forked from minhngoc25a/freetype2
340 lines
8.3 KiB
C
340 lines
8.3 KiB
C
/****************************************************************************
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*
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* ttmtx.c
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*
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* Load the metrics tables common to TTF and OTF fonts (body).
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*
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* Copyright (C) 2006-2019 by
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* David Turner, Robert Wilhelm, and Werner Lemberg.
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*
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* This file is part of the FreeType project, and may only be used,
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* modified, and distributed under the terms of the FreeType project
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* license, LICENSE.TXT. By continuing to use, modify, or distribute
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* this file you indicate that you have read the license and
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* understand and accept it fully.
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*
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*/
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#include <ft2build.h>
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#include FT_INTERNAL_DEBUG_H
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#include FT_INTERNAL_STREAM_H
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#include FT_TRUETYPE_TAGS_H
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#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
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#include FT_SERVICE_METRICS_VARIATIONS_H
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#endif
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#include "ttmtx.h"
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#include "sferrors.h"
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/* IMPORTANT: The TT_HoriHeader and TT_VertHeader structures should */
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/* be identical except for the names of their fields, */
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/* which are different. */
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/* */
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/* This ensures that `tt_face_load_hmtx' is able to read */
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/* both the horizontal and vertical headers. */
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/**************************************************************************
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*
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* The macro FT_COMPONENT is used in trace mode. It is an implicit
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* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
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* messages during execution.
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*/
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#undef FT_COMPONENT
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#define FT_COMPONENT ttmtx
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/**************************************************************************
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*
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* @Function:
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* tt_face_load_hmtx
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*
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* @Description:
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* Load the `hmtx' or `vmtx' table into a face object.
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*
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* @Input:
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* face ::
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* A handle to the target face object.
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*
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* stream ::
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* The input stream.
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*
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* vertical ::
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* A boolean flag. If set, load `vmtx'.
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*
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* @Return:
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* FreeType error code. 0 means success.
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*/
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FT_LOCAL_DEF( FT_Error )
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tt_face_load_hmtx( TT_Face face,
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FT_Stream stream,
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FT_Bool vertical )
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{
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FT_Error error;
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FT_ULong tag, table_size;
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FT_ULong* ptable_offset;
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FT_ULong* ptable_size;
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if ( vertical )
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{
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tag = TTAG_vmtx;
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ptable_offset = &face->vert_metrics_offset;
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ptable_size = &face->vert_metrics_size;
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}
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else
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{
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tag = TTAG_hmtx;
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ptable_offset = &face->horz_metrics_offset;
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ptable_size = &face->horz_metrics_size;
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}
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error = face->goto_table( face, tag, stream, &table_size );
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if ( error )
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goto Fail;
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*ptable_size = table_size;
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*ptable_offset = FT_STREAM_POS();
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Fail:
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return error;
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}
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/**************************************************************************
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*
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* @Function:
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* tt_face_load_hhea
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*
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* @Description:
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* Load the `hhea' or 'vhea' table into a face object.
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*
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* @Input:
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* face ::
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* A handle to the target face object.
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*
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* stream ::
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* The input stream.
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*
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* vertical ::
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* A boolean flag. If set, load `vhea'.
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*
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* @Return:
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* FreeType error code. 0 means success.
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*/
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FT_LOCAL_DEF( FT_Error )
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tt_face_load_hhea( TT_Face face,
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FT_Stream stream,
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FT_Bool vertical )
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{
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FT_Error error;
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TT_HoriHeader* header;
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static const FT_Frame_Field metrics_header_fields[] =
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{
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#undef FT_STRUCTURE
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#define FT_STRUCTURE TT_HoriHeader
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FT_FRAME_START( 36 ),
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FT_FRAME_ULONG ( Version ),
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FT_FRAME_SHORT ( Ascender ),
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FT_FRAME_SHORT ( Descender ),
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FT_FRAME_SHORT ( Line_Gap ),
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FT_FRAME_USHORT( advance_Width_Max ),
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FT_FRAME_SHORT ( min_Left_Side_Bearing ),
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FT_FRAME_SHORT ( min_Right_Side_Bearing ),
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FT_FRAME_SHORT ( xMax_Extent ),
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FT_FRAME_SHORT ( caret_Slope_Rise ),
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FT_FRAME_SHORT ( caret_Slope_Run ),
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FT_FRAME_SHORT ( caret_Offset ),
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FT_FRAME_SHORT ( Reserved[0] ),
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FT_FRAME_SHORT ( Reserved[1] ),
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FT_FRAME_SHORT ( Reserved[2] ),
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FT_FRAME_SHORT ( Reserved[3] ),
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FT_FRAME_SHORT ( metric_Data_Format ),
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FT_FRAME_USHORT( number_Of_HMetrics ),
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FT_FRAME_END
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};
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if ( vertical )
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{
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void *v = &face->vertical;
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error = face->goto_table( face, TTAG_vhea, stream, 0 );
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if ( error )
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goto Fail;
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header = (TT_HoriHeader*)v;
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}
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else
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{
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error = face->goto_table( face, TTAG_hhea, stream, 0 );
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if ( error )
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goto Fail;
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header = &face->horizontal;
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}
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if ( FT_STREAM_READ_FIELDS( metrics_header_fields, header ) )
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goto Fail;
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FT_TRACE3(( "Ascender: %5d\n", header->Ascender ));
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FT_TRACE3(( "Descender: %5d\n", header->Descender ));
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FT_TRACE3(( "number_Of_Metrics: %5u\n", header->number_Of_HMetrics ));
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header->long_metrics = NULL;
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header->short_metrics = NULL;
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Fail:
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return error;
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}
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/**************************************************************************
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*
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* @Function:
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* tt_face_get_metrics
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*
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* @Description:
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* Return the horizontal or vertical metrics in font units for a
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* given glyph. The values are the left side bearing (top side
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* bearing for vertical metrics) and advance width (advance height
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* for vertical metrics).
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*
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* @Input:
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* face ::
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* A pointer to the TrueType face structure.
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*
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* vertical ::
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* If set to TRUE, get vertical metrics.
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*
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* gindex ::
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* The glyph index.
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*
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* @Output:
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* abearing ::
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* The bearing, either left side or top side.
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*
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* aadvance ::
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* The advance width or advance height, depending on
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* the `vertical' flag.
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*/
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FT_LOCAL_DEF( void )
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tt_face_get_metrics( TT_Face face,
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FT_Bool vertical,
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FT_UInt gindex,
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FT_Short *abearing,
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FT_UShort *aadvance )
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{
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FT_Error error;
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FT_Stream stream = face->root.stream;
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TT_HoriHeader* header;
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FT_ULong table_pos, table_size, table_end;
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FT_UShort k;
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#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
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FT_Service_MetricsVariations var =
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(FT_Service_MetricsVariations)face->var;
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#endif
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if ( vertical )
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{
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void* v = &face->vertical;
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header = (TT_HoriHeader*)v;
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table_pos = face->vert_metrics_offset;
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table_size = face->vert_metrics_size;
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}
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else
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{
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header = &face->horizontal;
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table_pos = face->horz_metrics_offset;
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table_size = face->horz_metrics_size;
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}
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table_end = table_pos + table_size;
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k = header->number_Of_HMetrics;
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if ( k > 0 )
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{
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if ( gindex < (FT_UInt)k )
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{
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table_pos += 4 * gindex;
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if ( table_pos + 4 > table_end )
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goto NoData;
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if ( FT_STREAM_SEEK( table_pos ) ||
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FT_READ_USHORT( *aadvance ) ||
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FT_READ_SHORT( *abearing ) )
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goto NoData;
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}
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else
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{
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table_pos += 4 * ( k - 1 );
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if ( table_pos + 2 > table_end )
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goto NoData;
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if ( FT_STREAM_SEEK( table_pos ) ||
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FT_READ_USHORT( *aadvance ) )
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goto NoData;
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table_pos += 4 + 2 * ( gindex - k );
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if ( table_pos + 2 > table_end )
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*abearing = 0;
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else
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{
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if ( FT_STREAM_SEEK( table_pos ) )
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*abearing = 0;
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else
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(void)FT_READ_SHORT( *abearing );
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}
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}
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}
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else
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{
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NoData:
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*abearing = 0;
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*aadvance = 0;
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}
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#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
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if ( var )
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{
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FT_Face f = FT_FACE( face );
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FT_Int a = (FT_Int)*aadvance;
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FT_Int b = (FT_Int)*abearing;
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if ( vertical )
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{
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if ( var->vadvance_adjust )
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var->vadvance_adjust( f, gindex, &a );
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if ( var->tsb_adjust )
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var->tsb_adjust( f, gindex, &b );
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}
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else
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{
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if ( var->hadvance_adjust )
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var->hadvance_adjust( f, gindex, &a );
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if ( var->lsb_adjust )
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var->lsb_adjust( f, gindex, &b );
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}
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*aadvance = (FT_UShort)a;
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*abearing = (FT_Short)b;
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}
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#endif
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}
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/* END */
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