1 /***************************************************************************/
2 /*                                                                         */
3 /*  ftsynth.c                                                              */
4 /*                                                                         */
5 /*    FreeType synthesizing code for emboldening and slanting (body).      */
6 /*                                                                         */
7 /*  Copyright 2000-2006, 2010, 2012, 2013 by                               */
8 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
9 /*                                                                         */
10 /*  This file is part of the FreeType project, and may only be used,       */
11 /*  modified, and distributed under the terms of the FreeType project      */
12 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
13 /*  this file you indicate that you have read the license and              */
14 /*  understand and accept it fully.                                        */
15 /*                                                                         */
16 /***************************************************************************/
17 
18 
19 #include <ft2build.h>
20 #include FT_SYNTHESIS_H
21 #include FT_INTERNAL_DEBUG_H
22 #include FT_INTERNAL_OBJECTS_H
23 #include FT_OUTLINE_H
24 #include FT_BITMAP_H
25 
26 
27   /*************************************************************************/
28   /*                                                                       */
29   /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
30   /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
31   /* messages during execution.                                            */
32   /*                                                                       */
33 #undef  FT_COMPONENT
34 #define FT_COMPONENT  trace_synth
35 
36 
37   /*************************************************************************/
38   /*************************************************************************/
39   /****                                                                 ****/
40   /****   EXPERIMENTAL OBLIQUING SUPPORT                                ****/
41   /****                                                                 ****/
42   /*************************************************************************/
43   /*************************************************************************/
44 
45   /* documentation is in ftsynth.h */
46 
47   FT_EXPORT_DEF( void )
FT_GlyphSlot_Oblique(FT_GlyphSlot slot)48   FT_GlyphSlot_Oblique( FT_GlyphSlot  slot )
49   {
50     FT_Matrix    transform;
51     FT_Outline*  outline = &slot->outline;
52 
53 
54     /* only oblique outline glyphs */
55     if ( slot->format != FT_GLYPH_FORMAT_OUTLINE )
56       return;
57 
58     /* we don't touch the advance width */
59 
60     /* For italic, simply apply a shear transform, with an angle */
61     /* of about 12 degrees.                                      */
62 
63     transform.xx = 0x10000L;
64     transform.yx = 0x00000L;
65 
66     transform.xy = 0x0366AL;
67     transform.yy = 0x10000L;
68 
69     FT_Outline_Transform( outline, &transform );
70   }
71 
72 
73   /*************************************************************************/
74   /*************************************************************************/
75   /****                                                                 ****/
76   /****   EXPERIMENTAL EMBOLDENING SUPPORT                              ****/
77   /****                                                                 ****/
78   /*************************************************************************/
79   /*************************************************************************/
80 
81 
82   /* documentation is in ftsynth.h */
83 
84   FT_EXPORT_DEF( void )
FT_GlyphSlot_Embolden(FT_GlyphSlot slot)85   FT_GlyphSlot_Embolden( FT_GlyphSlot  slot )
86   {
87     FT_Library  library = slot->library;
88     FT_Face     face    = slot->face;
89     FT_Error    error;
90     FT_Pos      xstr, ystr;
91 
92 
93     if ( slot->format != FT_GLYPH_FORMAT_OUTLINE &&
94          slot->format != FT_GLYPH_FORMAT_BITMAP  )
95       return;
96 
97     /* some reasonable strength */
98     xstr = FT_MulFix( face->units_per_EM,
99                       face->size->metrics.y_scale ) / 24;
100     ystr = xstr;
101 
102     if ( slot->format == FT_GLYPH_FORMAT_OUTLINE )
103     {
104       /* ignore error */
105       (void)FT_Outline_EmboldenXY( &slot->outline, xstr, ystr );
106     }
107     else /* slot->format == FT_GLYPH_FORMAT_BITMAP */
108     {
109       /* round to full pixels */
110       xstr &= ~63;
111       if ( xstr == 0 )
112         xstr = 1 << 6;
113       ystr &= ~63;
114 
115       /*
116        * XXX: overflow check for 16-bit system, for compatibility
117        *      with FT_GlyphSlot_Embolden() since freetype-2.1.10.
118        *      unfortunately, this function return no informations
119        *      about the cause of error.
120        */
121       if ( ( ystr >> 6 ) > FT_INT_MAX || ( ystr >> 6 ) < FT_INT_MIN )
122       {
123         FT_TRACE1(( "FT_GlyphSlot_Embolden:" ));
124         FT_TRACE1(( "too strong embolding parameter ystr=%d\n", ystr ));
125         return;
126       }
127       error = FT_GlyphSlot_Own_Bitmap( slot );
128       if ( error )
129         return;
130 
131       error = FT_Bitmap_Embolden( library, &slot->bitmap, xstr, ystr );
132       if ( error )
133         return;
134     }
135 
136     if ( slot->advance.x )
137       slot->advance.x += xstr;
138 
139     if ( slot->advance.y )
140       slot->advance.y += ystr;
141 
142     slot->metrics.width        += xstr;
143     slot->metrics.height       += ystr;
144     slot->metrics.horiAdvance  += xstr;
145     slot->metrics.vertAdvance  += ystr;
146     slot->metrics.horiBearingY += ystr;
147 
148     /* XXX: 16-bit overflow case must be excluded before here */
149     if ( slot->format == FT_GLYPH_FORMAT_BITMAP )
150       slot->bitmap_top += (FT_Int)( ystr >> 6 );
151   }
152 
153 
154 /* END */
155