bench/subset/SubsetTranslateBench.cpp

/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "CodecBenchPriv.h"
#include "SubsetTranslateBench.h"
#include "SubsetBenchPriv.h"
#include "SkData.h"
#include "SkCodec.h"
#include "SkImageDecoder.h"
#include "SkOSFile.h"
#include "SkStream.h"

/*
 *
 * This benchmark is designed to test the performance of subset decoding.
 * It uses input dimensions to decode the entire image where each block is susbetW x subsetH.
 *
 */

SubsetTranslateBench::SubsetTranslateBench(const SkString& path,
                                           SkColorType colorType,
                                           uint32_t subsetWidth,
                                           uint32_t subsetHeight,
                                           bool useCodec)
    : fColorType(colorType)
    , fSubsetWidth(subsetWidth)
    , fSubsetHeight(subsetHeight)
    , fUseCodec(useCodec)
{
    // Parse the filename
    SkString baseName = SkOSPath::Basename(path.c_str());

    // Choose an informative color name
    const char* colorName = color_type_to_str(fColorType);

    fName.printf("%sSubsetTranslate_%dx%d_%s_%s", fUseCodec ? "Codec" : "Image", fSubsetWidth,
            fSubsetHeight, baseName.c_str(), colorName);
    
    // Perform the decode setup
    SkAutoTUnref<SkData> encoded(SkData::NewFromFileName(path.c_str()));
    fStream.reset(new SkMemoryStream(encoded));
}

const char* SubsetTranslateBench::onGetName() {
    return fName.c_str();
}

bool SubsetTranslateBench::isSuitableFor(Backend backend) {
    return kNonRendering_Backend == backend;
}

// Allows allocating the bitmap first, and then writing to them later (in startScanlineDecode)
static SkPMColor* get_colors(SkBitmap* bm) {
    SkColorTable* ct = bm->getColorTable();
    if (!ct) {
        return nullptr;
    }

    return const_cast<SkPMColor*>(ct->readColors());
}

void SubsetTranslateBench::onDraw(int n, SkCanvas* canvas) {
    // When the color type is kIndex8, we will need to store the color table.  If it is
    // used, it will be initialized by the codec.
    int colorCount = 256;
    SkPMColor colors[256];
    if (fUseCodec) {
        for (int count = 0; count < n; count++) {
            SkAutoTDelete<SkCodec> codec(SkCodec::NewFromStream(fStream->duplicate()));
            SkASSERT(SkCodec::kOutOfOrder_SkScanlineOrder != codec->getScanlineOrder());
            const SkImageInfo info = codec->getInfo().makeColorType(fColorType);

            SkBitmap bitmap;
            // Note that we use the same bitmap for all of the subsets.
            // It might be larger than necessary for the end subsets.
            SkImageInfo subsetInfo = info.makeWH(fSubsetWidth, fSubsetHeight);
            alloc_pixels(&bitmap, subsetInfo, colors, colorCount);

            for (int x = 0; x < info.width(); x += fSubsetWidth) {
                for (int y = 0; y < info.height(); y += fSubsetHeight) {
                    const uint32_t currSubsetWidth =
                            x + (int) fSubsetWidth > info.width() ?
                            info.width() - x : fSubsetWidth;
                    const uint32_t currSubsetHeight =
                            y + (int) fSubsetHeight > info.height() ?
                            info.height() - y : fSubsetHeight;

                    // The scanline decoder will handle subsetting in the x-dimension.
                    SkIRect subset = SkIRect::MakeXYWH(x, 0, currSubsetWidth,
                            codec->getInfo().height());
                    SkCodec::Options options;
                    options.fSubset = &subset;

                    SkDEBUGCODE(SkCodec::Result result =)
                    codec->startScanlineDecode(info, &options, get_colors(&bitmap), &colorCount);
                    SkASSERT(SkCodec::kSuccess == result);

                    SkDEBUGCODE(bool success =) codec->skipScanlines(y);
                    SkASSERT(success);

                    SkDEBUGCODE(uint32_t lines =) codec->getScanlines(bitmap.getPixels(),
                            currSubsetHeight, bitmap.rowBytes());
                    SkASSERT(currSubsetHeight == lines);
                }
            }
        }
    } else {
        // We create a color table here to satisfy allocPixels() when the output
        // type is kIndex8.  It's okay that this is uninitialized since we never
        // use it.
        SkAutoTUnref<SkColorTable> colorTable(new SkColorTable(colors, 0));
        for (int count = 0; count < n; count++) {
            int width, height;
            SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(fStream));
            SkAssertResult(decoder->buildTileIndex(fStream->duplicate(), &width, &height));
            SkBitmap bitmap;
            // Note that we use the same bitmap for all of the subsets.
            // It might be larger than necessary for the end subsets.
            // If we do not include this step, decodeSubset() would allocate space
            // for the pixels automatically, but this would not allow us to reuse the
            // same bitmap as the other subsets.  We want to reuse the same bitmap
            // because it gives a more fair comparison with SkCodec and is a common
            // use case of BitmapRegionDecoder.
            bitmap.allocPixels(SkImageInfo::Make(fSubsetWidth, fSubsetHeight,
                    fColorType, kOpaque_SkAlphaType), nullptr, colorTable);

            for (int x = 0; x < width; x += fSubsetWidth) {
                for (int y = 0; y < height; y += fSubsetHeight) {
                    const uint32_t currSubsetWidth = x + (int) fSubsetWidth > width ?
                            width - x : fSubsetWidth;
                    const uint32_t currSubsetHeight = y + (int) fSubsetHeight > height ?
                            height - y : fSubsetHeight;
                    SkIRect rect = SkIRect::MakeXYWH(x, y, currSubsetWidth,
                            currSubsetHeight);
                    SkAssertResult(decoder->decodeSubset(&bitmap, rect, fColorType));
                }
            }
        }
    }
}