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 10 SkDeviceLooper::SkDeviceLooper(const SkBitmap& base, 11 const SkRasterClip& rc, 12 const SkIRect& bounds, bool aa) 13 : fBaseBitmap(base) 14 , fBaseRC(rc) 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 fCurrBitmap = NULL; 20 fCurrRC = NULL; 21 22 SkIRect bitmapBounds = SkIRect::MakeWH(base.width(), base.height()); 23 if (!fClippedBounds.intersect(bounds, bitmapBounds)) { 24 fState = kDone_State; 25 } else if (this->fitsInDelta(bounds)) { 26 fState = kSimple_State; 27 } else { 28 // back up by 1 DX, so that next() will put us in a correct starting 29 // position. 30 fCurrOffset.set(fClippedBounds.left() - fDelta, 31 fClippedBounds.top()); 32 fState = kComplex_State; 33 } 34 } 35 36 SkDeviceLooper::~SkDeviceLooper() { 37 } 38 39 void SkDeviceLooper::mapRect(SkRect* dst, const SkRect& src) const { 40 SkASSERT(kDone_State != fState); 41 SkASSERT(fCurrBitmap); 42 SkASSERT(fCurrRC); 43 44 *dst = src; 45 dst->offset(SkIntToScalar(-fCurrOffset.fX), 46 SkIntToScalar(-fCurrOffset.fY)); 47 } 48 49 void SkDeviceLooper::mapMatrix(SkMatrix* dst, const SkMatrix& src) const { 50 SkASSERT(kDone_State != fState); 51 SkASSERT(fCurrBitmap); 52 SkASSERT(fCurrRC); 53 54 *dst = src; 55 dst->postTranslate(SkIntToScalar(-fCurrOffset.fX), 56 SkIntToScalar(-fCurrOffset.fY)); 57 } 58 59 bool SkDeviceLooper::computeCurrBitmapAndClip() { 60 SkASSERT(kComplex_State == fState); 61 62 SkIRect r = SkIRect::MakeXYWH(fCurrOffset.x(), fCurrOffset.y(), 63 fDelta, fDelta); 64 if (!fBaseBitmap.extractSubset(&fSubsetBitmap, r)) { 65 fState = kDone_State; 66 return false; 67 } 68 fSubsetBitmap.lockPixels(); 69 70 fBaseRC.translate(-r.left(), -r.top(), &fSubsetRC); 71 (void)fSubsetRC.op(SkIRect::MakeWH(fDelta, fDelta), SkRegion::kIntersect_Op); 72 73 fCurrBitmap = &fSubsetBitmap; 74 fCurrRC = &fSubsetRC; 75 return true; 76 } 77 78 bool SkDeviceLooper::next() { 79 switch (fState) { 80 case kDone_State: 81 // in theory, we should not get called here, since we must have 82 // previously returned false, but we check anyway. 83 break; 84 85 case kSimple_State: 86 // first time for simple 87 if (NULL == fCurrBitmap) { 88 fCurrBitmap = &fBaseBitmap; 89 fCurrRC = &fBaseRC; 90 fCurrOffset.set(0, 0); 91 return true; 92 } 93 // 2nd time for simple, we are done 94 break; 95 96 case kComplex_State: 97 // need to propogate fCurrOffset through clippedbounds 98 // left to right, until we wrap around and move down 99 100 if (fCurrOffset.x() + fDelta < fClippedBounds.right()) { 101 fCurrOffset.fX += fDelta; 102 return this->computeCurrBitmapAndClip(); 103 } 104 fCurrOffset.fX = fClippedBounds.left(); 105 if (fCurrOffset.y() + fDelta < fClippedBounds.bottom()) { 106 fCurrOffset.fY += fDelta; 107 return this->computeCurrBitmapAndClip(); 108 } 109 break; 110 } 111 112 fState = kDone_State; 113 return false; 114 } 115