181 lines
5.2 KiB
C
181 lines
5.2 KiB
C
/****************************************************************************
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*
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* ftsynth.c
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*
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* FreeType synthesizing code for emboldening and slanting (body).
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*
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* Copyright (C) 2000-2023 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 <freetype/ftsynth.h>
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#include <freetype/internal/ftdebug.h>
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#include <freetype/internal/ftobjs.h>
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#include <freetype/ftoutln.h>
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#include <freetype/ftbitmap.h>
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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 synth
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/*************************************************************************/
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/*************************************************************************/
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/**** ****/
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/**** EXPERIMENTAL OBLIQUING SUPPORT ****/
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/**** ****/
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/*************************************************************************/
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/*************************************************************************/
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/* documentation is in ftsynth.h */
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FT_EXPORT_DEF( void )
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FT_GlyphSlot_Oblique( FT_GlyphSlot slot )
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{
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/* Value '0x0366A' corresponds to a shear angle of about 12 degrees. */
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FT_GlyphSlot_Slant( slot, 0x0366A, 0 );
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}
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/* documentation is in ftsynth.h */
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FT_EXPORT_DEF( void )
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FT_GlyphSlot_Slant( FT_GlyphSlot slot,
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FT_Fixed xslant,
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FT_Fixed yslant )
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{
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FT_Matrix transform;
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FT_Outline* outline;
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if ( !slot )
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return;
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outline = &slot->outline;
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/* only oblique outline glyphs */
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if ( slot->format != FT_GLYPH_FORMAT_OUTLINE )
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return;
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/* we don't touch the advance width */
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/* For italic, simply apply a shear transform */
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transform.xx = 0x10000L;
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transform.yx = -yslant;
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transform.xy = xslant;
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transform.yy = 0x10000L;
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FT_Outline_Transform( outline, &transform );
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}
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/*************************************************************************/
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/*************************************************************************/
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/**** ****/
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/**** EXPERIMENTAL EMBOLDENING SUPPORT ****/
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/**** ****/
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/*************************************************************************/
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/*************************************************************************/
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/* documentation is in ftsynth.h */
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FT_EXPORT_DEF( void )
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FT_GlyphSlot_Embolden( FT_GlyphSlot slot )
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{
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FT_GlyphSlot_AdjustWeight( slot, 0x0AAA, 0x0AAA );
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}
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FT_EXPORT_DEF( void )
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FT_GlyphSlot_AdjustWeight( FT_GlyphSlot slot,
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FT_Fixed xdelta,
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FT_Fixed ydelta )
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{
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FT_Library library;
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FT_Size size;
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FT_Error error;
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FT_Pos xstr, ystr;
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if ( !slot )
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return;
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library = slot->library;
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size = slot->face->size;
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if ( slot->format != FT_GLYPH_FORMAT_OUTLINE &&
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slot->format != FT_GLYPH_FORMAT_BITMAP )
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return;
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/* express deltas in pixels in 26.6 format */
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xstr = (FT_Pos)size->metrics.x_ppem * xdelta / 1024;
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ystr = (FT_Pos)size->metrics.y_ppem * ydelta / 1024;
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if ( slot->format == FT_GLYPH_FORMAT_OUTLINE )
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FT_Outline_EmboldenXY( &slot->outline, xstr, ystr );
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else /* slot->format == FT_GLYPH_FORMAT_BITMAP */
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{
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/* round to full pixels */
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xstr &= ~63;
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if ( xstr == 0 )
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xstr = 1 << 6;
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ystr &= ~63;
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/*
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* XXX: overflow check for 16-bit system, for compatibility
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* with FT_GlyphSlot_Embolden() since FreeType 2.1.10.
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* unfortunately, this function return no informations
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* about the cause of error.
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*/
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if ( ( ystr >> 6 ) > FT_INT_MAX || ( ystr >> 6 ) < FT_INT_MIN )
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{
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FT_TRACE1(( "FT_GlyphSlot_Embolden:" ));
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FT_TRACE1(( "too strong emboldening parameter ystr=%ld\n", ystr ));
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return;
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}
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error = FT_GlyphSlot_Own_Bitmap( slot );
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if ( error )
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return;
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error = FT_Bitmap_Embolden( library, &slot->bitmap, xstr, ystr );
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if ( error )
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return;
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}
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if ( slot->advance.x )
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slot->advance.x += xstr;
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if ( slot->advance.y )
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slot->advance.y += ystr;
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slot->metrics.width += xstr;
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slot->metrics.height += ystr;
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slot->metrics.horiAdvance += xstr;
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slot->metrics.vertAdvance += ystr;
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slot->metrics.horiBearingY += ystr;
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/* XXX: 16-bit overflow case must be excluded before here */
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if ( slot->format == FT_GLYPH_FORMAT_BITMAP )
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slot->bitmap_top += (FT_Int)( ystr >> 6 );
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}
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/* END */
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