src/images/SkImageDecoder.cpp - skia - Git at Google

 /*
  * Copyright 2006 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 "SkImageDecoder.h"
 #include "SkBitmap.h"
 #include "SkImagePriv.h"
 #include "SkPixelRef.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
 #include "SkCanvas.h"

 SkImageDecoder::SkImageDecoder()
     : fPeeker(NULL)
 #ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
     , fChooser(NULL)
 #endif
     , fAllocator(NULL)
     , fSampleSize(1)
     , fDefaultPref(kUnknown_SkColorType)
     , fPreserveSrcDepth(false)
     , fDitherImage(true)
     , fSkipWritingZeroes(false)
     , fPreferQualityOverSpeed(false)
     , fRequireUnpremultipliedColors(false) {
 }

 SkImageDecoder::~SkImageDecoder() {
     SkSafeUnref(fPeeker);
 #ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
     SkSafeUnref(fChooser);
 #endif
     SkSafeUnref(fAllocator);
 }

 void SkImageDecoder::copyFieldsToOther(SkImageDecoder* other) {
     if (NULL == other) {
         return;
     }
     other->setPeeker(fPeeker);
 #ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
     other->setChooser(fChooser);
 #endif
     other->setAllocator(fAllocator);
     other->setSampleSize(fSampleSize);
     other->setPreserveSrcDepth(fPreserveSrcDepth);
     other->setDitherImage(fDitherImage);
     other->setSkipWritingZeroes(fSkipWritingZeroes);
     other->setPreferQualityOverSpeed(fPreferQualityOverSpeed);
     other->setRequireUnpremultipliedColors(fRequireUnpremultipliedColors);
 }

 SkImageDecoder::Format SkImageDecoder::getFormat() const {
     return kUnknown_Format;
 }

 const char* SkImageDecoder::getFormatName() const {
     return GetFormatName(this->getFormat());
 }

 const char* SkImageDecoder::GetFormatName(Format format) {
     switch (format) {
         case kUnknown_Format:
             return "Unknown Format";
         case kBMP_Format:
             return "BMP";
         case kGIF_Format:
             return "GIF";
         case kICO_Format:
             return "ICO";
         case kPKM_Format:
             return "PKM";
         case kKTX_Format:
             return "KTX";
         case kASTC_Format:
             return "ASTC";
         case kJPEG_Format:
             return "JPEG";
         case kPNG_Format:
             return "PNG";
         case kWBMP_Format:
             return "WBMP";
         case kWEBP_Format:
             return "WEBP";
         default:
             SkDEBUGFAIL("Invalid format type!");
     }
     return "Unknown Format";
 }

 SkImageDecoder::Peeker* SkImageDecoder::setPeeker(Peeker* peeker) {
     SkRefCnt_SafeAssign(fPeeker, peeker);
     return peeker;
 }

 #ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
 SkImageDecoder::Chooser* SkImageDecoder::setChooser(Chooser* chooser) {
     SkRefCnt_SafeAssign(fChooser, chooser);
     return chooser;
 }
 #endif

 SkBitmap::Allocator* SkImageDecoder::setAllocator(SkBitmap::Allocator* alloc) {
     SkRefCnt_SafeAssign(fAllocator, alloc);
     return alloc;
 }

 void SkImageDecoder::setSampleSize(int size) {
     if (size < 1) {
         size = 1;
     }
     fSampleSize = size;
 }

 #ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
 // TODO: change Chooser virtual to take colorType, so we can stop calling SkColorTypeToBitmapConfig
 //
 bool SkImageDecoder::chooseFromOneChoice(SkColorType colorType, int width, int height) const {
     Chooser* chooser = fChooser;

     if (NULL == chooser) {    // no chooser, we just say YES to decoding :)
         return true;
     }
     chooser->begin(1);
     chooser->inspect(0, SkColorTypeToBitmapConfig(colorType), width, height);
     return chooser->choose() == 0;
 }
 #endif

 bool SkImageDecoder::allocPixelRef(SkBitmap* bitmap,
                                    SkColorTable* ctable) const {
     return bitmap->allocPixels(fAllocator, ctable);
 }

 ///////////////////////////////////////////////////////////////////////////////

 SkColorType SkImageDecoder::getPrefColorType(SrcDepth srcDepth, bool srcHasAlpha) const {
     SkColorType ct = fDefaultPref;
     if (fPreserveSrcDepth) {
         switch (srcDepth) {
             case kIndex_SrcDepth:
                 ct = kIndex_8_SkColorType;
                 break;
             case k8BitGray_SrcDepth:
                 ct = kN32_SkColorType;
                 break;
             case k32Bit_SrcDepth:
                 ct = kN32_SkColorType;
                 break;
         }
     }
     return ct;
 }

 bool SkImageDecoder::decode(SkStream* stream, SkBitmap* bm, SkColorType pref, Mode mode) {
     // we reset this to false before calling onDecode
     fShouldCancelDecode = false;
     // assign this, for use by getPrefColorType(), in case fUsePrefTable is false
     fDefaultPref = pref;

     // pass a temporary bitmap, so that if we return false, we are assured of
     // leaving the caller's bitmap untouched.
     SkBitmap    tmp;
     if (!this->onDecode(stream, &tmp, mode)) {
         return false;
     }
     bm->swap(tmp);
     return true;
 }

 bool SkImageDecoder::decodeSubset(SkBitmap* bm, const SkIRect& rect, SkColorType pref) {
     // we reset this to false before calling onDecodeSubset
     fShouldCancelDecode = false;
     // assign this, for use by getPrefColorType(), in case fUsePrefTable is false
     fDefaultPref = pref;

     return this->onDecodeSubset(bm, rect);
 }

 bool SkImageDecoder::buildTileIndex(SkStreamRewindable* stream, int *width, int *height) {
     // we reset this to false before calling onBuildTileIndex
     fShouldCancelDecode = false;

     return this->onBuildTileIndex(stream, width, height);
 }

 bool SkImageDecoder::cropBitmap(SkBitmap *dst, SkBitmap *src, int sampleSize,
                                 int dstX, int dstY, int width, int height,
                                 int srcX, int srcY) {
     int w = width / sampleSize;
     int h = height / sampleSize;
     if (src->colorType() == kIndex_8_SkColorType) {
         // kIndex8 does not allow drawing via an SkCanvas, as is done below.
         // Instead, use extractSubset. Note that this shares the SkPixelRef and
         // SkColorTable.
         // FIXME: Since src is discarded in practice, this holds on to more
         // pixels than is strictly necessary. Switch to a copy if memory
         // savings are more important than speed here. This also means
         // that the pixels in dst can not be reused (though there is no
         // allocation, which was already done on src).
         int x = (dstX - srcX) / sampleSize;
         int y = (dstY - srcY) / sampleSize;
         SkIRect subset = SkIRect::MakeXYWH(x, y, w, h);
         return src->extractSubset(dst, subset);
     }
     // if the destination has no pixels then we must allocate them.
     if (dst->isNull()) {
         dst->setInfo(src->info().makeWH(w, h));

         if (!this->allocPixelRef(dst, NULL)) {
             SkDEBUGF(("failed to allocate pixels needed to crop the bitmap"));
             return false;
         }
     }
     // check to see if the destination is large enough to decode the desired
     // region. If this assert fails we will just draw as much of the source
     // into the destination that we can.
     if (dst->width() < w || dst->height() < h) {
         SkDEBUGF(("SkImageDecoder::cropBitmap does not have a large enough bitmap.\n"));
     }

     // Set the Src_Mode for the paint to prevent transparency issue in the
     // dest in the event that the dest was being re-used.
     SkPaint paint;
     paint.setXfermodeMode(SkXfermode::kSrc_Mode);

     SkCanvas canvas(*dst);
     canvas.drawSprite(*src, (srcX - dstX) / sampleSize,
                             (srcY - dstY) / sampleSize,
                             &paint);
     return true;
 }

 ///////////////////////////////////////////////////////////////////////////////

 bool SkImageDecoder::DecodeFile(const char file[], SkBitmap* bm, SkColorType pref,  Mode mode,
                                 Format* format) {
     SkASSERT(file);
     SkASSERT(bm);

     SkAutoTUnref<SkStreamRewindable> stream(SkStream::NewFromFile(file));
     if (stream.get()) {
         if (SkImageDecoder::DecodeStream(stream, bm, pref, mode, format)) {
             bm->pixelRef()->setURI(file);
             return true;
         }
     }
     return false;
 }

 bool SkImageDecoder::DecodeMemory(const void* buffer, size_t size, SkBitmap* bm, SkColorType pref,
                                   Mode mode, Format* format) {
     if (0 == size) {
         return false;
     }
     SkASSERT(buffer);

     SkMemoryStream  stream(buffer, size);
     return SkImageDecoder::DecodeStream(&stream, bm, pref, mode, format);
 }

 bool SkImageDecoder::DecodeStream(SkStreamRewindable* stream, SkBitmap* bm, SkColorType pref,
                                   Mode mode, Format* format) {
     SkASSERT(stream);
     SkASSERT(bm);

     bool success = false;
     SkImageDecoder* codec = SkImageDecoder::Factory(stream);

     if (NULL != codec) {
         success = codec->decode(stream, bm, pref, mode);
         if (success && format) {
             *format = codec->getFormat();
             if (kUnknown_Format == *format) {
                 if (stream->rewind()) {
                     *format = GetStreamFormat(stream);
                 }
             }
         }
         delete codec;
     }
     return success;
 }
	/*
	* Copyright 2006 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 "SkImageDecoder.h"
	#include "SkBitmap.h"
	#include "SkImagePriv.h"
	#include "SkPixelRef.h"
	#include "SkStream.h"
	#include "SkTemplates.h"
	#include "SkCanvas.h"

	SkImageDecoder::SkImageDecoder()
	: fPeeker(NULL)
	#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
	, fChooser(NULL)
	#endif
	, fAllocator(NULL)
	, fSampleSize(1)
	, fDefaultPref(kUnknown_SkColorType)
	, fPreserveSrcDepth(false)
	, fDitherImage(true)
	, fSkipWritingZeroes(false)
	, fPreferQualityOverSpeed(false)
	, fRequireUnpremultipliedColors(false) {
	}

	SkImageDecoder::~SkImageDecoder() {
	SkSafeUnref(fPeeker);
	#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
	SkSafeUnref(fChooser);
	#endif
	SkSafeUnref(fAllocator);
	}

	void SkImageDecoder::copyFieldsToOther(SkImageDecoder* other) {
	if (NULL == other) {
	return;
	}
	other->setPeeker(fPeeker);
	#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
	other->setChooser(fChooser);
	#endif
	other->setAllocator(fAllocator);
	other->setSampleSize(fSampleSize);
	other->setPreserveSrcDepth(fPreserveSrcDepth);
	other->setDitherImage(fDitherImage);
	other->setSkipWritingZeroes(fSkipWritingZeroes);
	other->setPreferQualityOverSpeed(fPreferQualityOverSpeed);
	other->setRequireUnpremultipliedColors(fRequireUnpremultipliedColors);
	}

	SkImageDecoder::Format SkImageDecoder::getFormat() const {
	return kUnknown_Format;
	}

	const char* SkImageDecoder::getFormatName() const {
	return GetFormatName(this->getFormat());
	}

	const char* SkImageDecoder::GetFormatName(Format format) {
	switch (format) {
	case kUnknown_Format:
	return "Unknown Format";
	case kBMP_Format:
	return "BMP";
	case kGIF_Format:
	return "GIF";
	case kICO_Format:
	return "ICO";
	case kPKM_Format:
	return "PKM";
	case kKTX_Format:
	return "KTX";
	case kASTC_Format:
	return "ASTC";
	case kJPEG_Format:
	return "JPEG";
	case kPNG_Format:
	return "PNG";
	case kWBMP_Format:
	return "WBMP";
	case kWEBP_Format:
	return "WEBP";
	default:
	SkDEBUGFAIL("Invalid format type!");
	}
	return "Unknown Format";
	}

	SkImageDecoder::Peeker* SkImageDecoder::setPeeker(Peeker* peeker) {
	SkRefCnt_SafeAssign(fPeeker, peeker);
	return peeker;
	}

	#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
	SkImageDecoder::Chooser* SkImageDecoder::setChooser(Chooser* chooser) {
	SkRefCnt_SafeAssign(fChooser, chooser);
	return chooser;
	}
	#endif

	SkBitmap::Allocator* SkImageDecoder::setAllocator(SkBitmap::Allocator* alloc) {
	SkRefCnt_SafeAssign(fAllocator, alloc);
	return alloc;
	}

	void SkImageDecoder::setSampleSize(int size) {
	if (size < 1) {
	size = 1;
	}
	fSampleSize = size;
	}

	#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
	// TODO: change Chooser virtual to take colorType, so we can stop calling SkColorTypeToBitmapConfig
	//
	bool SkImageDecoder::chooseFromOneChoice(SkColorType colorType, int width, int height) const {
	Chooser* chooser = fChooser;

	if (NULL == chooser) { // no chooser, we just say YES to decoding :)
	return true;
	}
	chooser->begin(1);
	chooser->inspect(0, SkColorTypeToBitmapConfig(colorType), width, height);
	return chooser->choose() == 0;
	}
	#endif

	bool SkImageDecoder::allocPixelRef(SkBitmap* bitmap,
	SkColorTable* ctable) const {
	return bitmap->allocPixels(fAllocator, ctable);
	}

	///////////////////////////////////////////////////////////////////////////////

	SkColorType SkImageDecoder::getPrefColorType(SrcDepth srcDepth, bool srcHasAlpha) const {
	SkColorType ct = fDefaultPref;
	if (fPreserveSrcDepth) {
	switch (srcDepth) {
	case kIndex_SrcDepth:
	ct = kIndex_8_SkColorType;
	break;
	case k8BitGray_SrcDepth:
	ct = kN32_SkColorType;
	break;
	case k32Bit_SrcDepth:
	ct = kN32_SkColorType;
	break;
	}
	}
	return ct;
	}

	bool SkImageDecoder::decode(SkStream* stream, SkBitmap* bm, SkColorType pref, Mode mode) {
	// we reset this to false before calling onDecode
	fShouldCancelDecode = false;
	// assign this, for use by getPrefColorType(), in case fUsePrefTable is false
	fDefaultPref = pref;

	// pass a temporary bitmap, so that if we return false, we are assured of
	// leaving the caller's bitmap untouched.
	SkBitmap tmp;
	if (!this->onDecode(stream, &tmp, mode)) {
	return false;
	}
	bm->swap(tmp);
	return true;
	}

	bool SkImageDecoder::decodeSubset(SkBitmap* bm, const SkIRect& rect, SkColorType pref) {
	// we reset this to false before calling onDecodeSubset
	fShouldCancelDecode = false;
	// assign this, for use by getPrefColorType(), in case fUsePrefTable is false
	fDefaultPref = pref;

	return this->onDecodeSubset(bm, rect);
	}

	bool SkImageDecoder::buildTileIndex(SkStreamRewindable* stream, int width, int height) {
	// we reset this to false before calling onBuildTileIndex
	fShouldCancelDecode = false;

	return this->onBuildTileIndex(stream, width, height);
	}

	bool SkImageDecoder::cropBitmap(SkBitmap dst, SkBitmap src, int sampleSize,
	int dstX, int dstY, int width, int height,
	int srcX, int srcY) {
	int w = width / sampleSize;
	int h = height / sampleSize;
	if (src->colorType() == kIndex_8_SkColorType) {
	// kIndex8 does not allow drawing via an SkCanvas, as is done below.
	// Instead, use extractSubset. Note that this shares the SkPixelRef and
	// SkColorTable.
	// FIXME: Since src is discarded in practice, this holds on to more
	// pixels than is strictly necessary. Switch to a copy if memory
	// savings are more important than speed here. This also means
	// that the pixels in dst can not be reused (though there is no
	// allocation, which was already done on src).
	int x = (dstX - srcX) / sampleSize;
	int y = (dstY - srcY) / sampleSize;
	SkIRect subset = SkIRect::MakeXYWH(x, y, w, h);
	return src->extractSubset(dst, subset);
	}
	// if the destination has no pixels then we must allocate them.
	if (dst->isNull()) {
	dst->setInfo(src->info().makeWH(w, h));

	if (!this->allocPixelRef(dst, NULL)) {
	SkDEBUGF(("failed to allocate pixels needed to crop the bitmap"));
	return false;
	}
	}
	// check to see if the destination is large enough to decode the desired
	// region. If this assert fails we will just draw as much of the source
	// into the destination that we can.
	if (dst->width() < w \|\| dst->height() < h) {
	SkDEBUGF(("SkImageDecoder::cropBitmap does not have a large enough bitmap.\n"));
	}

	// Set the Src_Mode for the paint to prevent transparency issue in the
	// dest in the event that the dest was being re-used.
	SkPaint paint;
	paint.setXfermodeMode(SkXfermode::kSrc_Mode);

	SkCanvas canvas(*dst);
	canvas.drawSprite(*src, (srcX - dstX) / sampleSize,
	(srcY - dstY) / sampleSize,
	&paint);
	return true;
	}

	///////////////////////////////////////////////////////////////////////////////

	bool SkImageDecoder::DecodeFile(const char file[], SkBitmap* bm, SkColorType pref, Mode mode,
	Format* format) {
	SkASSERT(file);
	SkASSERT(bm);

	SkAutoTUnref<SkStreamRewindable> stream(SkStream::NewFromFile(file));
	if (stream.get()) {
	if (SkImageDecoder::DecodeStream(stream, bm, pref, mode, format)) {
	bm->pixelRef()->setURI(file);
	return true;
	}
	}
	return false;
	}

	bool SkImageDecoder::DecodeMemory(const void* buffer, size_t size, SkBitmap* bm, SkColorType pref,
	Mode mode, Format* format) {
	if (0 == size) {
	return false;
	}
	SkASSERT(buffer);

	SkMemoryStream stream(buffer, size);
	return SkImageDecoder::DecodeStream(&stream, bm, pref, mode, format);
	}

	bool SkImageDecoder::DecodeStream(SkStreamRewindable* stream, SkBitmap* bm, SkColorType pref,
	Mode mode, Format* format) {
	SkASSERT(stream);
	SkASSERT(bm);

	bool success = false;
	SkImageDecoder* codec = SkImageDecoder::Factory(stream);

	if (NULL != codec) {
	success = codec->decode(stream, bm, pref, mode);
	if (success && format) {
	*format = codec->getFormat();
	if (kUnknown_Format == *format) {
	if (stream->rewind()) {
	*format = GetStreamFormat(stream);
	}
	}
	}
	delete codec;
	}
	return success;
	}