michael@0: 
michael@0: /*
michael@0:  * Copyright 2007 The Android Open Source Project
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #include "bmpdecoderhelper.h"
michael@0: #include "SkColorPriv.h"
michael@0: #include "SkImageDecoder.h"
michael@0: #include "SkScaledBitmapSampler.h"
michael@0: #include "SkStream.h"
michael@0: #include "SkStreamHelpers.h"
michael@0: #include "SkTDArray.h"
michael@0: 
michael@0: class SkBMPImageDecoder : public SkImageDecoder {
michael@0: public:
michael@0:     SkBMPImageDecoder() {}
michael@0: 
michael@0:     virtual Format getFormat() const SK_OVERRIDE {
michael@0:         return kBMP_Format;
michael@0:     }
michael@0: 
michael@0: protected:
michael@0:     virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode mode) SK_OVERRIDE;
michael@0: 
michael@0: private:
michael@0:     typedef SkImageDecoder INHERITED;
michael@0: };
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: DEFINE_DECODER_CREATOR(BMPImageDecoder);
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: static bool is_bmp(SkStreamRewindable* stream) {
michael@0:     static const char kBmpMagic[] = { 'B', 'M' };
michael@0: 
michael@0: 
michael@0:     char buffer[sizeof(kBmpMagic)];
michael@0: 
michael@0:     return stream->read(buffer, sizeof(kBmpMagic)) == sizeof(kBmpMagic) &&
michael@0:         !memcmp(buffer, kBmpMagic, sizeof(kBmpMagic));
michael@0: }
michael@0: 
michael@0: static SkImageDecoder* sk_libbmp_dfactory(SkStreamRewindable* stream) {
michael@0:     if (is_bmp(stream)) {
michael@0:         return SkNEW(SkBMPImageDecoder);
michael@0:     }
michael@0:     return NULL;
michael@0: }
michael@0: 
michael@0: static SkImageDecoder_DecodeReg gReg(sk_libbmp_dfactory);
michael@0: 
michael@0: static SkImageDecoder::Format get_format_bmp(SkStreamRewindable* stream) {
michael@0:     if (is_bmp(stream)) {
michael@0:         return SkImageDecoder::kBMP_Format;
michael@0:     }
michael@0:     return SkImageDecoder::kUnknown_Format;
michael@0: }
michael@0: 
michael@0: static SkImageDecoder_FormatReg gFormatReg(get_format_bmp);
michael@0: 
michael@0: ///////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: class SkBmpDecoderCallback : public image_codec::BmpDecoderCallback {
michael@0: public:
michael@0:     // we don't copy the bitmap, just remember the pointer
michael@0:     SkBmpDecoderCallback(bool justBounds) : fJustBounds(justBounds) {}
michael@0: 
michael@0:     // override from BmpDecoderCallback
michael@0:     virtual uint8* SetSize(int width, int height) {
michael@0:         fWidth = width;
michael@0:         fHeight = height;
michael@0:         if (fJustBounds) {
michael@0:             return NULL;
michael@0:         }
michael@0: 
michael@0:         fRGB.setCount(width * height * 3);  // 3 == r, g, b
michael@0:         return fRGB.begin();
michael@0:     }
michael@0: 
michael@0:     int width() const { return fWidth; }
michael@0:     int height() const { return fHeight; }
michael@0:     const uint8_t* rgb() const { return fRGB.begin(); }
michael@0: 
michael@0: private:
michael@0:     SkTDArray<uint8_t> fRGB;
michael@0:     int fWidth;
michael@0:     int fHeight;
michael@0:     bool fJustBounds;
michael@0: };
michael@0: 
michael@0: bool SkBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
michael@0:     // First read the entire stream, so that all of the data can be passed to
michael@0:     // the BmpDecoderHelper.
michael@0: 
michael@0:     // Allocated space used to hold the data.
michael@0:     SkAutoMalloc storage;
michael@0:     // Byte length of all of the data.
michael@0:     const size_t length = CopyStreamToStorage(&storage, stream);
michael@0:     if (0 == length) {
michael@0:         return 0;
michael@0:     }
michael@0: 
michael@0:     const bool justBounds = SkImageDecoder::kDecodeBounds_Mode == mode;
michael@0:     SkBmpDecoderCallback callback(justBounds);
michael@0: 
michael@0:     // Now decode the BMP into callback's rgb() array [r,g,b, r,g,b, ...]
michael@0:     {
michael@0:         image_codec::BmpDecoderHelper helper;
michael@0:         const int max_pixels = 16383*16383; // max width*height
michael@0:         if (!helper.DecodeImage((const char*)storage.get(), length,
michael@0:                                 max_pixels, &callback)) {
michael@0:             return false;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // we don't need this anymore, so free it now (before we try to allocate
michael@0:     // the bitmap's pixels) rather than waiting for its destructor
michael@0:     storage.free();
michael@0: 
michael@0:     int width = callback.width();
michael@0:     int height = callback.height();
michael@0:     SkBitmap::Config config = this->getPrefConfig(k32Bit_SrcDepth, false);
michael@0: 
michael@0:     // only accept prefConfig if it makes sense for us
michael@0:     if (SkBitmap::kARGB_4444_Config != config &&
michael@0:             SkBitmap::kRGB_565_Config != config) {
michael@0:         config = SkBitmap::kARGB_8888_Config;
michael@0:     }
michael@0: 
michael@0:     SkScaledBitmapSampler sampler(width, height, getSampleSize());
michael@0: 
michael@0:     bm->setConfig(config, sampler.scaledWidth(), sampler.scaledHeight(), 0,
michael@0:                   kOpaque_SkAlphaType);
michael@0: 
michael@0:     if (justBounds) {
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     if (!this->allocPixelRef(bm, NULL)) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     SkAutoLockPixels alp(*bm);
michael@0: 
michael@0:     if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, *this)) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     const int srcRowBytes = width * 3;
michael@0:     const int dstHeight = sampler.scaledHeight();
michael@0:     const uint8_t* srcRow = callback.rgb();
michael@0: 
michael@0:     srcRow += sampler.srcY0() * srcRowBytes;
michael@0:     for (int y = 0; y < dstHeight; y++) {
michael@0:         sampler.next(srcRow);
michael@0:         srcRow += sampler.srcDY() * srcRowBytes;
michael@0:     }
michael@0:     return true;
michael@0: }