ref: d0ab3a0dd8f6355b3603d0fb04043a9ae867639b
dir: /libfreetype/ttdriver.c/
/***************************************************************************/ /* */ /* ttdriver.c */ /* */ /* TrueType font driver implementation (body). */ /* */ /* Copyright 1996-2001, 2002 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 <ft2build.h> #include FT_INTERNAL_DEBUG_H #include FT_INTERNAL_STREAM_H #include FT_INTERNAL_SFNT_H #include FT_TRUETYPE_IDS_H #include "ttdriver.h" #include "ttgload.h" #include "tterrors.h" /*************************************************************************/ /* */ /* The macro FT_COMPONENT is used in trace mode. It is an implicit */ /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ /* messages during execution. */ /* */ #undef FT_COMPONENT #define FT_COMPONENT trace_ttdriver /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /**** ****/ /**** ****/ /**** F A C E S ****/ /**** ****/ /**** ****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ #undef PAIR_TAG #define PAIR_TAG( left, right ) ( ( (FT_ULong)left << 16 ) | \ (FT_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 FT_Error Get_Kerning( TT_Face face, FT_UInt left_glyph, FT_UInt right_glyph, FT_Vector* kerning ) { TT_Kern0_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! */ FT_ULong search_tag = PAIR_TAG( left_glyph, right_glyph ); FT_Long left, right; left = 0; right = face->num_kern_pairs - 1; while ( left <= right ) { FT_Int middle = left + ( ( right - left ) >> 1 ); FT_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. */ /* */ /* horz_resolution :: The horizontal resolution of the output device. */ /* */ /* vert_resolution :: The vertical resolution of the output device. */ /* */ /* <InOut> */ /* size :: A handle to the target size object. */ /* */ /* <Return> */ /* FreeType error code. 0 means success. */ /* */ static FT_Error Set_Char_Sizes( TT_Size size, FT_F26Dot6 char_width, FT_F26Dot6 char_height, FT_UInt horz_resolution, FT_UInt vert_resolution ) { FT_Size_Metrics* metrics = &size->root.metrics; TT_Face face = (TT_Face)size->root.face; FT_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 whether 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 + 36 ) / 72; dim_y = ( char_height * vert_resolution + 36 ) / 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 = (FT_UShort)( dim_x >> 6 ); metrics->y_ppem = (FT_UShort)( dim_y >> 6 ); } size->ttmetrics.valid = FALSE; #ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS size->strike_index = 0xFFFF; #endif return tt_size_reset( 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 FT_Error Set_Pixel_Sizes( TT_Size size, FT_UInt pixel_width, FT_UInt pixel_height ) { FT_UNUSED( pixel_width ); FT_UNUSED( pixel_height ); /* many things have been pre-computed by the base layer */ size->ttmetrics.valid = FALSE; #ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS size->strike_index = 0xFFFF; #endif return tt_size_reset( 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). */ /* */ /* <Return> */ /* FreeType error code. 0 means success. */ /* */ static FT_Error Load_Glyph( TT_GlyphSlot slot, TT_Size size, FT_UShort glyph_index, FT_Int32 load_flags ) { FT_Error error; if ( !slot ) return TT_Err_Invalid_Slot_Handle; /* check whether 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_size_reset( 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; } /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /**** ****/ /**** ****/ /**** D R I V E R I N T E R F A C E ****/ /**** ****/ /**** ****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ static FT_Module_Interface tt_get_interface( TT_Driver driver, const char* tt_interface ) { FT_Module sfntd = FT_Get_Module( driver->root.root.library, "sfnt" ); SFNT_Service sfnt; /* only return the default interface from the SFNT module */ if ( sfntd ) { sfnt = (SFNT_Service)( sfntd->clazz->module_interface ); if ( sfnt ) return sfnt->get_interface( FT_MODULE( driver ), tt_interface ); } return 0; } /* The FT_DriverInterface structure is defined in ftdriver.h. */ FT_CALLBACK_TABLE_DEF const FT_Driver_ClassRec tt_driver_class = { { ft_module_font_driver | ft_module_driver_scalable | #ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER ft_module_driver_has_hinter, #else 0, #endif sizeof ( TT_DriverRec ), "truetype", /* driver name */ 0x10000L, /* driver version == 1.0 */ 0x20000L, /* driver requires FreeType 2.0 or above */ (void*)0, /* driver specific interface */ (FT_Module_Constructor)tt_driver_init, (FT_Module_Destructor) tt_driver_done, (FT_Module_Requester) tt_get_interface, }, sizeof ( TT_FaceRec ), sizeof ( TT_SizeRec ), sizeof ( FT_GlyphSlotRec ), (FT_Face_InitFunc) tt_face_init, (FT_Face_DoneFunc) tt_face_done, (FT_Size_InitFunc) tt_size_init, (FT_Size_DoneFunc) tt_size_done, (FT_Slot_InitFunc) 0, (FT_Slot_DoneFunc) 0, (FT_Size_ResetPointsFunc) Set_Char_Sizes, (FT_Size_ResetPixelsFunc) Set_Pixel_Sizes, (FT_Slot_LoadFunc) Load_Glyph, (FT_Face_GetKerningFunc) Get_Kerning, (FT_Face_AttachFunc) 0, (FT_Face_GetAdvancesFunc) 0 }; /* END */