ref: f5dcdd5cfb6d66fd1e75508b7bd85da58973e921
dir: /src/truetype/ttdriver.c/
/***************************************************************************/ /* */ /* ttdriver.c */ /* */ /* TrueType font driver implementation (body). */ /* */ /* Copyright 1996-1999 by */ /* David Turner, Robert Wilhelm, and Werner Lemberg. */ /* */ /* This file is part of the FreeType project, and may only be used, */ /* modified, and distributed under the terms of the FreeType project */ /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ /* this file you indicate that you have read the license and */ /* understand and accept it fully. */ /* */ /***************************************************************************/ #include <freetype/internal/ftdebug.h> #include <freetype/internal/ftstream.h> #include <freetype/internal/sfnt.h> #include <freetype/ttnameid.h> #include <ttdriver.h> #include <ttgload.h> #undef FT_COMPONENT #define FT_COMPONENT trace_ttdriver /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /**** ****/ /**** ****/ /**** F A C E S ****/ /**** ****/ /**** ****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /****************************************************************** * * <Function> * find_encoding * * <Description> * return the FT_Encoding corresponding to a given * (platform_id,encoding_id) pair, as found in TrueType charmaps * * <Input> * platform_id :: * encoding_id :: * * <Return> * the corresponding FT_Encoding tag. ft_encoding_none by default * *****************************************************************/ static FT_Encoding find_encoding( int platform_id, int encoding_id ) { typedef struct TEncoding { int platform_id; int encoding_id; FT_Encoding encoding; } TEncoding; static const TEncoding tt_encodings[] = { { TT_PLATFORM_ISO, -1, ft_encoding_unicode }, { TT_PLATFORM_APPLE_UNICODE, -1, ft_encoding_unicode }, { TT_PLATFORM_MACINTOSH, TT_MAC_ID_ROMAN, ft_encoding_apple_roman }, { TT_PLATFORM_MICROSOFT, TT_MS_ID_UNICODE_CS, ft_encoding_unicode }, { TT_PLATFORM_MICROSOFT, TT_MS_ID_SJIS, ft_encoding_sjis }, { TT_PLATFORM_MICROSOFT, TT_MS_ID_BIG_5, ft_encoding_big5 } }; const TEncoding *cur, *limit; cur = tt_encodings; limit = cur + sizeof(tt_encodings)/sizeof(tt_encodings[0]); for ( ; cur < limit; cur++ ) { if (cur->platform_id == platform_id) { if (cur->encoding_id == encoding_id || cur->encoding_id == -1 ) return cur->encoding; } } return ft_encoding_none; } /*************************************************************************/ /* */ /* <Function> */ /* Init_Face */ /* */ /* <Description> */ /* A driver method used to initialize a new TrueType face object. */ /* */ /* <Input> */ /* resource :: A handle to the source resource. */ /* */ /* typeface_index :: An index of the face in the font resource. Used */ /* to access individual faces in font collections. */ /* */ /* <InOut> */ /* face :: A handle to the face object. */ /* */ /* <Return> */ /* FreeType error code. 0 means success. */ /* */ /* <Note> */ /* The `typeface_index' parameter field will be set to -1 if the */ /* engine only wants to test the format of the resource. This means */ /* that font drivers should simply check the font format, then return */ /* immediately with an error code of 0 (meaning success). The field */ /* `num_faces' should be set. */ /* */ /* Done_Face() will be called subsequently, whatever the result was. */ /* */ static TT_Error Init_Face( FT_Stream stream, TT_Face face, FT_Int typeface_index, FT_Int num_params, FT_Parameter* params ) { TT_Error error; /* initialize the TrueType face object */ error = TT_Init_Face( stream, face, typeface_index, num_params, params ); /* now set up root fields */ if ( !error && typeface_index >= 0 ) { FT_Face root = &face->root; FT_Int flags; TT_CharMap charmap; TT_Int n; FT_Memory memory; memory = root->memory; /*****************************************************************/ /* */ /* Compute face flags. */ /* */ flags = FT_FACE_FLAG_SCALABLE | /* scalable outlines */ FT_FACE_FLAG_SFNT | /* SFNT file format */ FT_FACE_FLAG_HORIZONTAL; /* horizontal data */ /* fixed width font ? */ if ( face->postscript.isFixedPitch ) flags |= FT_FACE_FLAG_FIXED_WIDTH; /* vertical information ? */ if ( face->vertical_info ) flags |= FT_FACE_FLAG_VERTICAL; /* kerning available ? */ if ( face->kern_pairs ) flags |= FT_FACE_FLAG_KERNING; root->face_flags = flags; /*****************************************************************/ /* */ /* Compute style flags. */ /* */ flags = 0; if ( face->os2.version != 0xFFFF ) { /* We have an OS/2 table, use the `fsSelection' field */ if ( face->os2.fsSelection & 1 ) flags |= FT_STYLE_FLAG_ITALIC; if ( face->os2.fsSelection & 32 ) flags |= FT_STYLE_FLAG_BOLD; } else { /* This is an old Mac font, use the header field */ if ( face->header.Mac_Style & 1 ) flags |= FT_STYLE_FLAG_BOLD; if ( face->header.Mac_Style & 2 ) flags |= FT_STYLE_FLAG_ITALIC; } face->root.style_flags = flags; /*****************************************************************/ /* */ /* Polish the charmaps. */ /* */ /* Try to set the charmap encoding according to the platform & */ /* encoding ID of each charmap. */ /* */ charmap = face->charmaps; root->num_charmaps = face->num_charmaps; /* allocate table of pointers */ if ( ALLOC_ARRAY( root->charmaps, root->num_charmaps, FT_CharMap ) ) return error; for ( n = 0; n < root->num_charmaps; n++, charmap++ ) { FT_Int platform = charmap->cmap.platformID; FT_Int encoding = charmap->cmap.platformEncodingID; charmap->root.face = (FT_Face)face; charmap->root.platform_id = platform; charmap->root.encoding_id = encoding; charmap->root.encoding = find_encoding(platform,encoding); /* now, set root->charmap with a unicode charmap wherever available */ if (!root->charmap && charmap->root.encoding == ft_encoding_unicode) root->charmap = (FT_CharMap)charmap; root->charmaps[n] = (FT_CharMap)charmap; } #ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS if ( face->num_sbit_strikes ) { face->root.num_fixed_sizes = face->num_sbit_strikes; if ( ALLOC_ARRAY( face->root.available_sizes, face->num_sbit_strikes, FT_Bitmap_Size ) ) return error; for ( n = 0 ; n < face->num_sbit_strikes ; n++ ) { face->root.available_sizes[n].width = face->sbit_strikes[n].x_ppem; face->root.available_sizes[n].height = face->sbit_strikes[n].y_ppem; } } else #else { root->num_fixed_sizes = 0; root->available_sizes = 0; } #endif /* TT_CONFIG_OPTION_EMBEDDED_BITMAPS */ /*****************************************************************/ /* */ /* Set up metrics. */ /* */ root->bbox.xMin = face->header.xMin; root->bbox.yMin = face->header.yMin; root->bbox.xMax = face->header.xMax; root->bbox.yMax = face->header.yMax; root->units_per_EM = face->header.Units_Per_EM; /* The ascender/descender/height are computed from the OS/2 table */ /* when found. Otherwise, they're taken from the horizontal header */ if ( face->os2.version != 0xFFFF ) { root->ascender = face->os2.sTypoAscender; root->descender = -face->os2.sTypoDescender; root->height = root->ascender + root->descender + face->os2.sTypoLineGap; } else { root->ascender = face->horizontal.Ascender; root->descender = face->horizontal.Descender; root->height = root->ascender + root->descender + face->horizontal.Line_Gap; } root->max_advance_width = face->horizontal.advance_Width_Max; root->max_advance_height = root->height; if ( face->vertical_info ) root->max_advance_height = face->vertical.advance_Height_Max; root->underline_position = face->postscript.underlinePosition; root->underline_thickness = face->postscript.underlineThickness; /* root->max_points - already set up */ /* root->max_contours - already set up */ } return error; } #undef PAIR_TAG #define PAIR_TAG( left, right ) ( ((TT_ULong)left << 16) | (TT_ULong)right ) /*************************************************************************/ /* */ /* <Function> */ /* Get_Kerning */ /* */ /* <Description> */ /* A driver method used to return the kerning vector between two */ /* glyphs of the same face. */ /* */ /* <Input> */ /* face :: A handle to the source face object. */ /* */ /* left_glyph :: The index of the left glyph in the kern pair. */ /* */ /* right_glyph :: The index of the right glyph in the kern pair. */ /* */ /* <Output> */ /* kerning :: The kerning vector. This is in font units for */ /* scalable formats, and in pixels for fixed-sizes */ /* formats. */ /* */ /* <Return> */ /* FreeType error code. 0 means success. */ /* */ /* <Note> */ /* Only horizontal layouts (left-to-right & right-to-left) are */ /* supported by this function. Other layouts, or more sophisticated */ /* kernings are out of scope of this method (the basic driver */ /* interface is meant to be simple). */ /* */ /* They can be implemented by format-specific interfaces. */ /* */ static TT_Error Get_Kerning( TT_Face face, TT_UInt left_glyph, TT_UInt right_glyph, TT_Vector* kerning ) { TT_Kern_0_Pair* pair; if ( !face ) return TT_Err_Invalid_Face_Handle; kerning->x = 0; kerning->y = 0; if ( face->kern_pairs ) { /* there are some kerning pairs in this font file! */ TT_ULong search_tag = PAIR_TAG( left_glyph, right_glyph ); TT_Long left, right; left = 0; right = face->num_kern_pairs - 1; while ( left <= right ) { TT_Int middle = left + ((right-left) >> 1); TT_ULong cur_pair; pair = face->kern_pairs + middle; cur_pair = PAIR_TAG( pair->left, pair->right ); if ( cur_pair == search_tag ) goto Found; if ( cur_pair < search_tag ) left = middle+1; else right = middle-1; } } Exit: return TT_Err_Ok; Found: kerning->x = pair->value; goto Exit; } #undef PAIR_TAG /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /**** ****/ /**** ****/ /**** S I Z E S ****/ /**** ****/ /**** ****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /* */ /* <Function> */ /* Set_Char_Sizes */ /* */ /* <Description> */ /* A driver method used to reset a size's character sizes (horizontal */ /* and vertical) expressed in fractional points. */ /* */ /* <Input> */ /* char_width :: The character width expressed in 26.6 fractional */ /* points. */ /* char_height :: The character height expressed in 26.6 fractional */ /* points. */ /* */ /* <InOut> */ /* size :: A handle to the target size object. */ /* */ /* <Return> */ /* FreeType error code. 0 means success. */ /* */ static TT_Error Set_Char_Sizes( TT_Size size, TT_F26Dot6 char_width, TT_F26Dot6 char_height, TT_UInt horz_resolution, TT_UInt vert_resolution ) { FT_Size_Metrics* metrics = &size->root.metrics; TT_Face face = (TT_Face)size->root.face; TT_Long dim_x, dim_y; /* This bit flag, when set, indicates that the pixel size must be */ /* truncated to an integer. Nearly all TrueType fonts have this */ /* bit set, as hinting won't work really well otherwise. */ /* */ /* However, for those rare fonts who do not set it, we override */ /* the default computations performed by the base layer. I really */ /* don't know if this is useful, but hey, that's the spec :-) */ /* */ if ( (face->header.Flags & 8) == 0 ) { /* Compute pixel sizes in 26.6 units */ dim_x = (char_width * horz_resolution) / 72; dim_y = (char_height * vert_resolution) / 72; metrics->x_scale = FT_DivFix( dim_x, face->root.units_per_EM ); metrics->y_scale = FT_DivFix( dim_y, face->root.units_per_EM ); metrics->x_ppem = (TT_UShort)(dim_x >> 6); metrics->y_ppem = (TT_UShort)(dim_y >> 6); } size->ttmetrics.valid = FALSE; return TT_Reset_Size( size ); } /*************************************************************************/ /* */ /* <Function> */ /* Set_Pixel_Sizes */ /* */ /* <Description> */ /* A driver method used to reset a size's character sizes (horizontal */ /* and vertical) expressed in integer pixels. */ /* */ /* <Input> */ /* pixel_width :: The character width expressed in integer pixels. */ /* */ /* pixel_height :: The character height expressed in integer pixels. */ /* */ /* <InOut> */ /* size :: A handle to the target size object. */ /* */ /* <Return> */ /* FreeType error code. 0 means success */ /* */ static TT_Error Set_Pixel_Sizes( TT_Size size, TT_UInt pixel_width, TT_UInt pixel_height ) { UNUSED(pixel_width); UNUSED(pixel_height); /* many things were pre-computed by the base layer */ size->ttmetrics.valid = FALSE; return TT_Reset_Size( size ); } /*************************************************************************/ /* */ /* <Function> */ /* Load_Glyph */ /* */ /* <Description> */ /* A driver method used to load a glyph within a given glyph slot. */ /* */ /* <Input> */ /* slot :: A handle to the target slot object where the glyph */ /* will be loaded. */ /* */ /* size :: A handle to the source face size at which the glyph */ /* must be scaled/loaded/etc. */ /* */ /* glyph_index :: The index of the glyph in the font file. */ /* */ /* load_flags :: A flag indicating what to load for this glyph. The */ /* FTLOAD_??? constants can be used to control the */ /* glyph loading process (e.g., whether the outline */ /* should be scaled, whether to load bitmaps or not, */ /* whether to hint the outline, etc). */ /* <Output> */ /* result :: A set of bit flags indicating the type of data that */ /* was loaded in the glyph slot (outline, bitmap, */ /* pixmap, etc). */ /* */ /* <Return> */ /* FreeType error code. 0 means success. */ /* */ static TT_Error Load_Glyph( TT_GlyphSlot slot, TT_Size size, TT_UShort glyph_index, TT_UInt load_flags ) { TT_Error error; if ( !slot ) return TT_Err_Invalid_Glyph_Handle; /* check that we want a scaled outline or bitmap */ if ( !size ) load_flags |= FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING; if ( load_flags & FT_LOAD_NO_SCALE ) size = NULL; /* reset the size object if necessary */ if ( size ) { /* these two object must have the same parent */ if ( size->root.face != slot->face ) return TT_Err_Invalid_Face_Handle; if ( !size->ttmetrics.valid ) { if ( FT_SET_ERROR( TT_Reset_Size( size ) ) ) return error; } } /* now load the glyph outline if necessary */ error = TT_Load_Glyph( size, slot, glyph_index, load_flags ); /* force drop-out mode to 2 - irrelevant now */ /* slot->outline.dropout_mode = 2; */ return error; } /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /**** ****/ /**** ****/ /**** C H A R A C T E R M A P P I N G S ****/ /**** ****/ /**** ****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /* */ /* <Function> */ /* Get_Char_Index */ /* */ /* <Description> */ /* Uses a charmap to return a given character code's glyph index. */ /* */ /* <Input> */ /* charmap :: A handle to the source charmap object. */ /* charcode :: The character code. */ /* */ /* <Return> */ /* Glyph index. 0 means `undefined character code'. */ /* */ static FT_UInt Get_Char_Index( TT_CharMap charmap, TT_Long charcode ) { TT_Error error; TT_Face face; TT_CMapTable* cmap; cmap = &charmap->cmap; face = (TT_Face)charmap->root.face; /* Load table if needed */ if ( !cmap->loaded ) { SFNT_Interface* sfnt = (SFNT_Interface*)face->sfnt; error = sfnt->load_charmap( face, cmap, face->root.stream ); if (error) return error; cmap->loaded = TRUE; } if ( cmap->get_index ) return cmap->get_index( cmap, charcode ); else return 0; } static void* tt_get_sfnt_table( TT_Face face, FT_Sfnt_Tag tag ) { void* table; switch (tag) { case ft_sfnt_head: table = &face->header; break; case ft_sfnt_hhea: table = &face->horizontal; break; case ft_sfnt_vhea: table = (face->vertical_info ? &face->vertical : 0 ); break; case ft_sfnt_os2: table = (face->os2.version == 0xFFFF ? 0 : &face->os2 ); break; case ft_sfnt_post: table = &face->postscript; break; case ft_sfnt_maxp: table = &face->max_profile; break; case ft_sfnt_pclt: table = face->pclt.Version ? &face->pclt : 0 ; break; default: table = 0; } return table; } static FTDriver_Interface tt_get_interface( TT_Driver driver, const char* interface ) { UNUSED(driver); if (strcmp(interface,"get_sfnt")==0) return (FTDriver_Interface)tt_get_sfnt_table; return 0; } /* The FT_DriverInterface structure is defined in ftdriver.h. */ const FT_DriverInterface tt_driver_interface = { sizeof ( TT_DriverRec ), sizeof ( TT_FaceRec ), sizeof ( TT_SizeRec ), sizeof ( FT_GlyphSlotRec ), "truetype", /* driver name */ 100, /* driver version == 1.0 */ 200, /* driver requires FreeType 2.0 or above */ (void*)0, (FTDriver_initDriver) TT_Init_Driver, (FTDriver_doneDriver) TT_Done_Driver, (FTDriver_getInterface) tt_get_interface, (FTDriver_initFace) Init_Face, (FTDriver_doneFace) TT_Done_Face, (FTDriver_getKerning) Get_Kerning, (FTDriver_initSize) TT_Init_Size, (FTDriver_doneSize) TT_Done_Size, (FTDriver_setCharSizes) Set_Char_Sizes, (FTDriver_setPixelSizes) Set_Pixel_Sizes, (FTDriver_initGlyphSlot) TT_Init_GlyphSlot, (FTDriver_doneGlyphSlot) TT_Done_GlyphSlot, (FTDriver_loadGlyph) Load_Glyph, (FTDriver_getCharIndex) Get_Char_Index, }; /*************************************************************************/ /* */ /* <Function> */ /* getDriverInterface */ /* */ /* <Description> */ /* This function is used when compiling the TrueType driver as a */ /* shared library (`.DLL' or `.so'). It will be used by the */ /* high-level library of FreeType to retrieve the address of the */ /* driver's generic interface. */ /* */ /* It shouldn't be implemented in a static build, as each driver must */ /* have the same function as an exported entry point. */ /* */ /* <Return> */ /* The address of the TrueType's driver generic interface. The */ /* format-specific interface can then be retrieved through the method */ /* interface->get_format_interface. */ /* */ #ifdef FT_CONFIG_OPTION_DYNAMIC_DRIVERS EXPORT_FUNC(FT_DriverInterface*) getDriverInterface( void ) { return &tt_driver_interface; } #endif /* CONFIG_OPTION_DYNAMIC_DRIVERS */ /* END */