Make SkPicture/SkImageGenerator default to SkCodec

src/images/SkImageDecoder_ktx.cpp

Index: src/images/SkImageDecoder_ktx.cpp
diff --git a/src/images/SkImageDecoder_ktx.cpp b/src/images/SkImageDecoder_ktx.cpp
index a95ab6f602d3610918b5874b10de50a76fd894de..019fa97678f8fa23275395068f7466afdf2d3a56 100644
--- a/src/images/SkImageDecoder_ktx.cpp
+++ b/src/images/SkImageDecoder_ktx.cpp
@@ -7,6 +7,7 @@
 
 #include "SkColorPriv.h"
 #include "SkImageDecoder.h"
+#include "SkImageGenerator.h"
 #include "SkPixelRef.h"
 #include "SkScaledBitmapSampler.h"
 #include "SkStream.h"
@@ -328,3 +329,101 @@ SkImageEncoder* sk_libktx_efactory(SkImageEncoder::Type t) {
 static SkImageDecoder_DecodeReg gReg(sk_libktx_dfactory);
 static SkImageDecoder_FormatReg gFormatReg(get_format_ktx);
 static SkImageEncoder_EncodeReg gEReg(sk_libktx_efactory);
+
+/////////////////////////////////////////////////////////////////////////////////////////
+// Old implementation of SkImageGenerator::NewFromEncoded which uses SkImageDecoder.
+// Here because it is only needed by DM and tests for Ktx.
+class BareMemoryAllocator : public SkBitmap::Allocator {
+    const SkImageInfo   fInfo;
+    void* const         fMemory;
+    const size_t        fRowBytes;
+
+public:
+    BareMemoryAllocator(const SkImageInfo& info, void* memory, size_t rowBytes)
+        : fInfo(info), fMemory(memory), fRowBytes(rowBytes)
+    {}
+
+protected:
+    bool allocPixelRef(SkBitmap* bm, SkColorTable* ctable) override {
+        const SkImageInfo bmi = bm->info();
+        if (bmi.width() != fInfo.width() || bmi.height() != fInfo.height() ||
+            bmi.colorType() != fInfo.colorType())
+        {
+            return false;
+        }
+        return bm->installPixels(bmi, fMemory, fRowBytes, ctable, nullptr, nullptr);
+    }
+};
+
+class SkImageDecoderGenerator : public SkImageGenerator {
+    const SkImageInfo               fInfo;
+    SkAutoTDelete<SkImageDecoder>   fDecoder;
+    SkAutoTUnref<SkData>            fData;
+
+public:
+    SkImageDecoderGenerator(const SkImageInfo& info, SkImageDecoder* decoder, SkData* data)
+        : INHERITED(info), fInfo(info), fDecoder(decoder), fData(SkRef(data))
+    {}
+
+protected:
+    SkData* onRefEncodedData(SK_REFENCODEDDATA_CTXPARAM) override {
+        return SkRef(fData.get());
+    }
+    bool onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
+                     SkPMColor ctableEntries[], int* ctableCount) override {
+        SkMemoryStream stream(fData->data(), fData->size(), false);
+        SkAutoTUnref<BareMemoryAllocator> allocator(
+                new BareMemoryAllocator(info, pixels, rowBytes));
+        fDecoder->setAllocator(allocator);
+        fDecoder->setRequireUnpremultipliedColors(kUnpremul_SkAlphaType == info.alphaType());
+
+        SkBitmap bm;
+        const SkImageDecoder::Result result = fDecoder->decode(&stream, &bm, info.colorType(),
+                                                               SkImageDecoder::kDecodePixels_Mode);
+        if (SkImageDecoder::kFailure == result) {
+            return false;
+        }
+
+        SkASSERT(info.colorType() == bm.info().colorType());
+
+        if (kIndex_8_SkColorType == info.colorType()) {
+            SkASSERT(ctableEntries);
+
+            SkColorTable* ctable = bm.getColorTable();
+            if (nullptr == ctable) {
+                return false;
+            }
+            const int count = ctable->count();
+            memcpy(ctableEntries, ctable->readColors(), count * sizeof(SkPMColor));
+            *ctableCount = count;
+        }
+        return true;
+    }
+
+    bool onGetYUV8Planes(SkISize sizes[3], void* planes[3], size_t rowBytes[3],
+                         SkYUVColorSpace* colorSpace) override {
+        SkMemoryStream stream(fData->data(), fData->size(), false);
+        return fDecoder->decodeYUV8Planes(&stream, sizes, planes, rowBytes, colorSpace);
+    }
+
+private:
+    typedef SkImageGenerator INHERITED;
+};
+
+SkImageGenerator* decoder_image_generator(SkData* data) {
+    SkMemoryStream stream(data->data(), data->size(), false);
+    SkImageDecoder* decoder = SkImageDecoder::Factory(&stream);
+    if (nullptr == decoder) {
+        return nullptr;
+    }
+
+    SkBitmap bm;
+    stream.rewind();
+    if (!decoder->decode(&stream, &bm, kUnknown_SkColorType, SkImageDecoder::kDecodeBounds_Mode)) {
+        delete decoder;
+        return nullptr;
+    }
+
+    return new SkImageDecoderGenerator(bm.info(), decoder, data);
+}
+