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