SkBlitter.cpp revision 1fc4c605def61d9e10489f9cd63dc378baa6ade3 
1/* libs/graphics/sgl/SkBlitter.cpp
2**
3** Copyright 2006, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18#include "SkBlitter.h"
19#include "SkAntiRun.h"
20#include "SkColor.h"
21#include "SkColorFilter.h"
22#include "SkMask.h"
23#include "SkMaskFilter.h"
24#include "SkTemplatesPriv.h"
25#include "SkUtils.h"
26#include "SkXfermode.h"
27
28SkBlitter::~SkBlitter() {}
29
30const SkBitmap* SkBlitter::justAnOpaqueColor(uint32_t* value)
31{
32    return NULL;
33}
34
35void SkBlitter::blitH(int x, int y, int width)
36{
37    SkASSERT(!"unimplemented");
38}
39
40void SkBlitter::blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[])
41{
42    SkASSERT(!"unimplemented");
43}
44
45void SkBlitter::blitV(int x, int y, int height, SkAlpha alpha)
46{
47    if (alpha == 255)
48        this->blitRect(x, y, 1, height);
49    else
50    {
51        int16_t runs[2];
52        runs[0] = 1;
53        runs[1] = 0;
54
55        while (--height >= 0)
56            this->blitAntiH(x, y++, &alpha, runs);
57    }
58}
59
60void SkBlitter::blitRect(int x, int y, int width, int height)
61{
62    while (--height >= 0)
63        this->blitH(x, y++, width);
64}
65
66//////////////////////////////////////////////////////////////////////////////
67
68static inline void bits_to_runs(SkBlitter* blitter, int x, int y, const uint8_t bits[],
69                                U8CPU left_mask, int rowBytes, U8CPU right_mask)
70{
71    int inFill = 0;
72    int pos = 0;
73
74    while (--rowBytes >= 0)
75    {
76        unsigned b = *bits++ & left_mask;
77        if (rowBytes == 0)
78            b &= right_mask;
79
80        for (unsigned test = 0x80; test != 0; test >>= 1)
81        {
82            if (b & test)
83            {
84                if (!inFill)
85                {
86                    pos = x;
87                    inFill = true;
88                }
89            }
90            else
91            {
92                if (inFill)
93                {
94                    blitter->blitH(pos, y, x - pos);
95                    inFill = false;
96                }
97            }
98            x += 1;
99        }
100        left_mask = 0xFF;
101    }
102
103    // final cleanup
104    if (inFill)
105        blitter->blitH(pos, y, x - pos);
106}
107
108void SkBlitter::blitMask(const SkMask& mask, const SkIRect& clip)
109{
110    SkASSERT(mask.fBounds.contains(clip));
111
112    if (mask.fFormat == SkMask::kBW_Format)
113    {
114        int cx = clip.fLeft;
115        int cy = clip.fTop;
116        int maskLeft = mask.fBounds.fLeft;
117        int mask_rowBytes = mask.fRowBytes;
118        int height = clip.height();
119
120        const uint8_t* bits = mask.getAddr1(cx, cy);
121
122        if (cx == maskLeft && clip.fRight == mask.fBounds.fRight)
123        {
124            while (--height >= 0)
125            {
126                bits_to_runs(this, cx, cy, bits, 0xFF, mask_rowBytes, 0xFF);
127                bits += mask_rowBytes;
128                cy += 1;
129            }
130        }
131        else
132        {
133            int left_edge = cx - maskLeft;
134            SkASSERT(left_edge >= 0);
135            int rite_edge = clip.fRight - maskLeft;
136            SkASSERT(rite_edge > left_edge);
137
138            int left_mask = 0xFF >> (left_edge & 7);
139            int rite_mask = 0xFF << (8 - (rite_edge & 7));
140            int full_runs = (rite_edge >> 3) - ((left_edge + 7) >> 3);
141
142            // check for empty right mask, so we don't read off the end (or go slower than we need to)
143            if (rite_mask == 0)
144            {
145                SkASSERT(full_runs >= 0);
146                full_runs -= 1;
147                rite_mask = 0xFF;
148            }
149            if (left_mask == 0xFF)
150                full_runs -= 1;
151
152            // back up manually so we can keep in sync with our byte-aligned src
153            // have cx reflect our actual starting x-coord
154            cx -= left_edge & 7;
155
156            if (full_runs < 0)
157            {
158                SkASSERT((left_mask & rite_mask) != 0);
159                while (--height >= 0)
160                {
161                    bits_to_runs(this, cx, cy, bits, left_mask, 1, rite_mask);
162                    bits += mask_rowBytes;
163                    cy += 1;
164                }
165            }
166            else
167            {
168                while (--height >= 0)
169                {
170                    bits_to_runs(this, cx, cy, bits, left_mask, full_runs + 2, rite_mask);
171                    bits += mask_rowBytes;
172                    cy += 1;
173                }
174            }
175        }
176    }
177    else
178    {
179        int                         width = clip.width();
180        SkAutoSTMalloc<64, int16_t> runStorage(width + 1);
181        int16_t*                    runs = runStorage.get();
182        const uint8_t*              aa = mask.getAddr(clip.fLeft, clip.fTop);
183
184        sk_memset16((uint16_t*)runs, 1, width);
185        runs[width] = 0;
186
187        int height = clip.height();
188        int y = clip.fTop;
189        while (--height >= 0)
190        {
191            this->blitAntiH(clip.fLeft, y, aa, runs);
192            aa += mask.fRowBytes;
193            y += 1;
194        }
195    }
196}
197
198/////////////////////// these guys are not virtual, just a helpers
199
200void SkBlitter::blitMaskRegion(const SkMask& mask, const SkRegion& clip) {
201    if (clip.quickReject(mask.fBounds)) {
202        return;
203    }
204
205    SkRegion::Cliperator clipper(clip, mask.fBounds);
206
207    while (!clipper.done()) {
208        const SkIRect& cr = clipper.rect();
209        this->blitMask(mask, cr);
210        clipper.next();
211    }
212}
213
214void SkBlitter::blitRectRegion(const SkIRect& rect, const SkRegion& clip) {
215    SkRegion::Cliperator clipper(clip, rect);
216
217    while (!clipper.done()) {
218        const SkIRect& cr = clipper.rect();
219        this->blitRect(cr.fLeft, cr.fTop, cr.width(), cr.height());
220        clipper.next();
221    }
222}
223
224void SkBlitter::blitRegion(const SkRegion& clip) {
225    SkRegion::Iterator iter(clip);
226
227    while (!iter.done()) {
228        const SkIRect& cr = iter.rect();
229        this->blitRect(cr.fLeft, cr.fTop, cr.width(), cr.height());
230        iter.next();
231    }
232}
233
234///////////////////////////////////////////////////////////////////////////////////////
235///////////////////////////////////////////////////////////////////////////////////////
236
237void SkNullBlitter::blitH(int x, int y, int width)
238{
239}
240
241void SkNullBlitter::blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[])
242{
243}
244
245void SkNullBlitter::blitV(int x, int y, int height, SkAlpha alpha)
246{
247}
248
249void SkNullBlitter::blitRect(int x, int y, int width, int height)
250{
251}
252
253void SkNullBlitter::blitMask(const SkMask& mask, const SkIRect& clip)
254{
255}
256
257const SkBitmap* SkNullBlitter::justAnOpaqueColor(uint32_t* value)
258{
259    return NULL;
260}
261
262///////////////////////////////////////////////////////////////////////////////////////
263///////////////////////////////////////////////////////////////////////////////////////
264
265static int compute_anti_width(const int16_t runs[])
266{
267    int width = 0;
268
269    for (;;)
270    {
271        int count = runs[0];
272
273        SkASSERT(count >= 0);
274        if (count == 0)
275            break;
276        width += count;
277        runs += count;
278
279        SkASSERT(width < 20000);
280    }
281    return width;
282}
283
284static inline bool y_in_rect(int y, const SkIRect& rect)
285{
286    return (unsigned)(y - rect.fTop) < (unsigned)rect.height();
287}
288
289static inline bool x_in_rect(int x, const SkIRect& rect)
290{
291    return (unsigned)(x - rect.fLeft) < (unsigned)rect.width();
292}
293
294void SkRectClipBlitter::blitH(int left, int y, int width)
295{
296    SkASSERT(width > 0);
297
298    if (!y_in_rect(y, fClipRect))
299        return;
300
301    int right = left + width;
302
303    if (left < fClipRect.fLeft)
304        left = fClipRect.fLeft;
305    if (right > fClipRect.fRight)
306        right = fClipRect.fRight;
307
308    width = right - left;
309    if (width > 0)
310        fBlitter->blitH(left, y, width);
311}
312
313void SkRectClipBlitter::blitAntiH(int left, int y, const SkAlpha aa[], const int16_t runs[])
314{
315    if (!y_in_rect(y, fClipRect) || left >= fClipRect.fRight)
316        return;
317
318    int x0 = left;
319    int x1 = left + compute_anti_width(runs);
320
321    if (x1 <= fClipRect.fLeft)
322        return;
323
324    SkASSERT(x0 < x1);
325    if (x0 < fClipRect.fLeft)
326    {
327        int dx = fClipRect.fLeft - x0;
328        SkAlphaRuns::BreakAt((int16_t*)runs, (uint8_t*)aa, dx);
329        runs += dx;
330        aa += dx;
331        x0 = fClipRect.fLeft;
332    }
333
334    SkASSERT(x0 < x1 && runs[x1 - x0] == 0);
335    if (x1 > fClipRect.fRight)
336    {
337        x1 = fClipRect.fRight;
338        SkAlphaRuns::BreakAt((int16_t*)runs, (uint8_t*)aa, x1 - x0);
339        ((int16_t*)runs)[x1 - x0] = 0;
340    }
341
342    SkASSERT(x0 < x1 && runs[x1 - x0] == 0);
343    SkASSERT(compute_anti_width(runs) == x1 - x0);
344
345    fBlitter->blitAntiH(x0, y, aa, runs);
346}
347
348void SkRectClipBlitter::blitV(int x, int y, int height, SkAlpha alpha)
349{
350    SkASSERT(height > 0);
351
352    if (!x_in_rect(x, fClipRect))
353        return;
354
355    int y0 = y;
356    int y1 = y + height;
357
358    if (y0 < fClipRect.fTop)
359        y0 = fClipRect.fTop;
360    if (y1 > fClipRect.fBottom)
361        y1 = fClipRect.fBottom;
362
363    if (y0 < y1)
364        fBlitter->blitV(x, y0, y1 - y0, alpha);
365}
366
367void SkRectClipBlitter::blitRect(int left, int y, int width, int height)
368{
369    SkIRect    r;
370
371    r.set(left, y, left + width, y + height);
372    if (r.intersect(fClipRect))
373        fBlitter->blitRect(r.fLeft, r.fTop, r.width(), r.height());
374}
375
376void SkRectClipBlitter::blitMask(const SkMask& mask, const SkIRect& clip)
377{
378    SkASSERT(mask.fBounds.contains(clip));
379
380    SkIRect    r = clip;
381
382    if (r.intersect(fClipRect))
383        fBlitter->blitMask(mask, r);
384}
385
386const SkBitmap* SkRectClipBlitter::justAnOpaqueColor(uint32_t* value)
387{
388    return fBlitter->justAnOpaqueColor(value);
389}
390
391///////////////////////////////////////////////////////////////////////////////////////
392///////////////////////////////////////////////////////////////////////////////////////
393
394void SkRgnClipBlitter::blitH(int x, int y, int width)
395{
396    SkRegion::Spanerator span(*fRgn, y, x, x + width);
397    int left, right;
398
399    while (span.next(&left, &right))
400    {
401        SkASSERT(left < right);
402        fBlitter->blitH(left, y, right - left);
403    }
404}
405
406void SkRgnClipBlitter::blitAntiH(int x, int y, const SkAlpha aa[], const int16_t runs[])
407{
408    int width = compute_anti_width(runs);
409    SkRegion::Spanerator span(*fRgn, y, x, x + width);
410    int left, right;
411    SkDEBUGCODE(const SkIRect& bounds = fRgn->getBounds();)
412
413    int prevRite = x;
414    while (span.next(&left, &right))
415    {
416        SkASSERT(x <= left);
417        SkASSERT(left < right);
418        SkASSERT(left >= bounds.fLeft && right <= bounds.fRight);
419
420        SkAlphaRuns::Break((int16_t*)runs, (uint8_t*)aa, left - x, right - left);
421
422        // now zero before left
423        if (left > prevRite)
424        {
425            int index = prevRite - x;
426            ((uint8_t*)aa)[index] = 0;   // skip runs after right
427            ((int16_t*)runs)[index] = SkToS16(left - prevRite);
428        }
429
430        prevRite = right;
431    }
432
433    if (prevRite > x)
434    {
435        ((int16_t*)runs)[prevRite - x] = 0;
436
437        if (x < 0) {
438            int skip = runs[0];
439            SkASSERT(skip >= -x);
440            aa += skip;
441            runs += skip;
442            x += skip;
443        }
444        fBlitter->blitAntiH(x, y, aa, runs);
445    }
446}
447
448void SkRgnClipBlitter::blitV(int x, int y, int height, SkAlpha alpha)
449{
450    SkIRect    bounds;
451    bounds.set(x, y, x + 1, y + height);
452
453    SkRegion::Cliperator    iter(*fRgn, bounds);
454
455    while (!iter.done())
456    {
457        const SkIRect& r = iter.rect();
458        SkASSERT(bounds.contains(r));
459
460        fBlitter->blitV(x, r.fTop, r.height(), alpha);
461        iter.next();
462    }
463}
464
465void SkRgnClipBlitter::blitRect(int x, int y, int width, int height)
466{
467    SkIRect    bounds;
468    bounds.set(x, y, x + width, y + height);
469
470    SkRegion::Cliperator    iter(*fRgn, bounds);
471
472    while (!iter.done())
473    {
474        const SkIRect& r = iter.rect();
475        SkASSERT(bounds.contains(r));
476
477        fBlitter->blitRect(r.fLeft, r.fTop, r.width(), r.height());
478        iter.next();
479    }
480}
481
482void SkRgnClipBlitter::blitMask(const SkMask& mask, const SkIRect& clip)
483{
484    SkASSERT(mask.fBounds.contains(clip));
485
486    SkRegion::Cliperator iter(*fRgn, clip);
487    const SkIRect&       r = iter.rect();
488    SkBlitter*           blitter = fBlitter;
489
490    while (!iter.done())
491    {
492        blitter->blitMask(mask, r);
493        iter.next();
494    }
495}
496
497const SkBitmap* SkRgnClipBlitter::justAnOpaqueColor(uint32_t* value)
498{
499    return fBlitter->justAnOpaqueColor(value);
500}
501
502///////////////////////////////////////////////////////////////////////////////////////
503///////////////////////////////////////////////////////////////////////////////////////
504
505SkBlitter* SkBlitterClipper::apply(SkBlitter* blitter, const SkRegion* clip, const SkIRect* ir)
506{
507    if (clip)
508    {
509        const SkIRect& clipR = clip->getBounds();
510
511        if (clip->isEmpty() || (ir && !SkIRect::Intersects(clipR, *ir)))
512            blitter = &fNullBlitter;
513        else if (clip->isRect())
514        {
515            if (ir == NULL || !clipR.contains(*ir))
516            {
517                fRectBlitter.init(blitter, clipR);
518                blitter = &fRectBlitter;
519            }
520        }
521        else
522        {
523            fRgnBlitter.init(blitter, clip);
524            blitter = &fRgnBlitter;
525        }
526    }
527    return blitter;
528}
529
530///////////////////////////////////////////////////////////////////////////////////////
531///////////////////////////////////////////////////////////////////////////////////////
532
533#include "SkColorShader.h"
534#include "SkColorPriv.h"
535
536class Sk3DShader : public SkShader {
537public:
538    Sk3DShader(SkShader* proxy) : fProxy(proxy)
539    {
540        proxy->safeRef();
541        fMask = NULL;
542    }
543    virtual ~Sk3DShader()
544    {
545        fProxy->safeUnref();
546    }
547    void setMask(const SkMask* mask) { fMask = mask; }
548
549    virtual bool setContext(const SkBitmap& device, const SkPaint& paint, const SkMatrix& matrix)
550    {
551        if (fProxy)
552            return fProxy->setContext(device, paint, matrix);
553        else
554        {
555            fPMColor = SkPreMultiplyColor(paint.getColor());
556            return this->INHERITED::setContext(device, paint, matrix);
557        }
558    }
559    virtual void shadeSpan(int x, int y, SkPMColor span[], int count)
560    {
561        if (fProxy)
562            fProxy->shadeSpan(x, y, span, count);
563
564        if (fMask == NULL)
565        {
566            if (fProxy == NULL)
567                sk_memset32(span, fPMColor, count);
568            return;
569        }
570
571        SkASSERT(fMask->fBounds.contains(x, y));
572        SkASSERT(fMask->fBounds.contains(x + count - 1, y));
573
574        size_t          size = fMask->computeImageSize();
575        const uint8_t*  alpha = fMask->getAddr(x, y);
576        const uint8_t*  mulp = alpha + size;
577        const uint8_t*  addp = mulp + size;
578
579        if (fProxy)
580        {
581            for (int i = 0; i < count; i++)
582            {
583                if (alpha[i])
584                {
585                    SkPMColor c = span[i];
586                    if (c)
587                    {
588                        unsigned a = SkGetPackedA32(c);
589                        unsigned r = SkGetPackedR32(c);
590                        unsigned g = SkGetPackedG32(c);
591                        unsigned b = SkGetPackedB32(c);
592
593                        unsigned mul = SkAlpha255To256(mulp[i]);
594                        unsigned add = addp[i];
595
596                        r = SkFastMin32(SkAlphaMul(r, mul) + add, a);
597                        g = SkFastMin32(SkAlphaMul(g, mul) + add, a);
598                        b = SkFastMin32(SkAlphaMul(b, mul) + add, a);
599
600                        span[i] = SkPackARGB32(a, r, g, b);
601                    }
602                }
603                else
604                    span[i] = 0;
605            }
606        }
607        else    // color
608        {
609            unsigned a = SkGetPackedA32(fPMColor);
610            unsigned r = SkGetPackedR32(fPMColor);
611            unsigned g = SkGetPackedG32(fPMColor);
612            unsigned b = SkGetPackedB32(fPMColor);
613            for (int i = 0; i < count; i++)
614            {
615                if (alpha[i])
616                {
617                    unsigned mul = SkAlpha255To256(mulp[i]);
618                    unsigned add = addp[i];
619
620                    span[i] = SkPackARGB32( a,
621                                            SkFastMin32(SkAlphaMul(r, mul) + add, a),
622                                            SkFastMin32(SkAlphaMul(g, mul) + add, a),
623                                            SkFastMin32(SkAlphaMul(b, mul) + add, a));
624                }
625                else
626                    span[i] = 0;
627            }
628        }
629    }
630
631    virtual void beginSession()
632    {
633        this->INHERITED::beginSession();
634        if (fProxy)
635            fProxy->beginSession();
636    }
637
638    virtual void endSession()
639    {
640        if (fProxy)
641            fProxy->endSession();
642        this->INHERITED::endSession();
643    }
644
645protected:
646    Sk3DShader(SkFlattenableReadBuffer& buffer) :
647        INHERITED(buffer)
648    {
649        fProxy = static_cast<SkShader*>(buffer.readFlattenable());
650        fPMColor = buffer.readU32();
651        fMask = NULL;
652    }
653
654    virtual void flatten(SkFlattenableWriteBuffer& buffer)
655    {
656        this->INHERITED::flatten(buffer);
657        buffer.writeFlattenable(fProxy);
658        buffer.write32(fPMColor);
659    }
660
661    virtual Factory getFactory()
662    {
663        return CreateProc;
664    }
665
666private:
667    static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer)
668    {
669        return SkNEW_ARGS(Sk3DShader, (buffer));
670    }
671
672    SkShader*       fProxy;
673    SkPMColor       fPMColor;
674    const SkMask*   fMask;
675
676    typedef SkShader INHERITED;
677};
678
679class Sk3DBlitter : public SkBlitter {
680public:
681    Sk3DBlitter(SkBlitter* proxy, Sk3DShader* shader, void (*killProc)(void*))
682        : fProxy(proxy), f3DShader(shader), fKillProc(killProc)
683    {
684        shader->ref();
685    }
686    virtual ~Sk3DBlitter()
687    {
688        f3DShader->unref();
689        fKillProc(fProxy);
690    }
691
692    virtual void blitH(int x, int y, int width)
693    {
694        fProxy->blitH(x, y, width);
695    }
696    virtual void blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[])
697    {
698        fProxy->blitAntiH(x, y, antialias, runs);
699    }
700    virtual void blitV(int x, int y, int height, SkAlpha alpha)
701    {
702        fProxy->blitV(x, y, height, alpha);
703    }
704    virtual void blitRect(int x, int y, int width, int height)
705    {
706        fProxy->blitRect(x, y, width, height);
707    }
708    virtual void blitMask(const SkMask& mask, const SkIRect& clip)
709    {
710        if (mask.fFormat == SkMask::k3D_Format)
711        {
712            f3DShader->setMask(&mask);
713
714            ((SkMask*)&mask)->fFormat = SkMask::kA8_Format;
715            fProxy->blitMask(mask, clip);
716            ((SkMask*)&mask)->fFormat = SkMask::k3D_Format;
717
718            f3DShader->setMask(NULL);
719        }
720        else
721            fProxy->blitMask(mask, clip);
722    }
723private:
724    SkBlitter*  fProxy;
725    Sk3DShader* f3DShader;
726    void        (*fKillProc)(void*);
727};
728
729///////////////////////////////////////////////////////////////////////////////////////
730///////////////////////////////////////////////////////////////////////////////////////
731
732#include "SkCoreBlitters.h"
733
734class SkAutoRestoreShader {
735public:
736    SkAutoRestoreShader(const SkPaint& p) : fPaint((SkPaint*)&p)
737    {
738        fShader = fPaint->getShader();
739        fShader->safeRef();
740    }
741    ~SkAutoRestoreShader()
742    {
743        fPaint->setShader(fShader);
744        fShader->safeUnref();
745    }
746private:
747    SkPaint*    fPaint;
748    SkShader*   fShader;
749};
750
751class SkAutoCallProc {
752public:
753    typedef void (*Proc)(void*);
754    SkAutoCallProc(void* obj, Proc proc)
755        : fObj(obj), fProc(proc)
756    {
757    }
758    ~SkAutoCallProc()
759    {
760        if (fObj && fProc)
761            fProc(fObj);
762    }
763    void* get() const { return fObj; }
764    void* detach()
765    {
766        void* obj = fObj;
767        fObj = NULL;
768        return obj;
769    }
770private:
771    void*   fObj;
772    Proc    fProc;
773};
774
775static void destroy_blitter(void* blitter)
776{
777    ((SkBlitter*)blitter)->~SkBlitter();
778}
779
780static void delete_blitter(void* blitter)
781{
782    SkDELETE((SkBlitter*)blitter);
783}
784
785static bool just_solid_color(const SkPaint& paint) {
786    if (paint.getAlpha() == 0xFF && paint.getColorFilter() == NULL) {
787        SkShader* shader = paint.getShader();
788        if (NULL == shader ||
789            (shader->getFlags() & SkShader::kOpaqueAlpha_Flag)) {
790            return true;
791        }
792    }
793    return false;
794}
795
796/** By analyzing the paint (with an xfermode), we may decide we can take
797    special action. This enum lists our possible actions
798 */
799enum XferInterp {
800    kNormal_XferInterp,         // no special interpretation, draw normally
801    kSrcOver_XferInterp,        // draw as if in srcover mode
802    kSkipDrawing_XferInterp     // draw nothing
803};
804
805static XferInterp interpret_xfermode(const SkPaint& paint, SkXfermode* xfer,
806                                     SkBitmap::Config deviceConfig) {
807    SkXfermode::Mode  mode;
808
809    if (SkXfermode::IsMode(xfer, &mode)) {
810        switch (mode) {
811            case SkXfermode::kSrc_Mode:
812                if (just_solid_color(paint)) {
813                    return kSrcOver_XferInterp;
814                }
815                break;
816            case SkXfermode::kDst_Mode:
817                return kSkipDrawing_XferInterp;
818            case SkXfermode::kSrcOver_Mode:
819                return kSrcOver_XferInterp;
820            case SkXfermode::kDstOver_Mode:
821                if (SkBitmap::kRGB_565_Config == deviceConfig) {
822                    return kSkipDrawing_XferInterp;
823                }
824                break;
825            case SkXfermode::kSrcIn_Mode:
826                if (SkBitmap::kRGB_565_Config == deviceConfig &&
827                    just_solid_color(paint)) {
828                    return kSrcOver_XferInterp;
829                }
830                break;
831            case SkXfermode::kDstIn_Mode:
832                if (just_solid_color(paint)) {
833                    return kSkipDrawing_XferInterp;
834                }
835                break;
836            default:
837                break;
838        }
839    }
840    return kNormal_XferInterp;
841}
842
843SkBlitter* SkBlitter::Choose(const SkBitmap& device,
844                             const SkMatrix& matrix,
845                             const SkPaint& paint,
846                             void* storage, size_t storageSize)
847{
848    SkASSERT(storageSize == 0 || storage != NULL);
849
850    SkBlitter*  blitter = NULL;
851
852    // which check, in case we're being called by a client with a dummy device
853    // (e.g. they have a bounder that always aborts the draw)
854    if (SkBitmap::kNo_Config == device.getConfig())
855    {
856        SK_PLACEMENT_NEW(blitter, SkNullBlitter, storage, storageSize);
857        return blitter;
858    }
859
860    SkAutoRestoreShader restore(paint);
861    SkShader* shader = paint.getShader();
862
863    Sk3DShader* shader3D = NULL;
864    if (paint.getMaskFilter() != NULL && paint.getMaskFilter()->getFormat() == SkMask::k3D_Format)
865    {
866        shader3D = SkNEW_ARGS(Sk3DShader, (shader));
867        ((SkPaint*)&paint)->setShader(shader3D)->unref();
868        shader = shader3D;
869    }
870
871    SkXfermode* mode = paint.getXfermode();
872    if (NULL != mode) {
873        switch (interpret_xfermode(paint, mode, device.config())) {
874            case kSrcOver_XferInterp:
875                mode = NULL;
876                break;
877            case kSkipDrawing_XferInterp:
878                SK_PLACEMENT_NEW(blitter, SkNullBlitter, storage, storageSize);
879                return blitter;
880            default:
881                break;
882        }
883    }
884
885    if (NULL == shader && (NULL != mode || paint.getColorFilter() != NULL)) {
886        // xfermodes (and filters) require shaders for our current blitters
887        shader = SkNEW(SkColorShader);
888        ((SkPaint*)&paint)->setShader(shader)->unref();
889    }
890
891    if (paint.getColorFilter() != NULL)
892    {
893        SkASSERT(shader);
894        shader = SkNEW_ARGS(SkFilterShader, (shader, paint.getColorFilter()));
895        ((SkPaint*)&paint)->setShader(shader)->unref();
896        // blitters should ignore the presence/absence of a filter, since
897        // if there is one, the shader will take care of it.
898    }
899
900    if (shader && !shader->setContext(device, paint, matrix)) {
901        return SkNEW(SkNullBlitter);
902    }
903
904    switch (device.getConfig()) {
905    case SkBitmap::kA1_Config:
906        SK_PLACEMENT_NEW_ARGS(blitter, SkA1_Blitter, storage, storageSize, (device, paint));
907        break;
908
909    case SkBitmap::kA8_Config:
910        if (shader)
911            SK_PLACEMENT_NEW_ARGS(blitter, SkA8_Shader_Blitter, storage, storageSize, (device, paint));
912        else
913            SK_PLACEMENT_NEW_ARGS(blitter, SkA8_Blitter, storage, storageSize, (device, paint));
914        break;
915
916    case SkBitmap::kARGB_4444_Config:
917        blitter = SkBlitter_ChooseD4444(device, paint, storage, storageSize);
918        break;
919
920    case SkBitmap::kRGB_565_Config:
921        blitter = SkBlitter_ChooseD565(device, paint, storage, storageSize);
922        break;
923
924    case SkBitmap::kARGB_8888_Config:
925        if (shader)
926            SK_PLACEMENT_NEW_ARGS(blitter, SkARGB32_Shader_Blitter, storage, storageSize, (device, paint));
927        else if (paint.getColor() == SK_ColorBLACK)
928            SK_PLACEMENT_NEW_ARGS(blitter, SkARGB32_Black_Blitter, storage, storageSize, (device, paint));
929        else if (paint.getAlpha() == 0xFF)
930            SK_PLACEMENT_NEW_ARGS(blitter, SkARGB32_Opaque_Blitter, storage, storageSize, (device, paint));
931        else
932            SK_PLACEMENT_NEW_ARGS(blitter, SkARGB32_Blitter, storage, storageSize, (device, paint));
933        break;
934
935    default:
936        SkASSERT(!"unsupported device config");
937        SK_PLACEMENT_NEW(blitter, SkNullBlitter, storage, storageSize);
938    }
939
940    if (shader3D)
941    {
942        void (*proc)(void*) = ((void*)storage == (void*)blitter) ? destroy_blitter : delete_blitter;
943        SkAutoCallProc  tmp(blitter, proc);
944
945        blitter = SkNEW_ARGS(Sk3DBlitter, (blitter, shader3D, proc));
946        (void)tmp.detach();
947    }
948    return blitter;
949}
950
951//////////////////////////////////////////////////////////////////////////////////////////////////////
952
953const uint16_t gMask_0F0F = 0xF0F;
954const uint32_t gMask_00FF00FF = 0xFF00FF;
955
956//////////////////////////////////////////////////////////////////////////////////////////////////////
957
958SkShaderBlitter::SkShaderBlitter(const SkBitmap& device, const SkPaint& paint)
959        : INHERITED(device) {
960    fShader = paint.getShader();
961    SkASSERT(fShader);
962
963    fShader->ref();
964    fShader->beginSession();
965    fShaderFlags = fShader->getFlags();
966}
967
968SkShaderBlitter::~SkShaderBlitter() {
969    fShader->endSession();
970    fShader->unref();
971}
972
973