--- /dev/null
+
+/*
+ * 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<SkylineSegment> 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));
+}
+