1 /*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "SkDeviceLooper.h"
9
SkDeviceLooper(const SkPixmap & base,const SkRasterClip & rc,const SkIRect & bounds,bool aa)10 SkDeviceLooper::SkDeviceLooper(const SkPixmap& base, const SkRasterClip& rc, const SkIRect& bounds,
11 bool aa)
12 : fBaseDst(base)
13 , fBaseRC(rc)
14 , fSubsetRC(rc.isForceConservativeRects())
15 , fDelta(aa ? kAA_Delta : kBW_Delta)
16 {
17 // sentinels that next() has not yet been called, and so our mapper functions
18 // should not be called either.
19 fCurrDst = nullptr;
20 fCurrRC = nullptr;
21
22 if (!rc.isEmpty()) {
23 // clip must be contained by the bitmap
24 SkASSERT(SkIRect::MakeWH(base.width(), base.height()).contains(rc.getBounds()));
25 }
26
27 if (rc.isEmpty() || !fClippedBounds.intersect(bounds, rc.getBounds())) {
28 fState = kDone_State;
29 } else if (this->fitsInDelta(fClippedBounds)) {
30 fState = kSimple_State;
31 } else {
32 // back up by 1 DX, so that next() will put us in a correct starting
33 // position.
34 fCurrOffset.set(fClippedBounds.left() - fDelta,
35 fClippedBounds.top());
36 fState = kComplex_State;
37 }
38 }
39
~SkDeviceLooper()40 SkDeviceLooper::~SkDeviceLooper() {}
41
mapRect(SkRect * dst,const SkRect & src) const42 void SkDeviceLooper::mapRect(SkRect* dst, const SkRect& src) const {
43 SkASSERT(kDone_State != fState);
44 SkASSERT(fCurrDst);
45 SkASSERT(fCurrRC);
46
47 *dst = src;
48 dst->offset(SkIntToScalar(-fCurrOffset.fX),
49 SkIntToScalar(-fCurrOffset.fY));
50 }
51
mapMatrix(SkMatrix * dst,const SkMatrix & src) const52 void SkDeviceLooper::mapMatrix(SkMatrix* dst, const SkMatrix& src) const {
53 SkASSERT(kDone_State != fState);
54 SkASSERT(fCurrDst);
55 SkASSERT(fCurrRC);
56
57 *dst = src;
58 dst->postTranslate(SkIntToScalar(-fCurrOffset.fX), SkIntToScalar(-fCurrOffset.fY));
59 }
60
computeCurrBitmapAndClip()61 bool SkDeviceLooper::computeCurrBitmapAndClip() {
62 SkASSERT(kComplex_State == fState);
63
64 SkIRect r = SkIRect::MakeXYWH(fCurrOffset.x(), fCurrOffset.y(),
65 fDelta, fDelta);
66 if (!fBaseDst.extractSubset(&fSubsetDst, r)) {
67 fSubsetRC.setEmpty();
68 } else {
69 fBaseRC.translate(-r.left(), -r.top(), &fSubsetRC);
70 (void)fSubsetRC.op(SkIRect::MakeWH(fDelta, fDelta), SkRegion::kIntersect_Op);
71 }
72
73 fCurrDst = &fSubsetDst;
74 fCurrRC = &fSubsetRC;
75 return !fCurrRC->isEmpty();
76 }
77
next_tile(const SkIRect & boundary,int delta,SkIPoint * offset)78 static bool next_tile(const SkIRect& boundary, int delta, SkIPoint* offset) {
79 // can we move to the right?
80 if (offset->x() + delta < boundary.right()) {
81 offset->fX += delta;
82 return true;
83 }
84
85 // reset to the left, but move down a row
86 offset->fX = boundary.left();
87 if (offset->y() + delta < boundary.bottom()) {
88 offset->fY += delta;
89 return true;
90 }
91
92 // offset is now outside of boundary, so we're done
93 return false;
94 }
95
next()96 bool SkDeviceLooper::next() {
97 switch (fState) {
98 case kDone_State:
99 // in theory, we should not get called here, since we must have
100 // previously returned false, but we check anyway.
101 break;
102
103 case kSimple_State:
104 // first time for simple
105 if (nullptr == fCurrDst) {
106 fCurrDst = &fBaseDst;
107 fCurrRC = &fBaseRC;
108 fCurrOffset.set(0, 0);
109 return true;
110 }
111 // 2nd time for simple, we are done
112 break;
113
114 case kComplex_State:
115 // need to propogate fCurrOffset through clippedbounds
116 // left to right, until we wrap around and move down
117
118 while (next_tile(fClippedBounds, fDelta, &fCurrOffset)) {
119 if (this->computeCurrBitmapAndClip()) {
120 return true;
121 }
122 }
123 break;
124 }
125 fState = kDone_State;
126 return false;
127 }
128