| /**************************************************************************** |
| * |
| * ftadvanc.c |
| * |
| * Quick computation of advance widths (body). |
| * |
| * Copyright (C) 2008-2022 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/ftadvanc.h> |
| #include <freetype/internal/ftobjs.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 */ |