/***************************************************************************/ /* */ /* 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 #include #include #include #include #include #undef FT_COMPONENT #define FT_COMPONENT trace_ttdriver /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /**** ****/ /**** ****/ /**** F A C E S ****/ /**** ****/ /**** ****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ #undef PAIR_TAG #define PAIR_TAG( left, right ) ( ((TT_ULong)left << 16) | (TT_ULong)right ) /*************************************************************************/ /* */ /* */ /* Get_Kerning */ /* */ /* */ /* A driver method used to return the kerning vector between two */ /* glyphs of the same face. */ /* */ /* */ /* 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. */ /* */ /* */ /* kerning :: The kerning vector. This is in font units for */ /* scalable formats, and in pixels for fixed-sizes */ /* formats. */ /* */ /* */ /* FreeType error code. 0 means success. */ /* */ /* */ /* 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 ****/ /**** ****/ /**** ****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /* */ /* */ /* Set_Char_Sizes */ /* */ /* */ /* A driver method used to reset a size's character sizes (horizontal */ /* and vertical) expressed in fractional points. */ /* */ /* */ /* char_width :: The character width expressed in 26.6 fractional */ /* points. */ /* char_height :: The character height expressed in 26.6 fractional */ /* points. */ /* */ /* */ /* size :: A handle to the target size object. */ /* */ /* */ /* 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 ); } /*************************************************************************/ /* */ /* */ /* Set_Pixel_Sizes */ /* */ /* */ /* A driver method used to reset a size's character sizes (horizontal */ /* and vertical) expressed in integer pixels. */ /* */ /* */ /* pixel_width :: The character width expressed in integer pixels. */ /* */ /* pixel_height :: The character height expressed in integer pixels. */ /* */ /* */ /* size :: A handle to the target size object. */ /* */ /* */ /* 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 ); } /*************************************************************************/ /* */ /* */ /* Load_Glyph */ /* */ /* */ /* A driver method used to load a glyph within a given glyph slot. */ /* */ /* */ /* 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). */ /* */ /* result :: A set of bit flags indicating the type of data that */ /* was loaded in the glyph slot (outline, bitmap, */ /* pixmap, etc). */ /* */ /* */ /* 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 ****/ /**** ****/ /**** ****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /* */ /* */ /* Get_Char_Index */ /* */ /* */ /* Uses a charmap to return a given character code's glyph index. */ /* */ /* */ /* charmap :: A handle to the source charmap object. */ /* charcode :: The character code. */ /* */ /* */ /* 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 FTDriver_Interface tt_get_interface( TT_Driver driver, const char* interface ) { FT_Driver sfntd = FT_Get_Driver( driver->root.library, "sfnt" ); SFNT_Interface* sfnt; /* only return the default interface from the SFNT module */ if (sfntd) { sfnt = (SFNT_Interface*)(sfntd->interface.format_interface); if (sfnt) return sfnt->get_interface( (FT_Driver)driver, interface ); } 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) TT_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, }; /*************************************************************************/ /* */ /* */ /* getDriverInterface */ /* */ /* */ /* 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. */ /* */ /* */ /* 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 */