blob: 0ad7b85ae4c653ec654968a2d512c730dcb060d3 [file] [log] [blame]
/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkSampler_DEFINED
#define SkSampler_DEFINED
#include "include/codec/SkCodec.h"
#include "include/core/SkTypes.h"
#include "include/private/SkNoncopyable.h"
#include "src/codec/SkCodecPriv.h"
#include <cstddef>
struct SkImageInfo;
class SkSampler : public SkNoncopyable {
public:
/**
* Update the sampler to sample every sampleX'th pixel. Returns the
* width after sampling.
*/
int setSampleX(int sampleX) {
return this->onSetSampleX(sampleX);
}
/**
* Update the sampler to sample every sampleY'th row.
*/
void setSampleY(int sampleY) {
fSampleY = sampleY;
}
/**
* Retrieve the value set for sampleY.
*/
int sampleY() const {
return fSampleY;
}
/**
* Based on fSampleY, return whether this row belongs in the output.
*
* @param row Row of the image, starting with the first row in the subset.
*/
bool rowNeeded(int row) const {
return (row - get_start_coord(fSampleY)) % fSampleY == 0;
}
/**
* Fill the remainder of the destination with 0.
*
* 0 has a different meaning depending on the SkColorType. For color types
* with transparency, this means transparent. For k565 and kGray, 0 is
* black.
*
* @param info
* Contains the color type of the rows to fill.
* Contains the pixel width of the destination rows to fill
* Contains the number of rows that we need to fill.
*
* @param dst
* The destination row to fill.
*
* @param rowBytes
* Stride in bytes of the destination.
*
* @param zeroInit
* Indicates whether memory is already zero initialized.
*/
static void Fill(const SkImageInfo& info, void* dst, size_t rowBytes,
SkCodec::ZeroInitialized zeroInit);
virtual int fillWidth() const = 0;
SkSampler()
: fSampleY(1)
{}
virtual ~SkSampler() {}
private:
int fSampleY;
virtual int onSetSampleX(int) = 0;
};
#endif // SkSampler_DEFINED