Hi, On Sat, 19 Aug 2006 12:51:29 -0400 "Qianqian Fang" <fangq@xxxxxxxxxxxxxxxxxxx> wrote: >I noticed that the fc-cache utility does not support SFNT ttf(or otf) >format well. It will output a fonts.cache-1 file with wrong font information. I guess fontconfig is designed for outline font, and bitmap-only fonts are left in the cold. >http://prdownloads.sourceforge.net/wqy/wqy-bitmapfont-ttf-0.7.0-4.tar.gz?download As the name tells, WQY fonts include collection of bitmap fonts for 12/13/15/16 pixels, and its glyf table includes single glyph only (for undefined character). If you built fontconfig-2.2.3 with additional "-DCHECK" CFLAGS and run fc-cache with debug environment variable (e.g. FC_DEBUG=9999), you will receive following result: Scanning file cjk-bitmap/wqy-bsong.ttf..."WenQuanYi Bitmap Song" "medium" TT_Load_Simple_Glyph: Too many instructions! 0x0000000d FT says 1 FC says 0 0x00000021 FT says 1 FC says 0 0x00000022 FT says 1 FC says 0 [snip] 0x0000ffe3 FT says 1 FC says 0 0x0000ffe5 FT says 1 FC says 0 33987 glyphs 4 encoded Bitmap missing char 0xd [snip] Bitmap missing char 0x2fd5 done caching, 1 fonts, 0 dirs "0x0000000d FT says 1 FC says 0" means that FreeType2 can load glyph for UCS2 codepoint 0x000d, but fontconfig ignores it. The line generating "0x00000022 FT says 1 FC says 0" is here: fcfreetype.c 1704 #ifdef CHECK 1705 for (ucs4 = 0; ucs4 < 0x10000; ucs4++) 1706 { 1707 FcBool FT_Has, FC_Has; 1708 1709 FT_Has = FT_Get_Char_Index (face, ucs4) != 0; 1710 FC_Has = FcCharSetHasChar (fcs, ucs4); 1711 if (FT_Has != FC_Has) 1712 { 1713 printf ("0x%08x FT says %d FC says %d\n", ucs4, FT_Has, FC_Has); 1714 } 1715 } 1716 #endif FT_Get_Char_Index() returns glyphID for given charcode, but it does not care about outline or bitmap. Therefore, "FT_Has" means if the font has anything to render "ucs4" (outline or bitmap). On the other hand, FcCharSetHasChar() checks whether given charcode is registered in fontconfig's charset database "fcs". Yes, you can remind "charset=" entry in fonts.cache-1. Where "fcs" comes from? Check FcFreeTypeCharSetAndSpacing(). 1592 FcCharSet * 1593 FcFreeTypeCharSetAndSpacing (FT_Face face, FcBlanks *blanks, int *spacing) 1594 { ... 1668 while (gindex) 1669 { 1670 page = ucs4 >> 8; 1671 leaf = 0; 1672 while ((ucs4 >> 8) == page) 1673 { 1674 glyph = FT_Get_Char_Index (face, ucs4); 1675 if (glyph && FcFreeTypeCheckGlyph (face, ucs4, 1676 glyph, blanks, &advance)) ... What FcFreeTypeCharSetAndSpacing() does? fcfreetype.c 1537 FcFreeTypeCheckGlyph (FT_Face face, FcChar32 ucs4, 1538 FT_UInt glyph, FcBlanks *blanks, 1539 FT_Pos *advance) 1540 { 1541 FT_Int load_flags = FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING; 1542 FT_GlyphSlot slot; 1543 1544 /* 1545 * When using scalable fonts, only report those glyphs 1546 * which can be scaled; otherwise those fonts will 1547 * only be available at some sizes, and never when 1548 * transformed. Avoid this by simply reporting bitmap-only 1549 * glyphs as missing 1550 */ 1551 if (face->face_flags & FT_FACE_FLAG_SCALABLE) 1552 load_flags |= FT_LOAD_NO_BITMAP; Here is the important part. face->face_flags is set by FreeType2 to notice the information about font, the detail of flags are found at: http://www.freetype.org/freetype2/docs/reference/ft2-base_interface.html#FT_FACE_FLAG_XXX You can find that FT_FACE_FLAG_SCALABLE means that the font includes vector glyph data (with no care about how many). Since WQY font has glyf table, the condition at #1551 is true. Then, load_cflags is set to ignore included bitmap data. Why? The reason is noted in above. The fontconfig designer wanted to avoid following scenario: 1. fontconfig make fc-charset info as superset of outline & bitmap data. 2. application expects as all character in fc-charset were scalable. 3. application tries to load a glyph image at arbitrary pixel size, but the font does not include vector data for the glyph and application is forced to use "scaled bitmap" which looks ugly. I'm trying to remove glyf table from WQY and notice to fontconfig that WQY is not "scalable", but not success yet. Regards, mpsuzuki _______________________________________________ Fontconfig mailing list Fontconfig@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/fontconfig
