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Diffstat (limited to 'src/freetype/ftadvanc.c')
| -rw-r--r-- | src/freetype/ftadvanc.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/src/freetype/ftadvanc.c b/src/freetype/ftadvanc.c new file mode 100644 index 0000000..1b5398f --- /dev/null +++ b/src/freetype/ftadvanc.c @@ -0,0 +1,175 @@ +/***************************************************************************/ +/* */ +/* ftadvanc.c */ +/* */ +/* Quick computation of advance widths (body). */ +/* */ +/* Copyright 2008-2018 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_ADVANCES_H +#include FT_INTERNAL_OBJECTS_H + + + static FT_Error + _ft_face_scale_advances( FT_Face face, + FT_Fixed* advances, + FT_UInt count, + FT_Int32 flags ) + { + FT_Fixed scale; + FT_UInt nn; + + + if ( flags & FT_LOAD_NO_SCALE ) + return FT_Err_Ok; + + if ( !face->size ) + return FT_THROW( Invalid_Size_Handle ); + + if ( flags & FT_LOAD_VERTICAL_LAYOUT ) + scale = face->size->metrics.y_scale; + else + scale = face->size->metrics.x_scale; + + /* this must be the same scaling as to get linear{Hori,Vert}Advance */ + /* (see `FT_Load_Glyph' implementation in src/base/ftobjs.c) */ + + for ( nn = 0; nn < count; nn++ ) + advances[nn] = FT_MulDiv( advances[nn], scale, 64 ); + + return FT_Err_Ok; + } + + + /* at the moment, we can perform fast advance retrieval only in */ + /* the following cases: */ + /* */ + /* - unscaled load */ + /* - unhinted load */ + /* - light-hinted load */ + /* - if a variations font, it must have an `HVAR' or `VVAR' */ + /* table (thus the old MM or GX fonts don't qualify; this */ + /* gets checked by the driver-specific functions) */ + +#define LOAD_ADVANCE_FAST_CHECK( face, flags ) \ + ( flags & ( FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING ) || \ + FT_LOAD_TARGET_MODE( flags ) == FT_RENDER_MODE_LIGHT ) + + + /* documentation is in ftadvanc.h */ + + FT_EXPORT_DEF( FT_Error ) + FT_Get_Advance( FT_Face face, + FT_UInt gindex, + FT_Int32 flags, + FT_Fixed *padvance ) + { + FT_Face_GetAdvancesFunc func; + + + if ( !face ) + return FT_THROW( Invalid_Face_Handle ); + + if ( !padvance ) + return FT_THROW( Invalid_Argument ); + + if ( gindex >= (FT_UInt)face->num_glyphs ) + return FT_THROW( Invalid_Glyph_Index ); + + func = face->driver->clazz->get_advances; + if ( func && LOAD_ADVANCE_FAST_CHECK( face, flags ) ) + { + FT_Error error; + + + error = func( face, gindex, 1, flags, padvance ); + if ( !error ) + return _ft_face_scale_advances( face, padvance, 1, flags ); + + if ( FT_ERR_NEQ( error, Unimplemented_Feature ) ) + return error; + } + + return FT_Get_Advances( face, gindex, 1, flags, padvance ); + } + + + /* documentation is in ftadvanc.h */ + + FT_EXPORT_DEF( FT_Error ) + FT_Get_Advances( FT_Face face, + FT_UInt start, + FT_UInt count, + FT_Int32 flags, + FT_Fixed *padvances ) + { + FT_Error error = FT_Err_Ok; + + FT_Face_GetAdvancesFunc func; + + FT_UInt num, end, nn; + FT_Int factor; + + + if ( !face ) + return FT_THROW( Invalid_Face_Handle ); + + if ( !padvances ) + return FT_THROW( Invalid_Argument ); + + num = (FT_UInt)face->num_glyphs; + end = start + count; + if ( start >= num || end < start || end > num ) + return FT_THROW( Invalid_Glyph_Index ); + + if ( count == 0 ) + return FT_Err_Ok; + + func = face->driver->clazz->get_advances; + if ( func && LOAD_ADVANCE_FAST_CHECK( face, flags ) ) + { + error = func( face, start, count, flags, padvances ); + if ( !error ) + return _ft_face_scale_advances( face, padvances, count, flags ); + + if ( FT_ERR_NEQ( error, Unimplemented_Feature ) ) + return error; + } + + error = FT_Err_Ok; + + if ( flags & FT_ADVANCE_FLAG_FAST_ONLY ) + return FT_THROW( Unimplemented_Feature ); + + flags |= (FT_UInt32)FT_LOAD_ADVANCE_ONLY; + factor = ( flags & FT_LOAD_NO_SCALE ) ? 1 : 1024; + for ( nn = 0; nn < count; nn++ ) + { + error = FT_Load_Glyph( face, start + nn, flags ); + if ( error ) + break; + + /* scale from 26.6 to 16.16, unless NO_SCALE was requested */ + padvances[nn] = ( flags & FT_LOAD_VERTICAL_LAYOUT ) + ? face->glyph->advance.y * factor + : face->glyph->advance.x * factor; + } + + return error; + } + + +/* END */ |