1/* 2 * Copyright 2014 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8#include "SkColorPriv.h" 9#include "SkData.h" 10#include "SkImageDecoder.h" 11#include "SkScaledBitmapSampler.h" 12#include "SkStream.h" 13#include "SkStreamPriv.h" 14#include "SkTextureCompressor.h" 15#include "SkTypes.h" 16 17#include "etc1.h" 18 19class SkPKMImageDecoder : public SkImageDecoder { 20public: 21 SkPKMImageDecoder() { } 22 23 Format getFormat() const override { 24 return kPKM_Format; 25 } 26 27protected: 28 Result onDecode(SkStream* stream, SkBitmap* bm, Mode) override; 29 30private: 31 typedef SkImageDecoder INHERITED; 32}; 33 34///////////////////////////////////////////////////////////////////////////////////////// 35 36SkImageDecoder::Result SkPKMImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) { 37 SkAutoTUnref<SkData> data(SkCopyStreamToData(stream)); 38 if (!data || !data->size()) { 39 return kFailure; 40 } 41 42 unsigned char* buf = (unsigned char*) data->data(); 43 44 // Make sure original PKM header is there... 45 SkASSERT(etc1_pkm_is_valid(buf)); 46 47 const unsigned short width = etc1_pkm_get_width(buf); 48 const unsigned short height = etc1_pkm_get_height(buf); 49 50 // Setup the sampler... 51 SkScaledBitmapSampler sampler(width, height, this->getSampleSize()); 52 53 // Set the config... 54 bm->setInfo(SkImageInfo::MakeN32(sampler.scaledWidth(), sampler.scaledHeight(), 55 kOpaque_SkAlphaType)); 56 if (SkImageDecoder::kDecodeBounds_Mode == mode) { 57 return kSuccess; 58 } 59 60 if (!this->allocPixelRef(bm, nullptr)) { 61 return kFailure; 62 } 63 64 // Lock the pixels, since we're about to write to them... 65 SkAutoLockPixels alp(*bm); 66 67 if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, *this)) { 68 return kFailure; 69 } 70 71 // Advance buffer past the header 72 buf += ETC_PKM_HEADER_SIZE; 73 74 // ETC1 Data is encoded as RGB pixels, so we should extract it as such 75 int nPixels = width * height; 76 SkAutoMalloc outRGBData(nPixels * 3); 77 uint8_t *outRGBDataPtr = reinterpret_cast<uint8_t *>(outRGBData.get()); 78 79 // Decode ETC1 80 if (!SkTextureCompressor::DecompressBufferFromFormat( 81 outRGBDataPtr, width*3, buf, width, height, SkTextureCompressor::kETC1_Format)) { 82 return kFailure; 83 } 84 85 // Set each of the pixels... 86 const int srcRowBytes = width * 3; 87 const int dstHeight = sampler.scaledHeight(); 88 const uint8_t *srcRow = reinterpret_cast<uint8_t *>(outRGBDataPtr); 89 srcRow += sampler.srcY0() * srcRowBytes; 90 for (int y = 0; y < dstHeight; ++y) { 91 sampler.next(srcRow); 92 srcRow += sampler.srcDY() * srcRowBytes; 93 } 94 95 return kSuccess; 96} 97 98///////////////////////////////////////////////////////////////////////////////////////// 99DEFINE_DECODER_CREATOR(PKMImageDecoder); 100///////////////////////////////////////////////////////////////////////////////////////// 101 102static bool is_pkm(SkStreamRewindable* stream) { 103 // Read the PKM header and make sure it's valid. 104 unsigned char buf[ETC_PKM_HEADER_SIZE]; 105 if (stream->read((void*)buf, ETC_PKM_HEADER_SIZE) != ETC_PKM_HEADER_SIZE) { 106 return false; 107 } 108 109 return SkToBool(etc1_pkm_is_valid(buf)); 110} 111 112static SkImageDecoder* sk_libpkm_dfactory(SkStreamRewindable* stream) { 113 if (is_pkm(stream)) { 114 return new SkPKMImageDecoder; 115 } 116 return nullptr; 117} 118 119static SkImageDecoder_DecodeReg gReg(sk_libpkm_dfactory); 120 121static SkImageDecoder::Format get_format_pkm(SkStreamRewindable* stream) { 122 if (is_pkm(stream)) { 123 return SkImageDecoder::kPKM_Format; 124 } 125 return SkImageDecoder::kUnknown_Format; 126} 127 128static SkImageDecoder_FormatReg gFormatReg(get_format_pkm); 129