aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/core/SkBlitter_RGB16.cpp
blob: 8a4d454e9ba5eba8c5f2f25fa65d5e26e8e04807 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065

/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#include "SkBlitRow.h"
#include "SkCoreBlitters.h"
#include "SkColorPriv.h"
#include "SkDither.h"
#include "SkShader.h"
#include "SkTemplatesPriv.h"
#include "SkUtils.h"
#include "SkXfermode.h"

#if defined(__ARM_HAVE_NEON) && defined(SK_CPU_LENDIAN)
    #define SK_USE_NEON
    #include <arm_neon.h>
#else
    // if we don't have neon, then our black blitter is worth the extra code
    #define USE_BLACK_BLITTER
#endif

void sk_dither_memset16(uint16_t dst[], uint16_t value, uint16_t other,
                        int count) {
    if (count > 0) {
        // see if we need to write one short before we can cast to an 4byte ptr
        // (we do this subtract rather than (unsigned)dst so we don't get warnings
        //  on 64bit machines)
        if (((char*)dst - (char*)0) & 2) {
            *dst++ = value;
            count -= 1;
            SkTSwap(value, other);
        }
        
        // fast way to set [value,other] pairs
#ifdef SK_CPU_BENDIAN
        sk_memset32((uint32_t*)dst, (value << 16) | other, count >> 1);
#else
        sk_memset32((uint32_t*)dst, (other << 16) | value, count >> 1);
#endif
        
        if (count & 1) {
            dst[count - 1] = value;
        }
    }
}

///////////////////////////////////////////////////////////////////////////////

class SkRGB16_Blitter : public SkRasterBlitter {
public:
    SkRGB16_Blitter(const SkBitmap& device, const SkPaint& paint);
    virtual void blitH(int x, int y, int width);
    virtual void blitAntiH(int x, int y, const SkAlpha* antialias,
                           const int16_t* runs);
    virtual void blitV(int x, int y, int height, SkAlpha alpha);
    virtual void blitRect(int x, int y, int width, int height);
    virtual void blitMask(const SkMask&,
                          const SkIRect&);
    virtual const SkBitmap* justAnOpaqueColor(uint32_t*);
    
protected:
    SkPMColor   fSrcColor32;
    uint32_t    fExpandedRaw16;
    unsigned    fScale;
    uint16_t    fColor16;       // already scaled by fScale
    uint16_t    fRawColor16;    // unscaled
    uint16_t    fRawDither16;   // unscaled
    SkBool8     fDoDither;
    
    // illegal
    SkRGB16_Blitter& operator=(const SkRGB16_Blitter&);
    
    typedef SkRasterBlitter INHERITED;
};

class SkRGB16_Opaque_Blitter : public SkRGB16_Blitter {
public:
    SkRGB16_Opaque_Blitter(const SkBitmap& device, const SkPaint& paint);
    virtual void blitH(int x, int y, int width);
    virtual void blitAntiH(int x, int y, const SkAlpha* antialias,
                           const int16_t* runs);
    virtual void blitV(int x, int y, int height, SkAlpha alpha);
    virtual void blitRect(int x, int y, int width, int height);
    virtual void blitMask(const SkMask&,
                          const SkIRect&);
    
private:
    typedef SkRGB16_Blitter INHERITED;
};

#ifdef USE_BLACK_BLITTER
class SkRGB16_Black_Blitter : public SkRGB16_Opaque_Blitter {
public:
    SkRGB16_Black_Blitter(const SkBitmap& device, const SkPaint& paint);
    virtual void blitMask(const SkMask&, const SkIRect&);
    virtual void blitAntiH(int x, int y, const SkAlpha* antialias,
                           const int16_t* runs);
    
private:
    typedef SkRGB16_Opaque_Blitter INHERITED;
};
#endif

class SkRGB16_Shader_Blitter : public SkShaderBlitter {
public:
    SkRGB16_Shader_Blitter(const SkBitmap& device, const SkPaint& paint);
    virtual ~SkRGB16_Shader_Blitter();
    virtual void blitH(int x, int y, int width);
    virtual void blitAntiH(int x, int y, const SkAlpha* antialias,
                           const int16_t* runs);
    virtual void blitRect(int x, int y, int width, int height);
    
protected:
    SkPMColor*      fBuffer;
    SkBlitRow::Proc fOpaqueProc;
    SkBlitRow::Proc fAlphaProc;
    
private:
    // illegal
    SkRGB16_Shader_Blitter& operator=(const SkRGB16_Shader_Blitter&);
    
    typedef SkShaderBlitter INHERITED;
};

// used only if the shader can perform shadSpan16
class SkRGB16_Shader16_Blitter : public SkRGB16_Shader_Blitter {
public:
    SkRGB16_Shader16_Blitter(const SkBitmap& device, const SkPaint& paint);
    virtual void blitH(int x, int y, int width);
    virtual void blitAntiH(int x, int y, const SkAlpha* antialias,
                           const int16_t* runs);
    virtual void blitRect(int x, int y, int width, int height);
    
private:
    typedef SkRGB16_Shader_Blitter INHERITED;
};

class SkRGB16_Shader_Xfermode_Blitter : public SkShaderBlitter {
public:
    SkRGB16_Shader_Xfermode_Blitter(const SkBitmap& device, const SkPaint& paint);
    virtual ~SkRGB16_Shader_Xfermode_Blitter();
    virtual void blitH(int x, int y, int width);
    virtual void blitAntiH(int x, int y, const SkAlpha* antialias,
                           const int16_t* runs);
    
private:
    SkXfermode* fXfermode;
    SkPMColor*  fBuffer;
    uint8_t*    fAAExpand;
    
    // illegal
    SkRGB16_Shader_Xfermode_Blitter& operator=(const SkRGB16_Shader_Xfermode_Blitter&);
    
    typedef SkShaderBlitter INHERITED;
};

///////////////////////////////////////////////////////////////////////////////
#ifdef USE_BLACK_BLITTER
SkRGB16_Black_Blitter::SkRGB16_Black_Blitter(const SkBitmap& device, const SkPaint& paint)
    : INHERITED(device, paint) {
    SkASSERT(paint.getShader() == NULL);
    SkASSERT(paint.getColorFilter() == NULL);
    SkASSERT(paint.getXfermode() == NULL);
    SkASSERT(paint.getColor() == SK_ColorBLACK);
}

#if 1
#define black_8_pixels(mask, dst)       \
    do {                                \
        if (mask & 0x80) dst[0] = 0;    \
        if (mask & 0x40) dst[1] = 0;    \
        if (mask & 0x20) dst[2] = 0;    \
        if (mask & 0x10) dst[3] = 0;    \
        if (mask & 0x08) dst[4] = 0;    \
        if (mask & 0x04) dst[5] = 0;    \
        if (mask & 0x02) dst[6] = 0;    \
        if (mask & 0x01) dst[7] = 0;    \
    } while (0)
#else
static inline black_8_pixels(U8CPU mask, uint16_t dst[])
{
    if (mask & 0x80) dst[0] = 0;
    if (mask & 0x40) dst[1] = 0;
    if (mask & 0x20) dst[2] = 0;
    if (mask & 0x10) dst[3] = 0;
    if (mask & 0x08) dst[4] = 0;
    if (mask & 0x04) dst[5] = 0;
    if (mask & 0x02) dst[6] = 0;
    if (mask & 0x01) dst[7] = 0;
}
#endif

#define SK_BLITBWMASK_NAME                  SkRGB16_Black_BlitBW
#define SK_BLITBWMASK_ARGS
#define SK_BLITBWMASK_BLIT8(mask, dst)      black_8_pixels(mask, dst)
#define SK_BLITBWMASK_GETADDR               getAddr16
#define SK_BLITBWMASK_DEVTYPE               uint16_t
#include "SkBlitBWMaskTemplate.h"

void SkRGB16_Black_Blitter::blitMask(const SkMask& mask,
                                     const SkIRect& clip) {
    if (mask.fFormat == SkMask::kBW_Format) {
        SkRGB16_Black_BlitBW(fDevice, mask, clip);
    } else {
        uint16_t* SK_RESTRICT device = fDevice.getAddr16(clip.fLeft, clip.fTop);
        const uint8_t* SK_RESTRICT alpha = mask.getAddr8(clip.fLeft, clip.fTop);
        unsigned width = clip.width();
        unsigned height = clip.height();
        unsigned deviceRB = fDevice.rowBytes() - (width << 1);
        unsigned maskRB = mask.fRowBytes - width;

        SkASSERT((int)height > 0);
        SkASSERT((int)width > 0);
        SkASSERT((int)deviceRB >= 0);
        SkASSERT((int)maskRB >= 0);

        do {
            unsigned w = width;
            do {
                unsigned aa = *alpha++;
                *device = SkAlphaMulRGB16(*device, SkAlpha255To256(255 - aa));
                device += 1;
            } while (--w != 0);
            device = (uint16_t*)((char*)device + deviceRB);
            alpha += maskRB;
        } while (--height != 0);
    }
}

void SkRGB16_Black_Blitter::blitAntiH(int x, int y,
                                      const SkAlpha* SK_RESTRICT antialias,
                                      const int16_t* SK_RESTRICT runs) {
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);

    for (;;) {
        int count = runs[0];
        SkASSERT(count >= 0);
        if (count <= 0) {
            return;
        }
        runs += count;

        unsigned aa = antialias[0];
        antialias += count;
        if (aa) {
            if (aa == 255) {
                memset(device, 0, count << 1);
            } else {
                aa = SkAlpha255To256(255 - aa);
                do {
                    *device = SkAlphaMulRGB16(*device, aa);
                    device += 1;
                } while (--count != 0);
                continue;
            }
        }
        device += count;
    }
}
#endif

///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////

SkRGB16_Opaque_Blitter::SkRGB16_Opaque_Blitter(const SkBitmap& device,
                                               const SkPaint& paint)
: INHERITED(device, paint) {}

void SkRGB16_Opaque_Blitter::blitH(int x, int y, int width) {
    SkASSERT(width > 0);
    SkASSERT(x + width <= fDevice.width());
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);
    uint16_t srcColor = fColor16;

    SkASSERT(fRawColor16 == srcColor);
    if (fDoDither) {
        uint16_t ditherColor = fRawDither16;
        if ((x ^ y) & 1) {
            SkTSwap(ditherColor, srcColor);
        }
        sk_dither_memset16(device, srcColor, ditherColor, width);
    } else {
        sk_memset16(device, srcColor, width);
    }
}

// return 1 or 0 from a bool
static inline int Bool2Int(int value) {
	return !!value;
}

void SkRGB16_Opaque_Blitter::blitAntiH(int x, int y,
                                       const SkAlpha* SK_RESTRICT antialias,
                                       const int16_t* SK_RESTRICT runs) {
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);
    uint16_t    srcColor = fRawColor16;
    uint32_t    srcExpanded = fExpandedRaw16;
    int         ditherInt = Bool2Int(fDoDither);
    uint16_t    ditherColor = fRawDither16;
    // if we have no dithering, this will always fail
    if ((x ^ y) & ditherInt) {
        SkTSwap(ditherColor, srcColor);
    }
    for (;;) {
        int count = runs[0];
        SkASSERT(count >= 0);
        if (count <= 0) {
            return;
        }
        runs += count;

        unsigned aa = antialias[0];
        antialias += count;
        if (aa) {
            if (aa == 255) {
                if (ditherInt) {
                    sk_dither_memset16(device, srcColor,
                                       ditherColor, count);
                } else {
                    sk_memset16(device, srcColor, count);
                }
            } else {
                // TODO: respect fDoDither
                unsigned scale5 = SkAlpha255To256(aa) >> 3;
                uint32_t src32 = srcExpanded * scale5;
                scale5 = 32 - scale5; // now we can use it on the device
                int n = count;
                do {
                    uint32_t dst32 = SkExpand_rgb_16(*device) * scale5;
                    *device++ = SkCompact_rgb_16((src32 + dst32) >> 5);
                } while (--n != 0);
                goto DONE;
            }
        }
        device += count;

    DONE:
        // if we have no dithering, this will always fail
        if (count & ditherInt) {
            SkTSwap(ditherColor, srcColor);
        }
    }
}

#define solid_8_pixels(mask, dst, color)    \
    do {                                    \
        if (mask & 0x80) dst[0] = color;    \
        if (mask & 0x40) dst[1] = color;    \
        if (mask & 0x20) dst[2] = color;    \
        if (mask & 0x10) dst[3] = color;    \
        if (mask & 0x08) dst[4] = color;    \
        if (mask & 0x04) dst[5] = color;    \
        if (mask & 0x02) dst[6] = color;    \
        if (mask & 0x01) dst[7] = color;    \
    } while (0)

#define SK_BLITBWMASK_NAME                  SkRGB16_BlitBW
#define SK_BLITBWMASK_ARGS                  , uint16_t color
#define SK_BLITBWMASK_BLIT8(mask, dst)      solid_8_pixels(mask, dst, color)
#define SK_BLITBWMASK_GETADDR               getAddr16
#define SK_BLITBWMASK_DEVTYPE               uint16_t
#include "SkBlitBWMaskTemplate.h"

static U16CPU blend_compact(uint32_t src32, uint32_t dst32, unsigned scale5) {
    return SkCompact_rgb_16(dst32 + ((src32 - dst32) * scale5 >> 5));
}

void SkRGB16_Opaque_Blitter::blitMask(const SkMask& mask,
                                      const SkIRect& clip) {
    if (mask.fFormat == SkMask::kBW_Format) {
        SkRGB16_BlitBW(fDevice, mask, clip, fColor16);
        return;
    }

    uint16_t* SK_RESTRICT device = fDevice.getAddr16(clip.fLeft, clip.fTop);
    const uint8_t* SK_RESTRICT alpha = mask.getAddr8(clip.fLeft, clip.fTop);
    int width = clip.width();
    int height = clip.height();
    unsigned    deviceRB = fDevice.rowBytes() - (width << 1);
    unsigned    maskRB = mask.fRowBytes - width;
    uint32_t    expanded32 = fExpandedRaw16;

#ifdef SK_USE_NEON
#define	UNROLL	8
    do {
        int w = width;
        if (w >= UNROLL) {
            uint32x4_t color;		/* can use same one */
            uint32x4_t dev_lo, dev_hi;
            uint32x4_t t1, t2;
            uint32x4_t wn1, wn2;
            uint16x4_t odev_lo, odev_hi;
            uint16x4_t alpha_lo, alpha_hi;
            uint16x8_t  alpha_full;
            
            color = vdupq_n_u32(expanded32);
            
            do {
                /* alpha is 8x8, widen and split to get pair of 16x4's */
                alpha_full = vmovl_u8(vld1_u8(alpha));
                alpha_full = vaddq_u16(alpha_full, vshrq_n_u16(alpha_full,7));
                alpha_full = vshrq_n_u16(alpha_full, 3);
                alpha_lo = vget_low_u16(alpha_full);
                alpha_hi = vget_high_u16(alpha_full);
                
                dev_lo = vmovl_u16(vld1_u16(device));
                dev_hi = vmovl_u16(vld1_u16(device+4));
                
                /* unpack in 32 bits */
                dev_lo = vorrq_u32(
                                   vandq_u32(dev_lo, vdupq_n_u32(0x0000F81F)),
                                   vshlq_n_u32(vandq_u32(dev_lo, 
                                                         vdupq_n_u32(0x000007E0)),
                                               16)
                                   );
                dev_hi = vorrq_u32(
                                   vandq_u32(dev_hi, vdupq_n_u32(0x0000F81F)),
                                   vshlq_n_u32(vandq_u32(dev_hi, 
                                                         vdupq_n_u32(0x000007E0)),
                                               16)
                                   );
                
                /* blend the two */
                t1 = vmulq_u32(vsubq_u32(color, dev_lo), vmovl_u16(alpha_lo));
                t1 = vshrq_n_u32(t1, 5);
                dev_lo = vaddq_u32(dev_lo, t1);
                
                t1 = vmulq_u32(vsubq_u32(color, dev_hi), vmovl_u16(alpha_hi));
                t1 = vshrq_n_u32(t1, 5);
                dev_hi = vaddq_u32(dev_hi, t1);
                
                /* re-compact and store */
                wn1 = vandq_u32(dev_lo, vdupq_n_u32(0x0000F81F)),
                wn2 = vshrq_n_u32(dev_lo, 16);
                wn2 = vandq_u32(wn2, vdupq_n_u32(0x000007E0));
                odev_lo = vmovn_u32(vorrq_u32(wn1, wn2));
                
                wn1 = vandq_u32(dev_hi, vdupq_n_u32(0x0000F81F)),
                wn2 = vshrq_n_u32(dev_hi, 16);
                wn2 = vandq_u32(wn2, vdupq_n_u32(0x000007E0));
                odev_hi = vmovn_u32(vorrq_u32(wn1, wn2));
                
                vst1_u16(device, odev_lo);
                vst1_u16(device+4, odev_hi);
                
                device += UNROLL;
                alpha += UNROLL;
                w -= UNROLL;
            } while (w >= UNROLL);
        }
        
        /* residuals (which is everything if we have no neon) */
        while (w > 0) {
            *device = blend_compact(expanded32, SkExpand_rgb_16(*device),
                                    SkAlpha255To256(*alpha++) >> 3);
            device += 1;
            --w;
        }
        device = (uint16_t*)((char*)device + deviceRB);
        alpha += maskRB;
    } while (--height != 0);
#undef	UNROLL
#else   // non-neon code
    do {
        int w = width;
        do {
            *device = blend_compact(expanded32, SkExpand_rgb_16(*device),
                                    SkAlpha255To256(*alpha++) >> 3);
            device += 1;
        } while (--w != 0);
        device = (uint16_t*)((char*)device + deviceRB);
        alpha += maskRB;
    } while (--height != 0);
#endif
}

void SkRGB16_Opaque_Blitter::blitV(int x, int y, int height, SkAlpha alpha) {
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);
    unsigned    deviceRB = fDevice.rowBytes();
    
    // TODO: respect fDoDither
    unsigned scale5 = SkAlpha255To256(alpha) >> 3;
    uint32_t src32 =  fExpandedRaw16 * scale5;
    scale5 = 32 - scale5;
    do {
        uint32_t dst32 = SkExpand_rgb_16(*device) * scale5;
        *device = SkCompact_rgb_16((src32 + dst32) >> 5);
        device = (uint16_t*)((char*)device + deviceRB);
    } while (--height != 0);
}

void SkRGB16_Opaque_Blitter::blitRect(int x, int y, int width, int height) {
    SkASSERT(x + width <= fDevice.width() && y + height <= fDevice.height());
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);
    unsigned    deviceRB = fDevice.rowBytes();
    uint16_t    color16 = fColor16;

    if (fDoDither) {
        uint16_t ditherColor = fRawDither16;
        if ((x ^ y) & 1) {
            SkTSwap(ditherColor, color16);
        }
        while (--height >= 0) {
            sk_dither_memset16(device, color16, ditherColor, width);
            SkTSwap(ditherColor, color16);
            device = (uint16_t*)((char*)device + deviceRB);
        }
    } else {  // no dither
        while (--height >= 0) {
            sk_memset16(device, color16, width);
            device = (uint16_t*)((char*)device + deviceRB);
        }
    }
}

///////////////////////////////////////////////////////////////////////////////

SkRGB16_Blitter::SkRGB16_Blitter(const SkBitmap& device, const SkPaint& paint)
    : INHERITED(device) {
    SkColor color = paint.getColor();

    fSrcColor32 = SkPreMultiplyColor(color);
    fScale = SkAlpha255To256(SkColorGetA(color));

    int r = SkColorGetR(color);
    int g = SkColorGetG(color);
    int b = SkColorGetB(color);

    fRawColor16 = fRawDither16 = SkPack888ToRGB16(r, g, b);
    // if we're dithered, use fRawDither16 to hold that.
    if ((fDoDither = paint.isDither()) != false) {
        fRawDither16 = SkDitherPack888ToRGB16(r, g, b);
    }

    fExpandedRaw16 = SkExpand_rgb_16(fRawColor16);

    fColor16 = SkPackRGB16( SkAlphaMul(r, fScale) >> (8 - SK_R16_BITS),
                            SkAlphaMul(g, fScale) >> (8 - SK_G16_BITS),
                            SkAlphaMul(b, fScale) >> (8 - SK_B16_BITS));
}

const SkBitmap* SkRGB16_Blitter::justAnOpaqueColor(uint32_t* value) {
    if (!fDoDither && 256 == fScale) {
        *value = fRawColor16;
        return &fDevice;
    }
    return NULL;
}

static uint32_t pmcolor_to_expand16(SkPMColor c) {
    unsigned r = SkGetPackedR32(c);
    unsigned g = SkGetPackedG32(c);
    unsigned b = SkGetPackedB32(c);
    return (g << 24) | (r << 13) | (b << 2);
}

static inline void blend32_16_row(SkPMColor src, uint16_t dst[], int count) {
    SkASSERT(count > 0);
    uint32_t src_expand = pmcolor_to_expand16(src);
    unsigned scale = SkAlpha255To256(0xFF - SkGetPackedA32(src)) >> 3;
    do {
        uint32_t dst_expand = SkExpand_rgb_16(*dst) * scale;
        *dst = SkCompact_rgb_16((src_expand + dst_expand) >> 5);
        dst += 1;
    } while (--count != 0);
}

void SkRGB16_Blitter::blitH(int x, int y, int width) {
    SkASSERT(width > 0);
    SkASSERT(x + width <= fDevice.width());
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);

    // TODO: respect fDoDither
    blend32_16_row(fSrcColor32, device, width);
}

void SkRGB16_Blitter::blitAntiH(int x, int y,
                                const SkAlpha* SK_RESTRICT antialias,
                                const int16_t* SK_RESTRICT runs) {
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);
    uint32_t    srcExpanded = fExpandedRaw16;
    unsigned    scale = fScale;

    // TODO: respect fDoDither
    for (;;) {
        int count = runs[0];
        SkASSERT(count >= 0);
        if (count <= 0) {
            return;
        }
        runs += count;

        unsigned aa = antialias[0];
        antialias += count;
        if (aa) {
            unsigned scale5 = SkAlpha255To256(aa) * scale >> (8 + 3);
            uint32_t src32 =  srcExpanded * scale5;
            scale5 = 32 - scale5;
            do {
                uint32_t dst32 = SkExpand_rgb_16(*device) * scale5;
                *device++ = SkCompact_rgb_16((src32 + dst32) >> 5);
            } while (--count != 0);
            continue;
        }
        device += count;
    }
}

static inline void blend_8_pixels(U8CPU bw, uint16_t dst[], unsigned dst_scale,
                                  U16CPU srcColor) {
    if (bw & 0x80) dst[0] = srcColor + SkAlphaMulRGB16(dst[0], dst_scale);
    if (bw & 0x40) dst[1] = srcColor + SkAlphaMulRGB16(dst[1], dst_scale);
    if (bw & 0x20) dst[2] = srcColor + SkAlphaMulRGB16(dst[2], dst_scale);
    if (bw & 0x10) dst[3] = srcColor + SkAlphaMulRGB16(dst[3], dst_scale);
    if (bw & 0x08) dst[4] = srcColor + SkAlphaMulRGB16(dst[4], dst_scale);
    if (bw & 0x04) dst[5] = srcColor + SkAlphaMulRGB16(dst[5], dst_scale);
    if (bw & 0x02) dst[6] = srcColor + SkAlphaMulRGB16(dst[6], dst_scale);
    if (bw & 0x01) dst[7] = srcColor + SkAlphaMulRGB16(dst[7], dst_scale);
}

#define SK_BLITBWMASK_NAME                  SkRGB16_BlendBW
#define SK_BLITBWMASK_ARGS                  , unsigned dst_scale, U16CPU src_color
#define SK_BLITBWMASK_BLIT8(mask, dst)      blend_8_pixels(mask, dst, dst_scale, src_color)
#define SK_BLITBWMASK_GETADDR               getAddr16
#define SK_BLITBWMASK_DEVTYPE               uint16_t
#include "SkBlitBWMaskTemplate.h"

void SkRGB16_Blitter::blitMask(const SkMask& mask,
                               const SkIRect& clip) {
    if (mask.fFormat == SkMask::kBW_Format) {
        SkRGB16_BlendBW(fDevice, mask, clip, 256 - fScale, fColor16);
        return;
    }

    uint16_t* SK_RESTRICT device = fDevice.getAddr16(clip.fLeft, clip.fTop);
    const uint8_t* SK_RESTRICT alpha = mask.getAddr8(clip.fLeft, clip.fTop);
    int width = clip.width();
    int height = clip.height();
    unsigned    deviceRB = fDevice.rowBytes() - (width << 1);
    unsigned    maskRB = mask.fRowBytes - width;
    uint32_t    color32 = fExpandedRaw16;

    unsigned scale256 = fScale;
    do {
        int w = width;
        do {
            unsigned aa = *alpha++;
            unsigned scale = SkAlpha255To256(aa) * scale256 >> (8 + 3);
            uint32_t src32 = color32 * scale;
            uint32_t dst32 = SkExpand_rgb_16(*device) * (32 - scale);
            *device++ = SkCompact_rgb_16((src32 + dst32) >> 5);
        } while (--w != 0);
        device = (uint16_t*)((char*)device + deviceRB);
        alpha += maskRB;
    } while (--height != 0);
}

void SkRGB16_Blitter::blitV(int x, int y, int height, SkAlpha alpha) {
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);
    unsigned    deviceRB = fDevice.rowBytes();

    // TODO: respect fDoDither
    unsigned scale5 = SkAlpha255To256(alpha) * fScale >> (8 + 3);
    uint32_t src32 =  fExpandedRaw16 * scale5;
    scale5 = 32 - scale5;
    do {
        uint32_t dst32 = SkExpand_rgb_16(*device) * scale5;
        *device = SkCompact_rgb_16((src32 + dst32) >> 5);
        device = (uint16_t*)((char*)device + deviceRB);
    } while (--height != 0);
}

void SkRGB16_Blitter::blitRect(int x, int y, int width, int height) {
    SkASSERT(x + width <= fDevice.width() && y + height <= fDevice.height());
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);
    unsigned    deviceRB = fDevice.rowBytes();
    SkPMColor src32 = fSrcColor32;

    while (--height >= 0) {
        blend32_16_row(src32, device, width);
        device = (uint16_t*)((char*)device + deviceRB);
    }
}

///////////////////////////////////////////////////////////////////////////////

SkRGB16_Shader16_Blitter::SkRGB16_Shader16_Blitter(const SkBitmap& device,
                                                   const SkPaint& paint)
    : SkRGB16_Shader_Blitter(device, paint) {
    SkASSERT(SkShader::CanCallShadeSpan16(fShaderFlags));
}

void SkRGB16_Shader16_Blitter::blitH(int x, int y, int width) {
    SkASSERT(x + width <= fDevice.width());

    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);
    SkShader*   shader = fShader;

    int alpha = shader->getSpan16Alpha();
    if (0xFF == alpha) {
        shader->shadeSpan16(x, y, device, width);
    } else {
        uint16_t* span16 = (uint16_t*)fBuffer;
        shader->shadeSpan16(x, y, span16, width);
        SkBlendRGB16(span16, device, SkAlpha255To256(alpha), width);
    }
}

void SkRGB16_Shader16_Blitter::blitRect(int x, int y, int width, int height) {
    SkShader*   shader = fShader;
    uint16_t*   dst = fDevice.getAddr16(x, y);
    size_t      dstRB = fDevice.rowBytes();
    int         alpha = shader->getSpan16Alpha();

    if (0xFF == alpha) {
        if (fShaderFlags & SkShader::kConstInY16_Flag) {
            // have the shader blit directly into the device the first time
            shader->shadeSpan16(x, y, dst, width);
            // and now just memcpy that line on the subsequent lines
            if (--height > 0) {
                const uint16_t* orig = dst;
                do {
                    dst = (uint16_t*)((char*)dst + dstRB);
                    memcpy(dst, orig, width << 1);
                } while (--height);
            }
        } else {    // need to call shadeSpan16 for every line
            do {
                shader->shadeSpan16(x, y, dst, width);
                y += 1;
                dst = (uint16_t*)((char*)dst + dstRB);
            } while (--height);
        }
    } else {
        int scale = SkAlpha255To256(alpha);
        uint16_t* span16 = (uint16_t*)fBuffer;
        if (fShaderFlags & SkShader::kConstInY16_Flag) {
            shader->shadeSpan16(x, y, span16, width);
            do {
                SkBlendRGB16(span16, dst, scale, width);
                dst = (uint16_t*)((char*)dst + dstRB);
            } while (--height);
        } else {
            do {
                shader->shadeSpan16(x, y, span16, width);
                SkBlendRGB16(span16, dst, scale, width);
                y += 1;
                dst = (uint16_t*)((char*)dst + dstRB);
            } while (--height);
        }
    }
}

void SkRGB16_Shader16_Blitter::blitAntiH(int x, int y,
                                         const SkAlpha* SK_RESTRICT antialias,
                                         const int16_t* SK_RESTRICT runs) {
    SkShader*   shader = fShader;
    SkPMColor* SK_RESTRICT span = fBuffer;
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);

    int alpha = shader->getSpan16Alpha();
    uint16_t* span16 = (uint16_t*)span;

    if (0xFF == alpha) {
        for (;;) {
            int count = *runs;
            if (count <= 0) {
                break;
            }
            SkASSERT(count <= fDevice.width()); // don't overrun fBuffer

            int aa = *antialias;
            if (aa == 255) {
                // go direct to the device!
                shader->shadeSpan16(x, y, device, count);
            } else if (aa) {
                shader->shadeSpan16(x, y, span16, count);
                SkBlendRGB16(span16, device, SkAlpha255To256(aa), count);
            }
            device += count;
            runs += count;
            antialias += count;
            x += count;
        }
    } else {  // span alpha is < 255
        alpha = SkAlpha255To256(alpha);
        for (;;) {
            int count = *runs;
            if (count <= 0) {
                break;
            }
            SkASSERT(count <= fDevice.width()); // don't overrun fBuffer

            int aa = SkAlphaMul(*antialias, alpha);
            if (aa) {
                shader->shadeSpan16(x, y, span16, count);
                SkBlendRGB16(span16, device, SkAlpha255To256(aa), count);
            }

            device += count;
            runs += count;
            antialias += count;
            x += count;
        }
    }
}

///////////////////////////////////////////////////////////////////////////////

SkRGB16_Shader_Blitter::SkRGB16_Shader_Blitter(const SkBitmap& device,
                                               const SkPaint& paint)
: INHERITED(device, paint) {
    SkASSERT(paint.getXfermode() == NULL);

    fBuffer = (SkPMColor*)sk_malloc_throw(device.width() * sizeof(SkPMColor));

    // compute SkBlitRow::Procs
    unsigned flags = 0;
    
    uint32_t shaderFlags = fShaderFlags;
    // shaders take care of global alpha, so we never set it in SkBlitRow
    if (!(shaderFlags & SkShader::kOpaqueAlpha_Flag)) {
        flags |= SkBlitRow::kSrcPixelAlpha_Flag;
        }
    // don't dither if the shader is really 16bit
    if (paint.isDither() && !(shaderFlags & SkShader::kIntrinsicly16_Flag)) {
        flags |= SkBlitRow::kDither_Flag;
    }
    // used when we know our global alpha is 0xFF
    fOpaqueProc = SkBlitRow::Factory(flags, SkBitmap::kRGB_565_Config);
    // used when we know our global alpha is < 0xFF
    fAlphaProc  = SkBlitRow::Factory(flags | SkBlitRow::kGlobalAlpha_Flag,
                                     SkBitmap::kRGB_565_Config);
}

SkRGB16_Shader_Blitter::~SkRGB16_Shader_Blitter() {
    sk_free(fBuffer);
}

void SkRGB16_Shader_Blitter::blitH(int x, int y, int width) {
    SkASSERT(x + width <= fDevice.width());

    fShader->shadeSpan(x, y, fBuffer, width);
    // shaders take care of global alpha, so we pass 0xFF (should be ignored)
    fOpaqueProc(fDevice.getAddr16(x, y), fBuffer, width, 0xFF, x, y);
}

void SkRGB16_Shader_Blitter::blitRect(int x, int y, int width, int height) {
    SkShader*       shader = fShader;
    SkBlitRow::Proc proc = fOpaqueProc;
    SkPMColor*      buffer = fBuffer;
    uint16_t*       dst = fDevice.getAddr16(x, y);
    size_t          dstRB = fDevice.rowBytes();

    if (fShaderFlags & SkShader::kConstInY32_Flag) {
        shader->shadeSpan(x, y, buffer, width);
        do {
            proc(dst, buffer, width, 0xFF, x, y);
            y += 1;
            dst = (uint16_t*)((char*)dst + dstRB);
        } while (--height);
    } else {
        do {
            shader->shadeSpan(x, y, buffer, width);
            proc(dst, buffer, width, 0xFF, x, y);
            y += 1;
            dst = (uint16_t*)((char*)dst + dstRB);
        } while (--height);
    }
}

static inline int count_nonzero_span(const int16_t runs[], const SkAlpha aa[]) {
    int count = 0;
    for (;;) {
        int n = *runs;
        if (n == 0 || *aa == 0) {
            break;
        }
        runs += n;
        aa += n;
        count += n;
    }
    return count;
}

void SkRGB16_Shader_Blitter::blitAntiH(int x, int y,
                                       const SkAlpha* SK_RESTRICT antialias,
                                       const int16_t* SK_RESTRICT runs) {
    SkShader*   shader = fShader;
    SkPMColor* SK_RESTRICT span = fBuffer;
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);

    for (;;) {
        int count = *runs;
        if (count <= 0) {
            break;
        }
        int aa = *antialias;
        if (0 == aa) {
            device += count;
            runs += count;
            antialias += count;
            x += count;
            continue;
        }

        int nonZeroCount = count + count_nonzero_span(runs + count, antialias + count);

        SkASSERT(nonZeroCount <= fDevice.width()); // don't overrun fBuffer
        shader->shadeSpan(x, y, span, nonZeroCount);

        SkPMColor* localSpan = span;
        for (;;) {
            SkBlitRow::Proc proc = (aa == 0xFF) ? fOpaqueProc : fAlphaProc;
            proc(device, localSpan, count, aa, x, y);

            x += count;
            device += count;
            runs += count;
            antialias += count;
            nonZeroCount -= count;
            if (nonZeroCount == 0) {
                break;
            }
            localSpan += count;
            SkASSERT(nonZeroCount > 0);
            count = *runs;
            SkASSERT(count > 0);
            aa = *antialias;
        }
    }
}

///////////////////////////////////////////////////////////////////////

SkRGB16_Shader_Xfermode_Blitter::SkRGB16_Shader_Xfermode_Blitter(
                                const SkBitmap& device, const SkPaint& paint)
: INHERITED(device, paint) {
    fXfermode = paint.getXfermode();
    SkASSERT(fXfermode);
    fXfermode->ref();

    int width = device.width();
    fBuffer = (SkPMColor*)sk_malloc_throw((width + (SkAlign4(width) >> 2)) * sizeof(SkPMColor));
    fAAExpand = (uint8_t*)(fBuffer + width);
}

SkRGB16_Shader_Xfermode_Blitter::~SkRGB16_Shader_Xfermode_Blitter() {
    fXfermode->unref();
    sk_free(fBuffer);
}

void SkRGB16_Shader_Xfermode_Blitter::blitH(int x, int y, int width) {
    SkASSERT(x + width <= fDevice.width());

    uint16_t*   device = fDevice.getAddr16(x, y);
    SkPMColor*  span = fBuffer;

    fShader->shadeSpan(x, y, span, width);
    fXfermode->xfer16(device, span, width, NULL);
}

void SkRGB16_Shader_Xfermode_Blitter::blitAntiH(int x, int y,
                                const SkAlpha* SK_RESTRICT antialias,
                                const int16_t* SK_RESTRICT runs) {
    SkShader*   shader = fShader;
    SkXfermode* mode = fXfermode;
    SkPMColor* SK_RESTRICT span = fBuffer;
    uint8_t* SK_RESTRICT aaExpand = fAAExpand;
    uint16_t* SK_RESTRICT device = fDevice.getAddr16(x, y);

    for (;;) {
        int count = *runs;
        if (count <= 0) {
            break;
        }
        int aa = *antialias;
        if (0 == aa) {
            device += count;
            runs += count;
            antialias += count;
            x += count;
            continue;
        }

        int nonZeroCount = count + count_nonzero_span(runs + count,
                                                      antialias + count);

        SkASSERT(nonZeroCount <= fDevice.width()); // don't overrun fBuffer
        shader->shadeSpan(x, y, span, nonZeroCount);

        x += nonZeroCount;
        SkPMColor* localSpan = span;
        for (;;) {
            if (aa == 0xFF) {
                mode->xfer16(device, localSpan, count, NULL);
            } else {
                SkASSERT(aa);
                memset(aaExpand, aa, count);
                mode->xfer16(device, localSpan, count, aaExpand);
            }
            device += count;
            runs += count;
            antialias += count;
            nonZeroCount -= count;
            if (nonZeroCount == 0) {
                break;
            }
            localSpan += count;
            SkASSERT(nonZeroCount > 0);
            count = *runs;
            SkASSERT(count > 0);
            aa = *antialias;
        }
    } 
}

///////////////////////////////////////////////////////////////////////////////

SkBlitter* SkBlitter_ChooseD565(const SkBitmap& device, const SkPaint& paint,
                                void* storage, size_t storageSize) {
    SkBlitter* blitter;
    SkShader* shader = paint.getShader();
    SkXfermode* mode = paint.getXfermode();

    // we require a shader if there is an xfermode, handled by our caller
    SkASSERT(NULL == mode || NULL != shader);

    if (shader) {
        if (mode) {
            SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Shader_Xfermode_Blitter,
                                  storage, storageSize, (device, paint));
        } else if (shader->canCallShadeSpan16()) {
            SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Shader16_Blitter,
                                  storage, storageSize, (device, paint));
        } else {
            SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Shader_Blitter,
                                  storage, storageSize, (device, paint));
        }
    } else {
        // no shader, no xfermode, (and we always ignore colorfilter)
        SkColor color = paint.getColor();
        if (0 == SkColorGetA(color)) {
            SK_PLACEMENT_NEW(blitter, SkNullBlitter, storage, storageSize);
#ifdef USE_BLACK_BLITTER
        } else if (SK_ColorBLACK == color) {
            SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Black_Blitter, storage,
                                  storageSize, (device, paint));
#endif
        } else if (0xFF == SkColorGetA(color)) {
            SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Opaque_Blitter, storage,
                                  storageSize, (device, paint));
        } else {
            SK_PLACEMENT_NEW_ARGS(blitter, SkRGB16_Blitter, storage,
                                  storageSize, (device, paint));
        }
    }
    
    return blitter;
}