• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /****************************************************************************
2  *
3  * ftbitmap.c
4  *
5  *   FreeType utility functions for bitmaps (body).
6  *
7  * Copyright (C) 2004-2020 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 <freetype/internal/ftdebug.h>
20 
21 #include <freetype/ftbitmap.h>
22 #include <freetype/ftimage.h>
23 #include <freetype/internal/ftobjs.h>
24 
25 
26   /**************************************************************************
27    *
28    * The macro FT_COMPONENT is used in trace mode.  It is an implicit
29    * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
30    * messages during execution.
31    */
32 #undef  FT_COMPONENT
33 #define FT_COMPONENT  bitmap
34 
35 
36   static
37   const FT_Bitmap  null_bitmap = { 0, 0, 0, NULL, 0, 0, 0, NULL };
38 
39 
40   /* documentation is in ftbitmap.h */
41 
42   FT_EXPORT_DEF( void )
FT_Bitmap_Init(FT_Bitmap * abitmap)43   FT_Bitmap_Init( FT_Bitmap  *abitmap )
44   {
45     if ( abitmap )
46       *abitmap = null_bitmap;
47   }
48 
49 
50   /* deprecated function name; retained for ABI compatibility */
51 
52   FT_EXPORT_DEF( void )
FT_Bitmap_New(FT_Bitmap * abitmap)53   FT_Bitmap_New( FT_Bitmap  *abitmap )
54   {
55     if ( abitmap )
56       *abitmap = null_bitmap;
57   }
58 
59 
60   /* documentation is in ftbitmap.h */
61 
62   FT_EXPORT_DEF( FT_Error )
FT_Bitmap_Copy(FT_Library library,const FT_Bitmap * source,FT_Bitmap * target)63   FT_Bitmap_Copy( FT_Library        library,
64                   const FT_Bitmap  *source,
65                   FT_Bitmap        *target)
66   {
67     FT_Memory  memory;
68     FT_Error   error  = FT_Err_Ok;
69 
70     FT_Int    pitch;
71     FT_ULong  size;
72 
73     FT_Int  source_pitch_sign, target_pitch_sign;
74 
75 
76     if ( !library )
77       return FT_THROW( Invalid_Library_Handle );
78 
79     if ( !source || !target )
80       return FT_THROW( Invalid_Argument );
81 
82     if ( source == target )
83       return FT_Err_Ok;
84 
85     source_pitch_sign = source->pitch < 0 ? -1 : 1;
86     target_pitch_sign = target->pitch < 0 ? -1 : 1;
87 
88     if ( !source->buffer )
89     {
90       *target = *source;
91       if ( source_pitch_sign != target_pitch_sign )
92         target->pitch = -target->pitch;
93 
94       return FT_Err_Ok;
95     }
96 
97     memory = library->memory;
98     pitch  = source->pitch;
99 
100     if ( pitch < 0 )
101       pitch = -pitch;
102     size = (FT_ULong)pitch * source->rows;
103 
104     if ( target->buffer )
105     {
106       FT_Int    target_pitch = target->pitch;
107       FT_ULong  target_size;
108 
109 
110       if ( target_pitch < 0 )
111         target_pitch = -target_pitch;
112       target_size = (FT_ULong)target_pitch * target->rows;
113 
114       if ( target_size != size )
115         (void)FT_QREALLOC( target->buffer, target_size, size );
116     }
117     else
118       (void)FT_QALLOC( target->buffer, size );
119 
120     if ( !error )
121     {
122       unsigned char *p;
123 
124 
125       p = target->buffer;
126       *target = *source;
127       target->buffer = p;
128 
129       if ( source_pitch_sign == target_pitch_sign )
130         FT_MEM_COPY( target->buffer, source->buffer, size );
131       else
132       {
133         /* take care of bitmap flow */
134         FT_UInt   i;
135         FT_Byte*  s = source->buffer;
136         FT_Byte*  t = target->buffer;
137 
138 
139         t += (FT_ULong)pitch * ( target->rows - 1 );
140 
141         for ( i = target->rows; i > 0; i-- )
142         {
143           FT_ARRAY_COPY( t, s, pitch );
144 
145           s += pitch;
146           t -= pitch;
147         }
148       }
149     }
150 
151     return error;
152   }
153 
154 
155   /* Enlarge `bitmap' horizontally and vertically by `xpixels' */
156   /* and `ypixels', respectively.                              */
157 
158   static FT_Error
ft_bitmap_assure_buffer(FT_Memory memory,FT_Bitmap * bitmap,FT_UInt xpixels,FT_UInt ypixels)159   ft_bitmap_assure_buffer( FT_Memory   memory,
160                            FT_Bitmap*  bitmap,
161                            FT_UInt     xpixels,
162                            FT_UInt     ypixels )
163   {
164     FT_Error        error;
165     unsigned int    pitch;
166     unsigned int    new_pitch;
167     FT_UInt         bpp;
168     FT_UInt         width, height;
169     unsigned char*  buffer = NULL;
170 
171 
172     width  = bitmap->width;
173     height = bitmap->rows;
174     pitch  = (unsigned int)FT_ABS( bitmap->pitch );
175 
176     switch ( bitmap->pixel_mode )
177     {
178     case FT_PIXEL_MODE_MONO:
179       bpp       = 1;
180       new_pitch = ( width + xpixels + 7 ) >> 3;
181       break;
182     case FT_PIXEL_MODE_GRAY2:
183       bpp       = 2;
184       new_pitch = ( width + xpixels + 3 ) >> 2;
185       break;
186     case FT_PIXEL_MODE_GRAY4:
187       bpp       = 4;
188       new_pitch = ( width + xpixels + 1 ) >> 1;
189       break;
190     case FT_PIXEL_MODE_GRAY:
191     case FT_PIXEL_MODE_LCD:
192     case FT_PIXEL_MODE_LCD_V:
193       bpp       = 8;
194       new_pitch = width + xpixels;
195       break;
196     default:
197       return FT_THROW( Invalid_Glyph_Format );
198     }
199 
200     /* if no need to allocate memory */
201     if ( ypixels == 0 && new_pitch <= pitch )
202     {
203       /* zero the padding */
204       FT_UInt  bit_width = pitch * 8;
205       FT_UInt  bit_last  = ( width + xpixels ) * bpp;
206 
207 
208       if ( bit_last < bit_width )
209       {
210         FT_Byte*  line  = bitmap->buffer + ( bit_last >> 3 );
211         FT_Byte*  end   = bitmap->buffer + pitch;
212         FT_UInt   shift = bit_last & 7;
213         FT_UInt   mask  = 0xFF00U >> shift;
214         FT_UInt   count = height;
215 
216 
217         for ( ; count > 0; count--, line += pitch, end += pitch )
218         {
219           FT_Byte*  write = line;
220 
221 
222           if ( shift > 0 )
223           {
224             write[0] = (FT_Byte)( write[0] & mask );
225             write++;
226           }
227           if ( write < end )
228             FT_MEM_ZERO( write, end - write );
229         }
230       }
231 
232       return FT_Err_Ok;
233     }
234 
235     /* otherwise allocate new buffer */
236     if ( FT_QALLOC_MULT( buffer, bitmap->rows + ypixels, new_pitch ) )
237       return error;
238 
239     /* new rows get added at the top of the bitmap, */
240     /* thus take care of the flow direction         */
241     if ( bitmap->pitch > 0 )
242     {
243       FT_UInt  len = ( width * bpp + 7 ) >> 3;
244 
245       unsigned char*  in  = bitmap->buffer;
246       unsigned char*  out = buffer;
247 
248       unsigned char*  limit = bitmap->buffer + pitch * bitmap->rows;
249       unsigned int    delta = new_pitch - len;
250 
251 
252       FT_MEM_ZERO( out, new_pitch * ypixels );
253       out += new_pitch * ypixels;
254 
255       while ( in < limit )
256       {
257         FT_MEM_COPY( out, in, len );
258         in  += pitch;
259         out += len;
260 
261         /* we use FT_QALLOC_MULT, which doesn't zero out the buffer;      */
262         /* consequently, we have to manually zero out the remaining bytes */
263         FT_MEM_ZERO( out, delta );
264         out += delta;
265       }
266     }
267     else
268     {
269       FT_UInt  len = ( width * bpp + 7 ) >> 3;
270 
271       unsigned char*  in  = bitmap->buffer;
272       unsigned char*  out = buffer;
273 
274       unsigned char*  limit = bitmap->buffer + pitch * bitmap->rows;
275       unsigned int    delta = new_pitch - len;
276 
277 
278       while ( in < limit )
279       {
280         FT_MEM_COPY( out, in, len );
281         in  += pitch;
282         out += len;
283 
284         FT_MEM_ZERO( out, delta );
285         out += delta;
286       }
287 
288       FT_MEM_ZERO( out, new_pitch * ypixels );
289     }
290 
291     FT_FREE( bitmap->buffer );
292     bitmap->buffer = buffer;
293 
294     /* set pitch only, width and height are left untouched */
295     if ( bitmap->pitch < 0 )
296       bitmap->pitch = -(int)new_pitch;
297     else
298       bitmap->pitch = (int)new_pitch;
299 
300     return FT_Err_Ok;
301   }
302 
303 
304   /* documentation is in ftbitmap.h */
305 
306   FT_EXPORT_DEF( FT_Error )
FT_Bitmap_Embolden(FT_Library library,FT_Bitmap * bitmap,FT_Pos xStrength,FT_Pos yStrength)307   FT_Bitmap_Embolden( FT_Library  library,
308                       FT_Bitmap*  bitmap,
309                       FT_Pos      xStrength,
310                       FT_Pos      yStrength )
311   {
312     FT_Error        error;
313     unsigned char*  p;
314     FT_Int          i, x, pitch;
315     FT_UInt         y;
316     FT_Int          xstr, ystr;
317 
318 
319     if ( !library )
320       return FT_THROW( Invalid_Library_Handle );
321 
322     if ( !bitmap || !bitmap->buffer )
323       return FT_THROW( Invalid_Argument );
324 
325     if ( ( ( FT_PIX_ROUND( xStrength ) >> 6 ) > FT_INT_MAX ) ||
326          ( ( FT_PIX_ROUND( yStrength ) >> 6 ) > FT_INT_MAX ) )
327       return FT_THROW( Invalid_Argument );
328 
329     xstr = (FT_Int)FT_PIX_ROUND( xStrength ) >> 6;
330     ystr = (FT_Int)FT_PIX_ROUND( yStrength ) >> 6;
331 
332     if ( xstr == 0 && ystr == 0 )
333       return FT_Err_Ok;
334     else if ( xstr < 0 || ystr < 0 )
335       return FT_THROW( Invalid_Argument );
336 
337     switch ( bitmap->pixel_mode )
338     {
339     case FT_PIXEL_MODE_GRAY2:
340     case FT_PIXEL_MODE_GRAY4:
341       {
342         FT_Bitmap  tmp;
343 
344 
345         /* convert to 8bpp */
346         FT_Bitmap_Init( &tmp );
347         error = FT_Bitmap_Convert( library, bitmap, &tmp, 1 );
348         if ( error )
349           return error;
350 
351         FT_Bitmap_Done( library, bitmap );
352         *bitmap = tmp;
353       }
354       break;
355 
356     case FT_PIXEL_MODE_MONO:
357       if ( xstr > 8 )
358         xstr = 8;
359       break;
360 
361     case FT_PIXEL_MODE_LCD:
362       xstr *= 3;
363       break;
364 
365     case FT_PIXEL_MODE_LCD_V:
366       ystr *= 3;
367       break;
368 
369     case FT_PIXEL_MODE_BGRA:
370       /* We don't embolden color glyphs. */
371       return FT_Err_Ok;
372     }
373 
374     error = ft_bitmap_assure_buffer( library->memory, bitmap,
375                                      (FT_UInt)xstr, (FT_UInt)ystr );
376     if ( error )
377       return error;
378 
379     /* take care of bitmap flow */
380     pitch = bitmap->pitch;
381     if ( pitch > 0 )
382       p = bitmap->buffer + pitch * ystr;
383     else
384     {
385       pitch = -pitch;
386       p = bitmap->buffer + (FT_UInt)pitch * ( bitmap->rows - 1 );
387     }
388 
389     /* for each row */
390     for ( y = 0; y < bitmap->rows; y++ )
391     {
392       /*
393        * Horizontally:
394        *
395        * From the last pixel on, make each pixel or'ed with the
396        * `xstr' pixels before it.
397        */
398       for ( x = pitch - 1; x >= 0; x-- )
399       {
400         unsigned char  tmp;
401 
402 
403         tmp = p[x];
404         for ( i = 1; i <= xstr; i++ )
405         {
406           if ( bitmap->pixel_mode == FT_PIXEL_MODE_MONO )
407           {
408             p[x] |= tmp >> i;
409 
410             /* the maximum value of 8 for `xstr' comes from here */
411             if ( x > 0 )
412               p[x] |= p[x - 1] << ( 8 - i );
413 
414 #if 0
415             if ( p[x] == 0xFF )
416               break;
417 #endif
418           }
419           else
420           {
421             if ( x - i >= 0 )
422             {
423               if ( p[x] + p[x - i] > bitmap->num_grays - 1 )
424               {
425                 p[x] = (unsigned char)( bitmap->num_grays - 1 );
426                 break;
427               }
428               else
429               {
430                 p[x] = (unsigned char)( p[x] + p[x - i] );
431                 if ( p[x] == bitmap->num_grays - 1 )
432                   break;
433               }
434             }
435             else
436               break;
437           }
438         }
439       }
440 
441       /*
442        * Vertically:
443        *
444        * Make the above `ystr' rows or'ed with it.
445        */
446       for ( x = 1; x <= ystr; x++ )
447       {
448         unsigned char*  q;
449 
450 
451         q = p - bitmap->pitch * x;
452         for ( i = 0; i < pitch; i++ )
453           q[i] |= p[i];
454       }
455 
456       p += bitmap->pitch;
457     }
458 
459     bitmap->width += (FT_UInt)xstr;
460     bitmap->rows += (FT_UInt)ystr;
461 
462     return FT_Err_Ok;
463   }
464 
465 
466   static FT_Byte
ft_gray_for_premultiplied_srgb_bgra(const FT_Byte * bgra)467   ft_gray_for_premultiplied_srgb_bgra( const FT_Byte*  bgra )
468   {
469     FT_UInt  a = bgra[3];
470     FT_UInt  l;
471 
472 
473     /* Short-circuit transparent color to avoid division by zero. */
474     if ( !a )
475       return 0;
476 
477     /*
478      * Luminosity for sRGB is defined using ~0.2126,0.7152,0.0722
479      * coefficients for RGB channels *on the linear colors*.
480      * A gamma of 2.2 is fair to assume.  And then, we need to
481      * undo the premultiplication too.
482      *
483      *   https://accessibility.kde.org/hsl-adjusted.php
484      *
485      * We do the computation with integers only, applying a gamma of 2.0.
486      * We guarantee 32-bit arithmetic to avoid overflow but the resulting
487      * luminosity fits into 16 bits.
488      *
489      */
490 
491     l = (  4732UL /* 0.0722 * 65536 */ * bgra[0] * bgra[0] +
492           46871UL /* 0.7152 * 65536 */ * bgra[1] * bgra[1] +
493           13933UL /* 0.2126 * 65536 */ * bgra[2] * bgra[2] ) >> 16;
494 
495     /*
496      * Final transparency can be determined as follows.
497      *
498      * - If alpha is zero, we want 0.
499      * - If alpha is zero and luminosity is zero, we want 255.
500      * - If alpha is zero and luminosity is one, we want 0.
501      *
502      * So the formula is a * (1 - l) = a - l * a.
503      *
504      * We still need to undo premultiplication by dividing l by a*a.
505      *
506      */
507 
508     return (FT_Byte)( a - l / a );
509   }
510 
511 
512   /* documentation is in ftbitmap.h */
513 
514   FT_EXPORT_DEF( FT_Error )
FT_Bitmap_Convert(FT_Library library,const FT_Bitmap * source,FT_Bitmap * target,FT_Int alignment)515   FT_Bitmap_Convert( FT_Library        library,
516                      const FT_Bitmap  *source,
517                      FT_Bitmap        *target,
518                      FT_Int            alignment )
519   {
520     FT_Error   error = FT_Err_Ok;
521     FT_Memory  memory;
522 
523     FT_Byte*  s;
524     FT_Byte*  t;
525 
526 
527     if ( !library )
528       return FT_THROW( Invalid_Library_Handle );
529 
530     if ( !source || !target )
531       return FT_THROW( Invalid_Argument );
532 
533     memory = library->memory;
534 
535     switch ( source->pixel_mode )
536     {
537     case FT_PIXEL_MODE_MONO:
538     case FT_PIXEL_MODE_GRAY:
539     case FT_PIXEL_MODE_GRAY2:
540     case FT_PIXEL_MODE_GRAY4:
541     case FT_PIXEL_MODE_LCD:
542     case FT_PIXEL_MODE_LCD_V:
543     case FT_PIXEL_MODE_BGRA:
544       {
545         FT_Int    pad, old_target_pitch, target_pitch;
546         FT_ULong  old_size;
547 
548 
549         old_target_pitch = target->pitch;
550         if ( old_target_pitch < 0 )
551           old_target_pitch = -old_target_pitch;
552 
553         old_size = target->rows * (FT_UInt)old_target_pitch;
554 
555         target->pixel_mode = FT_PIXEL_MODE_GRAY;
556         target->rows       = source->rows;
557         target->width      = source->width;
558 
559         pad = 0;
560         if ( alignment > 0 )
561         {
562           pad = (FT_Int)source->width % alignment;
563           if ( pad != 0 )
564             pad = alignment - pad;
565         }
566 
567         target_pitch = (FT_Int)source->width + pad;
568 
569         if ( target_pitch > 0                                               &&
570              (FT_ULong)target->rows > FT_ULONG_MAX / (FT_ULong)target_pitch )
571           return FT_THROW( Invalid_Argument );
572 
573         if ( FT_QREALLOC( target->buffer,
574                           old_size, target->rows * (FT_UInt)target_pitch ) )
575           return error;
576 
577         target->pitch = target->pitch < 0 ? -target_pitch : target_pitch;
578       }
579       break;
580 
581     default:
582       error = FT_THROW( Invalid_Argument );
583     }
584 
585     s = source->buffer;
586     t = target->buffer;
587 
588     /* take care of bitmap flow */
589     if ( source->pitch < 0 )
590       s -= source->pitch * (FT_Int)( source->rows - 1 );
591     if ( target->pitch < 0 )
592       t -= target->pitch * (FT_Int)( target->rows - 1 );
593 
594     switch ( source->pixel_mode )
595     {
596     case FT_PIXEL_MODE_MONO:
597       {
598         FT_UInt  i;
599 
600 
601         target->num_grays = 2;
602 
603         for ( i = source->rows; i > 0; i-- )
604         {
605           FT_Byte*  ss = s;
606           FT_Byte*  tt = t;
607           FT_UInt   j;
608 
609 
610           /* get the full bytes */
611           for ( j = source->width >> 3; j > 0; j-- )
612           {
613             FT_Int  val = ss[0]; /* avoid a byte->int cast on each line */
614 
615 
616             tt[0] = (FT_Byte)( ( val & 0x80 ) >> 7 );
617             tt[1] = (FT_Byte)( ( val & 0x40 ) >> 6 );
618             tt[2] = (FT_Byte)( ( val & 0x20 ) >> 5 );
619             tt[3] = (FT_Byte)( ( val & 0x10 ) >> 4 );
620             tt[4] = (FT_Byte)( ( val & 0x08 ) >> 3 );
621             tt[5] = (FT_Byte)( ( val & 0x04 ) >> 2 );
622             tt[6] = (FT_Byte)( ( val & 0x02 ) >> 1 );
623             tt[7] = (FT_Byte)(   val & 0x01 );
624 
625             tt += 8;
626             ss += 1;
627           }
628 
629           /* get remaining pixels (if any) */
630           j = source->width & 7;
631           if ( j > 0 )
632           {
633             FT_Int  val = *ss;
634 
635 
636             for ( ; j > 0; j-- )
637             {
638               tt[0] = (FT_Byte)( ( val & 0x80 ) >> 7);
639               val <<= 1;
640               tt   += 1;
641             }
642           }
643 
644           s += source->pitch;
645           t += target->pitch;
646         }
647       }
648       break;
649 
650 
651     case FT_PIXEL_MODE_GRAY:
652     case FT_PIXEL_MODE_LCD:
653     case FT_PIXEL_MODE_LCD_V:
654       {
655         FT_UInt  width = source->width;
656         FT_UInt  i;
657 
658 
659         target->num_grays = 256;
660 
661         for ( i = source->rows; i > 0; i-- )
662         {
663           FT_ARRAY_COPY( t, s, width );
664 
665           s += source->pitch;
666           t += target->pitch;
667         }
668       }
669       break;
670 
671 
672     case FT_PIXEL_MODE_GRAY2:
673       {
674         FT_UInt  i;
675 
676 
677         target->num_grays = 4;
678 
679         for ( i = source->rows; i > 0; i-- )
680         {
681           FT_Byte*  ss = s;
682           FT_Byte*  tt = t;
683           FT_UInt   j;
684 
685 
686           /* get the full bytes */
687           for ( j = source->width >> 2; j > 0; j-- )
688           {
689             FT_Int  val = ss[0];
690 
691 
692             tt[0] = (FT_Byte)( ( val & 0xC0 ) >> 6 );
693             tt[1] = (FT_Byte)( ( val & 0x30 ) >> 4 );
694             tt[2] = (FT_Byte)( ( val & 0x0C ) >> 2 );
695             tt[3] = (FT_Byte)( ( val & 0x03 ) );
696 
697             ss += 1;
698             tt += 4;
699           }
700 
701           j = source->width & 3;
702           if ( j > 0 )
703           {
704             FT_Int  val = ss[0];
705 
706 
707             for ( ; j > 0; j-- )
708             {
709               tt[0]  = (FT_Byte)( ( val & 0xC0 ) >> 6 );
710               val  <<= 2;
711               tt    += 1;
712             }
713           }
714 
715           s += source->pitch;
716           t += target->pitch;
717         }
718       }
719       break;
720 
721 
722     case FT_PIXEL_MODE_GRAY4:
723       {
724         FT_UInt  i;
725 
726 
727         target->num_grays = 16;
728 
729         for ( i = source->rows; i > 0; i-- )
730         {
731           FT_Byte*  ss = s;
732           FT_Byte*  tt = t;
733           FT_UInt   j;
734 
735 
736           /* get the full bytes */
737           for ( j = source->width >> 1; j > 0; j-- )
738           {
739             FT_Int  val = ss[0];
740 
741 
742             tt[0] = (FT_Byte)( ( val & 0xF0 ) >> 4 );
743             tt[1] = (FT_Byte)( ( val & 0x0F ) );
744 
745             ss += 1;
746             tt += 2;
747           }
748 
749           if ( source->width & 1 )
750             tt[0] = (FT_Byte)( ( ss[0] & 0xF0 ) >> 4 );
751 
752           s += source->pitch;
753           t += target->pitch;
754         }
755       }
756       break;
757 
758 
759     case FT_PIXEL_MODE_BGRA:
760       {
761         FT_UInt  i;
762 
763 
764         target->num_grays = 256;
765 
766         for ( i = source->rows; i > 0; i-- )
767         {
768           FT_Byte*  ss = s;
769           FT_Byte*  tt = t;
770           FT_UInt   j;
771 
772 
773           for ( j = source->width; j > 0; j-- )
774           {
775             tt[0] = ft_gray_for_premultiplied_srgb_bgra( ss );
776 
777             ss += 4;
778             tt += 1;
779           }
780 
781           s += source->pitch;
782           t += target->pitch;
783         }
784       }
785       break;
786 
787     default:
788       ;
789     }
790 
791     return error;
792   }
793 
794 
795   /* documentation is in ftbitmap.h */
796 
797   FT_EXPORT_DEF( FT_Error )
FT_Bitmap_Blend(FT_Library library,const FT_Bitmap * source_,const FT_Vector source_offset_,FT_Bitmap * target,FT_Vector * atarget_offset,FT_Color color)798   FT_Bitmap_Blend( FT_Library        library,
799                    const FT_Bitmap*  source_,
800                    const FT_Vector   source_offset_,
801                    FT_Bitmap*        target,
802                    FT_Vector        *atarget_offset,
803                    FT_Color          color )
804   {
805     FT_Error   error = FT_Err_Ok;
806     FT_Memory  memory;
807 
808     FT_Bitmap         source_bitmap;
809     const FT_Bitmap*  source;
810 
811     FT_Vector  source_offset;
812     FT_Vector  target_offset;
813 
814     FT_Bool  free_source_bitmap          = 0;
815     FT_Bool  free_target_bitmap_on_error = 0;
816 
817     FT_Pos  source_llx, source_lly, source_urx, source_ury;
818     FT_Pos  target_llx, target_lly, target_urx, target_ury;
819     FT_Pos  final_llx, final_lly, final_urx, final_ury;
820 
821     unsigned int  final_rows, final_width;
822     long          x, y;
823 
824 
825     if ( !library || !target || !source_ || !atarget_offset )
826       return FT_THROW( Invalid_Argument );
827 
828     memory = library->memory;
829 
830     if ( !( target->pixel_mode == FT_PIXEL_MODE_NONE     ||
831             ( target->pixel_mode == FT_PIXEL_MODE_BGRA &&
832               target->buffer                           ) ) )
833       return FT_THROW( Invalid_Argument );
834 
835     if ( source_->pixel_mode == FT_PIXEL_MODE_NONE )
836       return FT_Err_Ok;               /* nothing to do */
837 
838     /* pitches must have the same sign */
839     if ( target->pixel_mode == FT_PIXEL_MODE_BGRA &&
840          ( source_->pitch ^ target->pitch ) < 0   )
841       return FT_THROW( Invalid_Argument );
842 
843     if ( !( source_->width && source_->rows ) )
844       return FT_Err_Ok;               /* nothing to do */
845 
846     /* assure integer pixel offsets */
847     source_offset.x = FT_PIX_FLOOR( source_offset_.x );
848     source_offset.y = FT_PIX_FLOOR( source_offset_.y );
849     target_offset.x = FT_PIX_FLOOR( atarget_offset->x );
850     target_offset.y = FT_PIX_FLOOR( atarget_offset->y );
851 
852     /* get source bitmap dimensions */
853     source_llx = source_offset.x;
854     if ( FT_LONG_MIN + (FT_Pos)( source_->rows << 6 ) + 64 > source_offset.y )
855     {
856       FT_TRACE5((
857         "FT_Bitmap_Blend: y coordinate overflow in source bitmap\n" ));
858       return FT_THROW( Invalid_Argument );
859     }
860     source_lly = source_offset.y - ( source_->rows << 6 );
861 
862     if ( FT_LONG_MAX - (FT_Pos)( source_->width << 6 ) - 64 < source_llx )
863     {
864       FT_TRACE5((
865         "FT_Bitmap_Blend: x coordinate overflow in source bitmap\n" ));
866       return FT_THROW( Invalid_Argument );
867     }
868     source_urx = source_llx + ( source_->width << 6 );
869     source_ury = source_offset.y;
870 
871     /* get target bitmap dimensions */
872     if ( target->width && target->rows )
873     {
874       target_llx = target_offset.x;
875       if ( FT_LONG_MIN + (FT_Pos)( target->rows << 6 ) > target_offset.y )
876       {
877         FT_TRACE5((
878           "FT_Bitmap_Blend: y coordinate overflow in target bitmap\n" ));
879         return FT_THROW( Invalid_Argument );
880       }
881       target_lly = target_offset.y - ( target->rows << 6 );
882 
883       if ( FT_LONG_MAX - (FT_Pos)( target->width << 6 ) < target_llx )
884       {
885         FT_TRACE5((
886           "FT_Bitmap_Blend: x coordinate overflow in target bitmap\n" ));
887         return FT_THROW( Invalid_Argument );
888       }
889       target_urx = target_llx + ( target->width << 6 );
890       target_ury = target_offset.y;
891     }
892     else
893     {
894       target_llx = FT_LONG_MAX;
895       target_lly = FT_LONG_MAX;
896       target_urx = FT_LONG_MIN;
897       target_ury = FT_LONG_MIN;
898     }
899 
900     /* compute final bitmap dimensions */
901     final_llx = FT_MIN( source_llx, target_llx );
902     final_lly = FT_MIN( source_lly, target_lly );
903     final_urx = FT_MAX( source_urx, target_urx );
904     final_ury = FT_MAX( source_ury, target_ury );
905 
906     final_width = ( final_urx - final_llx ) >> 6;
907     final_rows  = ( final_ury - final_lly ) >> 6;
908 
909 #ifdef FT_DEBUG_LEVEL_TRACE
910     FT_TRACE5(( "FT_Bitmap_Blend:\n"
911                 "  source bitmap: (%ld, %ld) -- (%ld, %ld); %d x %d\n",
912       source_llx / 64, source_lly / 64,
913       source_urx / 64, source_ury / 64,
914       source_->width, source_->rows ));
915 
916     if ( target->width && target->rows )
917       FT_TRACE5(( "  target bitmap: (%ld, %ld) -- (%ld, %ld); %d x %d\n",
918         target_llx / 64, target_lly / 64,
919         target_urx / 64, target_ury / 64,
920         target->width, target->rows ));
921     else
922       FT_TRACE5(( "  target bitmap: empty\n" ));
923 
924     if ( final_width && final_rows )
925       FT_TRACE5(( "  final bitmap: (%ld, %ld) -- (%ld, %ld); %d x %d\n",
926         final_llx / 64, final_lly / 64,
927         final_urx / 64, final_ury / 64,
928         final_width, final_rows ));
929     else
930       FT_TRACE5(( "  final bitmap: empty\n" ));
931 #endif /* FT_DEBUG_LEVEL_TRACE */
932 
933     if ( !( final_width && final_rows ) )
934       return FT_Err_Ok;               /* nothing to do */
935 
936     /* for blending, set offset vector of final bitmap */
937     /* temporarily to (0,0)                            */
938     source_llx -= final_llx;
939     source_lly -= final_lly;
940 
941     if ( target->width && target->rows )
942     {
943       target_llx -= final_llx;
944       target_lly -= final_lly;
945     }
946 
947     /* set up target bitmap */
948     if ( target->pixel_mode == FT_PIXEL_MODE_NONE )
949     {
950       /* create new empty bitmap */
951       target->width      = final_width;
952       target->rows       = final_rows;
953       target->pixel_mode = FT_PIXEL_MODE_BGRA;
954       target->pitch      = (int)final_width * 4;
955       target->num_grays  = 256;
956 
957       if ( FT_LONG_MAX / target->pitch < (int)target->rows )
958       {
959         FT_TRACE5(( "FT_Blend_Bitmap: target bitmap too large (%d x %d)\n",
960                      final_width, final_rows ));
961         return FT_THROW( Invalid_Argument );
962       }
963 
964       if ( FT_ALLOC( target->buffer, target->pitch * (int)target->rows ) )
965         return error;
966 
967       free_target_bitmap_on_error = 1;
968     }
969     else if ( target->width != final_width ||
970               target->rows  != final_rows  )
971     {
972       /* adjust old bitmap to enlarged size */
973       int  pitch, new_pitch;
974 
975       unsigned char*  buffer = NULL;
976 
977 
978       pitch = target->pitch;
979 
980       if ( pitch < 0 )
981         pitch = -pitch;
982 
983       new_pitch = (int)final_width * 4;
984 
985       if ( FT_LONG_MAX / new_pitch < (int)final_rows )
986       {
987         FT_TRACE5(( "FT_Blend_Bitmap: target bitmap too large (%d x %d)\n",
988                      final_width, final_rows ));
989         return FT_THROW( Invalid_Argument );
990       }
991 
992       /* TODO: provide an in-buffer solution for large bitmaps */
993       /*       to avoid allocation of a new buffer             */
994       if ( FT_ALLOC( buffer, new_pitch * (int)final_rows ) )
995         goto Error;
996 
997       /* copy data to new buffer */
998       x = target_llx >> 6;
999       y = target_lly >> 6;
1000 
1001       /* the bitmap flow is from top to bottom, */
1002       /* but y is measured from bottom to top   */
1003       if ( target->pitch < 0 )
1004       {
1005         /* XXX */
1006       }
1007       else
1008       {
1009         unsigned char*  p =
1010           target->buffer;
1011         unsigned char*  q =
1012           buffer +
1013           ( final_rows - y - target->rows ) * new_pitch +
1014           x * 4;
1015         unsigned char*  limit_p =
1016           p + pitch * (int)target->rows;
1017 
1018 
1019         while ( p < limit_p )
1020         {
1021           FT_MEM_COPY( q, p, pitch );
1022 
1023           p += pitch;
1024           q += new_pitch;
1025         }
1026       }
1027 
1028       FT_FREE( target->buffer );
1029 
1030       target->width = final_width;
1031       target->rows  = final_rows;
1032 
1033       if ( target->pitch < 0 )
1034         target->pitch = -new_pitch;
1035       else
1036         target->pitch = new_pitch;
1037 
1038       target->buffer = buffer;
1039     }
1040 
1041     /* adjust source bitmap if necessary */
1042     if ( source_->pixel_mode != FT_PIXEL_MODE_GRAY )
1043     {
1044       FT_Bitmap_Init( &source_bitmap );
1045       error = FT_Bitmap_Convert( library, source_, &source_bitmap, 1 );
1046       if ( error )
1047         goto Error;
1048 
1049       source             = &source_bitmap;
1050       free_source_bitmap = 1;
1051     }
1052     else
1053       source = source_;
1054 
1055     /* do blending; the code below returns pre-multiplied channels, */
1056     /* similar to what FreeType gets from `CBDT' tables             */
1057     x = source_llx >> 6;
1058     y = source_lly >> 6;
1059 
1060     /* the bitmap flow is from top to bottom, */
1061     /* but y is measured from bottom to top   */
1062     if ( target->pitch < 0 )
1063     {
1064       /* XXX */
1065     }
1066     else
1067     {
1068       unsigned char*  p =
1069         source->buffer;
1070       unsigned char*  q =
1071         target->buffer +
1072         ( target->rows - y - source->rows ) * target->pitch +
1073         x * 4;
1074       unsigned char*  limit_p =
1075         p + source->pitch * (int)source->rows;
1076 
1077 
1078       while ( p < limit_p )
1079       {
1080         unsigned char*  r       = p;
1081         unsigned char*  s       = q;
1082         unsigned char*  limit_r = r + source->width;
1083 
1084 
1085         while ( r < limit_r )
1086         {
1087           int  aa = *r++;
1088           int  fa = color.alpha * aa / 255;
1089 
1090           int  fb = color.blue * fa / 255;
1091           int  fg = color.green * fa / 255;
1092           int  fr = color.red * fa / 255;
1093 
1094           int  ba2 = 255 - fa;
1095 
1096           int  bb = s[0];
1097           int  bg = s[1];
1098           int  br = s[2];
1099           int  ba = s[3];
1100 
1101 
1102           *s++ = (unsigned char)( bb * ba2 / 255 + fb );
1103           *s++ = (unsigned char)( bg * ba2 / 255 + fg );
1104           *s++ = (unsigned char)( br * ba2 / 255 + fr );
1105           *s++ = (unsigned char)( ba * ba2 / 255 + fa );
1106         }
1107 
1108         p += source->pitch;
1109         q += target->pitch;
1110       }
1111     }
1112 
1113     atarget_offset->x = final_llx;
1114     atarget_offset->y = final_lly + ( final_rows << 6 );
1115 
1116   Error:
1117     if ( error && free_target_bitmap_on_error )
1118       FT_Bitmap_Done( library, target );
1119 
1120     if ( free_source_bitmap )
1121       FT_Bitmap_Done( library, &source_bitmap );
1122 
1123     return error;
1124   }
1125 
1126 
1127   /* documentation is in ftbitmap.h */
1128 
1129   FT_EXPORT_DEF( FT_Error )
FT_GlyphSlot_Own_Bitmap(FT_GlyphSlot slot)1130   FT_GlyphSlot_Own_Bitmap( FT_GlyphSlot  slot )
1131   {
1132     if ( slot && slot->format == FT_GLYPH_FORMAT_BITMAP   &&
1133          !( slot->internal->flags & FT_GLYPH_OWN_BITMAP ) )
1134     {
1135       FT_Bitmap  bitmap;
1136       FT_Error   error;
1137 
1138 
1139       FT_Bitmap_Init( &bitmap );
1140       error = FT_Bitmap_Copy( slot->library, &slot->bitmap, &bitmap );
1141       if ( error )
1142         return error;
1143 
1144       slot->bitmap = bitmap;
1145       slot->internal->flags |= FT_GLYPH_OWN_BITMAP;
1146     }
1147 
1148     return FT_Err_Ok;
1149   }
1150 
1151 
1152   /* documentation is in ftbitmap.h */
1153 
1154   FT_EXPORT_DEF( FT_Error )
FT_Bitmap_Done(FT_Library library,FT_Bitmap * bitmap)1155   FT_Bitmap_Done( FT_Library  library,
1156                   FT_Bitmap  *bitmap )
1157   {
1158     FT_Memory  memory;
1159 
1160 
1161     if ( !library )
1162       return FT_THROW( Invalid_Library_Handle );
1163 
1164     if ( !bitmap )
1165       return FT_THROW( Invalid_Argument );
1166 
1167     memory = library->memory;
1168 
1169     FT_FREE( bitmap->buffer );
1170     *bitmap = null_bitmap;
1171 
1172     return FT_Err_Ok;
1173   }
1174 
1175 
1176 /* END */
1177