text: /*
   * 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 "DMSrcSink.h"
  #include "DDLPromiseImageHelper.h"
  #include "DDLTileHelper.h"
  #include "GrBackendSurface.h"
  #include "GrContextPriv.h"
  #include "GrGpu.h"
  #include "MemoryCache.h"
  #include "Resources.h"
  #include "SkAndroidCodec.h"
  #include "SkAutoMalloc.h"
  #include "SkAutoPixmapStorage.h"
  #include "SkCodec.h"
  #include "SkCodecImageGenerator.h"
  #include "SkColorSpace.h"
  #include "SkColorSpaceXformCanvas.h"
  #include "SkCommonFlags.h"
  #include "SkCommonFlagsGpu.h"
  #include "SkData.h"
  #include "SkDebugCanvas.h"
  #include "SkDeferredDisplayListRecorder.h"
  #include "SkDocument.h"
  #include "SkExecutor.h"
  #include "SkImageGenerator.h"
  #include "SkImageGeneratorCG.h"
  #include "SkImageGeneratorWIC.h"
  #include "SkImageInfoPriv.h"
  #include "SkLiteDL.h"
  #include "SkLiteRecorder.h"
  #include "SkMakeUnique.h"
  #include "SkMallocPixelRef.h"
  #include "SkMultiPictureDocumentPriv.h"
  #include "SkMultiPictureDraw.h"
  #include "SkNullCanvas.h"
  #include "SkOSFile.h"
  #include "SkOSPath.h"
  #include "SkOpts.h"
  #include "SkPictureCommon.h"
  #include "SkPictureData.h"
  #include "SkPictureRecorder.h"
  #include "SkPDFDocument.h"
  #include "SkRandom.h"
  #include "SkRecordDraw.h"
  #include "SkRecorder.h"
  #include "SkStream.h"
  #include "SkSurface.h"
  #include "SkSurfaceCharacterization.h"
  #include "SkSwizzler.h"
  #include "SkTLogic.h"
  #include "SkTaskGroup.h"
  #if defined(SK_BUILD_FOR_WIN)
      #include "SkAutoCoInitialize.h"
      #include "SkHRESULT.h"
      #include "SkTScopedComPtr.h"
      #include "SkXPSDocument.h"
      #include <XpsObjectModel.h>
  #endif
  
  #if defined(SK_ENABLE_SKOTTIE)
      #include "Skottie.h"
      #include "SkottieUtils.h"
  #endif
  
  #if defined(SK_XML)
      #include "SkSVGCanvas.h"
      #include "SkSVGDOM.h"
      #include "SkXMLWriter.h"
  #endif
  #include "TestUtils.h"
  
  #include <cmath>
  #include <functional>
  
  #include "../third_party/skcms/skcms.h"
  
  DEFINE_bool(multiPage, false, "For document-type backends, render the source"
              " into multiple pages");
  DEFINE_bool(RAW_threading, true, "Allow RAW decodes to run on multiple threads?");
  
  using sk_gpu_test::GrContextFactory;
  
  namespace DM {
  
  GMSrc::GMSrc(skiagm::GMFactory factory) : fFactory(factory) {}
  
  Error GMSrc::draw(SkCanvas* canvas) const {
      std::unique_ptr<skiagm::GM> gm(fFactory(nullptr));
      SkString errorMsg;
      skiagm::DrawResult drawResult = gm->draw(canvas, &errorMsg);
      if (skiagm::DrawResult::kSkip == drawResult) {
          return Error::Nonfatal(std::move(errorMsg));  // Cause this test to be skipped.
      }
      return "";
  }
  
  SkISize GMSrc::size() const {
      std::unique_ptr<skiagm::GM> gm(fFactory(nullptr));
      return gm->getISize();
  }
  
  Name GMSrc::name() const {
      std::unique_ptr<skiagm::GM> gm(fFactory(nullptr));
      return gm->getName();
  }
  
  void GMSrc::modifyGrContextOptions(GrContextOptions* options) const {
      std::unique_ptr<skiagm::GM> gm(fFactory(nullptr));
      gm->modifyGrContextOptions(options);
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  BRDSrc::BRDSrc(Path path, Mode mode, CodecSrc::DstColorType dstColorType, uint32_t sampleSize)
      : fPath(path)
      , fMode(mode)
      , fDstColorType(dstColorType)
      , fSampleSize(sampleSize)
  {}
  
  bool BRDSrc::veto(SinkFlags flags) const {
      // No need to test to non-raster or indirect backends.
      return flags.type != SinkFlags::kRaster
          || flags.approach != SinkFlags::kDirect;
  }
  
  static SkBitmapRegionDecoder* create_brd(Path path) {
      sk_sp<SkData> encoded(SkData::MakeFromFileName(path.c_str()));
      if (!encoded) {
          return nullptr;
      }
      return SkBitmapRegionDecoder::Create(encoded, SkBitmapRegionDecoder::kAndroidCodec_Strategy);
  }
  
  static inline void alpha8_to_gray8(SkBitmap* bitmap) {
      // Android requires kGray8 bitmaps to be tagged as kAlpha8.  Here we convert
      // them back to kGray8 so our test framework can draw them correctly.
      if (kAlpha_8_SkColorType == bitmap->info().colorType()) {
          SkImageInfo newInfo = bitmap->info().makeColorType(kGray_8_SkColorType)
                                              .makeAlphaType(kOpaque_SkAlphaType);
          *const_cast<SkImageInfo*>(&bitmap->info()) = newInfo;
      }
  }
  
  Error BRDSrc::draw(SkCanvas* canvas) const {
      SkColorType colorType = canvas->imageInfo().colorType();
      if (kRGB_565_SkColorType == colorType &&
              CodecSrc::kGetFromCanvas_DstColorType != fDstColorType) {
          return Error::Nonfatal("Testing non-565 to 565 is uninteresting.");
      }
      switch (fDstColorType) {
          case CodecSrc::kGetFromCanvas_DstColorType:
              break;
          case CodecSrc::kGrayscale_Always_DstColorType:
              colorType = kGray_8_SkColorType;
              break;
          default:
              SkASSERT(false);
              break;
      }
  
      std::unique_ptr<SkBitmapRegionDecoder> brd(create_brd(fPath));
      if (nullptr == brd.get()) {
          return Error::Nonfatal(SkStringPrintf("Could not create brd for %s.", fPath.c_str()));
      }
  
      auto recommendedCT = brd->computeOutputColorType(colorType);
      if (kRGB_565_SkColorType == colorType && recommendedCT != colorType) {
          return Error::Nonfatal("Skip decoding non-opaque to 565.");
      }
      colorType = recommendedCT;
  
      auto colorSpace = brd->computeOutputColorSpace(colorType, nullptr);
  
      const uint32_t width = brd->width();
      const uint32_t height = brd->height();
      // Visually inspecting very small output images is not necessary.
      if ((width / fSampleSize <= 10 || height / fSampleSize <= 10) && 1 != fSampleSize) {
          return Error::Nonfatal("Scaling very small images is uninteresting.");
      }
      switch (fMode) {
          case kFullImage_Mode: {
              SkBitmap bitmap;
              if (!brd->decodeRegion(&bitmap, nullptr, SkIRect::MakeXYWH(0, 0, width, height),
                      fSampleSize, colorType, false, colorSpace)) {
                  return "Cannot decode (full) region.";
              }
              alpha8_to_gray8(&bitmap);
  
              canvas->drawBitmap(bitmap, 0, 0);
              return "";
          }
          case kDivisor_Mode: {
              const uint32_t divisor = 2;
              if (width < divisor || height < divisor) {
                  return Error::Nonfatal("Divisor is larger than image dimension.");
              }
  
              // Use a border to test subsets that extend outside the image.
              // We will not allow the border to be larger than the image dimensions.  Allowing
              // these large borders causes off by one errors that indicate a problem with the
              // test suite, not a problem with the implementation.
              const uint32_t maxBorder = SkTMin(width, height) / (fSampleSize * divisor);
              const uint32_t scaledBorder = SkTMin(5u, maxBorder);
              const uint32_t unscaledBorder = scaledBorder * fSampleSize;
  
              // We may need to clear the canvas to avoid uninitialized memory.
              // Assume we are scaling a 780x780 image with sampleSize = 8.
              // The output image should be 97x97.
              // Each subset will be 390x390.
              // Each scaled subset be 48x48.
              // Four scaled subsets will only fill a 96x96 image.
              // The bottom row and last column will not be touched.
              // This is an unfortunate result of our rounding rules when scaling.
              // Maybe we need to consider testing scaled subsets without trying to
              // combine them to match the full scaled image?  Or maybe this is the
              // best we can do?
              canvas->clear(0);
  
              for (uint32_t x = 0; x < divisor; x++) {
                  for (uint32_t y = 0; y < divisor; y++) {
                      // Calculate the subset dimensions
                      uint32_t subsetWidth = width / divisor;
                      uint32_t subsetHeight = height / divisor;
                      const int left = x * subsetWidth;
                      const int top = y * subsetHeight;
  
                      // Increase the size of the last subset in each row or column, when the
                      // divisor does not divide evenly into the image dimensions
                      subsetWidth += (x + 1 == divisor) ? (width % divisor) : 0;
                      subsetHeight += (y + 1 == divisor) ? (height % divisor) : 0;
  
                      // Increase the size of the subset in order to have a border on each side
                      const int decodeLeft = left - unscaledBorder;
                      const int decodeTop = top - unscaledBorder;
                      const uint32_t decodeWidth = subsetWidth + unscaledBorder * 2;
                      const uint32_t decodeHeight = subsetHeight + unscaledBorder * 2;
                      SkBitmap bitmap;
                      if (!brd->decodeRegion(&bitmap, nullptr, SkIRect::MakeXYWH(decodeLeft,
                              decodeTop, decodeWidth, decodeHeight), fSampleSize, colorType, false,
                              colorSpace)) {
                          return "Cannot decode region.";
                      }
  
                      alpha8_to_gray8(&bitmap);
                      canvas->drawBitmapRect(bitmap,
                              SkRect::MakeXYWH((SkScalar) scaledBorder, (SkScalar) scaledBorder,
                                      (SkScalar) (subsetWidth / fSampleSize),
                                      (SkScalar) (subsetHeight / fSampleSize)),
                              SkRect::MakeXYWH((SkScalar) (left / fSampleSize),
                                      (SkScalar) (top / fSampleSize),
                                      (SkScalar) (subsetWidth / fSampleSize),
                                      (SkScalar) (subsetHeight / fSampleSize)),
                              nullptr);
                  }
              }
              return "";
          }
          default:
              SkASSERT(false);
              return "Error: Should not be reached.";
      }
  }
  
  SkISize BRDSrc::size() const {
      std::unique_ptr<SkBitmapRegionDecoder> brd(create_brd(fPath));
      if (brd) {
          return {SkTMax(1, brd->width() / (int)fSampleSize),
                  SkTMax(1, brd->height() / (int)fSampleSize)};
      }
      return {0, 0};
  }
  
  static SkString get_scaled_name(const Path& path, float scale) {
      return SkStringPrintf("%s_%.3f", SkOSPath::Basename(path.c_str()).c_str(), scale);
  }
  
  Name BRDSrc::name() const {
      // We will replicate the names used by CodecSrc so that images can
      // be compared in Gold.
      if (1 == fSampleSize) {
          return SkOSPath::Basename(fPath.c_str());
      }
      return get_scaled_name(fPath, 1.0f / (float) fSampleSize);
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  static bool serial_from_path_name(const SkString& path) {
      if (!FLAGS_RAW_threading) {
          static const char* const exts[] = {
              "arw", "cr2", "dng", "nef", "nrw", "orf", "raf", "rw2", "pef", "srw",
              "ARW", "CR2", "DNG", "NEF", "NRW", "ORF", "RAF", "RW2", "PEF", "SRW",
          };
          const char* actualExt = strrchr(path.c_str(), '.');
          if (actualExt) {
              actualExt++;
              for (auto* ext : exts) {
                  if (0 == strcmp(ext, actualExt)) {
                      return true;
                  }
              }
          }
      }
      return false;
  }
  
  CodecSrc::CodecSrc(Path path, Mode mode, DstColorType dstColorType, SkAlphaType dstAlphaType,
                     float scale)
      : fPath(path)
      , fMode(mode)
      , fDstColorType(dstColorType)
      , fDstAlphaType(dstAlphaType)
      , fScale(scale)
      , fRunSerially(serial_from_path_name(path))
  {}
  
  bool CodecSrc::veto(SinkFlags flags) const {
      // Test to direct raster backends (8888 and 565).
      return flags.type != SinkFlags::kRaster || flags.approach != SinkFlags::kDirect;
  }
  
  // Allows us to test decodes to non-native 8888.
  static void swap_rb_if_necessary(SkBitmap& bitmap, CodecSrc::DstColorType dstColorType) {
      if (CodecSrc::kNonNative8888_Always_DstColorType != dstColorType) {
          return;
      }
  
      for (int y = 0; y < bitmap.height(); y++) {
          uint32_t* row = (uint32_t*) bitmap.getAddr(0, y);
          SkOpts::RGBA_to_BGRA(row, row, bitmap.width());
      }
  }
  
  static bool get_decode_info(SkImageInfo* decodeInfo, SkColorType canvasColorType,
                              CodecSrc::DstColorType dstColorType, SkAlphaType dstAlphaType) {
      switch (dstColorType) {
          case CodecSrc::kGrayscale_Always_DstColorType:
              if (kRGB_565_SkColorType == canvasColorType) {
                  return false;
              }
              *decodeInfo = decodeInfo->makeColorType(kGray_8_SkColorType);
              break;
          case CodecSrc::kNonNative8888_Always_DstColorType:
              if (kRGB_565_SkColorType == canvasColorType
                      || kRGBA_F16_SkColorType == canvasColorType) {
                  return false;
              }
  #ifdef SK_PMCOLOR_IS_RGBA
              *decodeInfo = decodeInfo->makeColorType(kBGRA_8888_SkColorType);
  #else
              *decodeInfo = decodeInfo->makeColorType(kRGBA_8888_SkColorType);
  #endif
              break;
          default:
              if (kRGB_565_SkColorType == canvasColorType &&
                      kOpaque_SkAlphaType != decodeInfo->alphaType()) {
                  return false;
              }
  
              *decodeInfo = decodeInfo->makeColorType(canvasColorType);
              break;
      }
  
      *decodeInfo = decodeInfo->makeAlphaType(dstAlphaType);
      return true;
  }
  
  static void draw_to_canvas(SkCanvas* canvas, const SkImageInfo& info, void* pixels, size_t rowBytes,
                             CodecSrc::DstColorType dstColorType,
                             SkScalar left = 0, SkScalar top = 0) {
      SkBitmap bitmap;
      bitmap.installPixels(info, pixels, rowBytes);
      swap_rb_if_necessary(bitmap, dstColorType);
      canvas->drawBitmap(bitmap, left, top);
  }
  
  // For codec srcs, we want the "draw" step to be a memcpy.  Any interesting color space or
  // color format conversions should be performed by the codec.  Sometimes the output of the
  // decode will be in an interesting color space.  On our srgb and f16 backends, we need to
  // "pretend" that the color space is standard sRGB to avoid triggering color conversion
  // at draw time.
  static void set_bitmap_color_space(SkImageInfo* info) {
      *info = info->makeColorSpace(SkColorSpace::MakeSRGB());
  }
  
  Error CodecSrc::draw(SkCanvas* canvas) const {
      sk_sp<SkData> encoded(SkData::MakeFromFileName(fPath.c_str()));
      if (!encoded) {
          return SkStringPrintf("Couldn't read %s.", fPath.c_str());
      }
  
      std::unique_ptr<SkCodec> codec(SkCodec::MakeFromData(encoded));
      if (nullptr == codec.get()) {
          return SkStringPrintf("Couldn't create codec for %s.", fPath.c_str());
      }
  
      SkImageInfo decodeInfo = codec->getInfo();
      if (!get_decode_info(&decodeInfo, canvas->imageInfo().colorType(), fDstColorType,
                           fDstAlphaType)) {
          return Error::Nonfatal("Skipping uninteresting test.");
      }
  
      // Try to scale the image if it is desired
      SkISize size = codec->getScaledDimensions(fScale);
      if (size == decodeInfo.dimensions() && 1.0f != fScale) {
          return Error::Nonfatal("Test without scaling is uninteresting.");
      }
  
      // Visually inspecting very small output images is not necessary.  We will
      // cover these cases in unit testing.
      if ((size.width() <= 10 || size.height() <= 10) && 1.0f != fScale) {
          return Error::Nonfatal("Scaling very small images is uninteresting.");
      }
      decodeInfo = decodeInfo.makeWH(size.width(), size.height());
  
      const int bpp = decodeInfo.bytesPerPixel();
      const size_t rowBytes = size.width() * bpp;
      const size_t safeSize = decodeInfo.computeByteSize(rowBytes);
      SkAutoMalloc pixels(safeSize);
  
      SkCodec::Options options;
      if (kCodecZeroInit_Mode == fMode) {
          memset(pixels.get(), 0, size.height() * rowBytes);
          options.fZeroInitialized = SkCodec::kYes_ZeroInitialized;
      }
  
      SkImageInfo bitmapInfo = decodeInfo;
      set_bitmap_color_space(&bitmapInfo);
      if (kRGBA_8888_SkColorType == decodeInfo.colorType() ||
              kBGRA_8888_SkColorType == decodeInfo.colorType()) {
          bitmapInfo = bitmapInfo.makeColorType(kN32_SkColorType);
      }
  
      switch (fMode) {
          case kAnimated_Mode: {
              std::vector<SkCodec::FrameInfo> frameInfos = codec->getFrameInfo();
              if (frameInfos.size() <= 1) {
                  return SkStringPrintf("%s is not an animated image.", fPath.c_str());
              }
  
              // As in CodecSrc::size(), compute a roughly square grid to draw the frames
              // into. "factor" is the number of frames to draw on one row. There will be
              // up to "factor" rows as well.
              const float root = sqrt((float) frameInfos.size());
              const int factor = sk_float_ceil2int(root);
  
              // Used to cache a frame that future frames will depend on.
              SkAutoMalloc priorFramePixels;
              int cachedFrame = SkCodec::kNoFrame;
              for (int i = 0; static_cast<size_t>(i) < frameInfos.size(); i++) {
                  options.fFrameIndex = i;
                  // Check for a prior frame
                  const int reqFrame = frameInfos[i].fRequiredFrame;
                  if (reqFrame != SkCodec::kNoFrame && reqFrame == cachedFrame
                          && priorFramePixels.get()) {
                      // Copy into pixels
                      memcpy(pixels.get(), priorFramePixels.get(), safeSize);
                      options.fPriorFrame = reqFrame;
                  } else {
                      options.fPriorFrame = SkCodec::kNoFrame;
                  }
                  SkCodec::Result result = codec->getPixels(decodeInfo, pixels.get(),
                                                            rowBytes, &options);
                  if (SkCodec::kInvalidInput == result && i > 0) {
                      // Some of our test images have truncated later frames. Treat that
                      // the same as incomplete.
                      result = SkCodec::kIncompleteInput;
                  }
                  switch (result) {
                      case SkCodec::kSuccess:
                      case SkCodec::kErrorInInput:
                      case SkCodec::kIncompleteInput: {
                          // If the next frame depends on this one, store it in priorFrame.
                          // It is possible that we may discard a frame that future frames depend on,
                          // but the codec will simply redecode the discarded frame.
                          // Do this before calling draw_to_canvas, which premultiplies in place. If
                          // we're decoding to unpremul, we want to pass the unmodified frame to the
                          // codec for decoding the next frame.
                          if (static_cast<size_t>(i+1) < frameInfos.size()
                                  && frameInfos[i+1].fRequiredFrame == i) {
                              memcpy(priorFramePixels.reset(safeSize), pixels.get(), safeSize);
                              cachedFrame = i;
                          }
  
                          SkAutoCanvasRestore acr(canvas, true);
                          const int xTranslate = (i % factor) * decodeInfo.width();
                          const int yTranslate = (i / factor) * decodeInfo.height();
                          canvas->translate(SkIntToScalar(xTranslate), SkIntToScalar(yTranslate));
                          draw_to_canvas(canvas, bitmapInfo, pixels.get(), rowBytes, fDstColorType);
                          if (result != SkCodec::kSuccess) {
                              return "";
                          }
                          break;
                      }
                      case SkCodec::kInvalidConversion:
                          if (i > 0 && (decodeInfo.colorType() == kRGB_565_SkColorType)) {
                              return Error::Nonfatal(SkStringPrintf(
                                  "Cannot decode frame %i to 565 (%s).", i, fPath.c_str()));
                          }
                          // Fall through.
                      default:
                          return SkStringPrintf("Couldn't getPixels for frame %i in %s.",
                                                i, fPath.c_str());
                  }
              }
              break;
          }
          case kCodecZeroInit_Mode:
          case kCodec_Mode: {
              switch (codec->getPixels(decodeInfo, pixels.get(), rowBytes, &options)) {
                  case SkCodec::kSuccess:
                      // We consider these to be valid, since we should still decode what is
                      // available.
                  case SkCodec::kErrorInInput:
                  case SkCodec::kIncompleteInput:
                      break;
                  default:
                      // Everything else is considered a failure.
                      return SkStringPrintf("Couldn't getPixels %s.", fPath.c_str());
              }
  
              draw_to_canvas(canvas, bitmapInfo, pixels.get(), rowBytes, fDstColorType);
              break;
          }
          case kScanline_Mode: {
              void* dst = pixels.get();
              uint32_t height = decodeInfo.height();
              const bool useIncremental = [this]() {
                  auto exts = { "png", "PNG", "gif", "GIF" };
                  for (auto ext : exts) {
                      if (fPath.endsWith(ext)) {
                          return true;
                      }
                  }
                  return false;
              }();
              // ico may use the old scanline method or the new one, depending on whether it
              // internally holds a bmp or a png.
              const bool ico = fPath.endsWith("ico");
              bool useOldScanlineMethod = !useIncremental && !ico;
              if (useIncremental || ico) {
                  if (SkCodec::kSuccess == codec->startIncrementalDecode(decodeInfo, dst,
                          rowBytes, &options)) {
                      int rowsDecoded;
                      auto result = codec->incrementalDecode(&rowsDecoded);
                      if (SkCodec::kIncompleteInput == result || SkCodec::kErrorInInput == result) {
                          codec->fillIncompleteImage(decodeInfo, dst, rowBytes,
                                                     SkCodec::kNo_ZeroInitialized, height,
                                                     rowsDecoded);
                      }
                  } else {
                      if (useIncremental) {
                          // Error: These should support incremental decode.
                          return "Could not start incremental decode";
                      }
                      // Otherwise, this is an ICO. Since incremental failed, it must contain a BMP,
                      // which should work via startScanlineDecode
                      useOldScanlineMethod = true;
                  }
              }
  
              if (useOldScanlineMethod) {
                  if (SkCodec::kSuccess != codec->startScanlineDecode(decodeInfo)) {
                      return "Could not start scanline decoder";
                  }
  
                  // We do not need to check the return value.  On an incomplete
                  // image, memory will be filled with a default value.
                  codec->getScanlines(dst, height, rowBytes);
              }
  
              draw_to_canvas(canvas, bitmapInfo, dst, rowBytes, fDstColorType);
              break;
          }
          case kStripe_Mode: {
              const int height = decodeInfo.height();
              // This value is chosen arbitrarily.  We exercise more cases by choosing a value that
              // does not align with image blocks.
              const int stripeHeight = 37;
              const int numStripes = (height + stripeHeight - 1) / stripeHeight;
              void* dst = pixels.get();
  
              // Decode odd stripes
              if (SkCodec::kSuccess != codec->startScanlineDecode(decodeInfo, &options)) {
                  return "Could not start scanline decoder";
              }
  
              // This mode was designed to test the new skip scanlines API in libjpeg-turbo.
              // Jpegs have kTopDown_SkScanlineOrder, and at this time, it is not interesting
              // to run this test for image types that do not have this scanline ordering.
              // We only run this on Jpeg, which is always kTopDown.
              SkASSERT(SkCodec::kTopDown_SkScanlineOrder == codec->getScanlineOrder());
  
              for (int i = 0; i < numStripes; i += 2) {
                  // Skip a stripe
                  const int linesToSkip = SkTMin(stripeHeight, height - i * stripeHeight);
                  codec->skipScanlines(linesToSkip);
  
                  // Read a stripe
                  const int startY = (i + 1) * stripeHeight;
                  const int linesToRead = SkTMin(stripeHeight, height - startY);
                  if (linesToRead > 0) {
                      codec->getScanlines(SkTAddOffset<void>(dst, rowBytes * startY), linesToRead,
                                          rowBytes);
                  }
              }
  
              // Decode even stripes
              const SkCodec::Result startResult = codec->startScanlineDecode(decodeInfo);
              if (SkCodec::kSuccess != startResult) {
                  return "Failed to restart scanline decoder with same parameters.";
              }
              for (int i = 0; i < numStripes; i += 2) {
                  // Read a stripe
                  const int startY = i * stripeHeight;
                  const int linesToRead = SkTMin(stripeHeight, height - startY);
                  codec->getScanlines(SkTAddOffset<void>(dst, rowBytes * startY), linesToRead,
                                      rowBytes);
  
                  // Skip a stripe
                  const int linesToSkip = SkTMin(stripeHeight, height - (i + 1) * stripeHeight);
                  if (linesToSkip > 0) {
                      codec->skipScanlines(linesToSkip);
                  }
              }
  
              draw_to_canvas(canvas, bitmapInfo, dst, rowBytes, fDstColorType);
              break;
          }
          case kCroppedScanline_Mode: {
              const int width = decodeInfo.width();
              const int height = decodeInfo.height();
              // This value is chosen because, as we move across the image, it will sometimes
              // align with the jpeg block sizes and it will sometimes not.  This allows us
              // to test interestingly different code paths in the implementation.
              const int tileSize = 36;
              SkIRect subset;
              for (int x = 0; x < width; x += tileSize) {
                  subset = SkIRect::MakeXYWH(x, 0, SkTMin(tileSize, width - x), height);
                  options.fSubset = &subset;
                  if (SkCodec::kSuccess != codec->startScanlineDecode(decodeInfo, &options)) {
                      return "Could not start scanline decoder.";
                  }
  
                  codec->getScanlines(SkTAddOffset<void>(pixels.get(), x * bpp), height, rowBytes);
              }
  
              draw_to_canvas(canvas, bitmapInfo, pixels.get(), rowBytes, fDstColorType);
              break;
          }
          case kSubset_Mode: {
              // Arbitrarily choose a divisor.
              int divisor = 2;
              // Total width/height of the image.
              const int W = codec->getInfo().width();
              const int H = codec->getInfo().height();
              if (divisor > W || divisor > H) {
                  return Error::Nonfatal(SkStringPrintf("Cannot codec subset: divisor %d is too big "
                                                        "for %s with dimensions (%d x %d)", divisor,
                                                        fPath.c_str(), W, H));
              }
              // subset dimensions
              // SkWebpCodec, the only one that supports subsets, requires even top/left boundaries.
              const int w = SkAlign2(W / divisor);
              const int h = SkAlign2(H / divisor);
              SkIRect subset;
              options.fSubset = &subset;
              SkBitmap subsetBm;
              // We will reuse pixel memory from bitmap.
              void* dst = pixels.get();
              // Keep track of left and top (for drawing subsetBm into canvas). We could use
              // fScale * x and fScale * y, but we want integers such that the next subset will start
              // where the last one ended. So we'll add decodeInfo.width() and height().
              int left = 0;
              for (int x = 0; x < W; x += w) {
                  int top = 0;
                  for (int y = 0; y < H; y+= h) {
                      // Do not make the subset go off the edge of the image.
                      const int preScaleW = SkTMin(w, W - x);
                      const int preScaleH = SkTMin(h, H - y);
                      subset.setXYWH(x, y, preScaleW, preScaleH);
                      // And scale
                      // FIXME: Should we have a version of getScaledDimensions that takes a subset
                      // into account?
                      const int scaledW = SkTMax(1, SkScalarRoundToInt(preScaleW * fScale));
                      const int scaledH = SkTMax(1, SkScalarRoundToInt(preScaleH * fScale));
                      decodeInfo = decodeInfo.makeWH(scaledW, scaledH);
                      SkImageInfo subsetBitmapInfo = bitmapInfo.makeWH(scaledW, scaledH);
                      size_t subsetRowBytes = subsetBitmapInfo.minRowBytes();
                      const SkCodec::Result result = codec->getPixels(decodeInfo, dst, subsetRowBytes,
                              &options);
                      switch (result) {
                          case SkCodec::kSuccess:
                          case SkCodec::kErrorInInput:
                          case SkCodec::kIncompleteInput:
                              break;
                          default:
                              return SkStringPrintf("subset codec failed to decode (%d, %d, %d, %d) "
                                                    "from %s with dimensions (%d x %d)\t error %d",
                                                    x, y, decodeInfo.width(), decodeInfo.height(),
                                                    fPath.c_str(), W, H, result);
                      }
                      draw_to_canvas(canvas, subsetBitmapInfo, dst, subsetRowBytes, fDstColorType,
                                     SkIntToScalar(left), SkIntToScalar(top));
  
                      // translate by the scaled height.
                      top += decodeInfo.height();
                  }
                  // translate by the scaled width.
                  left += decodeInfo.width();
              }
              return "";
          }
          default:
              SkASSERT(false);
              return "Invalid fMode";
      }
      return "";
  }
  
  SkISize CodecSrc::size() const {
      sk_sp<SkData> encoded(SkData::MakeFromFileName(fPath.c_str()));
      std::unique_ptr<SkCodec> codec(SkCodec::MakeFromData(encoded));
      if (nullptr == codec) {
          return {0, 0};
      }
  
      auto imageSize = codec->getScaledDimensions(fScale);
      if (fMode == kAnimated_Mode) {
          // We'll draw one of each frame, so make it big enough to hold them all
          // in a grid. The grid will be roughly square, with "factor" frames per
          // row and up to "factor" rows.
          const size_t count = codec->getFrameInfo().size();
          const float root = sqrt((float) count);
          const int factor = sk_float_ceil2int(root);
          imageSize.fWidth  = imageSize.fWidth  * factor;
          imageSize.fHeight = imageSize.fHeight * sk_float_ceil2int((float) count / (float) factor);
      }
      return imageSize;
  }
  
  Name CodecSrc::name() const {
      if (1.0f == fScale) {
          Name name = SkOSPath::Basename(fPath.c_str());
          if (fMode == kAnimated_Mode) {
              name.append("_animated");
          }
          return name;
      }
      SkASSERT(fMode != kAnimated_Mode);
      return get_scaled_name(fPath, fScale);
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  AndroidCodecSrc::AndroidCodecSrc(Path path, CodecSrc::DstColorType dstColorType,
          SkAlphaType dstAlphaType, int sampleSize)
      : fPath(path)
      , fDstColorType(dstColorType)
      , fDstAlphaType(dstAlphaType)
      , fSampleSize(sampleSize)
      , fRunSerially(serial_from_path_name(path))
  {}
  
  bool AndroidCodecSrc::veto(SinkFlags flags) const {
      // No need to test decoding to non-raster or indirect backend.
      return flags.type != SinkFlags::kRaster
          || flags.approach != SinkFlags::kDirect;
  }
  
  Error AndroidCodecSrc::draw(SkCanvas* canvas) const {
      sk_sp<SkData> encoded(SkData::MakeFromFileName(fPath.c_str()));
      if (!encoded) {
          return SkStringPrintf("Couldn't read %s.", fPath.c_str());
      }
      std::unique_ptr<SkAndroidCodec> codec(SkAndroidCodec::MakeFromData(encoded));
      if (nullptr == codec) {
          return SkStringPrintf("Couldn't create android codec for %s.", fPath.c_str());
      }
  
      SkImageInfo decodeInfo = codec->getInfo();
      if (!get_decode_info(&decodeInfo, canvas->imageInfo().colorType(), fDstColorType,
                           fDstAlphaType)) {
          return Error::Nonfatal("Skipping uninteresting test.");
      }
  
      // Scale the image if it is desired.
      SkISize size = codec->getSampledDimensions(fSampleSize);
  
      // Visually inspecting very small output images is not necessary.  We will
      // cover these cases in unit testing.
      if ((size.width() <= 10 || size.height() <= 10) && 1 != fSampleSize) {
          return Error::Nonfatal("Scaling very small images is uninteresting.");
      }
      decodeInfo = decodeInfo.makeWH(size.width(), size.height());
  
      int bpp = decodeInfo.bytesPerPixel();
      size_t rowBytes = size.width() * bpp;
      SkAutoMalloc pixels(size.height() * rowBytes);
  
      SkBitmap bitmap;
      SkImageInfo bitmapInfo = decodeInfo;
      set_bitmap_color_space(&bitmapInfo);
      if (kRGBA_8888_SkColorType == decodeInfo.colorType() ||
              kBGRA_8888_SkColorType == decodeInfo.colorType()) {
          bitmapInfo = bitmapInfo.makeColorType(kN32_SkColorType);
      }
  
      // Create options for the codec.
      SkAndroidCodec::AndroidOptions options;
      options.fSampleSize = fSampleSize;
  
      switch (codec->getAndroidPixels(decodeInfo, pixels.get(), rowBytes, &options)) {
          case SkCodec::kSuccess:
          case SkCodec::kErrorInInput:
          case SkCodec::kIncompleteInput:
              break;
          default:
              return SkStringPrintf("Couldn't getPixels %s.", fPath.c_str());
      }
      draw_to_canvas(canvas, bitmapInfo, pixels.get(), rowBytes, fDstColorType);
      return "";
  }
  
  SkISize AndroidCodecSrc::size() const {
      sk_sp<SkData> encoded(SkData::MakeFromFileName(fPath.c_str()));
      std::unique_ptr<SkAndroidCodec> codec(SkAndroidCodec::MakeFromData(encoded));
      if (nullptr == codec) {
          return {0, 0};
      }
      return codec->getSampledDimensions(fSampleSize);
  }
  
  Name AndroidCodecSrc::name() const {
      // We will replicate the names used by CodecSrc so that images can
      // be compared in Gold.
      if (1 == fSampleSize) {
          return SkOSPath::Basename(fPath.c_str());
      }
      return get_scaled_name(fPath, 1.0f / (float) fSampleSize);
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  ImageGenSrc::ImageGenSrc(Path path, Mode mode, SkAlphaType alphaType, bool isGpu)
      : fPath(path)
      , fMode(mode)
      , fDstAlphaType(alphaType)
      , fIsGpu(isGpu)
      , fRunSerially(serial_from_path_name(path))
  {}
  
  bool ImageGenSrc::veto(SinkFlags flags) const {
      if (fIsGpu) {
          // MSAA runs tend to run out of memory and tests the same code paths as regular gpu configs.
          return flags.type != SinkFlags::kGPU || flags.approach != SinkFlags::kDirect ||
                 flags.multisampled == SinkFlags::kMultisampled;
      }
  
      return flags.type != SinkFlags::kRaster || flags.approach != SinkFlags::kDirect;
  }
  
  Error ImageGenSrc::draw(SkCanvas* canvas) const {
      if (kRGB_565_SkColorType == canvas->imageInfo().colorType()) {
          return Error::Nonfatal("Uninteresting to test image generator to 565.");
      }
  
      sk_sp<SkData> encoded(SkData::MakeFromFileName(fPath.c_str()));
      if (!encoded) {
          return SkStringPrintf("Couldn't read %s.", fPath.c_str());
      }
  
  #if defined(SK_BUILD_FOR_WIN)
      // Initialize COM in order to test with WIC.
      SkAutoCoInitialize com;
      if (!com.succeeded()) {
          return "Could not initialize COM.";
      }
  #endif
  
      std::unique_ptr<SkImageGenerator> gen(nullptr);
      switch (fMode) {
          case kCodec_Mode:
              gen = SkCodecImageGenerator::MakeFromEncodedCodec(encoded);
              if (!gen) {
                  return "Could not create codec image generator.";
              }
              break;
          case kPlatform_Mode: {
  #if defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)
              gen = SkImageGeneratorCG::MakeFromEncodedCG(encoded);
  #elif defined(SK_BUILD_FOR_WIN)
              gen = SkImageGeneratorWIC::MakeFromEncodedWIC(encoded);
  #endif
              if (!gen) {
                  return "Could not create platform image generator.";
              }
              break;
          }
          default:
              SkASSERT(false);
              return "Invalid image generator mode";
      }
  
      // Test deferred decoding path on GPU
      if (fIsGpu) {
          sk_sp<SkImage> image(SkImage::MakeFromGenerator(std::move(gen), nullptr));
          if (!image) {
              return "Could not create image from codec image generator.";
          }
          canvas->drawImage(image, 0, 0);
          return "";
      }
  
      // Test various color and alpha types on CPU
      SkImageInfo decodeInfo = gen->getInfo().makeAlphaType(fDstAlphaType);
  
      int bpp = decodeInfo.bytesPerPixel();
      size_t rowBytes = decodeInfo.width() * bpp;
      SkAutoMalloc pixels(decodeInfo.height() * rowBytes);
      if (!gen->getPixels(decodeInfo, pixels.get(), rowBytes)) {
          SkString err =
                  SkStringPrintf("Image generator could not getPixels() for %s\n", fPath.c_str());
  
  #if defined(SK_BUILD_FOR_WIN)
          if (kPlatform_Mode == fMode) {
              // Do not issue a fatal error for WIC flakiness.
              return Error::Nonfatal(err);
          }
  #endif
  
          return err;
      }
  
      set_bitmap_color_space(&decodeInfo);
      draw_to_canvas(canvas, decodeInfo, pixels.get(), rowBytes,
                     CodecSrc::kGetFromCanvas_DstColorType);
      return "";
  }
  
  SkISize ImageGenSrc::size() const {
      sk_sp<SkData> encoded(SkData::MakeFromFileName(fPath.c_str()));
      std::unique_ptr<SkCodec> codec(SkCodec::MakeFromData(encoded));
      if (nullptr == codec) {
          return {0, 0};
      }
      return codec->getInfo().dimensions();
  }
  
  Name ImageGenSrc::name() const {
      return SkOSPath::Basename(fPath.c_str());
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  ColorCodecSrc::ColorCodecSrc(Path path, bool decode_to_dst) : fPath(path)
                                                              , fDecodeToDst(decode_to_dst) {}
  
  bool ColorCodecSrc::veto(SinkFlags flags) const {
      // Test to direct raster backends (8888 and 565).
      return flags.type != SinkFlags::kRaster || flags.approach != SinkFlags::kDirect;
  }
  
  Error ColorCodecSrc::draw(SkCanvas* canvas) const {
      sk_sp<SkData> encoded(SkData::MakeFromFileName(fPath.c_str()));
      if (!encoded) {
          return SkStringPrintf("Couldn't read %s.", fPath.c_str());
      }
  
      std::unique_ptr<SkCodec> codec(SkCodec::MakeFromData(encoded));
      if (nullptr == codec) {
          return SkStringPrintf("Couldn't create codec for %s.", fPath.c_str());
      }
  
      SkImageInfo info = codec->getInfo();
      if (fDecodeToDst) {
          info = canvas->imageInfo().makeWH(info.width(),
                                            info.height());
      }
  
      SkBitmap bitmap;
      if (!bitmap.tryAllocPixels(info)) {
          return SkStringPrintf("Image(%s) is too large (%d x %d)",
                                fPath.c_str(), info.width(), info.height());
      }
  
      switch (auto r = codec->getPixels(info, bitmap.getPixels(), bitmap.rowBytes())) {
          case SkCodec::kSuccess:
          case SkCodec::kErrorInInput:
          case SkCodec::kIncompleteInput:
              canvas->drawBitmap(bitmap, 0,0);
              return "";
          case SkCodec::kInvalidConversion:
              // TODO(mtklein): why are there formats we can't decode to?
              return Error::Nonfatal("SkCodec can't decode to this format.");
          default:
              return SkStringPrintf("Couldn't getPixels %s. Error code %d", fPath.c_str(), r);
      }
  }
  
  SkISize ColorCodecSrc::size() const {
      sk_sp<SkData> encoded(SkData::MakeFromFileName(fPath.c_str()));
      std::unique_ptr<SkCodec> codec(SkCodec::MakeFromData(encoded));
      if (nullptr == codec) {
          return {0, 0};
      }
      return {codec->getInfo().width(), codec->getInfo().height()};
  }
  
  Name ColorCodecSrc::name() const {
      return SkOSPath::Basename(fPath.c_str());
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  SKPSrc::SKPSrc(Path path) : fPath(path) { }
  
  Error SKPSrc::draw(SkCanvas* canvas) const {
      std::unique_ptr<SkStream> stream = SkStream::MakeFromFile(fPath.c_str());
      if (!stream) {
          return SkStringPrintf("Couldn't read %s.", fPath.c_str());
      }
      sk_sp<SkPicture> pic(SkPicture::MakeFromStream(stream.get()));
      if (!pic) {
          return SkStringPrintf("Couldn't parse file %s.", fPath.c_str());
      }
      stream = nullptr;  // Might as well drop this when we're done with it.
      canvas->clipRect(SkRect::MakeWH(FLAGS_skpViewportSize, FLAGS_skpViewportSize));
      canvas->drawPicture(pic);
      return "";
  }
  
  static SkRect get_cull_rect_for_skp(const char* path) {
      std::unique_ptr<SkStream> stream = SkStream::MakeFromFile(path);
      if (!stream) {
          return SkRect::MakeEmpty();
      }
      SkPictInfo info;
      if (!SkPicture_StreamIsSKP(stream.get(), &info)) {
          return SkRect::MakeEmpty();
      }
  
      return info.fCullRect;
  }
  
  SkISize SKPSrc::size() const {
      SkRect viewport = get_cull_rect_for_skp(fPath.c_str());
      if (!viewport.intersect((SkRect::MakeWH(FLAGS_skpViewportSize, FLAGS_skpViewportSize)))) {
          return {0, 0};
      }
      return viewport.roundOut().size();
  }
  
  Name SKPSrc::name() const { return SkOSPath::Basename(fPath.c_str()); }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  BisectSrc::BisectSrc(Path path, const char* trail) : INHERITED(path), fTrail(trail) {}
  
  Error BisectSrc::draw(SkCanvas* canvas) const {
      struct FoundPath {
          SkPath fPath;
          SkPaint fPaint;
          SkMatrix fViewMatrix;
      };
  
      // This subclass of SkCanvas just extracts all the SkPaths (drawn via drawPath) from an SKP.
      class PathFindingCanvas : public SkCanvas {
      public:
          PathFindingCanvas(int width, int height) : SkCanvas(width, height, nullptr) {}
          const SkTArray<FoundPath>& foundPaths() const { return fFoundPaths; }
  
      private:
          void onDrawPath(const SkPath& path, const SkPaint& paint) override {
              fFoundPaths.push_back() = {path, paint, this->getTotalMatrix()};
          }
  
          SkTArray<FoundPath> fFoundPaths;
      };
  
      PathFindingCanvas pathFinder(canvas->getBaseLayerSize().width(),
                                   canvas->getBaseLayerSize().height());
      Error err = this->INHERITED::draw(&pathFinder);
      if (!err.isEmpty()) {
          return err;
      }
  
      int start = 0, end = pathFinder.foundPaths().count();
      for (const char* ch = fTrail.c_str(); *ch; ++ch) {
          int midpt = (start + end) / 2;
          if ('l' == *ch) {
              start = midpt;
          } else if ('r' == *ch) {
              end = midpt;
          }
      }
  
      for (int i = start; i < end; ++i) {
          const FoundPath& path = pathFinder.foundPaths()[i];
          SkAutoCanvasRestore acr(canvas, true);
          canvas->concat(path.fViewMatrix);
          canvas->drawPath(path.fPath, path.fPaint);
      }
  
      return "";
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  #if defined(SK_ENABLE_SKOTTIE)
  SkottieSrc::SkottieSrc(Path path) : fPath(std::move(path)) {}
  
  Error SkottieSrc::draw(SkCanvas* canvas) const {
      auto animation = skottie::Animation::Builder()
          .setResourceProvider(
                  skottie_utils::FileResourceProvider::Make(SkOSPath::Dirname(fPath.c_str())))
          .makeFromFile(fPath.c_str());
      if (!animation) {
          return SkStringPrintf("Unable to parse file: %s", fPath.c_str());
      }
  
      canvas->drawColor(SK_ColorWHITE);
  
      const auto t_rate = 1.0f / (kTileCount * kTileCount - 1);
  
      // Draw the frames in a shuffled order to exercise non-linear
      // frame progression. The film strip will still be in order left-to-right,
      // top-down, just not drawn in that order.
      static constexpr int frameOrder[] = { 4, 0, 3, 1, 2 };
      static_assert(SK_ARRAY_COUNT(frameOrder) == kTileCount, "");
  
      for (int i = 0; i < kTileCount; ++i) {
          const SkScalar y = frameOrder[i] * kTileSize;
  
          for (int j = 0; j < kTileCount; ++j) {
              const SkScalar x = frameOrder[j] * kTileSize;
              SkRect dest = SkRect::MakeXYWH(x, y, kTileSize, kTileSize);
  
              const auto t = t_rate * (frameOrder[i] * kTileCount + frameOrder[j]);
              {
                  SkAutoCanvasRestore acr(canvas, true);
                  canvas->clipRect(dest, true);
                  canvas->concat(SkMatrix::MakeRectToRect(SkRect::MakeSize(animation->size()),
                                                          dest,
                                                          SkMatrix::kCenter_ScaleToFit));
                  animation->seek(t);
                  animation->render(canvas);
              }
          }
      }
  
      return "";
  }
  
  SkISize SkottieSrc::size() const {
      return SkISize::Make(kTargetSize, kTargetSize);
  }
  
  Name SkottieSrc::name() const { return SkOSPath::Basename(fPath.c_str()); }
  
  bool SkottieSrc::veto(SinkFlags flags) const {
      // No need to test to non-(raster||gpu||vector) or indirect backends.
      bool type_ok = flags.type == SinkFlags::kRaster
                  || flags.type == SinkFlags::kGPU
                  || flags.type == SinkFlags::kVector;
  
      return !type_ok || flags.approach != SinkFlags::kDirect;
  }
  #endif
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  #if defined(SK_XML)
  // Used when the image doesn't have an intrinsic size.
  static const SkSize kDefaultSVGSize = {1000, 1000};
  
  // Used to force-scale tiny fixed-size images.
  static const SkSize kMinimumSVGSize = {128, 128};
  
  SVGSrc::SVGSrc(Path path)
      : fName(SkOSPath::Basename(path.c_str()))
      , fScale(1) {
  
      sk_sp<SkData> data(SkData::MakeFromFileName(path.c_str()));
      if (!data) {
          return;
      }
  
      SkMemoryStream stream(std::move(data));
      fDom = SkSVGDOM::MakeFromStream(stream);
      if (!fDom) {
          return;
      }
  
      const SkSize& sz = fDom->containerSize();
      if (sz.isEmpty()) {
          // no intrinsic size
          fDom->setContainerSize(kDefaultSVGSize);
      } else {
          fScale = SkTMax(1.f, SkTMax(kMinimumSVGSize.width()  / sz.width(),
                                      kMinimumSVGSize.height() / sz.height()));
      }
  }
  
  Error SVGSrc::draw(SkCanvas* canvas) const {
      if (!fDom) {
          return SkStringPrintf("Unable to parse file: %s", fName.c_str());
      }
  
      SkAutoCanvasRestore acr(canvas, true);
      canvas->scale(fScale, fScale);
      fDom->render(canvas);
  
      return "";
  }
  
  SkISize SVGSrc::size() const {
      if (!fDom) {
          return {0, 0};
      }
  
      return SkSize{fDom->containerSize().width() * fScale, fDom->containerSize().height() * fScale}
              .toRound();
  }
  
  Name SVGSrc::name() const { return fName; }
  
  bool SVGSrc::veto(SinkFlags flags) const {
      // No need to test to non-(raster||gpu||vector) or indirect backends.
      bool type_ok = flags.type == SinkFlags::kRaster
                  || flags.type == SinkFlags::kGPU
                  || flags.type == SinkFlags::kVector;
  
      return !type_ok || flags.approach != SinkFlags::kDirect;
  }
  
  #endif // defined(SK_XML)
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  MSKPSrc::MSKPSrc(Path path) : fPath(path) {
      std::unique_ptr<SkStreamAsset> stream = SkStream::MakeFromFile(fPath.c_str());
      int count = SkMultiPictureDocumentReadPageCount(stream.get());
      if (count > 0) {
          fPages.reset(count);
          (void)SkMultiPictureDocumentReadPageSizes(stream.get(), &fPages[0], fPages.count());
      }
  }
  
  int MSKPSrc::pageCount() const { return fPages.count(); }
  
  SkISize MSKPSrc::size() const { return this->size(0); }
  SkISize MSKPSrc::size(int i) const {
      return i >= 0 && i < fPages.count() ? fPages[i].fSize.toCeil() : SkISize{0, 0};
  }
  
  Error MSKPSrc::draw(SkCanvas* c) const { return this->draw(0, c); }
  Error MSKPSrc::draw(int i, SkCanvas* canvas) const {
      if (this->pageCount() == 0) {
          return SkStringPrintf("Unable to parse MultiPictureDocument file: %s", fPath.c_str());
      }
      if (i >= fPages.count() || i < 0) {
          return SkStringPrintf("MultiPictureDocument page number out of range: %d", i);
      }
      SkPicture* page = fPages[i].fPicture.get();
      if (!page) {
          std::unique_ptr<SkStreamAsset> stream = SkStream::MakeFromFile(fPath.c_str());
          if (!stream) {
              return SkStringPrintf("Unable to open file: %s", fPath.c_str());
          }
          if (!SkMultiPictureDocumentRead(stream.get(), &fPages[0], fPages.count())) {
              return SkStringPrintf("SkMultiPictureDocument reader failed on page %d: %s", i,
                                    fPath.c_str());
          }
          page = fPages[i].fPicture.get();
      }
      canvas->drawPicture(page);
      return "";
  }
  
  Name MSKPSrc::name() const { return SkOSPath::Basename(fPath.c_str()); }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  Error NullSink::draw(const Src& src, SkBitmap*, SkWStream*, SkString*) const {
      return src.draw(SkMakeNullCanvas().get());
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  static Error compare_bitmaps(const SkBitmap& reference, const SkBitmap& bitmap) {
      // The dimensions are a property of the Src only, and so should be identical.
      SkASSERT(reference.computeByteSize() == bitmap.computeByteSize());
      if (reference.computeByteSize() != bitmap.computeByteSize()) {
          return "Dimensions don't match reference";
      }
      // All SkBitmaps in DM are tight, so this comparison is easy.
      if (0 != memcmp(reference.getPixels(), bitmap.getPixels(), reference.computeByteSize())) {
          SkString encoded;
          SkString errString("Pixels don't match reference");
          if (bitmap_to_base64_data_uri(reference, &encoded)) {
              errString.append("\nExpected: ");
              errString.append(encoded);
          } else {
              errString.append("\nExpected image failed to encode: ");
              errString.append(encoded);
          }
          if (bitmap_to_base64_data_uri(bitmap, &encoded)) {
              errString.append("\nActual: ");
              errString.append(encoded);
          } else {
              errString.append("\nActual image failed to encode: ");
              errString.append(encoded);
          }
          return errString;
      }
      return "";
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  DEFINE_bool(gpuStats, false, "Append GPU stats to the log for each GPU task?");
  
  GPUSink::GPUSink(GrContextFactory::ContextType ct,
                   GrContextFactory::ContextOverrides overrides,
                   SkCommandLineConfigGpu::SurfType surfType,
                   int samples,
                   bool diText,
                   SkColorType colorType,
                   SkAlphaType alphaType,
                   sk_sp<SkColorSpace> colorSpace,
                   bool threaded,
                   const GrContextOptions& grCtxOptions)
          : fContextType(ct)
          , fContextOverrides(overrides)
          , fSurfType(surfType)
          , fSampleCount(samples)
          , fUseDIText(diText)
          , fColorType(colorType)
          , fAlphaType(alphaType)
          , fColorSpace(std::move(colorSpace))
          , fThreaded(threaded)
          , fBaseContextOptions(grCtxOptions) {}
  
  DEFINE_bool(drawOpClip, false, "Clip each GrDrawOp to its device bounds for testing.");
  
  Error GPUSink::draw(const Src& src, SkBitmap* dst, SkWStream* dstStream, SkString* log) const {
      return this->onDraw(src, dst, dstStream, log, fBaseContextOptions);
  }
  
  Error GPUSink::onDraw(const Src& src, SkBitmap* dst, SkWStream*, SkString* log,
                        const GrContextOptions& baseOptions) const {
      GrContextOptions grOptions = baseOptions;
  
      // We don't expect the src to mess with the persistent cache or the executor.
      SkDEBUGCODE(auto cache = grOptions.fPersistentCache);
      SkDEBUGCODE(auto exec = grOptions.fExecutor);
      src.modifyGrContextOptions(&grOptions);
      SkASSERT(cache == grOptions.fPersistentCache);
      SkASSERT(exec == grOptions.fExecutor);
  
      GrContextFactory factory(grOptions);
      const SkISize size = src.size();
      SkImageInfo info =
              SkImageInfo::Make(size.width(), size.height(), fColorType, fAlphaType, fColorSpace);
      sk_sp<SkSurface> surface;
      GrContext* context = factory.getContextInfo(fContextType, fContextOverrides).grContext();
      const int maxDimension = context->priv().caps()->maxTextureSize();
      if (maxDimension < SkTMax(size.width(), size.height())) {
          return Error::Nonfatal("Src too large to create a texture.\n");
      }
      uint32_t flags = fUseDIText ? SkSurfaceProps::kUseDeviceIndependentFonts_Flag : 0;
      SkSurfaceProps props(flags, SkSurfaceProps::kLegacyFontHost_InitType);
      GrBackendTexture backendTexture;
      GrBackendRenderTarget backendRT;
      switch (fSurfType) {
          case SkCommandLineConfigGpu::SurfType::kDefault:
              surface = SkSurface::MakeRenderTarget(context, SkBudgeted::kNo, info, fSampleCount,
                                                    &props);
              break;
          case SkCommandLineConfigGpu::SurfType::kBackendTexture:
              backendTexture = context->priv().getGpu()->createTestingOnlyBackendTexture(
                      nullptr, info.width(), info.height(), info.colorType(), true, GrMipMapped::kNo);
              surface = SkSurface::MakeFromBackendTexture(context, backendTexture,
                                                          kTopLeft_GrSurfaceOrigin, fSampleCount,
                                                          fColorType, info.refColorSpace(), &props);
              break;
          case SkCommandLineConfigGpu::SurfType::kBackendRenderTarget:
              if (1 == fSampleCount) {
                  auto colorType = SkColorTypeToGrColorType(info.colorType());
                  backendRT = context->priv().getGpu()->createTestingOnlyBackendRenderTarget(
                          info.width(), info.height(), colorType);
                  surface = SkSurface::MakeFromBackendRenderTarget(
                          context, backendRT, kBottomLeft_GrSurfaceOrigin, info.colorType(),
                          info.refColorSpace(), &props);
              }
              break;
      }
  
      if (!surface) {
          return "Could not create a surface.";
      }
      if (FLAGS_preAbandonGpuContext) {
          factory.abandonContexts();
      }
      SkCanvas* canvas = surface->getCanvas();
      Error err = src.draw(canvas);
      if (!err.isEmpty()) {
          return err;
      }
      surface->flush();
      if (FLAGS_gpuStats) {
          canvas->getGrContext()->priv().dumpCacheStats(log);
          canvas->getGrContext()->priv().dumpGpuStats(log);
      }
      if (info.colorType() == kRGB_565_SkColorType || info.colorType() == kARGB_4444_SkColorType ||
          info.colorType() == kRGB_888x_SkColorType) {
          // We don't currently support readbacks into these formats on the GPU backend. Convert to
          // 32 bit.
          info = SkImageInfo::Make(size.width(), size.height(), kRGBA_8888_SkColorType,
                                   kPremul_SkAlphaType, fColorSpace);
      }
      dst->allocPixels(info);
      canvas->readPixels(*dst, 0, 0);
      if (FLAGS_abandonGpuContext) {
          factory.abandonContexts();
      } else if (FLAGS_releaseAndAbandonGpuContext) {
          factory.releaseResourcesAndAbandonContexts();
      }
      if (!context->abandoned()) {
          surface.reset();
          if (backendTexture.isValid()) {
              context->priv().getGpu()->deleteTestingOnlyBackendTexture(backendTexture);
          }
          if (backendRT.isValid()) {
              context->priv().getGpu()->deleteTestingOnlyBackendRenderTarget(backendRT);
          }
      }
      if (grOptions.fPersistentCache) {
          context->storeVkPipelineCacheData();
      }
      return "";
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  GPUThreadTestingSink::GPUThreadTestingSink(GrContextFactory::ContextType ct,
                                             GrContextFactory::ContextOverrides overrides,
                                             SkCommandLineConfigGpu::SurfType surfType,
                                             int samples,
                                             bool diText,
                                             SkColorType colorType,
                                             SkAlphaType alphaType,
                                             sk_sp<SkColorSpace> colorSpace,
                                             bool threaded,
                                             const GrContextOptions& grCtxOptions)
          : INHERITED(ct, overrides, surfType, samples, diText, colorType, alphaType,
                      std::move(colorSpace), threaded, grCtxOptions)
          , fExecutor(SkExecutor::MakeFIFOThreadPool(FLAGS_gpuThreads)) {
      SkASSERT(fExecutor);
  }
  
  Error GPUThreadTestingSink::draw(const Src& src, SkBitmap* dst, SkWStream* wStream,
                                   SkString* log) const {
      // Draw twice, once with worker threads, and once without. Verify that we get the same result.
      // Also, force us to only use the software path renderer, so we really stress-test the threaded
      // version of that code.
      GrContextOptions contextOptions = this->baseContextOptions();
      contextOptions.fGpuPathRenderers = GpuPathRenderers::kNone;
      contextOptions.fExecutor = fExecutor.get();
  
      Error err = this->onDraw(src, dst, wStream, log, contextOptions);
      if (!err.isEmpty() || !dst) {
          return err;
      }
  
      SkBitmap reference;
      SkString refLog;
      SkDynamicMemoryWStream refStream;
      contextOptions.fExecutor = nullptr;
      Error refErr = this->onDraw(src, &reference, &refStream, &refLog, contextOptions);
      if (!refErr.isEmpty()) {
          return refErr;
      }
  
      return compare_bitmaps(reference, *dst);
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  GPUPersistentCacheTestingSink::GPUPersistentCacheTestingSink(
          GrContextFactory::ContextType ct,
          GrContextFactory::ContextOverrides overrides,
          SkCommandLineConfigGpu::SurfType surfType,
          int samples,
          bool diText,
          SkColorType colorType,
          SkAlphaType alphaType,
          sk_sp<SkColorSpace> colorSpace,
          bool threaded,
          const GrContextOptions& grCtxOptions)
          : INHERITED(ct, overrides, surfType, samples, diText, colorType, alphaType,
                      std::move(colorSpace), threaded, grCtxOptions) {}
  
  Error GPUPersistentCacheTestingSink::draw(const Src& src, SkBitmap* dst, SkWStream* wStream,
                                            SkString* log) const {
      // Draw twice, once with a cold cache, and again with a warm cache. Verify that we get the same
      // result.
      sk_gpu_test::MemoryCache memoryCache;
      GrContextOptions contextOptions = this->baseContextOptions();
      contextOptions.fPersistentCache = &memoryCache;
  
      Error err = this->onDraw(src, dst, wStream, log, contextOptions);
      if (!err.isEmpty() || !dst) {
          return err;
      }
  
      SkBitmap reference;
      SkString refLog;
      SkDynamicMemoryWStream refStream;
      memoryCache.resetNumCacheMisses();
      Error refErr = this->onDraw(src, &reference, &refStream, &refLog, contextOptions);
      if (!refErr.isEmpty()) {
          return refErr;
      }
      SkASSERT(!memoryCache.numCacheMisses());
  
      return compare_bitmaps(reference, *dst);
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  static Error draw_skdocument(const Src& src, SkDocument* doc, SkWStream* dst) {
      if (src.size().isEmpty()) {
          return "Source has empty dimensions";
      }
      SkASSERT(doc);
      int pageCount = src.pageCount();
      for (int i = 0; i < pageCount; ++i) {
          int width = src.size(i).width(), height = src.size(i).height();
          SkCanvas* canvas =
                  doc->beginPage(SkIntToScalar(width), SkIntToScalar(height));
          if (!canvas) {
              return "SkDocument::beginPage(w,h) returned nullptr";
          }
          Error err = src.draw(i, canvas);
          if (!err.isEmpty()) {
              return err;
          }
          doc->endPage();
      }
      doc->close();
      dst->flush();
      return "";
  }
  
  Error PDFSink::draw(const Src& src, SkBitmap*, SkWStream* dst, SkString*) const {
      SkPDF::Metadata metadata;
      metadata.fTitle = src.name();
      metadata.fSubject = "rendering correctness test";
      metadata.fCreator = "Skia/DM";
      metadata.fRasterDPI = fRasterDpi;
      metadata.fPDFA = fPDFA;
  #if SK_PDF_TEST_EXECUTOR
      std::unique_ptr<SkExecutor> executor = SkExecutor::MakeFIFOThreadPool();
      metadata.fExecutor = executor.get();
  #endif
      auto doc = SkPDF::MakeDocument(dst, metadata);
      if (!doc) {
          return "SkPDF::MakeDocument() returned nullptr";
      }
      return draw_skdocument(src, doc.get(), dst);
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  XPSSink::XPSSink() {}
  
  #ifdef SK_BUILD_FOR_WIN
  static SkTScopedComPtr<IXpsOMObjectFactory> make_xps_factory() {
      IXpsOMObjectFactory* factory;
      HRN(CoCreateInstance(CLSID_XpsOMObjectFactory,
                           nullptr,
                           CLSCTX_INPROC_SERVER,
                           IID_PPV_ARGS(&factory)));
      return SkTScopedComPtr<IXpsOMObjectFactory>(factory);
  }
  
  Error XPSSink::draw(const Src& src, SkBitmap*, SkWStream* dst, SkString*) const {
      SkAutoCoInitialize com;
      if (!com.succeeded()) {
          return "Could not initialize COM.";
      }
      SkTScopedComPtr<IXpsOMObjectFactory> factory = make_xps_factory();
      if (!factory) {
          return "Failed to create XPS Factory.";
      }
      auto doc = SkXPS::MakeDocument(dst, factory.get());
      if (!doc) {
          return "SkXPS::MakeDocument() returned nullptr";
      }
      return draw_skdocument(src, doc.get(), dst);
  }
  #else
  Error XPSSink::draw(const Src& src, SkBitmap*, SkWStream* dst, SkString*) const {
      return "XPS not supported on this platform.";
  }
  #endif
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  SKPSink::SKPSink() {}
  
  Error SKPSink::draw(const Src& src, SkBitmap*, SkWStream* dst, SkString*) const {
      SkSize size;
      size = src.size();
      SkPictureRecorder recorder;
      Error err = src.draw(recorder.beginRecording(size.width(), size.height()));
      if (!err.isEmpty()) {
          return err;
      }
      recorder.finishRecordingAsPicture()->serialize(dst);
      return "";
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  Error DebugSink::draw(const Src& src, SkBitmap*, SkWStream* dst, SkString*) const {
      SkDebugCanvas debugCanvas(src.size().width(), src.size().height());
      Error err = src.draw(&debugCanvas);
      if (!err.isEmpty()) {
          return err;
      }
      std::unique_ptr<SkCanvas> nullCanvas = SkMakeNullCanvas();
      UrlDataManager dataManager(SkString("data"));
      SkJSONWriter writer(dst, SkJSONWriter::Mode::kPretty);
      writer.beginObject(); // root
      debugCanvas.toJSON(writer, dataManager, debugCanvas.getSize(), nullCanvas.get());
      writer.endObject(); // root
      writer.flush();
      return "";
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  SVGSink::SVGSink(int pageIndex) : fPageIndex(pageIndex) {}
  
  Error SVGSink::draw(const Src& src, SkBitmap*, SkWStream* dst, SkString*) const {
  #if defined(SK_XML)
      if (src.pageCount() > 1) {
          int pageCount = src.pageCount();
          if (fPageIndex > pageCount - 1) {
              return Error(SkStringPrintf("Page index %d too high for document with only %d pages.",
                                          fPageIndex, pageCount));
          }
      }
      return src.draw(fPageIndex,
                      SkSVGCanvas::Make(SkRect::MakeWH(SkIntToScalar(src.size().width()),
                                                       SkIntToScalar(src.size().height())),
                                        dst)
                              .get());
  #else
      (void)fPageIndex;
      return Error("SVG sink is disabled.");
  #endif // SK_XML
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  RasterSink::RasterSink(SkColorType colorType, sk_sp<SkColorSpace> colorSpace)
      : fColorType(colorType)
      , fColorSpace(std::move(colorSpace)) {}
  
  Error RasterSink::draw(const Src& src, SkBitmap* dst, SkWStream*, SkString*) const {
      const SkISize size = src.size();
      // If there's an appropriate alpha type for this color type, use it, otherwise use premul.
      SkAlphaType alphaType = kPremul_SkAlphaType;
      (void)SkColorTypeValidateAlphaType(fColorType, alphaType, &alphaType);
  
      dst->allocPixelsFlags(SkImageInfo::Make(size.width(), size.height(),
                                              fColorType, alphaType, fColorSpace),
                            SkBitmap::kZeroPixels_AllocFlag);
  
      SkCanvas canvas(*dst);
      return src.draw(&canvas);
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  // Handy for front-patching a Src.  Do whatever up-front work you need, then call draw_to_canvas(),
  // passing the Sink draw() arguments, a size, and a function draws into an SkCanvas.
  // Several examples below.
  
  template <typename Fn>
  static Error draw_to_canvas(Sink* sink, SkBitmap* bitmap, SkWStream* stream, SkString* log,
                              SkISize size, const Fn& draw) {
      class ProxySrc : public Src {
      public:
          ProxySrc(SkISize size, const Fn& draw) : fSize(size), fDraw(draw) {}
          Error   draw(SkCanvas* canvas) const override { return fDraw(canvas); }
          Name    name() const override { return "ProxySrc"; }
          SkISize size() const override { return fSize; }
      private:
          SkISize   fSize;
          const Fn& fDraw;
      };
      return sink->draw(ProxySrc(size, draw), bitmap, stream, log);
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  DEFINE_bool(check, true, "If true, have most Via- modes fail if they affect the output.");
  
  // Is *bitmap identical to what you get drawing src into sink?
  static Error check_against_reference(const SkBitmap* bitmap, const Src& src, Sink* sink) {
      // We can only check raster outputs.
      // (Non-raster outputs like .pdf, .skp, .svg may differ but still draw identically.)
      if (FLAGS_check && bitmap) {
          SkBitmap reference;
          SkString log;
          SkDynamicMemoryWStream wStream;
          Error err = sink->draw(src, &reference, &wStream, &log);
          // If we can draw into this Sink via some pipeline, we should be able to draw directly.
          SkASSERT(err.isEmpty());
          if (!err.isEmpty()) {
              return err;
          }
          return compare_bitmaps(reference, *bitmap);
      }
      return "";
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  static SkISize auto_compute_translate(SkMatrix* matrix, int srcW, int srcH) {
      SkRect bounds = SkRect::MakeIWH(srcW, srcH);
      matrix->mapRect(&bounds);
      matrix->postTranslate(-bounds.x(), -bounds.y());
      return {SkScalarRoundToInt(bounds.width()), SkScalarRoundToInt(bounds.height())};
  }
  
  ViaMatrix::ViaMatrix(SkMatrix matrix, Sink* sink) : Via(sink), fMatrix(matrix) {}
  
  Error ViaMatrix::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
      SkMatrix matrix = fMatrix;
      SkISize size = auto_compute_translate(&matrix, src.size().width(), src.size().height());
      return draw_to_canvas(fSink.get(), bitmap, stream, log, size, [&](SkCanvas* canvas) {
          canvas->concat(matrix);
          return src.draw(canvas);
      });
  }
  
  // Undoes any flip or 90 degree rotate without changing the scale of the bitmap.
  // This should be pixel-preserving.
  ViaUpright::ViaUpright(SkMatrix matrix, Sink* sink) : Via(sink), fMatrix(matrix) {}
  
  Error ViaUpright::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
      Error err = fSink->draw(src, bitmap, stream, log);
      if (!err.isEmpty()) {
          return err;
      }
  
      SkMatrix inverse;
      if (!fMatrix.rectStaysRect() || !fMatrix.invert(&inverse)) {
          return "Cannot upright --matrix.";
      }
      SkMatrix upright = SkMatrix::I();
      upright.setScaleX(SkScalarSignAsScalar(inverse.getScaleX()));
      upright.setScaleY(SkScalarSignAsScalar(inverse.getScaleY()));
      upright.setSkewX(SkScalarSignAsScalar(inverse.getSkewX()));
      upright.setSkewY(SkScalarSignAsScalar(inverse.getSkewY()));
  
      SkBitmap uprighted;
      SkISize size = auto_compute_translate(&upright, bitmap->width(), bitmap->height());
      uprighted.allocPixels(bitmap->info().makeWH(size.width(), size.height()));
  
      SkCanvas canvas(uprighted);
      canvas.concat(upright);
      SkPaint paint;
      paint.setBlendMode(SkBlendMode::kSrc);
      canvas.drawBitmap(*bitmap, 0, 0, &paint);
  
      *bitmap = uprighted;
      return "";
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  Error ViaSerialization::draw(
          const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
      // Record our Src into a picture.
      auto size = src.size();
      SkPictureRecorder recorder;
      Error err = src.draw(recorder.beginRecording(SkIntToScalar(size.width()),
                                                   SkIntToScalar(size.height())));
      if (!err.isEmpty()) {
          return err;
      }
      sk_sp<SkPicture> pic(recorder.finishRecordingAsPicture());
  
      // Serialize it and then deserialize it.
      sk_sp<SkPicture> deserialized(SkPicture::MakeFromData(pic->serialize().get()));
  
      err = draw_to_canvas(fSink.get(), bitmap, stream, log, size, [&](SkCanvas* canvas) {
          canvas->drawPicture(deserialized);
          return "";
      });
      if (!err.isEmpty()) {
          return err;
      }
  
      return check_against_reference(bitmap, src, fSink.get());
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  ViaTiles::ViaTiles(int w, int h, SkBBHFactory* factory, Sink* sink)
      : Via(sink)
      , fW(w)
      , fH(h)
      , fFactory(factory) {}
  
  Error ViaTiles::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
      auto size = src.size();
      SkPictureRecorder recorder;
      Error err = src.draw(recorder.beginRecording(SkIntToScalar(size.width()),
                                                   SkIntToScalar(size.height()),
                                                   fFactory.get()));
      if (!err.isEmpty()) {
          return err;
      }
      sk_sp<SkPicture> pic(recorder.finishRecordingAsPicture());
  
      return draw_to_canvas(fSink.get(), bitmap, stream, log, src.size(), [&](SkCanvas* canvas) {
          const int xTiles = (size.width()  + fW - 1) / fW,
                    yTiles = (size.height() + fH - 1) / fH;
          SkMultiPictureDraw mpd(xTiles*yTiles);
          SkTArray<sk_sp<SkSurface>> surfaces;
  //        surfaces.setReserve(xTiles*yTiles);
  
          SkImageInfo info = canvas->imageInfo().makeWH(fW, fH);
          for (int j = 0; j < yTiles; j++) {
              for (int i = 0; i < xTiles; i++) {
                  // This lets our ultimate Sink determine the best kind of surface.
                  // E.g., if it's a GpuSink, the surfaces and images are textures.
                  auto s = canvas->makeSurface(info);
                  if (!s) {
                      s = SkSurface::MakeRaster(info);  // Some canvases can't create surfaces.
                  }
                  surfaces.push_back(s);
                  SkCanvas* c = s->getCanvas();
                  c->translate(SkIntToScalar(-i * fW),
                               SkIntToScalar(-j * fH));  // Line up the canvas with this tile.
                  mpd.add(c, pic.get());
              }
          }
          mpd.draw();
          for (int j = 0; j < yTiles; j++) {
              for (int i = 0; i < xTiles; i++) {
                  sk_sp<SkImage> image(surfaces[i+xTiles*j]->makeImageSnapshot());
                  canvas->drawImage(image, SkIntToScalar(i*fW), SkIntToScalar(j*fH));
              }
          }
          return "";
      });
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  ViaDDL::ViaDDL(int numReplays, int numDivisions, Sink* sink)
          : Via(sink), fNumReplays(numReplays), fNumDivisions(numDivisions) {}
  
  Error ViaDDL::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
      auto size = src.size();
      SkPictureRecorder recorder;
      Error err = src.draw(recorder.beginRecording(SkIntToScalar(size.width()),
                                                   SkIntToScalar(size.height())));
      if (!err.isEmpty()) {
          return err;
      }
      sk_sp<SkPicture> inputPicture(recorder.finishRecordingAsPicture());
  
      // this is our ultimate final drawing area/rect
      SkIRect viewport = SkIRect::MakeWH(size.fWidth, size.fHeight);
  
      DDLPromiseImageHelper promiseImageHelper;
      sk_sp<SkData> compressedPictureData = promiseImageHelper.deflateSKP(inputPicture.get());
      if (!compressedPictureData) {
          return SkStringPrintf("ViaDDL: Couldn't deflate SkPicture");
      }
      auto draw = [&](SkCanvas* canvas) -> Error {
          GrContext* context = canvas->getGrContext();
          if (!context || !context->priv().getGpu()) {
              return SkStringPrintf("DDLs are GPU only");
          }
  
          // This is here bc this is the first point where we have access to the context
          promiseImageHelper.uploadAllToGPU(context);
          // We draw N times, with a clear between.
          for (int replay = 0; replay < fNumReplays; ++replay) {
              if (replay > 0) {
                  // Clear the drawing of the previous replay
                  canvas->clear(SK_ColorTRANSPARENT);
              }
              // First, create all the tiles (including their individual dest surfaces)
              DDLTileHelper tiles(canvas, viewport, fNumDivisions);
  
              // Second, reinflate the compressed picture individually for each thread
              // This recreates the promise SkImages on each replay iteration. We are currently
              // relying on this to test using a SkPromiseImageTexture to fulfill different
              // SkImages. On each replay the promise SkImages are recreated in createSKPPerTile.
              tiles.createSKPPerTile(compressedPictureData.get(), promiseImageHelper);
  
              // Third, create the DDLs in parallel
              tiles.createDDLsInParallel();
  
              if (replay == fNumReplays - 1) {
                  // This drops the promiseImageHelper's refs on all the promise images if we're in
                  // the last run.
                  promiseImageHelper.reset();
              }
  
              // Fourth, synchronously render the display lists into the dest tiles
              // TODO: it would be cool to not wait until all the tiles are drawn to begin
              // drawing to the GPU and composing to the final surface
              tiles.drawAllTilesAndFlush(context, false);
  
              // Finally, compose the drawn tiles into the result
              // Note: the separation between the tiles and the final composition better
              // matches Chrome but costs us a copy
              tiles.composeAllTiles(canvas);
              context->flush();
          }
          return "";
      };
      return draw_to_canvas(fSink.get(), bitmap, stream, log, size, draw);
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  Error ViaPicture::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
      auto size = src.size();
      Error err = draw_to_canvas(fSink.get(), bitmap, stream, log, size, [&](SkCanvas* canvas) {
          SkPictureRecorder recorder;
          sk_sp<SkPicture> pic;
          Error err = src.draw(recorder.beginRecording(SkIntToScalar(size.width()),
                                                       SkIntToScalar(size.height())));
          if (!err.isEmpty()) {
              return err;
          }
          pic = recorder.finishRecordingAsPicture();
          canvas->drawPicture(pic);
          return err;
      });
      if (!err.isEmpty()) {
          return err;
      }
  
      return check_against_reference(bitmap, src, fSink.get());
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  #ifdef TEST_VIA_SVG
  #include "SkXMLWriter.h"
  #include "SkSVGCanvas.h"
  #include "SkSVGDOM.h"
  
  Error ViaSVG::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
      auto size = src.size();
      return draw_to_canvas(fSink.get(), bitmap, stream, log, size, [&](SkCanvas* canvas) -> Error {
          SkDynamicMemoryWStream wstream;
          SkXMLStreamWriter writer(&wstream);
          Error err = src.draw(SkSVGCanvas::Make(SkRect::Make(size), &writer).get());
          if (!err.isEmpty()) {
              return err;
          }
          std::unique_ptr<SkStream> rstream(wstream.detachAsStream());
          auto dom = SkSVGDOM::MakeFromStream(*rstream);
          if (dom) {
              dom->setContainerSize(SkSize::Make(size));
              dom->render(canvas);
          }
          return "";
      });
  }
  #endif
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  Error ViaLite::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
      auto size = src.size();
      SkIRect bounds = {0,0, size.width(), size.height()};
      Error err = draw_to_canvas(fSink.get(), bitmap, stream, log, size, [&](SkCanvas* canvas) {
          SkLiteDL dl;
          SkLiteRecorder rec;
          rec.reset(&dl, bounds);
  
          Error err = src.draw(&rec);
          if (!err.isEmpty()) {
              return err;
          }
          dl.draw(canvas);
          return err;
      });
      if (!err.isEmpty()) {
          return err;
      }
  
      return check_against_reference(bitmap, src, fSink.get());
  }
  
  /*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
  
  ViaCSXform::ViaCSXform(Sink* sink, sk_sp<SkColorSpace> cs, bool colorSpin)
      : Via(sink)
      , fCS(std::move(cs))
      , fColorSpin(colorSpin) {}
  
  Error ViaCSXform::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream, SkString* log) const {
      Error err = draw_to_canvas(fSink.get(), bitmap, stream, log, src.size(), [&](SkCanvas* canvas) {
          {
              SkAutoCanvasRestore acr(canvas, true);
              auto proxy = SkCreateColorSpaceXformCanvas(canvas, fCS);
              Error err = src.draw(proxy.get());
              if (!err.isEmpty()) {
                  return err;
              }
          }
  
          // Undo the color spin, so we can look at the pixels in Gold.
          if (fColorSpin) {
              SkBitmap pixels;
              pixels.allocPixels(canvas->imageInfo());
              canvas->readPixels(pixels, 0, 0);
  
              SkPaint rotateColors;
              SkScalar matrix[20] = { 0, 0, 1, 0, 0,   // B -> R
                                      1, 0, 0, 0, 0,   // R -> G
                                      0, 1, 0, 0, 0,   // G -> B
                                      0, 0, 0, 1, 0 };
              rotateColors.setBlendMode(SkBlendMode::kSrc);
              rotateColors.setColorFilter(SkColorFilter::MakeMatrixFilterRowMajor255(matrix));
              canvas->drawBitmap(pixels, 0, 0, &rotateColors);
          }
  
          return Error("");
      });
  
      if (!err.isEmpty()) {
          return err;
      }
  
      if (bitmap && !fColorSpin) {
          // It should be possible to do this without all the copies, but that (I think) requires
          // adding API to SkBitmap.
          SkAutoPixmapStorage pmap;
          pmap.alloc(bitmap->info());
          bitmap->readPixels(pmap);
          pmap.setColorSpace(fCS);
          bitmap->allocPixels(pmap.info());
          bitmap->writePixels(pmap);
      }
  
      return "";
  }
  
  }  // namespace DM
  