ref: ca46bc0cf22eb72e9fdc6782337715d0ac2bbd9e
dir: /src/sfnt/ttmtx.c/
/****************************************************************************
*
* ttmtx.c
*
* Load the metrics tables common to TTF and OTF fonts (body).
*
* Copyright (C) 2006-2022 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/internal/ftstream.h>
#include <freetype/tttags.h>
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
#include <freetype/internal/services/svmetric.h>
#endif
#include "ttmtx.h"
#include "sferrors.h"
/* IMPORTANT: The TT_HoriHeader and TT_VertHeader structures should */
/* be identical except for the names of their fields, */
/* which are different. */
/* */
/* This ensures that `tt_face_load_hmtx' is able to read */
/* both the horizontal and vertical headers. */
/**************************************************************************
*
* 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 ttmtx
/**************************************************************************
*
* @Function:
* tt_face_load_hmtx
*
* @Description:
* Load the `hmtx' or `vmtx' table into a face object.
*
* @Input:
* face ::
* A handle to the target face object.
*
* stream ::
* The input stream.
*
* vertical ::
* A boolean flag. If set, load `vmtx'.
*
* @Return:
* FreeType error code. 0 means success.
*/
FT_LOCAL_DEF( FT_Error )
tt_face_load_hmtx( TT_Face face,
FT_Stream stream,
FT_Bool vertical )
{
FT_Error error;
FT_ULong tag, table_size;
FT_ULong* ptable_offset;
FT_ULong* ptable_size;
if ( vertical )
{
tag = TTAG_vmtx;
ptable_offset = &face->vert_metrics_offset;
ptable_size = &face->vert_metrics_size;
}
else
{
tag = TTAG_hmtx;
ptable_offset = &face->horz_metrics_offset;
ptable_size = &face->horz_metrics_size;
}
error = face->goto_table( face, tag, stream, &table_size );
if ( error )
goto Fail;
*ptable_size = table_size;
*ptable_offset = FT_STREAM_POS();
Fail:
return error;
}
/**************************************************************************
*
* @Function:
* tt_face_load_hhea
*
* @Description:
* Load the `hhea' or 'vhea' table into a face object.
*
* @Input:
* face ::
* A handle to the target face object.
*
* stream ::
* The input stream.
*
* vertical ::
* A boolean flag. If set, load `vhea'.
*
* @Return:
* FreeType error code. 0 means success.
*/
FT_LOCAL_DEF( FT_Error )
tt_face_load_hhea( TT_Face face,
FT_Stream stream,
FT_Bool vertical )
{
FT_Error error;
TT_HoriHeader* header;
static const FT_Frame_Field metrics_header_fields[] =
{
#undef FT_STRUCTURE
#define FT_STRUCTURE TT_HoriHeader
FT_FRAME_START( 36 ),
FT_FRAME_ULONG ( Version ),
FT_FRAME_SHORT ( Ascender ),
FT_FRAME_SHORT ( Descender ),
FT_FRAME_SHORT ( Line_Gap ),
FT_FRAME_USHORT( advance_Width_Max ),
FT_FRAME_SHORT ( min_Left_Side_Bearing ),
FT_FRAME_SHORT ( min_Right_Side_Bearing ),
FT_FRAME_SHORT ( xMax_Extent ),
FT_FRAME_SHORT ( caret_Slope_Rise ),
FT_FRAME_SHORT ( caret_Slope_Run ),
FT_FRAME_SHORT ( caret_Offset ),
FT_FRAME_SHORT ( Reserved[0] ),
FT_FRAME_SHORT ( Reserved[1] ),
FT_FRAME_SHORT ( Reserved[2] ),
FT_FRAME_SHORT ( Reserved[3] ),
FT_FRAME_SHORT ( metric_Data_Format ),
FT_FRAME_USHORT( number_Of_HMetrics ),
FT_FRAME_END
};
if ( vertical )
{
void *v = &face->vertical;
error = face->goto_table( face, TTAG_vhea, stream, 0 );
if ( error )
goto Fail;
header = (TT_HoriHeader*)v;
}
else
{
error = face->goto_table( face, TTAG_hhea, stream, 0 );
if ( error )
goto Fail;
header = &face->horizontal;
}
if ( FT_STREAM_READ_FIELDS( metrics_header_fields, header ) )
goto Fail;
FT_TRACE3(( "Ascender: %5d\n", header->Ascender ));
FT_TRACE3(( "Descender: %5d\n", header->Descender ));
FT_TRACE3(( "number_Of_Metrics: %5u\n", header->number_Of_HMetrics ));
header->long_metrics = NULL;
header->short_metrics = NULL;
Fail:
return error;
}
/**************************************************************************
*
* @Function:
* tt_face_get_metrics
*
* @Description:
* Return the horizontal or vertical metrics in font units for a
* given glyph. The values are the left side bearing (top side
* bearing for vertical metrics) and advance width (advance height
* for vertical metrics).
*
* @Input:
* face ::
* A pointer to the TrueType face structure.
*
* vertical ::
* If set to TRUE, get vertical metrics.
*
* gindex ::
* The glyph index.
*
* @Output:
* abearing ::
* The bearing, either left side or top side.
*
* aadvance ::
* The advance width or advance height, depending on
* the `vertical' flag.
*/
FT_LOCAL_DEF( void )
tt_face_get_metrics( TT_Face face,
FT_Bool vertical,
FT_UInt gindex,
FT_Short *abearing,
FT_UShort *aadvance )
{
FT_Error error;
FT_Stream stream = face->root.stream;
TT_HoriHeader* header;
FT_ULong table_pos, table_size, table_end;
FT_UShort k;
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
FT_Service_MetricsVariations var =
(FT_Service_MetricsVariations)face->var;
#endif
if ( vertical )
{
void* v = &face->vertical;
header = (TT_HoriHeader*)v;
table_pos = face->vert_metrics_offset;
table_size = face->vert_metrics_size;
}
else
{
header = &face->horizontal;
table_pos = face->horz_metrics_offset;
table_size = face->horz_metrics_size;
}
table_end = table_pos + table_size;
k = header->number_Of_HMetrics;
if ( k > 0 )
{
if ( gindex < (FT_UInt)k )
{
table_pos += 4 * gindex;
if ( table_pos + 4 > table_end )
goto NoData;
if ( FT_STREAM_SEEK( table_pos ) ||
FT_READ_USHORT( *aadvance ) ||
FT_READ_SHORT( *abearing ) )
goto NoData;
}
else
{
table_pos += 4 * ( k - 1 );
if ( table_pos + 2 > table_end )
goto NoData;
if ( FT_STREAM_SEEK( table_pos ) ||
FT_READ_USHORT( *aadvance ) )
goto NoData;
table_pos += 4 + 2 * ( gindex - k );
if ( table_pos + 2 > table_end )
*abearing = 0;
else
{
if ( FT_STREAM_SEEK( table_pos ) )
*abearing = 0;
else
(void)FT_READ_SHORT( *abearing );
}
}
}
else
{
NoData:
*abearing = 0;
*aadvance = 0;
}
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
if ( var )
{
FT_Face f = FT_FACE( face );
FT_Int a = (FT_Int)*aadvance;
FT_Int b = (FT_Int)*abearing;
if ( vertical )
{
if ( var->vadvance_adjust )
var->vadvance_adjust( f, gindex, &a );
if ( var->tsb_adjust )
var->tsb_adjust( f, gindex, &b );
}
else
{
if ( var->hadvance_adjust )
var->hadvance_adjust( f, gindex, &a );
if ( var->lsb_adjust )
var->lsb_adjust( f, gindex, &b );
}
*aadvance = (FT_UShort)a;
*abearing = (FT_Short)b;
}
#endif
}
/* END */