diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/src/gpu/GrRectanizer_skyline.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gfx/skia/trunk/src/gpu/GrRectanizer_skyline.cpp Wed Dec 31 06:09:35 2014 +0100 @@ -0,0 +1,165 @@ + +/* + * Copyright 2013 Google Inc. + * + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#include "GrRectanizer.h" +#include "SkTDArray.h" + +// Pack rectangles and track the current silhouette +// Based in part on Jukka Jylänki's work at http://clb.demon.fi + +class GrRectanizerSkyline : public GrRectanizer { +public: + GrRectanizerSkyline(int w, int h) : GrRectanizer(w, h) { + reset(); + } + + virtual ~GrRectanizerSkyline() { + } + + virtual void reset() { + fAreaSoFar = 0; + fSkyline.reset(); + SkylineSegment* seg = fSkyline.append(1); + seg->fX = 0; + seg->fY = 0; + seg->fWidth = width(); + } + + virtual bool addRect(int w, int h, GrIPoint16* loc); + + virtual float percentFull() const { + return fAreaSoFar / ((float)this->width() * this->height()); + } + + virtual int stripToPurge(int height) const { return -1; } + virtual void purgeStripAtY(int yCoord) { } + + /////////////////////////////////////////////////////////////////////////// + + struct SkylineSegment { + int fX; + int fY; + int fWidth; + }; + + SkTDArray fSkyline; + + int32_t fAreaSoFar; + + bool rectangleFits(int skylineIndex, int width, int height, int* y) const; + void addSkylineLevel(int skylineIndex, int x, int y, int width, int height); +}; + +bool GrRectanizerSkyline::addRect(int width, int height, GrIPoint16* loc) { + if ((unsigned)width > (unsigned)this->width() || + (unsigned)height > (unsigned)this->height()) { + return false; + } + + // find position for new rectangle + int bestWidth = this->width() + 1; + int bestX; + int bestY = this->height() + 1; + int bestIndex = -1; + for (int i = 0; i < fSkyline.count(); ++i) { + int y; + if (this->rectangleFits(i, width, height, &y)) { + // minimize y position first, then width of skyline + if (y < bestY || (y == bestY && fSkyline[i].fWidth < bestWidth)) { + bestIndex = i; + bestWidth = fSkyline[i].fWidth; + bestX = fSkyline[i].fX; + bestY = y; + } + } + } + + // add rectangle to skyline + if (-1 != bestIndex) { + this->addSkylineLevel(bestIndex, bestX, bestY, width, height); + loc->fX = bestX; + loc->fY = bestY; + + fAreaSoFar += width*height; + return true; + } + + loc->fX = 0; + loc->fY = 0; + return false; +} + +bool GrRectanizerSkyline::rectangleFits(int skylineIndex, int width, int height, int* ypos) const { + int x = fSkyline[skylineIndex].fX; + if (x + width > this->width()) { + return false; + } + + int widthLeft = width; + int i = skylineIndex; + int y = fSkyline[skylineIndex].fY; + while (widthLeft > 0) { + y = SkMax32(y, fSkyline[i].fY); + if (y + height > this->height()) { + return false; + } + widthLeft -= fSkyline[i].fWidth; + ++i; + SkASSERT(i < fSkyline.count() || widthLeft <= 0); + } + + *ypos = y; + return true; +} + +void GrRectanizerSkyline::addSkylineLevel(int skylineIndex, int x, int y, int width, int height) { + SkylineSegment newSegment; + newSegment.fX = x; + newSegment.fY = y + height; + newSegment.fWidth = width; + fSkyline.insert(skylineIndex, 1, &newSegment); + + SkASSERT(newSegment.fX + newSegment.fWidth <= this->width()); + SkASSERT(newSegment.fY <= this->height()); + + // delete width of this skyline segment from following ones + for (int i = skylineIndex+1; i < fSkyline.count(); ++i) { + SkASSERT(fSkyline[i-1].fX <= fSkyline[i].fX); + + if (fSkyline[i].fX < fSkyline[i-1].fX + fSkyline[i-1].fWidth) { + int shrink = fSkyline[i-1].fX + fSkyline[i-1].fWidth - fSkyline[i].fX; + + fSkyline[i].fX += shrink; + fSkyline[i].fWidth -= shrink; + + if (fSkyline[i].fWidth <= 0) { + fSkyline.remove(i); + --i; + } + else + break; + } + else + break; + } + + // merge fSkylines + for (int i = 0; i < fSkyline.count()-1; ++i) { + if (fSkyline[i].fY == fSkyline[i+1].fY) { + fSkyline[i].fWidth += fSkyline[i+1].fWidth; + fSkyline.remove(i+1); + --i; + } + } +} + +/////////////////////////////////////////////////////////////////////////////// + +GrRectanizer* GrRectanizer::Factory(int width, int height) { + return SkNEW_ARGS(GrRectanizerSkyline, (width, height)); +}