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/***************************************************************************/
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/* FreeType synthesizing code for emboldening and slanting (body). */
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/* Copyright 2000-2001, 2002, 2003 by */
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/* David Turner, Robert Wilhelm, and Werner Lemberg. */
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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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#include FT_INTERNAL_OBJECTS_H
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#include FT_INTERNAL_CALC_H
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#include FT_TRIGONOMETRY_H
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#include FT_SYNTHESIS_H
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#define FT_BOLD_THRESHOLD 0x0100
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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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FT_GlyphSlot_Oblique( FT_GlyphSlot slot )
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FT_Outline* 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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/* we don't touch the advance width */
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/* For italic, simply apply a shear transform, with an angle */
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/* of about 12 degrees. */
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transform.xx = 0x10000L;
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transform.yx = 0x00000L;
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transform.xy = 0x06000L;
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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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/**** EXPERIMENTAL EMBOLDENING/OUTLINING SUPPORT ****/
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/*************************************************************************/
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/*************************************************************************/
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ft_test_extrema( FT_Outline* outline,
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FT_Vector *prev, *cur, *next;
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FT_Int c, first, last;
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/* we need to compute the `previous' and `next' point */
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/* for these extrema. */
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cur = outline->points + n;
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for ( c = 0; c < outline->n_contours; c++ )
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last = outline->contours[c];
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prev = outline->points + last;
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next = outline->points + first;
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product = FT_MulDiv( cur->x - prev->x, /* in.x */
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next->y - cur->y, /* out.y */
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FT_MulDiv( cur->y - prev->y, /* in.y */
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next->x - cur->x, /* out.x */
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product = product > 0 ? 1 : -1;
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/* Compute the orientation of path filling. It differs between TrueType */
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/* and Type1 formats. We could use the `FT_OUTLINE_REVERSE_FILL' flag, */
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/* but it is better to re-compute it directly (it seems that this flag */
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/* isn't correctly set for some weird composite glyphs currently). */
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/* We do this by computing bounding box points, and computing their */
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/* The function returns either 1 or -1. */
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ft_get_orientation( FT_Outline* outline )
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box.xMin = box.yMin = 32767;
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box.xMax = box.yMax = -32768;
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if ( outline->n_contours < 1 )
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last = outline->contours[outline->n_contours - 1];
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for ( n = 0; n <= last; n++ )
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x = outline->points[n].x;
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y = outline->points[n].y;
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/* test orientation of the xmin */
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n = ft_test_extrema( outline, indices.xMin );
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n = ft_test_extrema( outline, indices.yMin );
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n = ft_test_extrema( outline, indices.xMax );
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n = ft_test_extrema( outline, indices.yMax );
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FT_EXPORT_DEF( void )
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FT_GlyphSlot_Embolden( FT_GlyphSlot slot )
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FT_Vector v_prev, v_first, v_next, v_cur;
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FT_Outline* outline = &slot->outline;
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FT_Face face = FT_SLOT_FACE( slot );
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FT_Angle rotate, angle_in, angle_out;
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FT_Int c, n, first, orientation;
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/* only embolden outline glyph images */
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if ( slot->format != FT_GLYPH_FORMAT_OUTLINE )
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/* compute control distance */
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distance = FT_MulFix( face->units_per_EM / 60,
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face->size->metrics.y_scale );
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orientation = ft_get_orientation( outline );
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rotate = FT_ANGLE_PI2*orientation;
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points = outline->points;
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for ( c = 0; c < outline->n_contours; c++ )
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int last = outline->contours[c];
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v_first = points[first];
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v_prev = points[last];
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for ( n = first; n <= last; n++ )
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if ( n < last ) v_next = points[n + 1];
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else v_next = v_first;
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/* compute the in and out vectors */
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in.x = v_cur.x - v_prev.x;
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in.y = v_cur.y - v_prev.y;
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out.x = v_next.x - v_cur.x;
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out.y = v_next.y - v_cur.y;
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angle_in = FT_Atan2( in.x, in.y );
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angle_out = FT_Atan2( out.x, out.y );
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angle_diff = FT_Angle_Diff( angle_in, angle_out );
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scale = FT_Cos( angle_diff/2 );
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if ( scale < 0x400L && scale > -0x400L )
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d = FT_DivFix( distance, scale );
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FT_Vector_From_Polar( &in, d, angle_in + angle_diff/2 - rotate );
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outline->points[n].x = v_cur.x + distance + in.x;
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outline->points[n].y = v_cur.y + distance + in.y;
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slot->metrics.horiAdvance =
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( slot->metrics.horiAdvance + distance*4 ) & ~63;