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1 
2 /*
3  * Copyright 2006 The Android Open Source Project
4  *
5  * Use of this source code is governed by a BSD-style license that can be
6  * found in the LICENSE file.
7  */
8 
9 
10 #include "SkScanPriv.h"
11 #include "SkPath.h"
12 #include "SkMatrix.h"
13 #include "SkBlitter.h"
14 #include "SkRegion.h"
15 #include "SkAntiRun.h"
16 
17 #define SHIFT   2
18 #define SCALE   (1 << SHIFT)
19 #define MASK    (SCALE - 1)
20 
21 /** @file
22     We have two techniques for capturing the output of the supersampler:
23     - SUPERMASK, which records a large mask-bitmap
24         this is often faster for small, complex objects
25     - RLE, which records a rle-encoded scanline
26         this is often faster for large objects with big spans
27 
28     These blitters use two coordinate systems:
29     - destination coordinates, scale equal to the output - often
30         abbreviated with 'i' or 'I' in variable names
31     - supersampled coordinates, scale equal to the output * SCALE
32  */
33 
34 //#define FORCE_SUPERMASK
35 //#define FORCE_RLE
36 
37 ///////////////////////////////////////////////////////////////////////////////
38 
39 /// Base class for a single-pass supersampled blitter.
40 class BaseSuperBlitter : public SkBlitter {
41 public:
42     BaseSuperBlitter(SkBlitter* realBlitter, const SkIRect& ir,
43                      const SkRegion& clip, bool isInverse);
44 
45     /// Must be explicitly defined on subclasses.
blitAntiH(int x,int y,const SkAlpha antialias[],const int16_t runs[])46     virtual void blitAntiH(int x, int y, const SkAlpha antialias[],
47                            const int16_t runs[]) override {
48         SkDEBUGFAIL("How did I get here?");
49     }
50     /// May not be called on BaseSuperBlitter because it blits out of order.
blitV(int x,int y,int height,SkAlpha alpha)51     void blitV(int x, int y, int height, SkAlpha alpha) override {
52         SkDEBUGFAIL("How did I get here?");
53     }
54 
55 protected:
56     SkBlitter*  fRealBlitter;
57     /// Current y coordinate, in destination coordinates.
58     int         fCurrIY;
59     /// Widest row of region to be blitted, in destination coordinates.
60     int         fWidth;
61     /// Leftmost x coordinate in any row, in destination coordinates.
62     int         fLeft;
63     /// Leftmost x coordinate in any row, in supersampled coordinates.
64     int         fSuperLeft;
65 
66     SkDEBUGCODE(int fCurrX;)
67     /// Current y coordinate in supersampled coordinates.
68     int fCurrY;
69     /// Initial y coordinate (top of bounds).
70     int fTop;
71 
72     SkIRect fSectBounds;
73 };
74 
BaseSuperBlitter(SkBlitter * realBlit,const SkIRect & ir,const SkRegion & clip,bool isInverse)75 BaseSuperBlitter::BaseSuperBlitter(SkBlitter* realBlit, const SkIRect& ir, const SkRegion& clip,
76                                    bool isInverse) {
77     fRealBlitter = realBlit;
78 
79     SkIRect sectBounds;
80     if (isInverse) {
81         // We use the clip bounds instead of the ir, since we may be asked to
82         //draw outside of the rect when we're a inverse filltype
83         sectBounds = clip.getBounds();
84     } else {
85         if (!sectBounds.intersect(ir, clip.getBounds())) {
86             sectBounds.setEmpty();
87         }
88     }
89 
90     const int left = sectBounds.left();
91     const int right = sectBounds.right();
92 
93     fLeft = left;
94     fSuperLeft = SkLeftShift(left, SHIFT);
95     fWidth = right - left;
96     fTop = sectBounds.top();
97     fCurrIY = fTop - 1;
98     fCurrY = SkLeftShift(fTop, SHIFT) - 1;
99 
100     SkDEBUGCODE(fCurrX = -1;)
101 }
102 
103 /// Run-length-encoded supersampling antialiased blitter.
104 class SuperBlitter : public BaseSuperBlitter {
105 public:
106     SuperBlitter(SkBlitter* realBlitter, const SkIRect& ir, const SkRegion& clip, bool isInverse);
107 
~SuperBlitter()108     virtual ~SuperBlitter() {
109         this->flush();
110     }
111 
112     /// Once fRuns contains a complete supersampled row, flush() blits
113     /// it out through the wrapped blitter.
114     void flush();
115 
116     /// Blits a row of pixels, with location and width specified
117     /// in supersampled coordinates.
118     void blitH(int x, int y, int width) override;
119     /// Blits a rectangle of pixels, with location and size specified
120     /// in supersampled coordinates.
121     void blitRect(int x, int y, int width, int height) override;
122 
123 private:
124     // The next three variables are used to track a circular buffer that
125     // contains the values used in SkAlphaRuns. These variables should only
126     // ever be updated in advanceRuns(), and fRuns should always point to
127     // a valid SkAlphaRuns...
128     int         fRunsToBuffer;
129     void*       fRunsBuffer;
130     int         fCurrentRun;
131     SkAlphaRuns fRuns;
132 
133     // extra one to store the zero at the end
getRunsSz() const134     int getRunsSz() const { return (fWidth + 1 + (fWidth + 2)/2) * sizeof(int16_t); }
135 
136     // This function updates the fRuns variable to point to the next buffer space
137     // with adequate storage for a SkAlphaRuns. It mostly just advances fCurrentRun
138     // and resets fRuns to point to an empty scanline.
advanceRuns()139     void advanceRuns() {
140         const size_t kRunsSz = this->getRunsSz();
141         fCurrentRun = (fCurrentRun + 1) % fRunsToBuffer;
142         fRuns.fRuns = reinterpret_cast<int16_t*>(
143             reinterpret_cast<uint8_t*>(fRunsBuffer) + fCurrentRun * kRunsSz);
144         fRuns.fAlpha = reinterpret_cast<SkAlpha*>(fRuns.fRuns + fWidth + 1);
145         fRuns.reset(fWidth);
146     }
147 
148     int         fOffsetX;
149 };
150 
SuperBlitter(SkBlitter * realBlitter,const SkIRect & ir,const SkRegion & clip,bool isInverse)151 SuperBlitter::SuperBlitter(SkBlitter* realBlitter, const SkIRect& ir, const SkRegion& clip,
152                            bool isInverse)
153         : BaseSuperBlitter(realBlitter, ir, clip, isInverse)
154 {
155     fRunsToBuffer = realBlitter->requestRowsPreserved();
156     fRunsBuffer = realBlitter->allocBlitMemory(fRunsToBuffer * this->getRunsSz());
157     fCurrentRun = -1;
158 
159     this->advanceRuns();
160 
161     fOffsetX = 0;
162 }
163 
flush()164 void SuperBlitter::flush() {
165     if (fCurrIY >= fTop) {
166 
167         SkASSERT(fCurrentRun < fRunsToBuffer);
168         if (!fRuns.empty()) {
169             // SkDEBUGCODE(fRuns.dump();)
170             fRealBlitter->blitAntiH(fLeft, fCurrIY, fRuns.fAlpha, fRuns.fRuns);
171             this->advanceRuns();
172             fOffsetX = 0;
173         }
174 
175         fCurrIY = fTop - 1;
176         SkDEBUGCODE(fCurrX = -1;)
177     }
178 }
179 
180 /** coverage_to_partial_alpha() is being used by SkAlphaRuns, which
181     *accumulates* SCALE pixels worth of "alpha" in [0,(256/SCALE)]
182     to produce a final value in [0, 255] and handles clamping 256->255
183     itself, with the same (alpha - (alpha >> 8)) correction as
184     coverage_to_exact_alpha().
185 */
coverage_to_partial_alpha(int aa)186 static inline int coverage_to_partial_alpha(int aa) {
187     aa <<= 8 - 2*SHIFT;
188     return aa;
189 }
190 
191 /** coverage_to_exact_alpha() is being used by our blitter, which wants
192     a final value in [0, 255].
193 */
coverage_to_exact_alpha(int aa)194 static inline int coverage_to_exact_alpha(int aa) {
195     int alpha = (256 >> SHIFT) * aa;
196     // clamp 256->255
197     return alpha - (alpha >> 8);
198 }
199 
blitH(int x,int y,int width)200 void SuperBlitter::blitH(int x, int y, int width) {
201     SkASSERT(width > 0);
202 
203     int iy = y >> SHIFT;
204     SkASSERT(iy >= fCurrIY);
205 
206     x -= fSuperLeft;
207     // hack, until I figure out why my cubics (I think) go beyond the bounds
208     if (x < 0) {
209         width += x;
210         x = 0;
211     }
212 
213 #ifdef SK_DEBUG
214     SkASSERT(y != fCurrY || x >= fCurrX);
215 #endif
216     SkASSERT(y >= fCurrY);
217     if (fCurrY != y) {
218         fOffsetX = 0;
219         fCurrY = y;
220     }
221 
222     if (iy != fCurrIY) {  // new scanline
223         this->flush();
224         fCurrIY = iy;
225     }
226 
227     int start = x;
228     int stop = x + width;
229 
230     SkASSERT(start >= 0 && stop > start);
231     // integer-pixel-aligned ends of blit, rounded out
232     int fb = start & MASK;
233     int fe = stop & MASK;
234     int n = (stop >> SHIFT) - (start >> SHIFT) - 1;
235 
236     if (n < 0) {
237         fb = fe - fb;
238         n = 0;
239         fe = 0;
240     } else {
241         if (fb == 0) {
242             n += 1;
243         } else {
244             fb = SCALE - fb;
245         }
246     }
247 
248     fOffsetX = fRuns.add(x >> SHIFT, coverage_to_partial_alpha(fb),
249                          n, coverage_to_partial_alpha(fe),
250                          (1 << (8 - SHIFT)) - (((y & MASK) + 1) >> SHIFT),
251                          fOffsetX);
252 
253 #ifdef SK_DEBUG
254     fRuns.assertValid(y & MASK, (1 << (8 - SHIFT)));
255     fCurrX = x + width;
256 #endif
257 }
258 
259 #if 0 // UNUSED
260 static void set_left_rite_runs(SkAlphaRuns& runs, int ileft, U8CPU leftA,
261                                int n, U8CPU riteA) {
262     SkASSERT(leftA <= 0xFF);
263     SkASSERT(riteA <= 0xFF);
264 
265     int16_t* run = runs.fRuns;
266     uint8_t* aa = runs.fAlpha;
267 
268     if (ileft > 0) {
269         run[0] = ileft;
270         aa[0] = 0;
271         run += ileft;
272         aa += ileft;
273     }
274 
275     SkASSERT(leftA < 0xFF);
276     if (leftA > 0) {
277         *run++ = 1;
278         *aa++ = leftA;
279     }
280 
281     if (n > 0) {
282         run[0] = n;
283         aa[0] = 0xFF;
284         run += n;
285         aa += n;
286     }
287 
288     SkASSERT(riteA < 0xFF);
289     if (riteA > 0) {
290         *run++ = 1;
291         *aa++ = riteA;
292     }
293     run[0] = 0;
294 }
295 #endif
296 
blitRect(int x,int y,int width,int height)297 void SuperBlitter::blitRect(int x, int y, int width, int height) {
298     SkASSERT(width > 0);
299     SkASSERT(height > 0);
300 
301     // blit leading rows
302     while ((y & MASK)) {
303         this->blitH(x, y++, width);
304         if (--height <= 0) {
305             return;
306         }
307     }
308     SkASSERT(height > 0);
309 
310     // Since this is a rect, instead of blitting supersampled rows one at a
311     // time and then resolving to the destination canvas, we can blit
312     // directly to the destintion canvas one row per SCALE supersampled rows.
313     int start_y = y >> SHIFT;
314     int stop_y = (y + height) >> SHIFT;
315     int count = stop_y - start_y;
316     if (count > 0) {
317         y += count << SHIFT;
318         height -= count << SHIFT;
319 
320         // save original X for our tail blitH() loop at the bottom
321         int origX = x;
322 
323         x -= fSuperLeft;
324         // hack, until I figure out why my cubics (I think) go beyond the bounds
325         if (x < 0) {
326             width += x;
327             x = 0;
328         }
329 
330         // There is always a left column, a middle, and a right column.
331         // ileft is the destination x of the first pixel of the entire rect.
332         // xleft is (SCALE - # of covered supersampled pixels) in that
333         // destination pixel.
334         int ileft = x >> SHIFT;
335         int xleft = x & MASK;
336         // irite is the destination x of the last pixel of the OPAQUE section.
337         // xrite is the number of supersampled pixels extending beyond irite;
338         // xrite/SCALE should give us alpha.
339         int irite = (x + width) >> SHIFT;
340         int xrite = (x + width) & MASK;
341         if (!xrite) {
342             xrite = SCALE;
343             irite--;
344         }
345 
346         // Need to call flush() to clean up pending draws before we
347         // even consider blitV(), since otherwise it can look nonmonotonic.
348         SkASSERT(start_y > fCurrIY);
349         this->flush();
350 
351         int n = irite - ileft - 1;
352         if (n < 0) {
353             // If n < 0, we'll only have a single partially-transparent column
354             // of pixels to render.
355             xleft = xrite - xleft;
356             SkASSERT(xleft <= SCALE);
357             SkASSERT(xleft > 0);
358             xrite = 0;
359             fRealBlitter->blitV(ileft + fLeft, start_y, count,
360                 coverage_to_exact_alpha(xleft));
361         } else {
362             // With n = 0, we have two possibly-transparent columns of pixels
363             // to render; with n > 0, we have opaque columns between them.
364 
365             xleft = SCALE - xleft;
366 
367             // Using coverage_to_exact_alpha is not consistent with blitH()
368             const int coverageL = coverage_to_exact_alpha(xleft);
369             const int coverageR = coverage_to_exact_alpha(xrite);
370 
371             SkASSERT(coverageL > 0 || n > 0 || coverageR > 0);
372             SkASSERT((coverageL != 0) + n + (coverageR != 0) <= fWidth);
373 
374             fRealBlitter->blitAntiRect(ileft + fLeft, start_y, n, count,
375                                        coverageL, coverageR);
376         }
377 
378         // preamble for our next call to blitH()
379         fCurrIY = stop_y - 1;
380         fOffsetX = 0;
381         fCurrY = y - 1;
382         fRuns.reset(fWidth);
383         x = origX;
384     }
385 
386     // catch any remaining few rows
387     SkASSERT(height <= MASK);
388     while (--height >= 0) {
389         this->blitH(x, y++, width);
390     }
391 }
392 
393 ///////////////////////////////////////////////////////////////////////////////
394 
395 /// Masked supersampling antialiased blitter.
396 class MaskSuperBlitter : public BaseSuperBlitter {
397 public:
398     MaskSuperBlitter(SkBlitter* realBlitter, const SkIRect& ir, const SkRegion&, bool isInverse);
~MaskSuperBlitter()399     virtual ~MaskSuperBlitter() {
400         fRealBlitter->blitMask(fMask, fClipRect);
401     }
402 
403     void blitH(int x, int y, int width) override;
404 
CanHandleRect(const SkIRect & bounds)405     static bool CanHandleRect(const SkIRect& bounds) {
406 #ifdef FORCE_RLE
407         return false;
408 #endif
409         int width = bounds.width();
410         int64_t rb = SkAlign4(width);
411         // use 64bits to detect overflow
412         int64_t storage = rb * bounds.height();
413 
414         return (width <= MaskSuperBlitter::kMAX_WIDTH) &&
415                (storage <= MaskSuperBlitter::kMAX_STORAGE);
416     }
417 
418 private:
419     enum {
420 #ifdef FORCE_SUPERMASK
421         kMAX_WIDTH = 2048,
422         kMAX_STORAGE = 1024 * 1024 * 2
423 #else
424         kMAX_WIDTH = 32,    // so we don't try to do very wide things, where the RLE blitter would be faster
425         kMAX_STORAGE = 1024
426 #endif
427     };
428 
429     SkMask      fMask;
430     SkIRect     fClipRect;
431     // we add 1 because add_aa_span can write (unchanged) 1 extra byte at the end, rather than
432     // perform a test to see if stopAlpha != 0
433     uint32_t    fStorage[(kMAX_STORAGE >> 2) + 1];
434 };
435 
MaskSuperBlitter(SkBlitter * realBlitter,const SkIRect & ir,const SkRegion & clip,bool isInverse)436 MaskSuperBlitter::MaskSuperBlitter(SkBlitter* realBlitter, const SkIRect& ir, const SkRegion& clip,
437                                    bool isInverse)
438     : BaseSuperBlitter(realBlitter, ir, clip, isInverse)
439 {
440     SkASSERT(CanHandleRect(ir));
441     SkASSERT(!isInverse);
442 
443     fMask.fImage    = (uint8_t*)fStorage;
444     fMask.fBounds   = ir;
445     fMask.fRowBytes = ir.width();
446     fMask.fFormat   = SkMask::kA8_Format;
447 
448     fClipRect = ir;
449     if (!fClipRect.intersect(clip.getBounds())) {
450         SkASSERT(0);
451         fClipRect.setEmpty();
452     }
453 
454     // For valgrind, write 1 extra byte at the end so we don't read
455     // uninitialized memory. See comment in add_aa_span and fStorage[].
456     memset(fStorage, 0, fMask.fBounds.height() * fMask.fRowBytes + 1);
457 }
458 
add_aa_span(uint8_t * alpha,U8CPU startAlpha)459 static void add_aa_span(uint8_t* alpha, U8CPU startAlpha) {
460     /*  I should be able to just add alpha[x] + startAlpha.
461         However, if the trailing edge of the previous span and the leading
462         edge of the current span round to the same super-sampled x value,
463         I might overflow to 256 with this add, hence the funny subtract.
464     */
465     unsigned tmp = *alpha + startAlpha;
466     SkASSERT(tmp <= 256);
467     *alpha = SkToU8(tmp - (tmp >> 8));
468 }
469 
quadplicate_byte(U8CPU value)470 static inline uint32_t quadplicate_byte(U8CPU value) {
471     uint32_t pair = (value << 8) | value;
472     return (pair << 16) | pair;
473 }
474 
475 // Perform this tricky subtract, to avoid overflowing to 256. Our caller should
476 // only ever call us with at most enough to hit 256 (never larger), so it is
477 // enough to just subtract the high-bit. Actually clamping with a branch would
478 // be slower (e.g. if (tmp > 255) tmp = 255;)
479 //
saturated_add(uint8_t * ptr,U8CPU add)480 static inline void saturated_add(uint8_t* ptr, U8CPU add) {
481     unsigned tmp = *ptr + add;
482     SkASSERT(tmp <= 256);
483     *ptr = SkToU8(tmp - (tmp >> 8));
484 }
485 
486 // minimum count before we want to setup an inner loop, adding 4-at-a-time
487 #define MIN_COUNT_FOR_QUAD_LOOP  16
488 
add_aa_span(uint8_t * alpha,U8CPU startAlpha,int middleCount,U8CPU stopAlpha,U8CPU maxValue)489 static void add_aa_span(uint8_t* alpha, U8CPU startAlpha, int middleCount,
490                         U8CPU stopAlpha, U8CPU maxValue) {
491     SkASSERT(middleCount >= 0);
492 
493     saturated_add(alpha, startAlpha);
494     alpha += 1;
495 
496     if (middleCount >= MIN_COUNT_FOR_QUAD_LOOP) {
497         // loop until we're quad-byte aligned
498         while (SkTCast<intptr_t>(alpha) & 0x3) {
499             alpha[0] = SkToU8(alpha[0] + maxValue);
500             alpha += 1;
501             middleCount -= 1;
502         }
503 
504         int bigCount = middleCount >> 2;
505         uint32_t* qptr = reinterpret_cast<uint32_t*>(alpha);
506         uint32_t qval = quadplicate_byte(maxValue);
507         do {
508             *qptr++ += qval;
509         } while (--bigCount > 0);
510 
511         middleCount &= 3;
512         alpha = reinterpret_cast<uint8_t*> (qptr);
513         // fall through to the following while-loop
514     }
515 
516     while (--middleCount >= 0) {
517         alpha[0] = SkToU8(alpha[0] + maxValue);
518         alpha += 1;
519     }
520 
521     // potentially this can be off the end of our "legal" alpha values, but that
522     // only happens if stopAlpha is also 0. Rather than test for stopAlpha != 0
523     // every time (slow), we just do it, and ensure that we've allocated extra space
524     // (see the + 1 comment in fStorage[]
525     saturated_add(alpha, stopAlpha);
526 }
527 
blitH(int x,int y,int width)528 void MaskSuperBlitter::blitH(int x, int y, int width) {
529     int iy = (y >> SHIFT);
530 
531     SkASSERT(iy >= fMask.fBounds.fTop && iy < fMask.fBounds.fBottom);
532     iy -= fMask.fBounds.fTop;   // make it relative to 0
533 
534     // This should never happen, but it does.  Until the true cause is
535     // discovered, let's skip this span instead of crashing.
536     // See http://crbug.com/17569.
537     if (iy < 0) {
538         return;
539     }
540 
541 #ifdef SK_DEBUG
542     {
543         int ix = x >> SHIFT;
544         SkASSERT(ix >= fMask.fBounds.fLeft && ix < fMask.fBounds.fRight);
545     }
546 #endif
547 
548     x -= SkLeftShift(fMask.fBounds.fLeft, SHIFT);
549 
550     // hack, until I figure out why my cubics (I think) go beyond the bounds
551     if (x < 0) {
552         width += x;
553         x = 0;
554     }
555 
556     uint8_t* row = fMask.fImage + iy * fMask.fRowBytes + (x >> SHIFT);
557 
558     int start = x;
559     int stop = x + width;
560 
561     SkASSERT(start >= 0 && stop > start);
562     int fb = start & MASK;
563     int fe = stop & MASK;
564     int n = (stop >> SHIFT) - (start >> SHIFT) - 1;
565 
566 
567     if (n < 0) {
568         SkASSERT(row >= fMask.fImage);
569         SkASSERT(row < fMask.fImage + kMAX_STORAGE + 1);
570         add_aa_span(row, coverage_to_partial_alpha(fe - fb));
571     } else {
572         fb = SCALE - fb;
573         SkASSERT(row >= fMask.fImage);
574         SkASSERT(row + n + 1 < fMask.fImage + kMAX_STORAGE + 1);
575         add_aa_span(row,  coverage_to_partial_alpha(fb),
576                     n, coverage_to_partial_alpha(fe),
577                     (1 << (8 - SHIFT)) - (((y & MASK) + 1) >> SHIFT));
578     }
579 
580 #ifdef SK_DEBUG
581     fCurrX = x + width;
582 #endif
583 }
584 
585 ///////////////////////////////////////////////////////////////////////////////
586 
fitsInsideLimit(const SkRect & r,SkScalar max)587 static bool fitsInsideLimit(const SkRect& r, SkScalar max) {
588     const SkScalar min = -max;
589     return  r.fLeft > min && r.fTop > min &&
590             r.fRight < max && r.fBottom < max;
591 }
592 
overflows_short_shift(int value,int shift)593 static int overflows_short_shift(int value, int shift) {
594     const int s = 16 + shift;
595     return (SkLeftShift(value, s) >> s) - value;
596 }
597 
598 /**
599   Would any of the coordinates of this rectangle not fit in a short,
600   when left-shifted by shift?
601 */
rect_overflows_short_shift(SkIRect rect,int shift)602 static int rect_overflows_short_shift(SkIRect rect, int shift) {
603     SkASSERT(!overflows_short_shift(8191, SHIFT));
604     SkASSERT(overflows_short_shift(8192, SHIFT));
605     SkASSERT(!overflows_short_shift(32767, 0));
606     SkASSERT(overflows_short_shift(32768, 0));
607 
608     // Since we expect these to succeed, we bit-or together
609     // for a tiny extra bit of speed.
610     return overflows_short_shift(rect.fLeft, SHIFT) |
611            overflows_short_shift(rect.fRight, SHIFT) |
612            overflows_short_shift(rect.fTop, SHIFT) |
613            overflows_short_shift(rect.fBottom, SHIFT);
614 }
615 
safeRoundOut(const SkRect & src,SkIRect * dst,int32_t maxInt)616 static bool safeRoundOut(const SkRect& src, SkIRect* dst, int32_t maxInt) {
617     const SkScalar maxScalar = SkIntToScalar(maxInt);
618 
619     if (fitsInsideLimit(src, maxScalar)) {
620         src.roundOut(dst);
621         return true;
622     }
623     return false;
624 }
625 
AntiFillPath(const SkPath & path,const SkRegion & origClip,SkBlitter * blitter,bool forceRLE)626 void SkScan::AntiFillPath(const SkPath& path, const SkRegion& origClip,
627                           SkBlitter* blitter, bool forceRLE) {
628     if (origClip.isEmpty()) {
629         return;
630     }
631 
632     const bool isInverse = path.isInverseFillType();
633     SkIRect ir;
634 
635     if (!safeRoundOut(path.getBounds(), &ir, SK_MaxS32 >> SHIFT)) {
636 #if 0
637         const SkRect& r = path.getBounds();
638         SkDebugf("--- bounds can't fit in SkIRect\n", r.fLeft, r.fTop, r.fRight, r.fBottom);
639 #endif
640         return;
641     }
642     if (ir.isEmpty()) {
643         if (isInverse) {
644             blitter->blitRegion(origClip);
645         }
646         return;
647     }
648 
649     // If the intersection of the path bounds and the clip bounds
650     // will overflow 32767 when << by SHIFT, we can't supersample,
651     // so draw without antialiasing.
652     SkIRect clippedIR;
653     if (isInverse) {
654        // If the path is an inverse fill, it's going to fill the entire
655        // clip, and we care whether the entire clip exceeds our limits.
656        clippedIR = origClip.getBounds();
657     } else {
658        if (!clippedIR.intersect(ir, origClip.getBounds())) {
659            return;
660        }
661     }
662     if (rect_overflows_short_shift(clippedIR, SHIFT)) {
663         SkScan::FillPath(path, origClip, blitter);
664         return;
665     }
666 
667     // Our antialiasing can't handle a clip larger than 32767, so we restrict
668     // the clip to that limit here. (the runs[] uses int16_t for its index).
669     //
670     // A more general solution (one that could also eliminate the need to
671     // disable aa based on ir bounds (see overflows_short_shift) would be
672     // to tile the clip/target...
673     SkRegion tmpClipStorage;
674     const SkRegion* clipRgn = &origClip;
675     {
676         static const int32_t kMaxClipCoord = 32767;
677         const SkIRect& bounds = origClip.getBounds();
678         if (bounds.fRight > kMaxClipCoord || bounds.fBottom > kMaxClipCoord) {
679             SkIRect limit = { 0, 0, kMaxClipCoord, kMaxClipCoord };
680             tmpClipStorage.op(origClip, limit, SkRegion::kIntersect_Op);
681             clipRgn = &tmpClipStorage;
682         }
683     }
684     // for here down, use clipRgn, not origClip
685 
686     SkScanClipper   clipper(blitter, clipRgn, ir);
687     const SkIRect*  clipRect = clipper.getClipRect();
688 
689     if (clipper.getBlitter() == nullptr) { // clipped out
690         if (isInverse) {
691             blitter->blitRegion(*clipRgn);
692         }
693         return;
694     }
695 
696     // now use the (possibly wrapped) blitter
697     blitter = clipper.getBlitter();
698 
699     if (isInverse) {
700         sk_blit_above(blitter, ir, *clipRgn);
701     }
702 
703     SkIRect superRect, *superClipRect = nullptr;
704 
705     if (clipRect) {
706         superRect.set(SkLeftShift(clipRect->fLeft, SHIFT),
707                       SkLeftShift(clipRect->fTop, SHIFT),
708                       SkLeftShift(clipRect->fRight, SHIFT),
709                       SkLeftShift(clipRect->fBottom, SHIFT));
710         superClipRect = &superRect;
711     }
712 
713     SkASSERT(SkIntToScalar(ir.fTop) <= path.getBounds().fTop);
714 
715     // MaskSuperBlitter can't handle drawing outside of ir, so we can't use it
716     // if we're an inverse filltype
717     if (!isInverse && MaskSuperBlitter::CanHandleRect(ir) && !forceRLE) {
718         MaskSuperBlitter    superBlit(blitter, ir, *clipRgn, isInverse);
719         SkASSERT(SkIntToScalar(ir.fTop) <= path.getBounds().fTop);
720         sk_fill_path(path, superClipRect, &superBlit, ir.fTop, ir.fBottom, SHIFT, *clipRgn);
721     } else {
722         SuperBlitter    superBlit(blitter, ir, *clipRgn, isInverse);
723         sk_fill_path(path, superClipRect, &superBlit, ir.fTop, ir.fBottom, SHIFT, *clipRgn);
724     }
725 
726     if (isInverse) {
727         sk_blit_below(blitter, ir, *clipRgn);
728     }
729 }
730 
731 ///////////////////////////////////////////////////////////////////////////////
732 
733 #include "SkRasterClip.h"
734 
FillPath(const SkPath & path,const SkRasterClip & clip,SkBlitter * blitter)735 void SkScan::FillPath(const SkPath& path, const SkRasterClip& clip,
736                           SkBlitter* blitter) {
737     if (clip.isEmpty()) {
738         return;
739     }
740 
741     if (clip.isBW()) {
742         FillPath(path, clip.bwRgn(), blitter);
743     } else {
744         SkRegion        tmp;
745         SkAAClipBlitter aaBlitter;
746 
747         tmp.setRect(clip.getBounds());
748         aaBlitter.init(blitter, &clip.aaRgn());
749         SkScan::FillPath(path, tmp, &aaBlitter);
750     }
751 }
752 
AntiFillPath(const SkPath & path,const SkRasterClip & clip,SkBlitter * blitter)753 void SkScan::AntiFillPath(const SkPath& path, const SkRasterClip& clip,
754                           SkBlitter* blitter) {
755     if (clip.isEmpty()) {
756         return;
757     }
758 
759     if (clip.isBW()) {
760         AntiFillPath(path, clip.bwRgn(), blitter);
761     } else {
762         SkRegion        tmp;
763         SkAAClipBlitter aaBlitter;
764 
765         tmp.setRect(clip.getBounds());
766         aaBlitter.init(blitter, &clip.aaRgn());
767         SkScan::AntiFillPath(path, tmp, &aaBlitter, true);
768     }
769 }
770