path: root/image/test/gtest/TestDeinterlacingFilter.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "gtest/gtest.h"

#include "mozilla/gfx/2D.h"
#include "Common.h"
#include "Decoder.h"
#include "DecoderFactory.h"
#include "SourceBuffer.h"
#include "SurfaceFilters.h"
#include "SurfacePipe.h"

using namespace mozilla;
using namespace mozilla::gfx;
using namespace mozilla::image;

template <typename Func> void
WithDeinterlacingFilter(const IntSize& aSize,
                        bool aProgressiveDisplay,
                        Func aFunc)
{
  RefPtr<Decoder> decoder = CreateTrivialDecoder();
  ASSERT_TRUE(bool(decoder));

  WithFilterPipeline(decoder, Forward<Func>(aFunc),
                     DeinterlacingConfig<uint32_t> { aProgressiveDisplay },
                     SurfaceConfig { decoder, aSize,
                                     SurfaceFormat::B8G8R8A8, false });
}

template <typename Func> void
WithPalettedDeinterlacingFilter(const IntSize& aSize,
                                Func aFunc)
{
  RefPtr<Decoder> decoder = CreateTrivialDecoder();
  ASSERT_TRUE(decoder != nullptr);

  WithFilterPipeline(decoder, Forward<Func>(aFunc),
                     DeinterlacingConfig<uint8_t> { /* mProgressiveDisplay = */ true },
                     PalettedSurfaceConfig { decoder, aSize,
                                             IntRect(0, 0, 100, 100),
                                             SurfaceFormat::B8G8R8A8, 8,
                                             false });
}

void
AssertConfiguringDeinterlacingFilterFails(const IntSize& aSize)
{
  RefPtr<Decoder> decoder = CreateTrivialDecoder();
  ASSERT_TRUE(decoder != nullptr);

  AssertConfiguringPipelineFails(decoder,
                                 DeinterlacingConfig<uint32_t> { /* mProgressiveDisplay = */ true},
                                 SurfaceConfig { decoder, aSize,
                                                 SurfaceFormat::B8G8R8A8, false });
}

class ImageDeinterlacingFilter : public ::testing::Test
{
protected:
  AutoInitializeImageLib mInit;
};

TEST_F(ImageDeinterlacingFilter, WritePixels100_100)
{
  WithDeinterlacingFilter(IntSize(100, 100), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    CheckWritePixels(aDecoder, aFilter,
                     /* aOutputRect = */ Some(IntRect(0, 0, 100, 100)),
                     /* aInputRect = */ Some(IntRect(0, 0, 100, 100)));
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixels99_99)
{
  WithDeinterlacingFilter(IntSize(99, 99), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    CheckWritePixels(aDecoder, aFilter,
                     /* aOutputRect = */ Some(IntRect(0, 0, 99, 99)),
                     /* aInputRect = */ Some(IntRect(0, 0, 99, 99)));
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixels8_8)
{
  WithDeinterlacingFilter(IntSize(8, 8), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    CheckWritePixels(aDecoder, aFilter,
                     /* aOutputRect = */ Some(IntRect(0, 0, 8, 8)),
                     /* aInputRect = */ Some(IntRect(0, 0, 8, 8)));
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixels7_7)
{
  WithDeinterlacingFilter(IntSize(7, 7), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    CheckWritePixels(aDecoder, aFilter,
                     /* aOutputRect = */ Some(IntRect(0, 0, 7, 7)),
                     /* aInputRect = */ Some(IntRect(0, 0, 7, 7)));
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixels3_3)
{
  WithDeinterlacingFilter(IntSize(3, 3), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    CheckWritePixels(aDecoder, aFilter,
                     /* aOutputRect = */ Some(IntRect(0, 0, 3, 3)),
                     /* aInputRect = */ Some(IntRect(0, 0, 3, 3)));
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixels1_1)
{
  WithDeinterlacingFilter(IntSize(1, 1), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    CheckWritePixels(aDecoder, aFilter,
                     /* aOutputRect = */ Some(IntRect(0, 0, 1, 1)),
                     /* aInputRect = */ Some(IntRect(0, 0, 1, 1)));
  });
}

TEST_F(ImageDeinterlacingFilter, PalettedWritePixels)
{
  WithPalettedDeinterlacingFilter(IntSize(100, 100),
                                  [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    CheckPalettedWritePixels(aDecoder, aFilter);
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixelsNonProgressiveOutput51_52)
{
  WithDeinterlacingFilter(IntSize(51, 52), /* aProgressiveDisplay = */ false,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    // Fill the image. The output should be green for even rows and red for odd
    // rows but we need to write the rows in the order that the deinterlacer
    // expects them.
    uint32_t count = 0;
    auto result = aFilter->WritePixels<uint32_t>([&]() {
      uint32_t row = count / 51;  // Integer division.
      ++count;

      // Note that we use a switch statement here, even though it's quite
      // verbose, because it's useful to have the mappings between input and
      // output rows available when debugging these tests.

      switch (row) {
        // First pass. Output rows are positioned at 8n + 0.
        case 0:  // Output row 0.
        case 1:  // Output row 8.
        case 2:  // Output row 16.
        case 3:  // Output row 24.
        case 4:  // Output row 32.
        case 5:  // Output row 40.
        case 6:  // Output row 48.
          return AsVariant(BGRAColor::Green().AsPixel());

        // Second pass. Rows are positioned at 8n + 4.
        case 7:   // Output row 4.
        case 8:   // Output row 12.
        case 9:   // Output row 20.
        case 10:  // Output row 28.
        case 11:  // Output row 36.
        case 12:  // Output row 44.
          return AsVariant(BGRAColor::Green().AsPixel());

        // Third pass. Rows are positioned at 4n + 2.
        case 13:  // Output row 2.
        case 14:  // Output row 6.
        case 15:  // Output row 10.
        case 16:  // Output row 14.
        case 17:  // Output row 18.
        case 18:  // Output row 22.
        case 19:  // Output row 26.
        case 20:  // Output row 30.
        case 21:  // Output row 34.
        case 22:  // Output row 38.
        case 23:  // Output row 42.
        case 24:  // Output row 46.
        case 25:  // Output row 50.
          return AsVariant(BGRAColor::Green().AsPixel());

        // Fourth pass. Rows are positioned at 2n + 1.
        case 26:  // Output row 1.
        case 27:  // Output row 3.
        case 28:  // Output row 5.
        case 29:  // Output row 7.
        case 30:  // Output row 9.
        case 31:  // Output row 11.
        case 32:  // Output row 13.
        case 33:  // Output row 15.
        case 34:  // Output row 17.
        case 35:  // Output row 19.
        case 36:  // Output row 21.
        case 37:  // Output row 23.
        case 38:  // Output row 25.
        case 39:  // Output row 27.
        case 40:  // Output row 29.
        case 41:  // Output row 31.
        case 42:  // Output row 33.
        case 43:  // Output row 35.
        case 44:  // Output row 37.
        case 45:  // Output row 39.
        case 46:  // Output row 41.
        case 47:  // Output row 43.
        case 48:  // Output row 45.
        case 49:  // Output row 47.
        case 50:  // Output row 49.
        case 51:  // Output row 51.
          return AsVariant(BGRAColor::Red().AsPixel());

        default:
          MOZ_ASSERT_UNREACHABLE("Unexpected row");
          return AsVariant(BGRAColor::Transparent().AsPixel());
      }
    });
    EXPECT_EQ(WriteState::FINISHED, result);
    EXPECT_EQ(51u * 52u, count);

    AssertCorrectPipelineFinalState(aFilter,
                                    IntRect(0, 0, 51, 52),
                                    IntRect(0, 0, 51, 52));

    // Check that the generated image is correct. As mentioned above, we expect
    // even rows to be green and odd rows to be red.
    RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
    RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();

    for (uint32_t row = 0; row < 52; ++row) {
      EXPECT_TRUE(RowsAreSolidColor(surface, row, 1,
                                    row % 2 == 0 ? BGRAColor::Green()
                                                 : BGRAColor::Red()));
    }
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixelsOutput20_20)
{
  WithDeinterlacingFilter(IntSize(20, 20), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    // Fill the image. The output should be green for even rows and red for odd
    // rows but we need to write the rows in the order that the deinterlacer
    // expects them.
    uint32_t count = 0;
    auto result = aFilter->WritePixels<uint32_t>([&]() {
      uint32_t row = count / 20;  // Integer division.
      ++count;

      // Note that we use a switch statement here, even though it's quite
      // verbose, because it's useful to have the mappings between input and
      // output rows available when debugging these tests.

      switch (row) {
        // First pass. Output rows are positioned at 8n + 0.
        case 0:  // Output row 0.
        case 1:  // Output row 8.
        case 2:  // Output row 16.
          return AsVariant(BGRAColor::Green().AsPixel());

        // Second pass. Rows are positioned at 8n + 4.
        case 3:  // Output row 4.
        case 4:  // Output row 12.
          return AsVariant(BGRAColor::Green().AsPixel());

        // Third pass. Rows are positioned at 4n + 2.
        case 5: // Output row 2.
        case 6: // Output row 6.
        case 7: // Output row 10.
        case 8: // Output row 14.
        case 9: // Output row 18.
          return AsVariant(BGRAColor::Green().AsPixel());

        // Fourth pass. Rows are positioned at 2n + 1.
        case 10:  // Output row 1.
        case 11:  // Output row 3.
        case 12:  // Output row 5.
        case 13:  // Output row 7.
        case 14:  // Output row 9.
        case 15:  // Output row 11.
        case 16:  // Output row 13.
        case 17:  // Output row 15.
        case 18:  // Output row 17.
        case 19:  // Output row 19.
          return AsVariant(BGRAColor::Red().AsPixel());

        default:
          MOZ_ASSERT_UNREACHABLE("Unexpected row");
          return AsVariant(BGRAColor::Transparent().AsPixel());
      }
    });
    EXPECT_EQ(WriteState::FINISHED, result);
    EXPECT_EQ(20u * 20u, count);

    AssertCorrectPipelineFinalState(aFilter,
                                    IntRect(0, 0, 20, 20),
                                    IntRect(0, 0, 20, 20));

    // Check that the generated image is correct. As mentioned above, we expect
    // even rows to be green and odd rows to be red.
    RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
    RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();

    for (uint32_t row = 0; row < 20; ++row) {
      EXPECT_TRUE(RowsAreSolidColor(surface, row, 1,
                                    row % 2 == 0 ? BGRAColor::Green()
                                                 : BGRAColor::Red()));
    }
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixelsOutput7_7)
{
  WithDeinterlacingFilter(IntSize(7, 7), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    // Fill the image. The output should be a repeating pattern of two green
    // rows followed by two red rows but we need to write the rows in the order
    // that the deinterlacer expects them.
    uint32_t count = 0;
    auto result = aFilter->WritePixels<uint32_t>([&]() {
      uint32_t row = count / 7;  // Integer division.
      ++count;

      switch (row) {
        // First pass. Output rows are positioned at 8n + 0.
        case 0:  // Output row 0.
          return AsVariant(BGRAColor::Green().AsPixel());

        // Second pass. Rows are positioned at 8n + 4.
        case 1:  // Output row 4.
          return AsVariant(BGRAColor::Green().AsPixel());

        // Third pass. Rows are positioned at 4n + 2.
        case 2: // Output row 2.
        case 3: // Output row 6.
          return AsVariant(BGRAColor::Red().AsPixel());

        // Fourth pass. Rows are positioned at 2n + 1.
        case 4:  // Output row 1.
          return AsVariant(BGRAColor::Green().AsPixel());

        case 5:  // Output row 3.
          return AsVariant(BGRAColor::Red().AsPixel());

        case 6:  // Output row 5.
          return AsVariant(BGRAColor::Green().AsPixel());

        default:
          MOZ_ASSERT_UNREACHABLE("Unexpected row");
          return AsVariant(BGRAColor::Transparent().AsPixel());
      }
    });
    EXPECT_EQ(WriteState::FINISHED, result);
    EXPECT_EQ(7u * 7u, count);

    AssertCorrectPipelineFinalState(aFilter,
                                    IntRect(0, 0, 7, 7),
                                    IntRect(0, 0, 7, 7));

    // Check that the generated image is correct. As mentioned above, we expect
    // two green rows, followed by two red rows, then two green rows, etc.
    RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
    RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();

    for (uint32_t row = 0; row < 7; ++row) {
      BGRAColor color = row == 0 || row == 1 || row == 4 || row == 5
                      ? BGRAColor::Green()
                      : BGRAColor::Red();
      EXPECT_TRUE(RowsAreSolidColor(surface, row, 1, color));
    }
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixelsOutput3_3)
{
  WithDeinterlacingFilter(IntSize(3, 3), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    // Fill the image. The output should be green, red, green in that order, but
    // we need to write the rows in the order that the deinterlacer expects
    // them.
    uint32_t count = 0;
    auto result = aFilter->WritePixels<uint32_t>([&]() {
      uint32_t row = count / 3;  // Integer division.
      ++count;

      switch (row) {
        // First pass. Output rows are positioned at 8n + 0.
        case 0:  // Output row 0.
          return AsVariant(BGRAColor::Green().AsPixel());

        // Second pass. Rows are positioned at 8n + 4.
        // No rows for this pass.

        // Third pass. Rows are positioned at 4n + 2.
        case 1: // Output row 2.
          return AsVariant(BGRAColor::Green().AsPixel());

        // Fourth pass. Rows are positioned at 2n + 1.
        case 2:  // Output row 1.
          return AsVariant(BGRAColor::Red().AsPixel());

        default:
          MOZ_ASSERT_UNREACHABLE("Unexpected row");
          return AsVariant(BGRAColor::Transparent().AsPixel());
      }
    });
    EXPECT_EQ(WriteState::FINISHED, result);
    EXPECT_EQ(3u * 3u, count);

    AssertCorrectPipelineFinalState(aFilter,
                                    IntRect(0, 0, 3, 3),
                                    IntRect(0, 0, 3, 3));

    // Check that the generated image is correct. As mentioned above, we expect
    // green, red, green in that order.
    RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
    RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();

    for (uint32_t row = 0; row < 3; ++row) {
      EXPECT_TRUE(RowsAreSolidColor(surface, row, 1,
                                    row == 0 || row == 2 ? BGRAColor::Green()
                                                         : BGRAColor::Red()));
    }
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixelsOutput1_1)
{
  WithDeinterlacingFilter(IntSize(1, 1), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    // Fill the image. The output should be a single red row.
    uint32_t count = 0;
    auto result = aFilter->WritePixels<uint32_t>([&]() {
      ++count;
      return AsVariant(BGRAColor::Red().AsPixel());
    });
    EXPECT_EQ(WriteState::FINISHED, result);
    EXPECT_EQ(1u, count);

    AssertCorrectPipelineFinalState(aFilter,
                                    IntRect(0, 0, 1, 1),
                                    IntRect(0, 0, 1, 1));

    // Check that the generated image is correct. As mentioned above, we expect
    // a single red row.
    RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
    RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();

    EXPECT_TRUE(RowsAreSolidColor(surface, 0, 1, BGRAColor::Red()));
  });
}

void
WriteRowAndCheckInterlacerOutput(Decoder* aDecoder,
                                 SurfaceFilter* aFilter,
                                 BGRAColor aColor,
                                 WriteState aNextState,
                                 IntRect aInvalidRect,
                                 uint32_t aFirstHaeberliRow,
                                 uint32_t aLastHaeberliRow)
{
  uint32_t count = 0;

  auto result = aFilter->WritePixels<uint32_t>([&]() -> NextPixel<uint32_t> {
    if (count < 7) {
      ++count;
      return AsVariant(aColor.AsPixel());
    }
    return AsVariant(WriteState::NEED_MORE_DATA);
  });

  EXPECT_EQ(aNextState, result);
  EXPECT_EQ(7u, count);

  // Assert that we got the expected invalidation region.
  Maybe<SurfaceInvalidRect> invalidRect = aFilter->TakeInvalidRect();
  EXPECT_TRUE(invalidRect.isSome());
  EXPECT_EQ(aInvalidRect, invalidRect->mInputSpaceRect);
  EXPECT_EQ(aInvalidRect, invalidRect->mOutputSpaceRect);

  // Check that the portion of the image generated so far is correct. The rows
  // from aFirstHaeberliRow to aLastHaeberliRow should be filled with aColor.
  // Note that this is not the same as the set of rows in aInvalidRect, because
  // after writing a row the deinterlacer seeks to the next row to write, which
  // may involve copying previously-written rows in the buffer to the output
  // even though they don't change in this pass.
  RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
  RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();

  for (uint32_t row = aFirstHaeberliRow; row <= aLastHaeberliRow; ++row) {
    EXPECT_TRUE(RowsAreSolidColor(surface, row, 1, aColor));
  }
}

TEST_F(ImageDeinterlacingFilter, WritePixelsIntermediateOutput7_7)
{
  WithDeinterlacingFilter(IntSize(7, 7), /* aProgressiveDisplay = */ true,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    // Fill the image. The output should be a repeating pattern of two green
    // rows followed by two red rows but we need to write the rows in the order
    // that the deinterlacer expects them.

    // First pass. Output rows are positioned at 8n + 0.

    // Output row 0. The invalid rect is the entire image because this is the
    // end of the first pass.
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Green(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 0, 7, 7), 0, 4);

    // Second pass. Rows are positioned at 8n + 4.

    // Output row 4. The invalid rect is the entire image because this is the
    // end of the second pass.
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Green(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 0, 7, 7), 1, 4);

    // Third pass. Rows are positioned at 4n + 2.

    // Output row 2. The invalid rect contains the Haeberli rows for this output
    // row (rows 2 and 3) as well as the rows that we copy from previous passes
    // when seeking to the next output row (rows 4 and 5).
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Red(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 2, 7, 4), 2, 3);

    // Output row 6. The invalid rect is the entire image because this is the
    // end of the third pass.
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Red(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 0, 7, 7), 6, 6);

    // Fourth pass. Rows are positioned at 2n + 1.

    // Output row 1. The invalid rect contains the Haeberli rows for this output
    // row (just row 1) as well as the rows that we copy from previous passes
    // when seeking to the next output row (row 2).
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Green(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 1, 7, 2), 1, 1);

    // Output row 3. The invalid rect contains the Haeberli rows for this output
    // row (just row 3) as well as the rows that we copy from previous passes
    // when seeking to the next output row (row 4).
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Red(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 3, 7, 2), 3, 3);

    // Output row 5. The invalid rect contains the Haeberli rows for this output
    // row (just row 5) as well as the rows that we copy from previous passes
    // when seeking to the next output row (row 6).
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Green(),
                                     WriteState::FINISHED,
                                     IntRect(0, 5, 7, 2), 5, 5);

    // Assert that we're in the expected final state.
    EXPECT_TRUE(aFilter->IsSurfaceFinished());
    Maybe<SurfaceInvalidRect> invalidRect = aFilter->TakeInvalidRect();
    EXPECT_TRUE(invalidRect.isNothing());

    // Check that the generated image is correct. As mentioned above, we expect
    // two green rows, followed by two red rows, then two green rows, etc.
    RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
    RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();

    for (uint32_t row = 0; row < 7; ++row) {
      BGRAColor color = row == 0 || row == 1 || row == 4 || row == 5
                      ? BGRAColor::Green()
                      : BGRAColor::Red();
      EXPECT_TRUE(RowsAreSolidColor(surface, row, 1, color));
    }
  });
}

TEST_F(ImageDeinterlacingFilter, WritePixelsNonProgressiveIntermediateOutput7_7)
{
  WithDeinterlacingFilter(IntSize(7, 7), /* aProgressiveDisplay = */ false,
                          [](Decoder* aDecoder, SurfaceFilter* aFilter) {
    // Fill the image. The output should be a repeating pattern of two green
    // rows followed by two red rows but we need to write the rows in the order
    // that the deinterlacer expects them.

    // First pass. Output rows are positioned at 8n + 0.

    // Output row 0. The invalid rect is the entire image because this is the
    // end of the first pass.
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Green(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 0, 7, 7), 0, 0);

    // Second pass. Rows are positioned at 8n + 4.

    // Output row 4. The invalid rect is the entire image because this is the
    // end of the second pass.
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Green(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 0, 7, 7), 4, 4);

    // Third pass. Rows are positioned at 4n + 2.

    // Output row 2. The invalid rect contains the Haeberli rows for this output
    // row (rows 2 and 3) as well as the rows that we copy from previous passes
    // when seeking to the next output row (rows 4 and 5).
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Red(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 2, 7, 4), 2, 2);

    // Output row 6. The invalid rect is the entire image because this is the
    // end of the third pass.
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Red(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 0, 7, 7), 6, 6);

    // Fourth pass. Rows are positioned at 2n + 1.

    // Output row 1. The invalid rect contains the Haeberli rows for this output
    // row (just row 1) as well as the rows that we copy from previous passes
    // when seeking to the next output row (row 2).
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Green(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 1, 7, 2), 1, 1);

    // Output row 3. The invalid rect contains the Haeberli rows for this output
    // row (just row 3) as well as the rows that we copy from previous passes
    // when seeking to the next output row (row 4).
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Red(),
                                     WriteState::NEED_MORE_DATA,
                                     IntRect(0, 3, 7, 2), 3, 3);

    // Output row 5. The invalid rect contains the Haeberli rows for this output
    // row (just row 5) as well as the rows that we copy from previous passes
    // when seeking to the next output row (row 6).
    WriteRowAndCheckInterlacerOutput(aDecoder, aFilter, BGRAColor::Green(),
                                     WriteState::FINISHED,
                                     IntRect(0, 5, 7, 2), 5, 5);

    // Assert that we're in the expected final state.
    EXPECT_TRUE(aFilter->IsSurfaceFinished());
    Maybe<SurfaceInvalidRect> invalidRect = aFilter->TakeInvalidRect();
    EXPECT_TRUE(invalidRect.isNothing());

    // Check that the generated image is correct. As mentioned above, we expect
    // two green rows, followed by two red rows, then two green rows, etc.
    RawAccessFrameRef currentFrame = aDecoder->GetCurrentFrameRef();
    RefPtr<SourceSurface> surface = currentFrame->GetSourceSurface();

    for (uint32_t row = 0; row < 7; ++row) {
      BGRAColor color = row == 0 || row == 1 || row == 4 || row == 5
                      ? BGRAColor::Green()
                      : BGRAColor::Red();
      EXPECT_TRUE(RowsAreSolidColor(surface, row, 1, color));
    }
  });
}


TEST_F(ImageDeinterlacingFilter, DeinterlacingFailsFor0_0)
{
  // A 0x0 input size is invalid, so configuration should fail.
  AssertConfiguringDeinterlacingFilterFails(IntSize(0, 0));
}

TEST_F(ImageDeinterlacingFilter, DeinterlacingFailsForMinus1_Minus1)
{
  // A negative input size is invalid, so configuration should fail.
  AssertConfiguringDeinterlacingFilterFails(IntSize(-1, -1));
}