michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkDeviceLooper.h"
michael@0: 
michael@0: SkDeviceLooper::SkDeviceLooper(const SkBitmap& base,
michael@0:                                const SkRasterClip& rc,
michael@0:                                const SkIRect& bounds, bool aa)
michael@0: : fBaseBitmap(base)
michael@0: , fBaseRC(rc)
michael@0: , fDelta(aa ? kAA_Delta : kBW_Delta)
michael@0: {
michael@0:     // sentinels that next() has not yet been called, and so our mapper functions
michael@0:     // should not be called either.
michael@0:     fCurrBitmap = NULL;
michael@0:     fCurrRC = NULL;
michael@0: 
michael@0:     if (!rc.isEmpty()) {
michael@0:         // clip must be contained by the bitmap
michael@0:         SkASSERT(SkIRect::MakeWH(base.width(), base.height()).contains(rc.getBounds()));
michael@0:     }
michael@0: 
michael@0:     if (rc.isEmpty() || !fClippedBounds.intersect(bounds, rc.getBounds())) {
michael@0:         fState = kDone_State;
michael@0:     } else if (this->fitsInDelta(fClippedBounds)) {
michael@0:         fState = kSimple_State;
michael@0:     } else {
michael@0:         // back up by 1 DX, so that next() will put us in a correct starting
michael@0:         // position.
michael@0:         fCurrOffset.set(fClippedBounds.left() - fDelta,
michael@0:                         fClippedBounds.top());
michael@0:         fState = kComplex_State;
michael@0:     }
michael@0: }
michael@0: 
michael@0: SkDeviceLooper::~SkDeviceLooper() {
michael@0: }
michael@0: 
michael@0: void SkDeviceLooper::mapRect(SkRect* dst, const SkRect& src) const {
michael@0:     SkASSERT(kDone_State != fState);
michael@0:     SkASSERT(fCurrBitmap);
michael@0:     SkASSERT(fCurrRC);
michael@0: 
michael@0:     *dst = src;
michael@0:     dst->offset(SkIntToScalar(-fCurrOffset.fX),
michael@0:                 SkIntToScalar(-fCurrOffset.fY));
michael@0: }
michael@0: 
michael@0: void SkDeviceLooper::mapMatrix(SkMatrix* dst, const SkMatrix& src) const {
michael@0:     SkASSERT(kDone_State != fState);
michael@0:     SkASSERT(fCurrBitmap);
michael@0:     SkASSERT(fCurrRC);
michael@0: 
michael@0:     *dst = src;
michael@0:     dst->postTranslate(SkIntToScalar(-fCurrOffset.fX),
michael@0:                        SkIntToScalar(-fCurrOffset.fY));
michael@0: }
michael@0: 
michael@0: bool SkDeviceLooper::computeCurrBitmapAndClip() {
michael@0:     SkASSERT(kComplex_State == fState);
michael@0: 
michael@0:     SkIRect r = SkIRect::MakeXYWH(fCurrOffset.x(), fCurrOffset.y(),
michael@0:                                   fDelta, fDelta);
michael@0:     if (!fBaseBitmap.extractSubset(&fSubsetBitmap, r)) {
michael@0:         fSubsetRC.setEmpty();
michael@0:     } else {
michael@0:         fSubsetBitmap.lockPixels();
michael@0:         fBaseRC.translate(-r.left(), -r.top(), &fSubsetRC);
michael@0:         (void)fSubsetRC.op(SkIRect::MakeWH(fDelta, fDelta),
michael@0:                            SkRegion::kIntersect_Op);
michael@0:     }
michael@0: 
michael@0:     fCurrBitmap = &fSubsetBitmap;
michael@0:     fCurrRC = &fSubsetRC;
michael@0:     return !fCurrRC->isEmpty();
michael@0: }
michael@0: 
michael@0: static bool next_tile(const SkIRect& boundary, int delta, SkIPoint* offset) {
michael@0:     // can we move to the right?
michael@0:     if (offset->x() + delta < boundary.right()) {
michael@0:         offset->fX += delta;
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     // reset to the left, but move down a row
michael@0:     offset->fX = boundary.left();
michael@0:     if (offset->y() + delta < boundary.bottom()) {
michael@0:         offset->fY += delta;
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     // offset is now outside of boundary, so we're done
michael@0:     return false;
michael@0: }
michael@0: 
michael@0: bool SkDeviceLooper::next() {
michael@0:     switch (fState) {
michael@0:         case kDone_State:
michael@0:             // in theory, we should not get called here, since we must have
michael@0:             // previously returned false, but we check anyway.
michael@0:             break;
michael@0: 
michael@0:         case kSimple_State:
michael@0:             // first time for simple
michael@0:             if (NULL == fCurrBitmap) {
michael@0:                 fCurrBitmap = &fBaseBitmap;
michael@0:                 fCurrRC = &fBaseRC;
michael@0:                 fCurrOffset.set(0, 0);
michael@0:                 return true;
michael@0:             }
michael@0:             // 2nd time for simple, we are done
michael@0:             break;
michael@0: 
michael@0:         case kComplex_State:
michael@0:             // need to propogate fCurrOffset through clippedbounds
michael@0:             // left to right, until we wrap around and move down
michael@0: 
michael@0:             while (next_tile(fClippedBounds, fDelta, &fCurrOffset)) {
michael@0:                 if (this->computeCurrBitmapAndClip()) {
michael@0:                     return true;
michael@0:                 }
michael@0:             }
michael@0:             break;
michael@0:     }
michael@0:     fState = kDone_State;
michael@0:     return false;
michael@0: }