C++ SkImageInfo::alphaType方法代码示例

SkCodec::Result SkPngCodec::initializeSwizzler(const SkImageInfo& requestedInfo,
                                               const Options& options,
                                               SkPMColor ctable[],
                                               int* ctableCount) {
    // FIXME: Could we use the return value of setjmp to specify the type of
    // error?
    if (setjmp(png_jmpbuf(fPng_ptr))) {
        SkCodecPrintf("setjmp long jump!\n");
        return kInvalidInput;
    }
    png_read_update_info(fPng_ptr, fInfo_ptr);

    if (SkEncodedInfo::kPalette_Color == this->getEncodedInfo().color()) {
        if (!this->createColorTable(requestedInfo.colorType(),
                kPremul_SkAlphaType == requestedInfo.alphaType(), ctableCount)) {
            return kInvalidInput;
        }
    }

    // Copy the color table to the client if they request kIndex8 mode
    copy_color_table(requestedInfo, fColorTable, ctable, ctableCount);

    // Create the swizzler.  SkPngCodec retains ownership of the color table.
    const SkPMColor* colors = get_color_ptr(fColorTable.get());
    fSwizzler.reset(SkSwizzler::CreateSwizzler(this->getEncodedInfo(), colors, requestedInfo,
            options));
    SkASSERT(fSwizzler);

    return kSuccess;
}

void SkCodec::fillIncompleteImage(const SkImageInfo& info, void* dst, size_t rowBytes,
        ZeroInitialized zeroInit, int linesRequested, int linesDecoded) {

    void* fillDst;
    const uint32_t fillValue = this->getFillValue(info.colorType(), info.alphaType());
    const int linesRemaining = linesRequested - linesDecoded;
    SkSampler* sampler = this->getSampler(false);

    switch (this->getScanlineOrder()) {
        case kTopDown_SkScanlineOrder:
        case kNone_SkScanlineOrder: {
            const SkImageInfo fillInfo = info.makeWH(info.width(), linesRemaining);
            fillDst = SkTAddOffset<void>(dst, linesDecoded * rowBytes);
            fill_proc(fillInfo, fillDst, rowBytes, fillValue, zeroInit, sampler);
            break;
        }
        case kBottomUp_SkScanlineOrder: {
            fillDst = dst;
            const SkImageInfo fillInfo = info.makeWH(info.width(), linesRemaining);
            fill_proc(fillInfo, fillDst, rowBytes, fillValue, zeroInit, sampler);
            break;
        }
        case kOutOfOrder_SkScanlineOrder: {
            SkASSERT(1 == linesRequested || this->getInfo().height() == linesRequested);
            const SkImageInfo fillInfo = info.makeWH(info.width(), 1);
            for (int srcY = linesDecoded; srcY < linesRequested; srcY++) {
                fillDst = SkTAddOffset<void>(dst, this->outputScanline(srcY) * rowBytes);
                fill_proc(fillInfo, fillDst, rowBytes, fillValue, zeroInit, sampler);
            }
            break;
        }
    }
}

bool SkPngCodec::initializeSwizzler(const SkImageInfo& requestedInfo,
                                    const Options& options,
                                    SkPMColor ctable[],
                                    int* ctableCount) {
    if (setjmp(png_jmpbuf(fPng_ptr))) {
        return false;
    }
    png_read_update_info(fPng_ptr, fInfo_ptr);

    if (SkEncodedInfo::kPalette_Color == this->getEncodedInfo().color()) {
        if (!this->createColorTable(requestedInfo.colorType(),
                kPremul_SkAlphaType == requestedInfo.alphaType(), ctableCount)) {
            return false;
        }
    }

    // Copy the color table to the client if they request kIndex8 mode
    copy_color_table(requestedInfo, fColorTable, ctable, ctableCount);

    // Create the swizzler.  SkPngCodec retains ownership of the color table.
    const SkPMColor* colors = get_color_ptr(fColorTable.get());
    fSwizzler.reset(SkSwizzler::CreateSwizzler(this->getEncodedInfo(), colors, requestedInfo,
            options));
    SkASSERT(fSwizzler);

    return true;
}

static void test_peek(skiatest::Reporter* reporter, SkImage* image, bool expectPeekSuccess) {
    SkImageInfo info;
    size_t rowBytes;
    const void* addr = image->peekPixels(&info, &rowBytes);
    bool success = SkToBool(addr);
    REPORTER_ASSERT(reporter, expectPeekSuccess == success);
    if (success) {
        REPORTER_ASSERT(reporter, 20 == info.width());
        REPORTER_ASSERT(reporter, 20 == info.height());
        REPORTER_ASSERT(reporter, kN32_SkColorType == info.colorType());
        REPORTER_ASSERT(reporter, kPremul_SkAlphaType == info.alphaType() ||
                        kOpaque_SkAlphaType == info.alphaType());
        REPORTER_ASSERT(reporter, info.minRowBytes() <= rowBytes);
        REPORTER_ASSERT(reporter, SkPreMultiplyColor(SK_ColorWHITE) == *(const SkPMColor*)addr);
    }
}

SkImage* SkImage::NewFromBitmap(const SkBitmap& bm) {
    SkPixelRef* pr = bm.pixelRef();
    if (nullptr == pr) {
        return nullptr;
    }

#if SK_SUPPORT_GPU
    if (GrTexture* tex = pr->getTexture()) {
        SkAutoTUnref<GrTexture> unrefCopy;
        if (!bm.isImmutable()) {
            const bool notBudgeted = false;
            tex = GrDeepCopyTexture(tex, notBudgeted);
            if (nullptr == tex) {
                return nullptr;
            }
            unrefCopy.reset(tex);
        }
        const SkImageInfo info = bm.info();
        return new SkImage_Gpu(info.width(), info.height(), bm.getGenerationID(), info.alphaType(),
                               tex, 0, SkSurface::kNo_Budgeted);
    }
#endif

    // This will check for immutable (share or copy)
    return SkNewImageFromRasterBitmap(bm, nullptr);
}

/*
 * Performs the decoding
 */
SkCodec::Result SkBmpMaskCodec::decode(const SkImageInfo& dstInfo,
                                       void* dst, size_t dstRowBytes,
                                       const Options& opts) {
    // Set constant values
    const int width = dstInfo.width();
    const int height = dstInfo.height();
    const size_t rowBytes = SkAlign4(compute_row_bytes(width, this->bitsPerPixel()));

    // Iterate over rows of the image
    uint8_t* srcRow = fSrcBuffer.get();
    for (int y = 0; y < height; y++) {
        // Read a row of the input
        if (this->stream()->read(srcRow, rowBytes) != rowBytes) {
            SkCodecPrintf("Warning: incomplete input stream.\n");
            // Fill the destination image on failure
            SkPMColor fillColor = dstInfo.alphaType() == kOpaque_SkAlphaType ?
                    SK_ColorBLACK : SK_ColorTRANSPARENT;
            if (kNo_ZeroInitialized == opts.fZeroInitialized || 0 != fillColor) {
                void* dstStart = this->getDstStartRow(dst, dstRowBytes, y);
                SkSwizzler::Fill(dstStart, dstInfo, dstRowBytes, dstInfo.height() - y, fillColor,
                        nullptr);
            }
            return kIncompleteInput;
        }

        // Decode the row in destination format
        int row = SkBmpCodec::kBottomUp_RowOrder == this->rowOrder() ? height - 1 - y : y;
        void* dstRow = SkTAddOffset<void>(dst, row * dstRowBytes);
        fMaskSwizzler->swizzle(dstRow, srcRow);
    }

    // Finished decoding the entire image
    return kSuccess;
}

sk_sp<SkImage> SkSurface_Gpu::onNewImageSnapshot(SkBudgeted budgeted, ForceCopyMode forceCopyMode) {
    GrRenderTarget* rt = fDevice->accessDrawContext()->accessRenderTarget();
    SkASSERT(rt);
    GrTexture* tex = rt->asTexture();
    SkAutoTUnref<GrTexture> copy;
    // If the original render target is a buffer originally created by the client, then we don't
    // want to ever retarget the SkSurface at another buffer we create. Force a copy now to avoid
    // copy-on-write.
    if (kYes_ForceCopyMode == forceCopyMode || !tex || rt->resourcePriv().refsWrappedObjects()) {
        GrSurfaceDesc desc = fDevice->accessDrawContext()->desc();
        GrContext* ctx = fDevice->context();
        desc.fFlags = desc.fFlags & ~kRenderTarget_GrSurfaceFlag;
        copy.reset(ctx->textureProvider()->createTexture(desc, budgeted));
        if (!copy) {
            return nullptr;
        }
        if (!ctx->copySurface(copy, rt)) {
            return nullptr;
        }
        tex = copy;
    }
    const SkImageInfo info = fDevice->imageInfo();
    sk_sp<SkImage> image;
    if (tex) {
        image = sk_make_sp<SkImage_Gpu>(info.width(), info.height(), kNeedNewImageUniqueID,
                                        info.alphaType(), tex, sk_ref_sp(info.colorSpace()),
                                        budgeted);
    }
    return image;
}

    virtual Result onGetPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
                               const Options&,
                               SkPMColor ctableEntries[], int* ctableCount) override {
        SkMemoryStream stream(fData->data(), fData->size(), false);
        SkAutoTUnref<BareMemoryAllocator> allocator(SkNEW_ARGS(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 kInvalidInput;
        }

        SkASSERT(info.colorType() == bm.info().colorType());

        if (kIndex_8_SkColorType == info.colorType()) {
            SkASSERT(ctableEntries);

            SkColorTable* ctable = bm.getColorTable();
            if (NULL == ctable) {
                return kInvalidConversion;
            }
            const int count = ctable->count();
            memcpy(ctableEntries, ctable->readColors(), count * sizeof(SkPMColor));
            *ctableCount = count;
        }
        if (SkImageDecoder::kPartialSuccess == result) {
            return kIncompleteInput;
        }
        return kSuccess;
    }

static SkImageInfo make_premul(const SkImageInfo& info) {
    if (kUnpremul_SkAlphaType == info.alphaType()) {
        return info.makeAlphaType(kPremul_SkAlphaType);
    }

    return info;
}

sk_sp<SkImage> SkImage::MakeFromBitmap(const SkBitmap& bm) {
    SkPixelRef* pr = bm.pixelRef();
    if (nullptr == pr) {
        return nullptr;
    }

#if SK_SUPPORT_GPU
    if (GrTexture* tex = pr->getTexture()) {
        SkAutoTUnref<GrTexture> unrefCopy;
        if (!bm.isImmutable()) {
            tex = GrDeepCopyTexture(tex, SkBudgeted::kNo);
            if (nullptr == tex) {
                return nullptr;
            }
            unrefCopy.reset(tex);
        }
        const SkImageInfo info = bm.info();
        return sk_make_sp<SkImage_Gpu>(info.width(), info.height(), bm.getGenerationID(),
                                       info.alphaType(), tex, sk_ref_sp(info.colorSpace()),
                                       SkBudgeted::kNo);
    }
#endif

    // This will check for immutable (share or copy)
    return SkMakeImageFromRasterBitmap(bm);
}

static bool compatibleInfo(const SkImageInfo& src, const SkImageInfo& dst)
{
    if (src == dst)
        return true;

    // It is legal to write kOpaque_SkAlphaType pixels into a kPremul_SkAlphaType buffer.
    // This can happen when DeferredImageDecoder allocates an kOpaque_SkAlphaType image
    // generator based on cached frame info, while the ImageFrame-allocated dest bitmap
    // stays kPremul_SkAlphaType.
    if (src.alphaType() == kOpaque_SkAlphaType && dst.alphaType() == kPremul_SkAlphaType) {
        const SkImageInfo& tmp = src.makeAlphaType(kPremul_SkAlphaType);
        return tmp == dst;
    }

    return false;
}

bool SkAnimatedImage::Frame::init(const SkImageInfo& info, OnInit onInit) {
    if (fBitmap.getPixels()) {
        if (fBitmap.pixelRef()->unique()) {
            SkAssertResult(fBitmap.setAlphaType(info.alphaType()));
            return true;
        }

        // An SkCanvas provided to onDraw is still holding a reference.
        // Copy before we decode to ensure that we don't overwrite the
        // expected contents of the image.
        if (OnInit::kRestoreIfNecessary == onInit) {
            SkBitmap tmp;
            if (!tmp.tryAllocPixels(info)) {
                return false;
            }

            memcpy(tmp.getPixels(), fBitmap.getPixels(), fBitmap.computeByteSize());
            using std::swap;
            swap(tmp, fBitmap);
            return true;
        }
    }

    return fBitmap.tryAllocPixels(info);
}

static bool ico_conversion_possible(const SkImageInfo& dstInfo) {
    // We only support kN32_SkColorType.
    // This makes sense for BMP-in-ICO.  The presence of an AND
    // mask (which changes colors and adds transparency) means that
    // we cannot use k565 or kIndex8.
    // FIXME: For PNG-in-ICO, we could technically support whichever
    //        color types that the png supports.
    if (kN32_SkColorType != dstInfo.colorType()) {
        return false;
    }

    // We only support transparent alpha types.  This is necessary for
    // BMP-in-ICOs since there will be an AND mask.
    // FIXME: For opaque PNG-in-ICOs, we should be able to support kOpaque.
    return kPremul_SkAlphaType == dstInfo.alphaType() ||
           kUnpremul_SkAlphaType == dstInfo.alphaType();
}

    int readRows(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, int count, int startRow)
    override {
        if (setjmp(png_jmpbuf(fPng_ptr))) {
            SkCodecPrintf("Failed to get scanlines.\n");
            // FIXME (msarett): Returning 0 is pessimistic.  If we can complete a single pass,
            // we may be able to report that all of the memory has been initialized.  Even if we
            // fail on the first pass, we can still report than some scanlines are initialized.
            return 0;
        }

        SkAutoTMalloc<uint8_t> storage(count * fSrcRowBytes);
        uint8_t* srcRow;
        for (int i = 0; i < fNumberPasses; i++) {
            // Discard rows that we planned to skip.
            for (int y = 0; y < startRow; y++){
                png_read_row(fPng_ptr, fSwizzlerSrcRow, nullptr);
            }
            // Read rows we care about into storage.
            srcRow = storage.get();
            for (int y = 0; y < count; y++) {
                png_read_row(fPng_ptr, srcRow, nullptr);
                srcRow += fSrcRowBytes;
            }
            // Discard rows that we don't need.
            for (int y = 0; y < this->getInfo().height() - startRow - count; y++) {
                png_read_row(fPng_ptr, fSwizzlerSrcRow, nullptr);
            }
        }

        // Swizzle and xform the rows we care about
        void* swizzlerDstRow = dst;
        size_t swizzlerDstRowBytes = rowBytes;

        bool colorXform = fColorXform &&
                apply_xform_on_decode(dstInfo.colorType(), this->getEncodedInfo().color());
        if (colorXform) {
            swizzlerDstRow = fColorXformSrcRow;
            swizzlerDstRowBytes = 0;
        }

        SkAlphaType xformAlphaType = xform_alpha_type(dstInfo.alphaType(),
                                                      this->getInfo().alphaType());
        srcRow = storage.get();
        for (int y = 0; y < count; y++) {
            fSwizzler->swizzle(swizzlerDstRow, srcRow);
            srcRow = SkTAddOffset<uint8_t>(srcRow, fSrcRowBytes);

            if (colorXform) {
                fColorXform->apply(dst, (const uint32_t*) swizzlerDstRow, fSwizzler->swizzleWidth(),
                                   dstInfo.colorType(), xformAlphaType);
                dst = SkTAddOffset<void>(dst, rowBytes);
            }

            swizzlerDstRow = SkTAddOffset<void>(swizzlerDstRow, swizzlerDstRowBytes);
        }

        return count;
    }

SkCodec::Result SkCodec::getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes,
                                   const Options* options, SkPMColor ctable[], int* ctableCount) {
    if (kUnknown_SkColorType == info.colorType()) {
        return kInvalidConversion;
    }
    if (NULL == pixels) {
        return kInvalidParameters;
    }
    if (rowBytes < info.minRowBytes()) {
        return kInvalidParameters;
    }

    if (kIndex_8_SkColorType == info.colorType()) {
        if (NULL == ctable || NULL == ctableCount) {
            return kInvalidParameters;
        }
    } else {
        if (ctableCount) {
            *ctableCount = 0;
        }
        ctableCount = NULL;
        ctable = NULL;
    }

    {
        SkAlphaType canonical;
        if (!SkColorTypeValidateAlphaType(info.colorType(), info.alphaType(), &canonical)
            || canonical != info.alphaType())
        {
            return kInvalidConversion;
        }
    }

    // Default options.
    Options optsStorage;
    if (NULL == options) {
        options = &optsStorage;
    }
    const Result result = this->onGetPixels(info, pixels, rowBytes, *options, ctable, ctableCount);

    if ((kIncompleteInput == result || kSuccess == result) && ctableCount) {
        SkASSERT(*ctableCount >= 0 && *ctableCount <= 256);
    }
    return result;
}