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