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Side by Side Diff: skia/sgl/SkScan_Path.cpp

Issue 113827: Remove the remainder of the skia source code from the Chromium repo.... (Closed) Base URL: svn://chrome-svn/chrome/trunk/src/
Patch Set: Created 11 years, 7 months ago
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1 /* libs/graphics/sgl/SkScan_Path.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 "SkScanPriv.h"
19 #include "SkBlitter.h"
20 #include "SkEdge.h"
21 #include "SkGeometry.h"
22 #include "SkPath.h"
23 #include "SkRegion.h"
24 #include "SkTemplates.h"
25
26 #define kEDGE_HEAD_Y SK_MinS32
27 #define kEDGE_TAIL_Y SK_MaxS32
28
29 #ifdef SK_DEBUG
30 static void validate_sort(const SkEdge* edge)
31 {
32 int y = kEDGE_HEAD_Y;
33
34 while (edge->fFirstY != SK_MaxS32)
35 {
36 edge->validate();
37 SkASSERT(y <= edge->fFirstY);
38
39 y = edge->fFirstY;
40 edge = edge->fNext;
41 }
42 }
43 #else
44 #define validate_sort(edge)
45 #endif
46
47 static inline void remove_edge(SkEdge* edge)
48 {
49 edge->fPrev->fNext = edge->fNext;
50 edge->fNext->fPrev = edge->fPrev;
51 }
52
53 static inline void swap_edges(SkEdge* prev, SkEdge* next)
54 {
55 SkASSERT(prev->fNext == next && next->fPrev == prev);
56
57 // remove prev from the list
58 prev->fPrev->fNext = next;
59 next->fPrev = prev->fPrev;
60
61 // insert prev after next
62 prev->fNext = next->fNext;
63 next->fNext->fPrev = prev;
64 next->fNext = prev;
65 prev->fPrev = next;
66 }
67
68 static void backward_insert_edge_based_on_x(SkEdge* edge SkDECLAREPARAM(int, cur r_y))
69 {
70 SkFixed x = edge->fX;
71
72 for (;;)
73 {
74 SkEdge* prev = edge->fPrev;
75
76 // add 1 to curr_y since we may have added new edges (built from curves)
77 // that start on the next scanline
78 SkASSERT(prev && prev->fFirstY <= curr_y + 1);
79
80 if (prev->fX <= x)
81 break;
82
83 swap_edges(prev, edge);
84 }
85 }
86
87 static void insert_new_edges(SkEdge* newEdge, int curr_y)
88 {
89 SkASSERT(newEdge->fFirstY >= curr_y);
90
91 while (newEdge->fFirstY == curr_y)
92 {
93 SkEdge* next = newEdge->fNext;
94 backward_insert_edge_based_on_x(newEdge SkPARAM(curr_y));
95 newEdge = next;
96 }
97 }
98
99 #ifdef SK_DEBUG
100 static void validate_edges_for_y(const SkEdge* edge, int curr_y)
101 {
102 while (edge->fFirstY <= curr_y)
103 {
104 SkASSERT(edge->fPrev && edge->fNext);
105 SkASSERT(edge->fPrev->fNext == edge);
106 SkASSERT(edge->fNext->fPrev == edge);
107 SkASSERT(edge->fFirstY <= edge->fLastY);
108
109 SkASSERT(edge->fPrev->fX <= edge->fX);
110 edge = edge->fNext;
111 }
112 }
113 #else
114 #define validate_edges_for_y(edge, curr_y)
115 #endif
116
117 #if defined _WIN32 && _MSC_VER >= 1300 // disable warning : local variable used without having been initialized
118 #pragma warning ( push )
119 #pragma warning ( disable : 4701 )
120 #endif
121
122 typedef void (*PrePostProc)(SkBlitter* blitter, int y, bool isStartOfScanline);
123 #define PREPOST_START true
124 #define PREPOST_END false
125
126 static void walk_edges(SkEdge* prevHead, SkPath::FillType fillType,
127 SkBlitter* blitter, int stop_y, PrePostProc proc)
128 {
129 validate_sort(prevHead->fNext);
130
131 int curr_y = prevHead->fNext->fFirstY;
132 // returns 1 for evenodd, -1 for winding, regardless of inverse-ness
133 int windingMask = (fillType & 1) ? 1 : -1;
134
135 for (;;)
136 {
137 int w = 0;
138 int left SK_INIT_TO_AVOID_WARNING;
139 bool in_interval = false;
140 SkEdge* currE = prevHead->fNext;
141 SkFixed prevX = prevHead->fX;
142
143 validate_edges_for_y(currE, curr_y);
144
145 if (proc) {
146 proc(blitter, curr_y, PREPOST_START); // pre-proc
147 }
148
149 while (currE->fFirstY <= curr_y)
150 {
151 SkASSERT(currE->fLastY >= curr_y);
152
153 int x = (currE->fX + SK_Fixed1/2) >> 16;
154 w += currE->fWinding;
155 if ((w & windingMask) == 0) // we finished an interval
156 {
157 SkASSERT(in_interval);
158 int width = x - left;
159 SkASSERT(width >= 0);
160 if (width)
161 blitter->blitH(left, curr_y, width);
162 in_interval = false;
163 }
164 else if (!in_interval)
165 {
166 left = x;
167 in_interval = true;
168 }
169
170 SkEdge* next = currE->fNext;
171 SkFixed newX;
172
173 if (currE->fLastY == curr_y) // are we done with this edge?
174 {
175 if (currE->fCurveCount < 0)
176 {
177 if (((SkCubicEdge*)currE)->updateCubic())
178 {
179 SkASSERT(currE->fFirstY == curr_y + 1);
180
181 newX = currE->fX;
182 goto NEXT_X;
183 }
184 }
185 else if (currE->fCurveCount > 0)
186 {
187 if (((SkQuadraticEdge*)currE)->updateQuadratic())
188 {
189 newX = currE->fX;
190 goto NEXT_X;
191 }
192 }
193 remove_edge(currE);
194 }
195 else
196 {
197 SkASSERT(currE->fLastY > curr_y);
198 newX = currE->fX + currE->fDX;
199 currE->fX = newX;
200 NEXT_X:
201 if (newX < prevX) // ripple currE backwards until it is x-sort ed
202 backward_insert_edge_based_on_x(currE SkPARAM(curr_y));
203 else
204 prevX = newX;
205 }
206 currE = next;
207 SkASSERT(currE);
208 }
209
210 if (proc) {
211 proc(blitter, curr_y, PREPOST_END); // post-proc
212 }
213
214 curr_y += 1;
215 if (curr_y >= stop_y)
216 break;
217
218 // now currE points to the first edge with a Yint larger than curr_y
219 insert_new_edges(currE, curr_y);
220 }
221 }
222
223 ///////////////////////////////////////////////////////////////////////////////
224
225 // this guy overrides blitH, and will call its proxy blitter with the inverse
226 // of the spans it is given (clipped to the left/right of the cliprect)
227 //
228 // used to implement inverse filltypes on paths
229 //
230 class InverseBlitter : public SkBlitter {
231 public:
232 void setBlitter(SkBlitter* blitter, const SkIRect& clip, int shift) {
233 fBlitter = blitter;
234 fFirstX = clip.fLeft << shift;
235 fLastX = clip.fRight << shift;
236 }
237 void prepost(int y, bool isStart) {
238 if (isStart) {
239 fPrevX = fFirstX;
240 } else {
241 int invWidth = fLastX - fPrevX;
242 if (invWidth > 0) {
243 fBlitter->blitH(fPrevX, y, invWidth);
244 }
245 }
246 }
247
248 // overrides
249 virtual void blitH(int x, int y, int width) {
250 int invWidth = x - fPrevX;
251 if (invWidth > 0) {
252 fBlitter->blitH(fPrevX, y, invWidth);
253 }
254 fPrevX = x + width;
255 }
256
257 // we do not expect to get called with these entrypoints
258 virtual void blitAntiH(int, int, const SkAlpha[], const int16_t runs[]) {
259 SkASSERT(!"blitAntiH unexpected");
260 }
261 virtual void blitV(int x, int y, int height, SkAlpha alpha) {
262 SkASSERT(!"blitV unexpected");
263 }
264 virtual void blitRect(int x, int y, int width, int height) {
265 SkASSERT(!"blitRect unexpected");
266 }
267 virtual void blitMask(const SkMask&, const SkIRect& clip) {
268 SkASSERT(!"blitMask unexpected");
269 }
270 virtual const SkBitmap* justAnOpaqueColor(uint32_t* value) {
271 SkASSERT(!"justAnOpaqueColor unexpected");
272 return NULL;
273 }
274
275 private:
276 SkBlitter* fBlitter;
277 int fFirstX, fLastX, fPrevX;
278 };
279
280 static void PrePostInverseBlitterProc(SkBlitter* blitter, int y, bool isStart) {
281 ((InverseBlitter*)blitter)->prepost(y, isStart);
282 }
283
284 ///////////////////////////////////////////////////////////////////////////////
285
286 #if defined _WIN32 && _MSC_VER >= 1300
287 #pragma warning ( pop )
288 #endif
289
290 /* Our line edge relies on the maximum span being <= 512, so that it can
291 use FDot6 and keep the dx,dy in 16bits (for much faster slope divide).
292 This function returns true if the specified line is too big.
293 */
294 static inline bool line_too_big(const SkPoint pts[2])
295 {
296 SkScalar dx = pts[1].fX - pts[0].fX;
297 SkScalar dy = pts[1].fY - pts[0].fY;
298
299 return SkScalarAbs(dx) > SkIntToScalar(511) ||
300 SkScalarAbs(dy) > SkIntToScalar(511);
301 }
302
303 static int build_edges(SkEdge edge[], const SkPath& path,
304 const SkIRect* clipRect, SkEdge* list[], int shiftUp) {
305 SkEdge** start = list;
306 SkPath::Iter iter(path, true);
307 SkPoint pts[4];
308 SkPath::Verb verb;
309
310 while ((verb = iter.next(pts)) != SkPath::kDone_Verb) {
311 switch (verb) {
312 case SkPath::kLine_Verb:
313 if (edge->setLine(pts[0], pts[1], clipRect, shiftUp)) {
314 *list++ = edge;
315 edge = (SkEdge*)((char*)edge + sizeof(SkEdge));
316 }
317 break;
318 case SkPath::kQuad_Verb: {
319 SkPoint tmp[5];
320 SkPoint* p = tmp;
321 int count = SkChopQuadAtYExtrema(pts, tmp);
322
323 do {
324 if (((SkQuadraticEdge*)edge)->setQuadratic(p, clipRect,
325 shiftUp))
326 {
327 *list++ = edge;
328 edge = (SkEdge*)((char*)edge + sizeof(SkQuadraticEdge));
329 }
330 p += 2;
331 } while (--count >= 0);
332 break;
333 }
334 case SkPath::kCubic_Verb: {
335 SkPoint tmp[10];
336 SkPoint* p = tmp;
337 int count = SkChopCubicAtYExtrema(pts, tmp);
338 SkASSERT(count >= 0 && count <= 2);
339
340 do {
341 if (((SkCubicEdge*)edge)->setCubic(p, clipRect, shiftUp))
342 {
343 *list++ = edge;
344 edge = (SkEdge*)((char*)edge + sizeof(SkCubicEdge));
345 }
346 p += 3;
347 } while (--count >= 0);
348 break;
349 }
350 default:
351 break;
352 }
353 }
354 return (int)(list - start);
355 }
356
357 extern "C" {
358 static int edge_compare(const void* a, const void* b)
359 {
360 const SkEdge* edgea = *(const SkEdge**)a;
361 const SkEdge* edgeb = *(const SkEdge**)b;
362
363 int valuea = edgea->fFirstY;
364 int valueb = edgeb->fFirstY;
365
366 if (valuea == valueb)
367 {
368 valuea = edgea->fX;
369 valueb = edgeb->fX;
370 }
371 return valuea - valueb;
372 }
373 }
374
375 static SkEdge* sort_edges(SkEdge* list[], int count, SkEdge** last)
376 {
377 qsort(list, count, sizeof(SkEdge*), edge_compare);
378
379 // now make the edges linked in sorted order
380 for (int i = 1; i < count; i++)
381 {
382 list[i - 1]->fNext = list[i];
383 list[i]->fPrev = list[i - 1];
384 }
385
386 *last = list[count - 1];
387 return list[0];
388 }
389
390 /* 'quick' computation of the max sized needed to allocated for
391 our edgelist.
392 */
393 static int worst_case_edge_count(const SkPath& path, size_t* storage)
394 {
395 size_t size = 0;
396 int edgeCount = 0;
397
398 SkPath::Iter iter(path, true);
399 SkPath::Verb verb;
400
401 while ((verb = iter.next(NULL)) != SkPath::kDone_Verb)
402 {
403 switch (verb) {
404 case SkPath::kLine_Verb:
405 edgeCount += 1;
406 size += sizeof(SkQuadraticEdge); // treat line like Quad (in case its > 512)
407 break;
408 case SkPath::kQuad_Verb:
409 edgeCount += 2; // might need 2 edges when we ch op on Y extrema
410 size += 2 * sizeof(SkQuadraticEdge);
411 break;
412 case SkPath::kCubic_Verb:
413 edgeCount += 3; // might need 3 edges when we ch op on Y extrema
414 size += 3 * sizeof(SkCubicEdge);
415 break;
416 default:
417 break;
418 }
419 }
420
421 SkASSERT(storage);
422 *storage = size;
423 return edgeCount;
424 }
425
426 /* Much faster than worst_case_edge_count, but over estimates even more
427 */
428 static int cheap_worst_case_edge_count(const SkPath& path, size_t* storage)
429 {
430 int ptCount = path.getPoints(NULL, 0);
431 int edgeCount = ptCount;
432 *storage = edgeCount * sizeof(SkCubicEdge);
433 return edgeCount;
434 }
435
436 // clipRect may be null, even though we always have a clip. This indicates that
437 // the path is contained in the clip, and so we can ignore it during the blit
438 //
439 // clipRect (if no null) has already been shifted up
440 //
441 void sk_fill_path(const SkPath& path, const SkIRect* clipRect, SkBlitter* blitte r,
442 int stop_y, int shiftEdgesUp, const SkRegion& clipRgn)
443 {
444 SkASSERT(&path && blitter);
445
446 size_t size;
447 int maxCount = cheap_worst_case_edge_count(path, &size);
448
449 #ifdef SK_DEBUG
450 {
451 size_t size2;
452 int maxCount2 = worst_case_edge_count(path, &size2);
453
454 SkASSERT(maxCount >= maxCount2 && size >= size2);
455 }
456 #endif
457
458 SkAutoMalloc memory(maxCount * sizeof(SkEdge*) + size);
459 SkEdge** list = (SkEdge**)memory.get();
460 SkEdge* edge = (SkEdge*)(list + maxCount);
461 int count = build_edges(edge, path, clipRect, list, shiftEdgesUp );
462 SkEdge headEdge, tailEdge, *last;
463
464 SkASSERT(count <= maxCount);
465 if (count == 0) {
466 return;
467 }
468 SkASSERT(count > 1);
469
470 // this returns the first and last edge after they're sorted into a dlink li st
471 edge = sort_edges(list, count, &last);
472
473 headEdge.fPrev = NULL;
474 headEdge.fNext = edge;
475 headEdge.fFirstY = kEDGE_HEAD_Y;
476 headEdge.fX = SK_MinS32;
477 edge->fPrev = &headEdge;
478
479 tailEdge.fPrev = last;
480 tailEdge.fNext = NULL;
481 tailEdge.fFirstY = kEDGE_TAIL_Y;
482 last->fNext = &tailEdge;
483
484 // now edge is the head of the sorted linklist
485
486 stop_y <<= shiftEdgesUp;
487 if (clipRect && stop_y > clipRect->fBottom) {
488 stop_y = clipRect->fBottom;
489 }
490
491 InverseBlitter ib;
492 PrePostProc proc = NULL;
493
494 if (path.isInverseFillType()) {
495 ib.setBlitter(blitter, clipRgn.getBounds(), shiftEdgesUp);
496 blitter = &ib;
497 proc = PrePostInverseBlitterProc;
498 }
499
500 walk_edges(&headEdge, path.getFillType(), blitter, stop_y, proc);
501 }
502
503 void sk_blit_above_and_below(SkBlitter* blitter, const SkIRect& ir,
504 const SkRegion& clip) {
505 const SkIRect& cr = clip.getBounds();
506 SkIRect tmp;
507
508 tmp.fLeft = cr.fLeft;
509 tmp.fRight = cr.fRight;
510
511 tmp.fTop = cr.fTop;
512 tmp.fBottom = ir.fTop;
513 if (!tmp.isEmpty()) {
514 blitter->blitRectRegion(tmp, clip);
515 }
516
517 tmp.fTop = ir.fBottom;
518 tmp.fBottom = cr.fBottom;
519 if (!tmp.isEmpty()) {
520 blitter->blitRectRegion(tmp, clip);
521 }
522 }
523
524 //////////////////////////////////////////////////////////////////////////////// /////
525
526 SkScanClipper::SkScanClipper(SkBlitter* blitter, const SkRegion* clip, const SkI Rect& ir)
527 {
528 fBlitter = NULL; // null means blit nothing
529 fClipRect = NULL;
530
531 if (clip)
532 {
533 fClipRect = &clip->getBounds();
534 if (!SkIRect::Intersects(*fClipRect, ir)) // completely clipped out
535 return;
536
537 if (clip->isRect())
538 {
539 if (fClipRect->contains(ir))
540 fClipRect = NULL;
541 else
542 {
543 // only need a wrapper blitter if we're horizontally clipped
544 if (fClipRect->fLeft > ir.fLeft || fClipRect->fRight < ir.fRight )
545 {
546 fRectBlitter.init(blitter, *fClipRect);
547 blitter = &fRectBlitter;
548 }
549 }
550 }
551 else
552 {
553 fRgnBlitter.init(blitter, clip);
554 blitter = &fRgnBlitter;
555 }
556 }
557 fBlitter = blitter;
558 }
559
560 ///////////////////////////////////////////////////////////////////////////////
561
562 void SkScan::FillPath(const SkPath& path, const SkRegion& clip,
563 SkBlitter* blitter) {
564 if (clip.isEmpty()) {
565 return;
566 }
567
568 SkRect r;
569 SkIRect ir;
570
571 path.computeBounds(&r, SkPath::kFast_BoundsType);
572 r.round(&ir);
573 if (ir.isEmpty()) {
574 if (path.isInverseFillType()) {
575 blitter->blitRegion(clip);
576 }
577 return;
578 }
579
580 SkScanClipper clipper(blitter, &clip, ir);
581
582 blitter = clipper.getBlitter();
583 if (blitter) {
584 if (path.isInverseFillType()) {
585 sk_blit_above_and_below(blitter, ir, clip);
586 }
587 sk_fill_path(path, clipper.getClipRect(), blitter, ir.fBottom, 0, clip);
588 } else {
589 // what does it mean to not have a blitter if path.isInverseFillType???
590 }
591 }
592
593 ///////////////////////////////////////////////////////////////////////////////
594
595 static int build_tri_edges(SkEdge edge[], const SkPoint pts[],
596 const SkIRect* clipRect, SkEdge* list[]) {
597 SkEdge** start = list;
598
599 if (edge->setLine(pts[0], pts[1], clipRect, 0)) {
600 *list++ = edge;
601 edge = (SkEdge*)((char*)edge + sizeof(SkEdge));
602 }
603 if (edge->setLine(pts[1], pts[2], clipRect, 0)) {
604 *list++ = edge;
605 edge = (SkEdge*)((char*)edge + sizeof(SkEdge));
606 }
607 if (edge->setLine(pts[2], pts[0], clipRect, 0)) {
608 *list++ = edge;
609 }
610 return (int)(list - start);
611 }
612
613
614 void sk_fill_triangle(const SkPoint pts[], const SkIRect* clipRect,
615 SkBlitter* blitter, const SkIRect& ir) {
616 SkASSERT(pts && blitter);
617
618 SkEdge edgeStorage[3];
619 SkEdge* list[3];
620
621 int count = build_tri_edges(edgeStorage, pts, clipRect, list);
622 if (count < 2) {
623 return;
624 }
625
626 SkEdge headEdge, tailEdge, *last;
627
628 // this returns the first and last edge after they're sorted into a dlink li st
629 SkEdge* edge = sort_edges(list, count, &last);
630
631 headEdge.fPrev = NULL;
632 headEdge.fNext = edge;
633 headEdge.fFirstY = kEDGE_HEAD_Y;
634 headEdge.fX = SK_MinS32;
635 edge->fPrev = &headEdge;
636
637 tailEdge.fPrev = last;
638 tailEdge.fNext = NULL;
639 tailEdge.fFirstY = kEDGE_TAIL_Y;
640 last->fNext = &tailEdge;
641
642 // now edge is the head of the sorted linklist
643 int stop_y = ir.fBottom;
644 if (clipRect && stop_y > clipRect->fBottom) {
645 stop_y = clipRect->fBottom;
646 }
647 walk_edges(&headEdge, SkPath::kEvenOdd_FillType, blitter, stop_y, NULL);
648 }
649
650 void SkScan::FillTriangle(const SkPoint pts[], const SkRegion* clip,
651 SkBlitter* blitter) {
652 if (clip && clip->isEmpty()) {
653 return;
654 }
655
656 SkRect r;
657 SkIRect ir;
658 r.set(pts, 3);
659 r.round(&ir);
660 if (ir.isEmpty()) {
661 return;
662 }
663
664 SkScanClipper clipper(blitter, clip, ir);
665
666 blitter = clipper.getBlitter();
667 if (NULL != blitter) {
668 sk_fill_triangle(pts, clipper.getClipRect(), blitter, ir);
669 }
670 }
671
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