/*
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* Copyright 2014 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef GrRectanizer_pow2_DEFINED
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#define GrRectanizer_pow2_DEFINED
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#include "GrRectanizer.h"
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#include "SkMathPriv.h"
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#include "SkMalloc.h"
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#include "SkIPoint16.h"
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// This Rectanizer quantizes the incoming rects to powers of 2. Each power
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// of two can have, at most, one active row/shelf. Once a row/shelf for
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// a particular power of two gets full its fRows entry is recycled to point
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// to a new row.
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// The skyline algorithm almost always provides a better packing.
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class GrRectanizerPow2 : public GrRectanizer {
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public:
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GrRectanizerPow2(int w, int h) : INHERITED(w, h) {
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this->reset();
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}
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~GrRectanizerPow2() override {}
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void reset() override {
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fNextStripY = 0;
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fAreaSoFar = 0;
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sk_bzero(fRows, sizeof(fRows));
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}
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bool addRect(int w, int h, SkIPoint16* loc) override;
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float percentFull() const override {
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return fAreaSoFar / ((float)this->width() * this->height());
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}
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private:
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static const int kMIN_HEIGHT_POW2 = 2;
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static const int kMaxExponent = 16;
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struct Row {
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SkIPoint16 fLoc;
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// fRowHeight is actually known by this struct's position in fRows
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// but it is used to signal if there exists an open row of this height
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int fRowHeight;
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bool canAddWidth(int width, int containerWidth) const {
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return fLoc.fX + width <= containerWidth;
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}
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};
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Row fRows[kMaxExponent]; // 0-th entry will be unused
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int fNextStripY;
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int32_t fAreaSoFar;
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static int HeightToRowIndex(int height) {
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SkASSERT(height >= kMIN_HEIGHT_POW2);
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int index = 32 - SkCLZ(height - 1);
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SkASSERT(index < kMaxExponent);
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return index;
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}
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bool canAddStrip(int height) const {
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return fNextStripY + height <= this->height();
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}
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void initRow(Row* row, int rowHeight) {
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row->fLoc.set(0, fNextStripY);
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row->fRowHeight = rowHeight;
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fNextStripY += rowHeight;
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}
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typedef GrRectanizer INHERITED;
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};
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#endif
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