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/*
* Copyright 2007 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "bmpdecoderhelper.h"
#include "SkColorPriv.h"
#include "SkImageDecoder.h"
#include "SkScaledBitmapSampler.h"
#include "SkStream.h"
#include "SkStreamPriv.h"
#include "SkTDArray.h"
class SkBMPImageDecoder : public SkImageDecoder {
public:
SkBMPImageDecoder() {}
virtual Format getFormat() const SK_OVERRIDE {
return kBMP_Format;
}
protected:
virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode mode) SK_OVERRIDE;
private:
typedef SkImageDecoder INHERITED;
};
///////////////////////////////////////////////////////////////////////////////
DEFINE_DECODER_CREATOR(BMPImageDecoder);
///////////////////////////////////////////////////////////////////////////////
static bool is_bmp(SkStreamRewindable* stream) {
static const char kBmpMagic[] = { 'B', 'M' };
char buffer[sizeof(kBmpMagic)];
return stream->read(buffer, sizeof(kBmpMagic)) == sizeof(kBmpMagic) &&
!memcmp(buffer, kBmpMagic, sizeof(kBmpMagic));
}
static SkImageDecoder* sk_libbmp_dfactory(SkStreamRewindable* stream) {
if (is_bmp(stream)) {
return SkNEW(SkBMPImageDecoder);
}
return NULL;
}
static SkImageDecoder_DecodeReg gReg(sk_libbmp_dfactory);
static SkImageDecoder::Format get_format_bmp(SkStreamRewindable* stream) {
if (is_bmp(stream)) {
return SkImageDecoder::kBMP_Format;
}
return SkImageDecoder::kUnknown_Format;
}
static SkImageDecoder_FormatReg gFormatReg(get_format_bmp);
///////////////////////////////////////////////////////////////////////////////
class SkBmpDecoderCallback : public image_codec::BmpDecoderCallback {
public:
// we don't copy the bitmap, just remember the pointer
SkBmpDecoderCallback(bool justBounds) : fJustBounds(justBounds) {}
// override from BmpDecoderCallback
virtual uint8* SetSize(int width, int height) {
fWidth = width;
fHeight = height;
if (fJustBounds) {
return NULL;
}
fRGB.setCount(width * height * 3); // 3 == r, g, b
return fRGB.begin();
}
int width() const { return fWidth; }
int height() const { return fHeight; }
const uint8_t* rgb() const { return fRGB.begin(); }
private:
SkTDArray<uint8_t> fRGB;
int fWidth;
int fHeight;
bool fJustBounds;
};
bool SkBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
// First read the entire stream, so that all of the data can be passed to
// the BmpDecoderHelper.
// Allocated space used to hold the data.
SkAutoMalloc storage;
// Byte length of all of the data.
const size_t length = SkCopyStreamToStorage(&storage, stream);
if (0 == length) {
return 0;
}
const bool justBounds = SkImageDecoder::kDecodeBounds_Mode == mode;
SkBmpDecoderCallback callback(justBounds);
// Now decode the BMP into callback's rgb() array [r,g,b, r,g,b, ...]
{
image_codec::BmpDecoderHelper helper;
const int max_pixels = 16383*16383; // max width*height
if (!helper.DecodeImage((const char*)storage.get(), length,
max_pixels, &callback)) {
return false;
}
}
// we don't need this anymore, so free it now (before we try to allocate
// the bitmap's pixels) rather than waiting for its destructor
storage.free();
int width = callback.width();
int height = callback.height();
SkColorType colorType = this->getPrefColorType(k32Bit_SrcDepth, false);
// only accept prefConfig if it makes sense for us
if (kARGB_4444_SkColorType != colorType && kRGB_565_SkColorType != colorType) {
colorType = kN32_SkColorType;
}
SkScaledBitmapSampler sampler(width, height, getSampleSize());
bm->setInfo(SkImageInfo::Make(sampler.scaledWidth(), sampler.scaledHeight(),
colorType, kOpaque_SkAlphaType));
if (justBounds) {
return true;
}
if (!this->allocPixelRef(bm, NULL)) {
return false;
}
SkAutoLockPixels alp(*bm);
if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, *this)) {
return false;
}
const int srcRowBytes = width * 3;
const int dstHeight = sampler.scaledHeight();
const uint8_t* srcRow = callback.rgb();
srcRow += sampler.srcY0() * srcRowBytes;
for (int y = 0; y < dstHeight; y++) {
sampler.next(srcRow);
srcRow += sampler.srcDY() * srcRowBytes;
}
return true;
}
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