + + + + + + + + + 9 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +------------------------------------------------------------------ +Code English Translation Description +------------------------------------------------------------------ +"C" CharCell A monospaced font that follows the + standard typewriter character cell + model (that is, the glyphs of the + font can be modeled by X clients as + "boxes" of the same width and + height that are imaged side-by-side + to form text strings or top-to-bot- + tom to form text lines). By defi- + nition, all glyphs have the same + logical character width, and no + glyphs have "ink" outside of the + character cell. There is no kern- + ing (that is, on a per-character + basis with positive metrics: 0 <= + left-bearing <= right-bearing <= + width; with negative metrics: width + <= left-bearing <= right-bearing <= + zero). Also, the vertical extents + of the font do not exceed the ver- + tical spacing (that is, on a per- + character basis: ascent <= font- + ascent and descent <= font- + descent). The cell height = font- + descent + font-ascent, and the + width = AVERAGE_WIDTH. +------------------------------------------------------------------ + + +3.1.2.11. AVERAGE_WIDTH Field + +AVERAGE_WIDTH is an integer-string typographic metric value that gives +the unweighted arithmetic mean of the absolute value of the width of +each glyph in the font (measured in tenths of pixels), multiplied by -1 +if the dominant writing direction for the font is right-to-left. A +leading "~" (TILDE) indicates a negative value. For monospaced and +character cell fonts, this is the width of all glyphs in the font. Zero +is used to indicate a scalable font (see section 5). + +3.1.2.12. CHARSET_REGISTRY and CHARSET_ENCODING Fields + +The character set used to encode the glyphs of the font (and implicitly +the font's glyph repertoire), as maintained by the X Consortium charac- +ter set registry. CHARSET_REGISTRY is an x-registered-name that identi- +fies the registration authority that owns the specified encoding. +CHARSET_ENCODING is a registered name that identifies the coded charac- +ter set as defined by that registration authority and, optionally, a +subsetting hint. + +Although the X protocol does not explicitly have any knowledge about +character set encodings, it is expected that server implementors will +prefer to embed knowledge of certain proprietary or standard charsets + + + + 10 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +into their font library for reasons of performance and convenience. The +CHARSET_REGISTRY and CHARSET_ENCODING fields or properties allow an X +client font request to specify a specific charset mapping in server +environments where multiple charsets are supported. The availability of +any particular character set is font and server implementation depen- +dent. + +To prevent collisions when defining character set names, it is recom- +mended that CHARSET_REGISTRY and CHARSET_ENCODING name pairs be con- +structed according to the following conventions: + + CharsetRegistry ::= StdCharsetRegistryName | PrivCharsetReg- + istryName + CharsetEncoding ::= StdCharsetEncodingName | PrivCharsetEn- + codingName + StdCharsetRegistryName ::= StdOrganizationId StdNumber | StdOrgani- + zationId StdNumber Dot Year +PrivCharsetRegistryName ::= OrganizationId STRING8 + StdCharsetEncodingName ::= STRING8-numeric part number of refer- + enced standard +PrivCharsetEncodingName ::= STRING8 + StdOrganizationId ::= STRING8-the registered name or acronym + of the referenced standard organization + StdNumber ::= STRING8-referenced standard number + OrganizationId ::= STRING8-the registered name or acronym + of the organization + Dot ::= OCTET-"." (FULL STOP) + Year ::= STRING8-numeric year (for example, 1989) + + +The X Consortium shall maintain and publish a registry of such character +set names for use in X protocol font names and properties as specified +in XLFD. + +The ISO Latin-1 character set shall be registered by the X Consortium as +the CHARSET_REGISTRY-CHARSET_ENCODING value pair: "ISO8859-1". + +If the CHARSET_ENCODING contains a "[" (LEFT SQUARE BRACKET), the "[" +and the characters after it up to a "]" (RIGHT SQUARE BRACKET) are a +subsetting hint telling the font source that the client is interested +only in a subset of the characters of the font. The font source can, +optionally, return a font that contains only those characters or any +superset of those characters. The client can expect to obtain valid +glyphs and metrics only for those characters, and not for any other +characters in the font. The font properties may optionally be calcu- +lated by considering only the characters in the subset. + +The BNF for the subsetting hint is + + Subset ::= LeftBracket RangeList RightBracket + RangeList ::= Range | Range Space RangeList + Range ::= Number | Number Underscore Number + Number ::= "0x" HexNumber | DecNumber + + + + + 11 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + + HexNumber ::= HexDigit | HexDigit HexNumber + DecNumber ::= DecDigit | DecDigit DecNumber + DecDigit ::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" + HexDigit ::= DecDigit | "a" | "b" | "c" | "d" | "e" | "f" + LeftBracket ::= "[" (LEFT SQUARE BRACKET) +RightBracket ::= "]" (RIGHT SQUARE BRACKET) + Space ::= " " (SPACE) + Underscore ::= "_" (LOW LINE) + + +Each Range specifies characters that are to be part of the subset +included in the font. A Range containing two Numbers specifies the +first and last character, inclusively, of a range of characters. A +Range that is a single Number specifies a single character to be +included in the font. A HexNumber is interpreted as a hexadecimal num- +ber. A DecNumber is interpreted as a decimal number. The font consists +of the union of all the Ranges in the RangeList. + +For example, + -misc-fixed-medium-r-normal--0-0-0-0-c-0-iso8859-1[65 70 80_90] +tells the font source that the client is interested only in characters +65, 70, and 80-90. + +3.1.3. Examples + +The following examples of font names are derived from the screen fonts +shipped with the X Consortium distribution. + +------------------------------------------------------------------------------ +Font X FontName +------------------------------------------------------------------------------ +75-dpi Fonts +Charter 12 pt -Bitstream-Charter-Medium-R-Nor- + mal--12-120-75-75-P-68-ISO8859-1 +Charter Bold -Bitstream-Charter-Bold-R-Nor- +12 pt mal--12-120-75-75-P-76-ISO8859-1 +Charter Bold -Bitstream-Charter-Bold-I-Nor- +Italic 12 pt mal--12-120-75-75-P-75-ISO8859-1 +Charter Italic -Bitstream-Charter-Medium-I-Nor- +12 pt mal--12-120-75-75-P-66-ISO8859-1 +Courier 8 pt -Adobe-Courier-Medium-R-Normal--8-80-75-75-M-50-ISO8859-1 +Courier 10 pt -Adobe-Courier-Medium-R-Normal--10-100-75-75-M-60-ISO8859-1 +Courier 12 pt -Adobe-Courier-Medium-R-Normal--12-120-75-75-M-70-ISO8859-1 +Courier 24 pt -Adobe-Courier-Medium-R-Normal--24-240-75-75-M-150-ISO8859-1 +Courier Bold -Adobe-Courier-Bold-R-Normal--10-100-75-75-M-60-ISO8859-1 +10 pt +Courier Bold -Adobe-Courier-Bold-O-Normal--10-100-75-75-M-60-ISO8859-1 +Oblique 10 pt +Courier -Adobe-Courier-Medium-O-Normal--10-100-75-75-M-60-ISO8859-1 +Oblique 10 pt +100-dpi Fonts +Symbol 10 pt -Adobe-Symbol-Medium-R-Normal--14-100-100-100-P-85-Adobe- + FONTSPECIFIC + + + + + 12 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +------------------------------------------------------------------------------ +Font X FontName +------------------------------------------------------------------------------ +Symbol 14 pt -Adobe-Symbol-Medium-R-Normal--20-140-100-100-P-107-Adobe- + FONTSPECIFIC +Symbol 18 pt -Adobe-Symbol-Medium-R-Normal--25-180-100-100-P-142-Adobe- + FONTSPECIFIC +Symbol 24 pt -Adobe-Symbol-Medium-R-Normal--34-240-100-100-P-191-Adobe- + FONTSPECIFIC +Times Bold 10 -Adobe-Times-Bold-R-Normal--14-100-100-100-P-76-ISO8859-1 +pt +Times Bold -Adobe-Times-Bold-I-Normal--14-100-100-100-P-77-ISO8859-1 +Italic 10 pt +Times Italic -Adobe-Times-Medium-I-Normal--14-100-100-100-P-73-ISO8859-1 +10 pt +Times Roman 10 -Adobe-Times-Medium-R-Normal--14-100-100-100-P-74-ISO8859-1 +pt +------------------------------------------------------------------------------ + + +3.2. Font Properties + +All font properties are optional but will generally include the font +name fields and, on a font-by-font basis, any other useful font descrip- +tive and use information that may be required to use the font intelli- +gently. The XLFD specifies an extensive set of standard X font proper- +ties, their interpretation, and fallback rules when the property is not +defined for a given font. The goal is to provide client applications +with enough font information to be able to make automatic formatting and +display decisions with good typographic results. + +Font property names use the ISO 8859-1 encoding. + +Additional standard X font property definitions may be defined in the +future and private properties may exist in X fonts at any time. Private +font properties should be defined to conform to the general mechanism +defined in the X protocol to prevent overlap of name space and ambiguous +property names, that is, private font property names are of the form: +"_" (LOW LINE), followed by the organizational identifier, followed by +"_" (LOW LINE), and terminated with the property name. + +The Backus-Naur Form syntax description of X font properties is as fol- +lows: + + Properties ::= OptFontPropList +OptFontPropList ::= NULL | OptFontProp OptFontPropList + OptFontProp ::= PrivateFontProp | XFontProp +PrivateFontProp ::= STRING8 | Underscore OrganizationId + Underscore STRING8 + + + + + + + + + 13 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + + XFontProp ::= FOUNDRY | FAMILY_NAME | WEIGHT_NAME | + SLANT | SETWIDTH_NAME | + ADD_STYLE_NAME | PIXEL_SIZE | + POINT_SIZE | RESOLUTION_X | RESOLU- + TION_Y | SPACING | AVERAGE_WIDTH | + CHARSET_REGISTRY | CHARSET_ENCODING | + QUAD_WIDTH | RESOLUTION | MIN_SPACE | + NORM_SPACE | MAX_SPACE | END_SPACE | + SUPERSCRIPT_X | SUPERSCRIPT_Y | SUB- + SCRIPT_X | SUBSCRIPT_Y | UNDER- + LINE_POSITION | UNDERLINE_THICKNESS | + STRIKEOUT_ASCENT | STRIKEOUT_DESCENT + | ITALIC_ANGLE | X_HEIGHT | WEIGHT | + FACE_NAME | FULL_NAME | FONT | COPY- + RIGHT | AVG_CAPITAL_WIDTH | AVG_LOW- + ERCASE_WIDTH | RELATIVE_SETWIDTH | + RELATIVE_WEIGHT | CAP_HEIGHT | SUPER- + SCRIPT_ SIZE | FIGURE_WIDTH | SUB- + SCRIPT_SIZE | SMALL_CAP_SIZE | NOTICE + | DESTINATION | FONT_TYPE | FONT_VER- + SION | RASTERIZER_NAME | RASTER- + IZER_VERSION | RAW_ASCENT | + RAW_DESCENT | RAW_* | AXIS_NAMES | + AXIS_LIMITS | AXIS_TYPES + Underscore ::= OCTET-"_" (LOW LINE) + OrganizationId ::= STRING8-the registered name of the + organization + + +3.2.1. FOUNDRY + +FOUNDRY is as defined in the FontName except that the property type is +ATOM. + +FOUNDRY cannot be calculated or defaulted if not supplied as a font +property. + +3.2.2. FAMILY_NAME + +FAMILY_NAME is as defined in the FontName except that the property type +is ATOM. + +FAMILY_NAME cannot be calculated or defaulted if not supplied as a font +property. + +3.2.3. WEIGHT_NAME + +WEIGHT_NAME is as defined in the FontName except that the property type +is ATOM. + +WEIGHT_NAME can be defaulted if not supplied as a font property, as fol- +lows: + + + + + + 14 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + + if (WEIGHT_NAME undefined) then + WEIGHT_NAME = ATOM("Medium") + + +3.2.4. SLANT + +SLANT is as defined in the FontName except that the property type is +ATOM. + +SLANT can be defaulted if not supplied as a font property, as follows: + + + if (SLANT undefined) then + SLANT = ATOM("R") + + +3.2.5. SETWIDTH_NAME + +SETWIDTH_NAME is as defined in the FontName except that the property +type is ATOM. + +SETWIDTH_NAME can be defaulted if not supplied as a font property, as +follows: + + + if (SETWIDTH_NAME undefined) then + SETWIDTH_NAME = ATOM("Normal") + + +3.2.6. ADD_STYLE_NAME + +ADD_STYLE_NAME is as defined in the FontName except that the property +type is ATOM. + +ADD_STYLE_NAME can be defaulted if not supplied as a font property, as +follows: + + + if (ADD_STYLE_NAME undefined) then + ADD_STYLE_NAME = ATOM("") + + +3.2.7. PIXEL_SIZE + +PIXEL_SIZE is as defined in the FontName except that the property type +is INT32. + +X clients requiring pixel values for the various typographic fixed spa- +ces (em space, en space, and thin space) can use the following algorithm +for computing these values from other properties specified for a font: + + + + + + + + 15 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + + DeciPointsPerInch = 722.7 + EMspace = ROUND ((RESOLUTION_X * POINT_SIZE) / DeciPointsPerInch) + ENspace = ROUND (EMspace / 2) + THINspace = ROUND (EMspace / 3) + + +where a slash (/) denotes real division, an asterisk (*) denotes real +multiplication, and ROUND denotes a function that rounds its real argu- +ment a up or down to the next integer. This rounding is done according +to X = FLOOR (a + 0.5), where FLOOR is a function that rounds its real +argument down to the nearest integer. + +PIXEL_SIZE can be approximated if not supplied as a font property, +according to the following algorithm: + + + DeciPointsPerInch = 722.7 + if (PIXEL_SIZE undefined) then + PIXEL_SIZE = ROUND ((RESOLUTION_Y * POINT_SIZE) / DeciPointsPerInch) + + +3.2.8. POINT_SIZE + +POINT_SIZE is as defined in the FontName except that the property type +is INT32. + +X clients requiring device-independent values for em space, en space, +and thin space can use the following algorithm: + + + EMspace = ROUND (POINT_SIZE / 10) + ENspace = ROUND (POINT_SIZE / 20) + THINspace = ROUND (POINT_SIZE / 30) + + +Design POINT_SIZE cannot be calculated or approximated. + +3.2.9. RESOLUTION_X + +RESOLUTION_X is as defined in the FontName except that the property type +is CARD32. + +RESOLUTION_X cannot be calculated or approximated. + +3.2.10. RESOLUTION_Y + +RESOLUTION_Y is as defined in the FontName except that the property type +is CARD32. + +RESOLUTION_X cannot be calculated or approximated. + + + + + + + + 16 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +3.2.11. SPACING + +SPACING is as defined in the FontName except that the property type is +ATOM. + +SPACING can be calculated if not supplied as a font property, according +to the definitions given above for the FontName. + +3.2.12. AVERAGE_WIDTH + +AVERAGE_WIDTH is as defined in the FontName except that the property +type is INT32. + +AVERAGE_WIDTH can be calculated if not provided as a font property, +according to the following algorithm: + + + if (AVERAGE_WIDTH undefined) then + AVERAGE_WIDTH = ROUND (MEAN (ABS (width of each glyph in font)) * 10) + * (if (dominant writing direction L-to-R) then 1 else -1) + + +where MEAN is a function that returns the arithmetic mean of its argu- +ments. + +X clients that require values for the number of characters per inch +(pitch) of a monospaced font can use the following algorithm using the +AVERAGE_WIDTH and RESOLUTION_X font properties: + + + if (SPACING not proportional) then + CharPitch = (RESOLUTION_X * 10) / AVERAGE_WIDTH + + +3.2.13. CHARSET_REGISTRY + +CHARSET_REGISTRY is as defined in the FontName except that the property +type is ATOM. + +CHARSET_REGISTRY cannot be defaulted if not supplied as a font property. + +3.2.14. CHARSET_ENCODING + +CHARSET_ENCODING is as defined in the FontName except that the property +type is ATOM. + +CHARSET_ENCODING cannot be defaulted if not supplied as a font property. + +3.2.15. MIN_SPACE + +MIN_SPACE is an integer value (of type INT32) that gives the recommended +minimum word-space value to be used with this font. + + + + + + 17 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +MIN_SPACE can be approximated if not provided as a font property, +according to the following algorithm: + + + if (MIN_SPACE undefined) then + MIN_SPACE = ROUND(0.75 * NORM_SPACE) + + +3.2.16. NORM_SPACE + +NORM_SPACE is an integer value (of type INT32) that gives the recom- +mended normal word-space value to be used with this font. + +NORM_SPACE can be approximated if not provided as a font property, +according to the following algorithm: + + +DeciPointsPerInch = 722.7 +if (NORM_SPACE undefined) then + if (SPACE glyph exists) then + NORM_SPACE = width of SPACE + else NORM_SPACE = ROUND((0.33 * RESOLUTION_X * POINT_SIZE)/ DeciPointsPerInch) + + +3.2.17. MAX_SPACE + +MAX_SPACE is an integer value (of type INT32) that gives the recommended +maximum word-space value to be used with this font. + +MAX_SPACE can be approximated if not provided as a font property, +according to the following algorithm: + + + if (MAX_SPACE undefined) then + MAX_SPACE = ROUND(1.5 * NORM_SPACE) + + +3.2.18. END_SPACE + +END_SPACE is an integer value (of type INT32) that gives the recommended +spacing at the end of sentences. + +END_SPACE can be approximated if not provided as a font property, +according to the following algorithm: + + + if (END_SPACE undefined) then + END_SPACE = NORM_SPACE + + +3.2.19. AVG_CAPITAL_WIDTH + +AVG_CAPITAL_WIDTH is an integer value (of type INT32) that gives the +unweighted arithmetic mean of the absolute value of the width of each + + + + 18 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +capital glyph in the font, in tenths of pixels, multiplied by -1 if the +dominant writing direction for the font is right-to-left. This property +applies to both Latin and non-Latin fonts. For Latin fonts, capitals +are the glyphs A through Z. This property is usually used for font +matching or substitution. + +AVG_CAPITAL_WIDTH can be calculated if not provided as a font property, +according to the following algorithm: + + + if (AVG_CAPITAL_WIDTH undefined) then + if (capitals exist) then + AVG_CAPITAL_WIDTH = ROUND (MEAN + (ABS (width of each capital glyph)) * 10) + * (if (dominant writing direction L-to-R) then 1 else -1) + else AVG_CAPITAL_WIDTH undefined + + +3.2.20. AVG_LOWERCASE_WIDTH + +AVG_LOWERCASE_WIDTH is an integer value (of type INT32) that gives the +unweighted arithmetic mean width of the absolute value of the width of +each lowercase glyph in the font in tenths of pixels, multiplied by -1 +if the dominant writing direction for the font is right-to-left. For +Latin fonts, lowercase are the glyphs a through z. This property is +usually used for font matching or substitution. + +Where appropriate, AVG_LOWERCASE_WIDTH can be approximated if not pro- +vided as a font property, according to the following algorithm: + + + if (AVG_LOWERCASE_WIDTH undefined) then + if (lowercase exists) then + AVG_LOWERCASE_WIDTH = ROUND (MEAN + (ABS (width of each lowercase glyph)) * 10) + * (if (dominant writing direction L-to-R) then 1 else -1) + else AVG_LOWERCASE_WIDTH undefined + + +3.2.21. QUAD_WIDTH + +QUAD_WIDTH is an integer typographic metric (of type INT32) that gives +the width of a quad (em) space. + + Note + + Because all typographic fixed spaces (em, en, and thin) are + constant for a given font size (that is, they do not vary + according to setwidth), the use of this font property has been + deprecated. X clients that require typographic fixed space + values are encouraged to discontinue use of QUAD_WIDTH and + compute these values from other font properties (for example, + PIXEL_SIZE). X clients that require a font-dependent width + value should use either the FIGURE_WIDTH or one of the average + + + + 19 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + + character width font properties (AVERAGE_WIDTH, AVG_CAPI- + TAL_WIDTH or AVG_LOWERCASE_WIDTH). + + +3.2.22. FIGURE_WIDTH + +FIGURE_WIDTH is an integer typographic metric (of type INT32) that gives +the width of the tabular figures and the dollar sign, if suitable for +tabular setting (all widths equal). For Latin fonts, these tabular fig- +ures are the Arabic numerals 0 through 9. + +FIGURE_WIDTH can be approximated if not supplied as a font property, +according to the following algorithm: + + + if (numerals and DOLLAR sign are defined & widths are equal) then + FIGURE_WIDTH = width of DOLLAR + else FIGURE_WIDTH property undefined + + +3.2.23. SUPERSCRIPT_X + +SUPERSCRIPT_X is an integer value (of type INT32) that gives the recom- +mended horizontal offset in pixels from the position point to the X ori- +gin of synthetic superscript text. If the current position point is at +[X,Y], then superscripts should begin at [X + SUPERSCRIPT_X, Y - SUPER- +SCRIPT_Y]. + +SUPERSCRIPT_X can be approximated if not provided as a font property, +according to the following algorithm: + + + if (SUPERSCRIPT_X undefined) then + if (TANGENT(ITALIC_ANGLE) defined) then + SUPERSCRIPT_X = ROUND((0.40 * CAP_HEIGHT) / TANGENT(ITALIC_ANGLE)) + else SUPERSCRIPT_X = ROUND(0.40 * CAP_HEIGHT) + + +where TANGENT is a trigonometric function that returns the tangent of +its argument, which is in 1/64 degrees. + +3.2.24. SUPERSCRIPT_Y + +SUPERSCRIPT_Y is an integer value (of type INT32) that gives the recom- +mended vertical offset in pixels from the position point to the Y origin +of synthetic superscript text. If the current position point is at +[X,Y], then superscripts should begin at [X + SUPERSCRIPT_X, Y - SUPER- +SCRIPT_Y]. + +SUPERSCRIPT_Y can be approximated if not provided as a font property, +according to the following algorithm: + + + + + + + 20 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + + if (SUPERSCRIPT_Y undefined) then + SUPERSCRIPT_Y = ROUND(0.40 * CAP_HEIGHT) + + +3.2.25. SUBSCRIPT_X + +SUBSCRIPT_X is an integer value (of type INT32) that gives the recom- +mended horizontal offset in pixels from the position point to the X ori- +gin of synthetic subscript text. If the current position point is at +[X,Y], then subscripts should begin at [X + SUBSCRIPT_X, Y + SUB- +SCRIPT_Y]. + +SUBSCRIPT_X can be approximated if not provided as a font property, +according to the following algorithm: + + + if (SUBSCRIPT_X undefined) then + if (TANGENT(ITALIC_ANGLE) defined) then + SUBSCRIPT_X = ROUND((0.40 * CAP_HEIGHT) / TANGENT(ITALIC_ANGLE)) + else SUBSCRIPT_X = ROUND(0.40 * CAP_HEIGHT) + + +3.2.26. SUBSCRIPT_Y + +SUBSCRIPT_Y is an integer value (of type INT32) that gives the recom- +mended vertical offset in pixels from the position point to the Y origin +of synthetic subscript text. If the current position point is at [X,Y], +then subscripts should begin at [X + SUBSCRIPT_X, Y + SUBSCRIPT_Y]. + +SUBSCRIPT_Y can be approximated if not provided as a font property, +according to the following algorithm: + + + if (SUBSCRIPT_Y undefined) then + SUBSCRIPT_Y = ROUND(0.40 * CAP_HEIGHT) + + +3.2.27. SUPERSCRIPT_SIZE + +SUPERSCRIPT_SIZE is an integer value (of type INT32) that gives the rec- +ommended body size of synthetic superscripts to be used with this font, +in pixels. This will generally be smaller than the size of the current +font; that is, superscripts are imaged from a smaller font offset +according to SUPERSCRIPT_X and SUPERSCRIPT_Y. + +SUPERSCRIPT_SIZE can be approximated if not provided as a font property, +according to the following algorithm: + + + if (SUPERSCRIPT_SIZE undefined) then + SUPERSCRIPT_SIZE = ROUND(0.60 * PIXEL_SIZE) + + + + + + + 21 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +3.2.28. SUBSCRIPT_SIZE + +SUBSCRIPT_SIZE is an integer value (of type INT32) that gives the recom- +mended body size of synthetic subscripts to be used with this font, in +pixels. As with SUPERSCRIPT_SIZE, this will generally be smaller than +the size of the current font; that is, subscripts are imaged from a +smaller font offset according to SUBSCRIPT_X and SUBSCRIPT_Y. + +SUBSCRIPT_SIZE can be approximated if not provided as a font property, +according to the algorithm: + + + if (SUBSCRIPT_SIZE undefined) then + SUBSCRIPT_SIZE = ROUND(0.60 * PIXEL_SIZE) + + +3.2.29. SMALL_CAP_SIZE + +SMALL_CAP_SIZE is an integer value (of type INT32) that gives the recom- +mended body size of synthetic small capitals to be used with this font, +in pixels. Small capitals are generally imaged from a smaller font of +slightly more weight. No offset [X,Y] is necessary. + +SMALL_CAP_SIZE can be approximated if not provided as a font property, +according to the following algorithm: + + + if (SMALL_CAP_SIZE undefined) then + SMALL_CAP_SIZE = ROUND(PIXEL_SIZE * ((X_HEIGHT + + ((CAP_HEIGHT - X_HEIGHT) / 3)) / CAP_HEIGHT)) + + +3.2.30. UNDERLINE_POSITION + +UNDERLINE_POSITION is an integer value (of type INT32) that gives the +recommended vertical offset in pixels from the baseline to the top of +the underline. If the current position point is at [X,Y], the top of +the baseline is given by [X, Y + UNDERLINE_POSITION]. + +UNDERLINE_POSITION can be approximated if not provided as a font prop- +erty, according to the following algorithm: + + + if (UNDERLINE_POSITION undefined) then + UNDERLINE_POSITION = ROUND((maximum descent) / 2) + +where maximum descent is the maximum descent (below the baseline) in +pixels of any glyph in the font. + +3.2.31. UNDERLINE_THICKNESS + +UNDERLINE_THICKNESS is an integer value (of type INT32) that gives the +recommended underline thickness, in pixels. + + + + + 22 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +UNDERLINE_THICKNESS can be approximated if not provided as a font prop- +erty, according to the following algorithm: + + + CapStemWidth = average width of the stems of capitals + if (UNDERLINE_THICKNESS undefined) then + UNDERLINE_THICKNESS = CapStemWidth + + +3.2.32. STRIKEOUT_ASCENT + +STRIKEOUT_ASCENT is an integer value (of type INT32) that gives the ver- +tical ascent for boxing or voiding glyphs in this font. If the current +position is at [X,Y] and the string extent is EXTENT, the upper-left +corner of the strikeout box is at [X, Y - STRIKEOUT_ASCENT] and the +lower-right corner of the box is at [X + EXTENT, Y + STRIKEOUT_DESCENT]. + +STRIKEOUT_ASCENT can be approximated if not provided as a font property, +according to the following algorithm: + + + if (STRIKEOUT_ASCENT undefined) + STRIKEOUT_ASCENT = maximum ascent + +where maximum ascent is the maximum ascent (above the baseline) in pix- +els of any glyph in the font. + +3.2.33. STRIKEOUT_DESCENT + +STRIKEOUT_DESCENT is an integer value (of type INT32) that gives the +vertical descent for boxing or voiding glyphs in this font. If the cur- +rent position is at [X,Y] and the string extent is EXTENT, the upper- +left corner of the strikeout box is at [X, Y - STRIKEOUT_ASCENT] and the +lower-right corner of the box is at [X + EXTENT, Y + STRIKEOUT_DESCENT]. + +STRIKEOUT_DESCENT can be approximated if not provided as a font prop- +erty, according to the following algorithm: + + + if (STRIKEOUT_DESCENT undefined) + STRIKEOUT_DESCENT = maximum descent + +where maximum descent is the maximum descent (below the baseline) in +pixels of any glyph in the font. + +3.2.34. ITALIC_ANGLE + +ITALIC_ANGLE is an integer value (of type INT32) that gives the nominal +posture angle of the typeface design, in 1/64 degrees, measured from the +glyph origin counterclockwise from the three o'clock position. + +ITALIC_ANGLE can be defaulted if not provided as a font property, +according to the following algorithm: + + + + + 23 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + + if (ITALIC_ANGLE undefined) then + ITALIC_ANGLE = (90 * 64) + + +3.2.35. CAP_HEIGHT + +CAP_HEIGHT is an integer value (of type INT32) that gives the nominal +height of the capital letters contained in the font, as specified by the +FOUNDRY or typeface designer. + +Certain clients require CAP_HEIGHT to compute scale factors and posi- +tioning offsets for synthesized glyphs where this information or +designed glyphs are not explicitly provided by the font (for example, +small capitals, superiors, inferiors, and so on). CAP_HEIGHT is also a +critical factor in font matching and substitution. + +CAP_HEIGHT can be approximated if not provided as a font property, +according to the following algorithm: + + + if (CAP_HEIGHT undefined) then + if (Latin font) then + CAP_HEIGHT = XCharStruct.ascent[glyph X] + else if (capitals exist) then + CAP_HEIGHT = XCharStruct.ascent[some unaccented capital glyph] + else CAP_HEIGHT undefined + + +3.2.36. X_HEIGHT + +X_HEIGHT is an integer value (of type INT32) that gives the nominal +height above the baseline of the lowercase glyphs contained in the font, +as specified by the FOUNDRY or typeface designer. + +As with CAP_HEIGHT, X_HEIGHT is required by certain clients to compute +scale factors for synthesized small capitals where this information is +not explicitly provided by the font resource. X_HEIGHT is a critical +factor in font matching and substitution. + +X_HEIGHT can be approximated if not provided as a font property, accord- +ing to the following algorithm: + + + if (X_HEIGHT undefined) then + if (Latin font) then + X_HEIGHT = XCharStruct.ascent[glyph x] + else if (lowercase exists) then + X_HEIGHT = XCharStruct.ascent[some unaccented lc glyph without an ascender] + else X_HEIGHT undefined + + + + + + + + + 24 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +3.2.37. RELATIVE_SETWIDTH + +RELATIVE_SETWIDTH is an unsigned integer value (of type CARD32) that +gives the coded proportionate width of the font, relative to all known +fonts of the same typeface family, according to the type designer's or +FOUNDRY's judgment. + +RELATIVE_SETWIDTH ranges from 10 to 90 or is 0 if undefined or unknown. +The following reference values are defined: + +--------------------------------------------------------------------------- +Code English Translation Description +--------------------------------------------------------------------------- +0 Undefined Undefined or unknown +10 UltraCondensed The lowest ratio of average width to height +20 ExtraCondensed +30 Condensed Condensed, Narrow, Compressed, ... +40 SemiCondensed +50 Medium Medium, Normal, Regular, ... +60 SemiExpanded SemiExpanded, DemiExpanded, ... +70 Expanded +80 ExtraExpanded ExtraExpanded, Wide, ... +90 UltraExpanded The highest ratio of average width to height +--------------------------------------------------------------------------- + + +RELATIVE_SETWIDTH can be defaulted if not provided as a font property, +according to the following algorithm: + + + if (RELATIVE_SETWIDTH undefined) then + RELATIVE_SETWIDTH = 50 + + +For polymorphic fonts, RELATIVE_SETWIDTH is not necessarily a linear +function of the font's setwidth axis. + +X clients that want to obtain a calculated proportionate width of the +font (that is, a font-independent way of identifying the proportionate +width across all fonts and all font vendors) can use the following algo- +rithm: + + + SETWIDTH = AVG_CAPITAL_WIDTH / (CAP_HEIGHT * 10) + + +where SETWIDTH is a real number with zero being the narrowest calculated +setwidth. + +3.2.38. RELATIVE_WEIGHT + +RELATIVE_WEIGHT is an unsigned integer value (of type CARD32) that gives +the coded weight of the font, relative to all known fonts of the same +typeface family, according to the type designer's or FOUNDRY's judgment. + + + + 25 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +RELATIVE_WEIGHT ranges from 10 to 90 or is 0 if undefined or unknown. +The following reference values are defined: + +----------------------------------------------------------------------- +Code English Translation Description +----------------------------------------------------------------------- +0 Undefined Undefined or unknown +10 UltraLight The lowest ratio of stem width to height +20 ExtraLight +30 Light +40 SemiLight SemiLight, Book, ... +50 Medium Medium, Normal, Regular,... +60 SemiBold SemiBold, DemiBold, ... +70 Bold +80 ExtraBold ExtraBold, Heavy, ... +90 UltraBold UltraBold, Black, ..., the highest ratio + of stem width to height +----------------------------------------------------------------------- + + +RELATIVE_WEIGHT can be defaulted if not provided as a font property, +according to the following algorithm: + + + if (RELATIVE_WEIGHT undefined) then + RELATIVE_WEIGHT = 50 + + +For polymorphic fonts, RELATIVE_WEIGHT is not necessarily a linear func- +tion of the font's weight axis. + +3.2.39. WEIGHT + +Calculated WEIGHT is an unsigned integer value (of type CARD32) that +gives the calculated weight of the font, computed as the ratio of capi- +tal stem width to CAP_HEIGHT, in the range 0 to 1000, where 0 is the +lightest weight. + +WEIGHT can be calculated if not supplied as a font property, according +to the following algorithm: + + + CapStemWidth = average width of the stems of capitals + if (WEIGHT undefined) then + WEIGHT = ROUND ((CapStemWidth * 1000) / CAP_HEIGHT) + + +A calculated value for weight is necessary when matching fonts from dif- +ferent families because both the RELATIVE_WEIGHT and the WEIGHT_NAME are +assigned by the typeface supplier, according to its tradition and prac- +tice, and therefore, are somewhat subjective. Calculated WEIGHT pro- +vides a font-independent way of identifying the weight across all fonts +and all font vendors. + + + + + 26 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +3.2.40. RESOLUTION + +RESOLUTION is an integer value (of type INT32) that gives the resolution +for which this font was created, measured in 1/100 pixels per point. + + Note + + As independent horizontal and vertical design resolution com- + ponents are required to accommodate displays with nonsquare + aspect ratios, the use of this font property has been depre- + cated, and independent RESOLUTION_X and RESOLUTION_Y font name + fields/properties have been defined (see sections 3.1.2.9 and + 3.1.2.10). X clients are encouraged to discontinue use of the + RESOLUTION property and are encouraged to use the appropriate + X,Y resolution properties, as required. + + +3.2.41. FONT + +FONT is a string (of type ATOM) that gives the full XLFD name of the +font--that is, the value can be used to open another instance of the +same font. + +If not provided, the FONT property cannot be calculated. + +3.2.42. FACE_NAME + +FACE_NAME is a human-understandable string (of type ATOM) that gives the +full device-independent typeface name, including the owner, weight, +slant, set, and so on but not the resolution, size, and so on. This +property may be used as feedback during font selection. + +FACE_NAME cannot be calculated or approximated if not provided as a font +property. + +3.2.43. FULL_NAME + +FULL_NAME is the same as FACE_NAME. Its use is deprecated, but it is +found on some old fonts. + +3.2.44. COPYRIGHT + +COPYRIGHT is a human-understandable string (of type ATOM) that gives the +copyright information of the legal owner of the digital font data. + +This information is a required component of a font but is independent of +the particular format used to represent it (that is, it cannot be cap- +tured as a comment that could later be thrown away for efficiency rea- +sons). + +COPYRIGHT cannot be calculated or approximated if not provided as a font +property. + + + + + + 27 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +3.2.45. NOTICE + +NOTICE is a human-understandable string (of type ATOM) that gives the +copyright information of the legal owner of the font design or, if not +applicable, the trademark information for the typeface FAMILY_NAME. + +Typeface design and trademark protection laws vary from country to coun- +try, the USA having no design copyright protection currently while vari- +ous countries in Europe offer both design and typeface family name +trademark protection. As with COPYRIGHT, this information is a required +component of a font but is independent of the particular format used to +represent it. + +NOTICE cannot be calculated or approximated if not provided as a font +property. + +3.2.46. DESTINATION + +DESTINATION is an unsigned integer code (of type CARD32) that gives the +font design destination, that is, whether it was designed as a screen +proofing font to match printer font glyph widths (WYSIWYG), as an opti- +mal video font (possibly with corresponding printer font) for extended +screen viewing (video text), and so on. + +The font design considerations are very different, and at current dis- +play resolutions, the readability and legibility of these two kinds of +screen fonts are very different. DESTINATION allows publishing clients +that use X to model the printed page and video text clients, such as on- +line documentation browsers, to query for X screen fonts that suit their +particular requirements. + +The encoding is as follows: + +-------------------------------------------------------------------- +Code English Translation Description +-------------------------------------------------------------------- +0 WYSIWYG The font is optimized to match the + typographic design and metrics of an + equivalent printer font. +1 Video text The font is optimized for screen leg- + ibility and readability. +-------------------------------------------------------------------- + + + +3.2.47. FONT_TYPE + +FONT_TYPE is a human-understandable string (of type ATOM) that describes +the format of the font data as they are read from permanent storage by +the current font source. It is a static attribute of the source data. +It can be used by clients to select a type of bitmap or outline font +without regard to the rasterizer used to render the font. + + + + + + 28 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +Predefined values are as follows: + +---------------------------------------------------------------- +Value When applicable +---------------------------------------------------------------- +"Bitmap" Hand-tuned bitmap fonts. Some attempt has been + made to optimize the visual appearance of the font + for the requested size and resolution. +"Prebuilt" All bitmap format fonts that cannot be described + as "Bitmap", that is, hand-tuned. For example, a + bitmap format font that was generated mechanically + using a scalable font rasterizer would be consid- + ered "Prebuilt", not "Bitmap". +"Type 1" Any Type 1 font. +"TrueType" Any TrueType font. +"Speedo" Any Speedo font. +"F3" Any F3 font. +---------------------------------------------------------------- + + +Other values may be registered with the X Consortium. + +3.2.48. FONT_VERSION + +FONT_VERSION is a human-understandable string (of type ATOM) that +describes the formal or informal version of the font. None is a valid +value. + +3.2.49. RASTERIZER_NAME + +RASTERIZER_NAME is a human-understandable string (of type ATOM) that is +the specific name of the rasterizer that has performed some rasteriza- +tion operation (such as scaling from outlines) on this font. + +To define a RASTERIZER_NAME, the following format is recommended: + +RasterizerName ::= OrganizationId Space Rasterizer +OrganizationId ::= STRING8--the X Registry ORGANIZATION + name of the rasterizer implementor or + maintainer. + Rasterizer ::= the case-sensitive, human-understand- + able product name of the rasterizer. + Words within this name should be sep- + arated by a single SPACE. + Space ::= OCTET-" " (SPACE) + + +Examples: + X Consortium Bit Scaler + X Consortium Type 1 Rasterizer + X Consortium Speedo Rasterizer + Adobe Type Manager + Sun TypeScaler + + + + + 29 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +If RASTERIZER_NAME is not defined, or is None, no rasterization opera- +tion has been applied to the FONT_TYPE. + +3.2.50. RASTERIZER_VERSION + +RASTERIZER_VERSION is a human-understandable string (of type ATOM) that +represents the formal or informal version of a font rasterizer. The +RASTERIZER_VERSION should match the corresponding product version number +known to users, when applicable. + +3.2.51. RAW_ASCENT + +For a font with a transformation matrix, RAW_ASCENT is the font ascent +in 1000 pixel metrics (see section 4.1). + +3.2.52. RAW_DESCENT + +For a font with a transformation matrix, RAW_DESCENT is the font descent +in 1000 pixel metrics (see section 4.1). + +3.2.53. RAW_* + +For a font with a transformation matrix, all font properties that repre- +sent horizontal or vertical sizes or displacements will be accompanied +by a new property, named as the original except prefixed with "RAW_", +that is computed as described in section 4.1. + +3.2.54. AXIS_NAMES + +AXIS_NAMES is a list of all the names of the axes for a polymorphic +font, separated by a null (0) byte. These names are suitable for pre- +sentation in a user interface (see section 6). + +3.2.55. AXIS_LIMITS + +AXIS_LIMITS is a list of integers, two for each axis, giving the minimum +and maximum allowable values for that axis of a polymorphic font (see +section 6). + +3.2.56. AXIS_TYPES + +AXIS_TYPES is like AXIS_NAMES, but can be registered as having specific +semantics (see section 6). + +3.3. Built-in Font Property Atoms + +The following font property atom definitions were predefined in the ini- +tial version of the core protocol: + +---------------------------------------------- +Font Property/Atom Name Property Type +---------------------------------------------- +MIN_SPACE INT32 + + + + + 30 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +---------------------------------------------- +Font Property/Atom Name Property Type +---------------------------------------------- +NORM_SPACE INT32 +MAX_SPACE INT32 +END_SPACE INT32 +SUPERSCRIPT_X INT32 +SUPERSCRIPT_Y INT32 +SUBSCRIPT_X INT32 +SUBSCRIPT_Y INT32 +UNDERLINE_POSITION INT32 +UNDERLINE_THICKNESS INT32 +STRIKEOUT_ASCENT INT32 +STRIKEOUT_DESCENT INT32 +FONT_ASCENT INT32 +FONT_DESCENT INT32 +ITALIC_ANGLE INT32 +X_HEIGHT INT32 +QUAD_WIDTH INT32 - deprecated +WEIGHT CARD32 +POINT_SIZE INT32 +RESOLUTION CARD32 - deprecated +COPYRIGHT ATOM +FULL_NAME ATOM - deprecated +FAMILY_NAME ATOM +DEFAULT_CHAR CARD32 +---------------------------------------------- + + +4. Matrix Transformations + +An XLFD name presented to the server can have the POINT_SIZE or +PIXEL_SIZE field begin with the character "[". If the first character +of the field is "[", the character must be followed with ASCII represen- +tations of four floating point numbers and a trailing "]", with white +space separating the numbers and optional white space separating the +numbers from the "[" and "]" characters. Numbers use standard floating +point syntax but use the character "~" to represent a minus sign in the +mantissa or exponent. + +The BNF for a matrix transformation string is as follows: + + MatrixString ::= LeftBracket OptionalSpace Float Space Float Space Float + Space Float OptionalSpace RightBracket +OptionalSpace ::= "" | Space + Space ::= SpaceChar | SpaceChar Space + Float ::= Mantissa | Mantissa Exponent + Mantissa ::= Sign Number | Number + Sign ::= Plus | Tilde + Number ::= Integer | Integer Dot Integer | Dot Integer + Integer ::= Digit | Digit Integer + Digit ::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" + Exponent ::= "e" SignedInteger | "E" SignedInteger + + + + + 31 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +SignedInteger ::= Sign Integer | Integer + LeftBracket ::= OCTET - "[" (LEFT SQUARE BRACKET) + RightBracket ::= OCTET - "]" (RIGHT SQUARE BRACKET) + SpaceChar ::= OCTET - " " (SPACE) + Tilde ::= OCTET - "~" (TILDE) + Plus ::= OCTET - "+" (PLUS) + Dot ::= OCTET - "." (FULL STOP) + + +The string "[a b c d]" represents a graphical transformation of the +glyphs in the font by the matrix + +[ a b 0 ] +[ c d 0 ] +[ 0 0 1 ] + + +All transformations occur around the origin of the glyph. The relation- +ship between the current scalar values and the matrix transformation +values is that the scalar value "N" in the POINT_SIZE field produces the +same glyphs as the matrix "[N/10 0 0 N/10]" in that field, and the +scalar value "N" in the PIXEL_SIZE field produces the same glyphs as the +matrix "[N*RESOLUTION_X/RESOLUTION_Y 0 0 N]" in that field. + +If matrices are specified for both the POINT_SIZE and PIXEL_SIZE, they +must bear the following relationship to each other within an implementa- +tion-specific tolerance: + PIXEL_SIZE_MATRIX = [Sx 0 0 Sy] * POINT_SIZE_MATRIX +where + Sx = RESOLUTION_X / 72.27 + Sy = RESOLUTION_Y / 72.27 + +If either the POINT_SIZE or PIXEL_SIZE field is unspecified (either "0" +or wildcarded), the preceding formulas can be used to compute one from +the other. + +4.1. Metrics and Font Properties + +In this section, the phrase "1000 pixel metrics" means the metrics that +would be obtained if the rasterizer took the base untransformed design +used to generate the transformed font and scaled it linearly to a height +of 1000 pixels, with no rotation component. Note that there may be no +way for the application to actually request this font since the raster- +izer may use different outlines or rasterization techniques at that size +from the ones used to generate the transformed font. + +Notes on properties and metrics: + +The per-char ink metrics (lbearing, rbearing, ascent, and descent) rep- +resent the ink extent of the transformed glyph around its origin. + +The per-char width is the x component of the transformed character +width. + + + + + 32 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +The font ascent and descent are the y component of the transformed font +ascent or descent. + +The FONT property returns a name reflecting the matrix being used--that +is, the name returned can be used to open another instance of the same +font. The returned name is not necessarily an exact copy of the +requested name. If, for example, the user requests + -misc-fixed-medium-r-normal--0-[2e1 0 0.0 +10.0]-72-72-c-0-iso8859-1 +the resulting FONT property might be + -misc-fixed-medium-r-normal--[19.9 0 0 10]-[20 0 0 +10]-72-72-c-0-iso8859-1 +The FONT property will always include matrices in both the PIXEL_SIZE +and the POINT_SIZE fields. + +To allow accurate client positioning of transformed characters, the +attributes field of the XCharInfo contains the width of the character in +1000 pixel metrics. This attributes field should be interpreted as a +signed integer. + +There will always be 2 new font properties defined, RAW_ASCENT and +RAW_DESCENT, that hold the ascent and descent in 1000 pixel metrics. + +All font properties that represent horizontal widths or displacements +have as their value the x component of the transformed width or dis- +placement. All font properties that represent vertical heights or dis- +placements have as their value the y component of the transformed height +or displacement. Each such property will be accompanied by a new prop- +erty, named as the original except prefixed with "RAW_", that gives the +value of the width, height, or displacement in 1000 pixel metrics. + +5. Scalable Fonts + +The XLFD is designed to support scalable fonts. A scalable font is a +font source from which instances of arbitrary size can be derived. A +scalable font source might be one or more outlines together with zero or +more hand-tuned bitmap fonts at specific sizes and resolutions, or it +might be a programmatic description together with zero or more bitmap +fonts, or some other format (perhaps even just a single bitmap font). + +The following definitions are useful for discussing scalable fonts: + +Well-formed XLFD pattern + + A pattern string containing 14 hyphens, one of which is the first + character of the pattern. Wildcard characters are permitted in the + fields of a well-formed XLFD pattern. + +Scalable font name + + A well-formed XLFD pattern containing no wildcards and containing + the digit "0" in the PIXEL_SIZE, POINT_SIZE, and AVERAGE_WIDTH + fields. + + + + + + 33 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +Scalable fields + + The XLFD fields PIXEL_SIZE, POINT_SIZE, RESOLUTION_X, RESOLUTION_Y, + and AVERAGE_WIDTH. + +Derived instance + + The result of replacing the scalable fields of a font name with + values to yield a font name that could actually be produced from + the font source. A scaling engine is permitted, but not required, + to interpret the scalable fields in font names to support anamor- + phic scaling. + +Global list + + The list of names that would be returned by an X server for a List- + Fonts protocol request on the pattern "*" if there were no protocol + restrictions on the total number of names returned. + + +The global list consists of font names derived from font sources. If a +single font source can support multiple character sets (specified in the +CHARSET_REGISTRY and CHARSET_ENCODING fields), each such character set +should be used to form a separate font name in the list. For a nonscal- +able font source, the simple font name for each character set is +included in the global list. For a scalable font source, a scalable +font name for each character set is included in the list. In addition +to the scalable font name, specific derived instance names may also be +included in the list. The relative order of derived instances with +respect to the scalable font name is not constrained. Finally, font +name aliases may also be included in the list. The relative order of +aliases with respect to the real font name is not constrained. + +The values of the RESOLUTION_X and RESOLUTION_Y fields of a scalable +font name are implementation dependent, but to maximize backward compat- +ibility, they should be reasonable nonzero values, for example, a reso- +lution close to that provided by the screen (in a single-screen server). +Because some existing applications rely on seeing a collection of point +and pixel sizes, server vendors are strongly encouraged in the near term +to provide a mechanism for including, for each scalable font name, a set +of specific derived instance names. For font sources that contain a +collection of hand-tuned bitmap fonts, including names of these +instances in the global list is recommended and sufficient. + +The X protocol request OpenFont on a scalable font name returns a font +corresponding to an implementation-dependent derived instance of that +font name. + +The X protocol request ListFonts on a well-formed XLFD pattern returns +the following. Starting with the global list, if the actual pattern +argument has values containing no wildcards in scalable fields, then +substitute each such field into the corresponding field in each scalable +font name in the list. For each resulting font name, if the remaining +scalable fields cannot be replaced with values to produce a derived + + + + 34 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +instance, remove the font name from the list. Now take the modified +list, and perform a simple pattern match against the pattern argument. +ListFonts returns the resulting list. + +For example, given the global list: + + -Linotype-Times-Bold-I-Normal--0-0-100-100-P-0-ISO8859-1 + -Linotype-Times-Bold-R-Normal--0-0-100-100-P-0-ISO8859-1 + -Linotype-Times-Medium-I-Normal--0-0-100-100-P-0-ISO8859-1 + -Linotype-Times-Medium-R-Normal--0-0-100-100-P-0-ISO8859-1 + + +a ListFonts request with the pattern: + + + -*-Times-*-R-Normal--*-120-100-100-P-*-ISO8859-1 + + +would return: + + -Linotype-Times-Bold-R-Normal--0-120-100-100-P-0-ISO8859-1 + -Linotype-Times-Medium-R-Normal--0-120-100-100-P-0-ISO8859-1 + + +ListFonts on a pattern containing wildcards that is not a well-formed +XLFD pattern is only required to return the list obtained by performing +a simple pattern match against the global list. X servers are permit- +ted, but not required, to use a more sophisticated matching algorithm. + +6. Polymorphic Fonts + +Fonts that can be varied in ways other than size or resolution are +called polymorphic fonts. Multiple Master Type 1 font programs are one +type of a polymorphic font. Current examples of axes along which the +fonts can be varied are width, weight, and optical size; others might +include formality or x-height. + +To support polymorphic fonts, special values indicating variability are +defined for the following XLFD fields: + WEIGHT_NAME + SLANT + SETWIDTH_NAME + ADD_STYLE_NAME + +The string "0" is the special polymorphic value. In the WEIGHT_NAME, +SLANT, or SETWIDTH_NAME field, "0" must be the entire field. There may +be multiple polymorphic values in the ADD_STYLE_NAME field. They are +surrounded by "[" and "]" and separated by a Space, as "[0 0]". The +polymorphic values may coexist with other data in the field. It is rec- +ommended that the polymorphic values be at the end of the ADD_STYLE_NAME +field. + +The font-matching algorithms for a font with polymorphic fields are +identical to the matching algorithms for a font with scalable fields. + + + + 35 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +There are three new font properties to describe the axes of variation, +AXIS_NAMES, AXIS_LIMITS, and AXIS_TYPES. AXIS_NAMES is a list of all +the names of the axes for the font, separated by a null (0) byte. These +names are suitable for presentation in a user interface. AXIS_LIMITS is +a list of integers, two for each axis, giving the minimum and maximum +allowable values for that axis. AXIS_TYPES is like AXIS_NAMES, but can +be registered as having specific semantics. + +The axes are listed in the properties in the same order as they appear +in the font name. They are matched with font name fields by looking for +the special polymorphic values in the font name. + +Examples: + +The Adobe Myriad MM font program has width and weight axes. Weight can +vary from 215 to 830, and width from 300 to 700. + + Name: + -Adobe-Myriad MM-0-R-0--0-0-0-0-P-0-ISO8859-1 + AXIS_NAMES: + Weight, Width + AXIS_LIMITS: + 215, 830, 300, 700 + AXIS_TYPES: + Adobe-Weight, Adobe-Width + Sample derived instance: + -Adobe-Myriad MM-412-R-575--*-120-100-100-P-*-ISO8859-1 + + +The Adobe Minion MM Italic font program has width, weight, and optical +size axes. + + Name: + -Adobe-Minion MM-0-I-0-[0]-0-0-0-0-P-0-ISO8859-1 + AXIS_NAMES: + Weight, Width, Optical size + AXIS_LIMITS: + 345, 620, 450, 600, 6, 72 + AXIS_TYPES: + Adobe-Weight, Adobe-Width, Adobe-OpticalSize + Sample derived instance: + -Adobe-Minion MM-550-I-480-[18]-*-180-100-100-P-*-ISO8859-1 + + +The Adobe Minion MM Swash Italic font program has the same axes and val- +ues. This shows how "[0]" in the ADD_STYLE_NAME field can coexist with +other words. + + Name: + -Adobe-Minion MM-0-I-0-Swash[0]-0-0-0-0-P-0-ISO8859-1 + AXIS_NAMES: + Weight, Width, Optical size + AXIS_LIMITS: + 345, 620, 450, 600, 6, 72 + + + + 36 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + + AXIS_TYPES: + Adobe-Weight, Adobe-Width, Adobe-OpticalSize + Sample derived instance: + -Adobe-Minion MM-550-I-480-Swash[18]-*-180-100-100-P-*-ISO8859-1 + + +The XYZ Abc font, a hypothetical font, has optical size and x-height +axes. This shows how there can be more than one polymorphic value in +the ADD_STYLE_NAME field. + + Name: + -XYZ-Abc-Medium-R-Normal-[0 0]-0-0-0-0-P-0-ISO8859-1 + AXIS_NAMES: + Optical size, X-height + AXIS_LIMITS: + 6, 72, 400, 600 + AXIS_TYPES: + XYZ-OpticalSize, XYZ-Xheight + Sample derived instance: + -XYZ-Abc-Medium-R-Normal-[14 510]-*-140-100-100-P-*-ISO8859-1 + + +If an axis allows negative values, a client requests a negative value by +using "~" (TILDE) as a minus sign. + +Axis types can be registered with the X Consortium, along with their +semantics. + +If a font name that contains the polymorphic value or a wildcard in a +polymorphic field is presented to a font source, the font source is free +to substitute any value that is convenient. However, font sources +should try to use a value that would be considered normal or medium for +the particular font. For example, if an optical size variable is unre- +solved, the font source should provide a value appropriate to the size +of the font. + +The result of specifying an out-of-range value for a polymorphic field +is undefined. The font source may treat this as a BadName error, treat +the value as if it were the closest legal value, or extrapolate to try +to accommodate the value. + +7. Affected Elements of Xlib and the X Protocol + +The following X protocol requests must support the XLFD conventions: + +o OpenFont - for the name argument + +o ListFonts - for the pattern argument + +o ListFontsWithInfo - for the pattern argument + +In addition, the following Xlib functions must support the XLFD conven- +tions: + + + + + 37 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +o XLoadFont - for the name argument + +o XListFontsWithInfo - for the pattern argument + +o XLoadQueryFont - for the name argument + +o XListFonts - for the pattern argument + +8. BDF Conformance + +The bitmap font distribution and interchange format adopted by the X +Consortium (BDF V2.1) provides a general mechanism for identifying the +font name of an X font and a variable list of font properties, but it +does not mandate the syntax or semantics of the font name or the seman- +tics of the font properties that might be provided in a BDF font. This +section identifies the requirements for BDF fonts that conform to XLFD. + +8.1. XLFD Conformance Requirements + +A BDF font conforms to the XLFD specification if and only if the follow- +ing conditions are satisfied: + +o The value for the BDF item FONT conforms to the syntax and semantic + definition of a XLFD FontName string. + +o The FontName begins with the X FontNameRegistry prefix: "-". + +o All XLFD FontName fields are defined. + +o Any FontProperties provided conform in name and semantics to the + XLFD FontProperty definitions. + +A simple method of testing for conformance would entail verifying that +the FontNameRegistry prefix is the string "-", that the number of field +delimiters in the string and coded field values are valid, and that each +font property name either matches a standard XLFD property name or fol- +lows the definition of a private property. + +8.2. FONT_ASCENT, FONT_DESCENT, and DEFAULT_CHAR + +FONT_ASCENT, FONT_DESCENT, and DEFAULT_CHAR are provided in the BDF +specification as properties that are moved to the XFontStruct by the BDF +font compiler in generating the X server-specific binary font encoding. +If present, these properties shall comply with the following semantic +definitions. + +8.2.1. FONT_ASCENT + +FONT_ASCENT is an integer value (of type INT32) that gives the recom- +mended typographic ascent above the baseline for determining interline +spacing. Specific glyphs of the font may extend beyond this. If the +current position point for line n is at [X,Y], then the origin of the +next line m = n + 1 (allowing for a possible font change) is [X, Y + +FONT_DESCENTn + FONT_ASCENTm]. + + + + 38 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +FONT_ASCENT can be approximated if not provided as a font property, +according to the following algorithm: + + + if (FONT_ASCENT undefined) then + FONT_ASCENT = maximum ascent + +where maximum ascent is the maximum ascent (above the baseline) in pix- +els of any glyph in the font. + +8.2.2. FONT_DESCENT + +FONT_DESCENT is an integer value (of type INT32) that gives the recom- +mended typographic descent below the baseline for determining interline +spacing. Specific glyphs of the font may extend beyond this. If the +current position point for line n is at [X,Y], then the origin of the +next line m = n+1 (allowing for a possible font change) is [X, Y + +FONT_DESCENTn + FONT_ASCENTm]. + +The logical extent of the font is inclusive between the Y-coordinate +values: Y - FONT_ASCENT and Y + FONT_DESCENT + 1. + +FONT_DESCENT can be approximated if not provided as a font property, +according to the following algorithm: + + + if (FONT_DESCENT undefined) then + FONT_DESCENT = maximum descent + +where maximum descent is the maximum descent (below the baseline) in +pixels of any glyph in the font. + +8.2.3. DEFAULT_CHAR + +The DEFAULT_CHAR is an unsigned integer value (of type CARD32) that +specifies the index of the default character to be used by the X server +when an attempt is made to display an undefined or nonexistent character +in the font. (For a font using a 2-byte matrix format, the index bytes +are encoded in the integer as byte1 * 65536 + byte2.) If the +DEFAULT_CHAR itself specifies an undefined or nonexistent character in +the font, then no display is performed. + +DEFAULT_CHAR cannot be approximated if not provided as a font property. + + + + + + + + + + + + + + + 39 + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + 40 + + + + + + + + + + Table of Contents + + +1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 1 +2. Requirements and Goals . . . . . . . . . . . . . . . . . . . . . 1 +2.1. Provide Unique and Descriptive Font Names . . . . . . . . . . . 2 +2.2. Support Multiple Font Vendors and Character Sets . . . . . . . 2 +2.3. Support Scalable and Polymorphic Fonts . . . . . . . . . . . . 2 +2.4. Support Transformations and Subsetting of Fonts . . . . . . . . 2 +2.5. Be Independent of X Server and Operating or File System +Implementations . . . . . . . . . . . . . . . . . . . . . . . . . . 2 +2.6. Support Arbitrarily Complex Font Matching and Substitution + . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 +2.7. Be Extensible . . . . . . . . . . . . . . . . . . . . . . . . . 3 +3. X Logical Font Description . . . . . . . . . . . . . . . . . . . 3 +3.1. FontName . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 +3.1.1. FontName Syntax . . . . . . . . . . . . . . . . . . . . . . . 4 +3.1.2. FontName Field Definitions . . . . . . . . . . . . . . . . . 5 +3.1.2.1. FOUNDRY Field . . . . . . . . . . . . . . . . . . . . . . . 5 +3.1.2.2. FAMILY_NAME Field . . . . . . . . . . . . . . . . . . . . . 6 +3.1.2.3. WEIGHT_NAME Field . . . . . . . . . . . . . . . . . . . . . 6 +3.1.2.4. SLANT Field . . . . . . . . . . . . . . . . . . . . . . . . 7 +3.1.2.5. SETWIDTH_NAME Field . . . . . . . . . . . . . . . . . . . . 7 +3.1.2.6. ADD_STYLE_NAME Field . . . . . . . . . . . . . . . . . . . 8 +3.1.2.7. PIXEL_SIZE Field . . . . . . . . . . . . . . . . . . . . . 8 +3.1.2.8. POINT_SIZE Field . . . . . . . . . . . . . . . . . . . . . 8 +3.1.2.9. RESOLUTION_X and RESOLUTION_Y Fields . . . . . . . . . . . 9 +3.1.2.10. SPACING Field . . . . . . . . . . . . . . . . . . . . . . 9 +3.1.2.11. AVERAGE_WIDTH Field . . . . . . . . . . . . . . . . . . . 10 +3.1.2.12. CHARSET_REGISTRY and CHARSET_ENCODING Fields . . . . . . . 10 +3.1.3. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 12 +3.2. Font Properties . . . . . . . . . . . . . . . . . . . . . . . . 13 +3.2.1. FOUNDRY . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 +3.2.2. FAMILY_NAME . . . . . . . . . . . . . . . . . . . . . . . . . 14 +3.2.3. WEIGHT_NAME . . . . . . . . . . . . . . . . . . . . . . . . . 14 +3.2.4. SLANT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 +3.2.5. SETWIDTH_NAME . . . . . . . . . . . . . . . . . . . . . . . . 15 +3.2.6. ADD_STYLE_NAME . . . . . . . . . . . . . . . . . . . . . . . 15 +3.2.7. PIXEL_SIZE . . . . . . . . . . . . . . . . . . . . . . . . . 15 +3.2.8. POINT_SIZE . . . . . . . . . . . . . . . . . . . . . . . . . 16 +3.2.9. RESOLUTION_X . . . . . . . . . . . . . . . . . . . . . . . . 16 +3.2.10. RESOLUTION_Y . . . . . . . . . . . . . . . . . . . . . . . . 16 +3.2.11. SPACING . . . . . . . . . . . . . . . . . . . . . . . . . . 17 +3.2.12. AVERAGE_WIDTH . . . . . . . . . . . . . . . . . . . . . . . 17 +3.2.13. CHARSET_REGISTRY . . . . . . . . . . . . . . . . . . . . . . 17 +3.2.14. CHARSET_ENCODING . . . . . . . . . . . . . . . . . . . . . . 17 +3.2.15. MIN_SPACE . . . . . . . . . . . . . . . . . . . . . . . . . 17 +3.2.16. NORM_SPACE . . . . . . . . . . . . . . . . . . . . . . . . . 18 +3.2.17. MAX_SPACE . . . . . . . . . . . . . . . . . . . . . . . . . 18 +3.2.18. END_SPACE . . . . . . . . . . . . . . . . . . . . . . . . . 18 +3.2.19. AVG_CAPITAL_WIDTH . . . . . . . . . . . . . . . . . . . . . 18 +3.2.20. AVG_LOWERCASE_WIDTH . . . . . . . . . . . . . . . . . . . . 19 +3.2.21. QUAD_WIDTH . . . . . . . . . . . . . . . . . . . . . . . . . 19 + + + + i + + + + + +X Logical Font Description Conventions X11, Release 6.4 + + +3.2.22. FIGURE_WIDTH . . . . . . . . . . . . . . . . . . . . . . . . 20 +3.2.23. SUPERSCRIPT_X . . . . . . . . . . . . . . . . . . . . . . . 20 +3.2.24. SUPERSCRIPT_Y . . . . . . . . . . . . . . . . . . . . . . . 20 +3.2.25. SUBSCRIPT_X . . . . . . . . . . . . . . . . . . . . . . . . 21 +3.2.26. SUBSCRIPT_Y . . . . . . . . . . . . . . . . . . . . . . . . 21 +3.2.27. SUPERSCRIPT_SIZE . . . . . . . . . . . . . . . . . . . . . . 21 +3.2.28. SUBSCRIPT_SIZE . . . . . . . . . . . . . . . . . . . . . . . 22 +3.2.29. SMALL_CAP_SIZE . . . . . . . . . . . . . . . . . . . . . . . 22 +3.2.30. UNDERLINE_POSITION . . . . . . . . . . . . . . . . . . . . . 22 +3.2.31. UNDERLINE_THICKNESS . . . . . . . . . . . . . . . . . . . . 22 +3.2.32. STRIKEOUT_ASCENT . . . . . . . . . . . . . . . . . . . . . . 23 +3.2.33. STRIKEOUT_DESCENT . . . . . . . . . . . . . . . . . . . . . 23 +3.2.34. ITALIC_ANGLE . . . . . . . . . . . . . . . . . . . . . . . . 23 +3.2.35. CAP_HEIGHT . . . . . . . . . . . . . . . . . . . . . . . . . 24 +3.2.36. X_HEIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . 24 +3.2.37. RELATIVE_SETWIDTH . . . . . . . . . . . . . . . . . . . . . 25 +3.2.38. RELATIVE_WEIGHT . . . . . . . . . . . . . . . . . . . . . . 25 +3.2.39. WEIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 +3.2.40. RESOLUTION . . . . . . . . . . . . . . . . . . . . . . . . . 27 +3.2.41. FONT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 +3.2.42. FACE_NAME . . . . . . . . . . . . . . . . . . . . . . . . . 27 +3.2.43. FULL_NAME . . . . . . . . . . . . . . . . . . . . . . . . . 27 +3.2.44. COPYRIGHT . . . . . . . . . . . . . . . . . . . . . . . . . 27 +3.2.45. NOTICE . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 +3.2.46. DESTINATION . . . . . . . . . . . . . . . . . . . . . . . . 28 +3.2.47. FONT_TYPE . . . . . . . . . . . . . . . . . . . . . . . . . 28 +3.2.48. FONT_VERSION . . . . . . . . . . . . . . . . . . . . . . . . 29 +3.2.49. RASTERIZER_NAME . . . . . . . . . . . . . . . . . . . . . . 29 +3.2.50. RASTERIZER_VERSION . . . . . . . . . . . . . . . . . . . . . 30 +3.2.51. RAW_ASCENT . . . . . . . . . . . . . . . . . . . . . . . . . 30 +3.2.52. RAW_DESCENT . . . . . . . . . . . . . . . . . . . . . . . . 30 +3.2.53. RAW_* . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 +3.2.54. AXIS_NAMES . . . . . . . . . . . . . . . . . . . . . . . . . 30 +3.2.55. AXIS_LIMITS . . . . . . . . . . . . . . . . . . . . . . . . 30 +3.2.56. AXIS_TYPES . . . . . . . . . . . . . . . . . . . . . . . . . 30 +3.3. Built-in Font Property Atoms . . . . . . . . . . . . . . . . . 30 +4. Matrix Transformations . . . . . . . . . . . . . . . . . . . . . 31 +4.1. Metrics and Font Properties . . . . . . . . . . . . . . . . . . 32 +5. Scalable Fonts . . . . . . . . . . . . . . . . . . . . . . . . . 33 +6. Polymorphic Fonts . . . . . . . . . . . . . . . . . . . . . . . . 35 +7. Affected Elements of Xlib and the X Protocol . . . . . . . . . . 37 +8. BDF Conformance . . . . . . . . . . . . . . . . . . . . . . . . . 38 +8.1. XLFD Conformance Requirements . . . . . . . . . . . . . . . . . 38 +8.2. FONT_ASCENT, FONT_DESCENT, and DEFAULT_CHAR . . . . . . . . . . 38 +8.2.1. FONT_ASCENT . . . . . . . . . . . . . . . . . . . . . . . . . 38 +8.2.2. FONT_DESCENT . . . . . . . . . . . . . . . . . . . . . . . . 39 +8.2.3. DEFAULT_CHAR . . . . . . . . . . . . . . . . . . . . . . . . 39 + + + + + + + + + + + ii + + -- 2.28.0
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