diff --git a/graphics/composer/2.2/utils/vts/Android.bp b/graphics/composer/2.2/utils/vts/Android.bp
index c6b524d..4016120 100644
--- a/graphics/composer/2.2/utils/vts/Android.bp
+++ b/graphics/composer/2.2/utils/vts/Android.bp
@@ -19,12 +19,15 @@
     defaults: ["hidl_defaults"],
     srcs: [
         "ComposerVts.cpp",
+        "ReadbackVts.cpp",
     ],
     static_libs: [
         "VtsHalHidlTargetTestBase",
         "android.hardware.graphics.composer@2.1",
         "android.hardware.graphics.composer@2.1-vts",
         "android.hardware.graphics.composer@2.2",
+        "android.hardware.graphics.mapper@2.1",
+        "android.hardware.graphics.mapper@2.1-vts",
     ],
     export_static_lib_headers: [
         "android.hardware.graphics.composer@2.1-vts",
diff --git a/graphics/composer/2.2/utils/vts/ReadbackVts.cpp b/graphics/composer/2.2/utils/vts/ReadbackVts.cpp
new file mode 100644
index 0000000..8eabaef
--- /dev/null
+++ b/graphics/composer/2.2/utils/vts/ReadbackVts.cpp
@@ -0,0 +1,247 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <composer-vts/2.2/ReadbackVts.h>
+
+namespace android {
+namespace hardware {
+namespace graphics {
+namespace composer {
+namespace V2_2 {
+namespace vts {
+
+void TestLayer::write(const std::shared_ptr<CommandWriterBase>& writer) {
+    writer->selectLayer(mLayer);
+    writer->setLayerDisplayFrame(mDisplayFrame);
+    writer->setLayerSourceCrop(mSourceCrop);
+    writer->setLayerZOrder(mZOrder);
+    writer->setLayerSurfaceDamage(mSurfaceDamage);
+    writer->setLayerTransform(mTransform);
+    writer->setLayerPlaneAlpha(mAlpha);
+    writer->setLayerBlendMode(mBlendMode);
+}
+
+int32_t ReadbackHelper::GetBytesPerPixel(PixelFormat pixelFormat) {
+    switch (pixelFormat) {
+        case PixelFormat::RGBA_8888:
+            return 4;
+        case PixelFormat::RGB_888:
+            return 3;
+        default:
+            return -1;
+    }
+}
+
+void ReadbackHelper::fillBuffer(int32_t width, int32_t height, uint32_t stride, void* bufferData,
+                                PixelFormat pixelFormat,
+                                std::vector<IComposerClient::Color> desiredPixelColors) {
+    ASSERT_TRUE(pixelFormat == PixelFormat::RGB_888 || pixelFormat == PixelFormat::RGBA_8888);
+    int32_t bytesPerPixel = GetBytesPerPixel(pixelFormat);
+    ASSERT_NE(-1, bytesPerPixel);
+    for (int row = 0; row < height; row++) {
+        for (int col = 0; col < width; col++) {
+            int pixel = row * width + col;
+            IComposerClient::Color srcColor = desiredPixelColors[pixel];
+
+            int offset = (row * stride + col) * bytesPerPixel;
+            uint8_t* pixelColor = (uint8_t*)bufferData + offset;
+            pixelColor[0] = srcColor.r;
+            pixelColor[1] = srcColor.g;
+            pixelColor[2] = srcColor.b;
+
+            if (bytesPerPixel == 4) {
+                pixelColor[3] = srcColor.a;
+            }
+        }
+    }
+}
+
+void ReadbackHelper::clearColors(std::vector<IComposerClient::Color>& expectedColors, int32_t width,
+                                 int32_t height, int32_t displayWidth) {
+    for (int row = 0; row < height; row++) {
+        for (int col = 0; col < width; col++) {
+            int pixel = row * displayWidth + col;
+            expectedColors[pixel] = BLACK;
+        }
+    }
+}
+
+void ReadbackHelper::fillColorsArea(std::vector<IComposerClient::Color>& expectedColors,
+                                    int32_t stride, IComposerClient::Rect area,
+                                    IComposerClient::Color color) {
+    for (int row = area.top; row < area.bottom; row++) {
+        for (int col = area.left; col < area.right; col++) {
+            int pixel = row * stride + col;
+            expectedColors[pixel] = color;
+        }
+    }
+}
+
+bool ReadbackHelper::readbackSupported(const PixelFormat& pixelFormat, const Dataspace& dataspace,
+                                       const Error error) {
+    if (error != Error::NONE) {
+        return false;
+    }
+    // TODO: add support for RGBA_1010102
+    if (pixelFormat != PixelFormat::RGB_888 && pixelFormat != PixelFormat::RGBA_8888) {
+        return false;
+    }
+    if (dataspace != Dataspace::V0_SRGB) {
+        return false;
+    }
+    return true;
+}
+
+ReadbackBuffer::ReadbackBuffer(Display display, const std::shared_ptr<ComposerClient>& client,
+                               const std::shared_ptr<Gralloc>& gralloc, uint32_t width,
+                               uint32_t height, PixelFormat pixelFormat, Dataspace dataspace) {
+    mDisplay = display;
+
+    mComposerClient = client;
+    mGralloc = gralloc;
+
+    mPixelFormat = pixelFormat;
+    mDataspace = dataspace;
+
+    mInfo.width = width;
+    mInfo.height = height;
+    mInfo.layerCount = 1;
+    mInfo.format = mPixelFormat;
+    mInfo.usage = static_cast<uint64_t>(BufferUsage::CPU_READ_OFTEN | BufferUsage::GPU_TEXTURE);
+
+    mAccessRegion.top = 0;
+    mAccessRegion.left = 0;
+    mAccessRegion.width = width;
+    mAccessRegion.height = height;
+}
+
+ReadbackBuffer::~ReadbackBuffer() {
+    if (mBufferHandle != nullptr) {
+        mGralloc->freeBuffer(mBufferHandle);
+    }
+}
+
+void ReadbackBuffer::setReadbackBuffer() {
+    if (mBufferHandle != nullptr) {
+        mGralloc->freeBuffer(mBufferHandle);
+        mBufferHandle = nullptr;
+    }
+    mBufferHandle = mGralloc->allocate(mInfo, /*import*/ true, &mStride);
+    ASSERT_NE(false, mGralloc->validateBufferSize(mBufferHandle, mInfo, mStride));
+    ASSERT_NO_FATAL_FAILURE(mComposerClient->setReadbackBuffer(mDisplay, mBufferHandle, -1));
+}
+
+void ReadbackBuffer::checkReadbackBuffer(std::vector<IComposerClient::Color> expectedColors) {
+    // lock buffer for reading
+    int32_t fenceHandle;
+    ASSERT_NO_FATAL_FAILURE(mComposerClient->getReadbackBufferFence(mDisplay, &fenceHandle));
+
+    void* bufData = mGralloc->lock(mBufferHandle, mInfo.usage, mAccessRegion, fenceHandle);
+    ASSERT_TRUE(mPixelFormat == PixelFormat::RGB_888 || mPixelFormat == PixelFormat::RGBA_8888);
+    int32_t bytesPerPixel = ReadbackHelper::GetBytesPerPixel(mPixelFormat);
+    ASSERT_NE(-1, bytesPerPixel);
+    for (int row = 0; row < mInfo.height; row++) {
+        for (int col = 0; col < mInfo.width; col++) {
+            int pixel = row * mInfo.width + col;
+            int offset = (row * mStride + col) * bytesPerPixel;
+            uint8_t* pixelColor = (uint8_t*)bufData + offset;
+
+            ASSERT_EQ(expectedColors[pixel].r, pixelColor[0]);
+            ASSERT_EQ(expectedColors[pixel].g, pixelColor[1]);
+            ASSERT_EQ(expectedColors[pixel].b, pixelColor[2]);
+        }
+    }
+    int32_t unlockFence = mGralloc->unlock(mBufferHandle);
+    if (unlockFence != -1) {
+        sync_wait(unlockFence, -1);
+        close(unlockFence);
+    }
+}
+
+void TestColorLayer::write(const std::shared_ptr<CommandWriterBase>& writer) {
+    TestLayer::write(writer);
+    writer->setLayerCompositionType(IComposerClient::Composition::SOLID_COLOR);
+    writer->setLayerColor(mColor);
+}
+
+TestBufferLayer::TestBufferLayer(const std::shared_ptr<ComposerClient>& client,
+                                 const std::shared_ptr<Gralloc>& gralloc, Display display,
+                                 int32_t width, int32_t height, PixelFormat format,
+                                 IComposerClient::Composition composition)
+    : TestLayer{client, display} {
+    mGralloc = gralloc;
+    mComposition = composition;
+    mInfo.width = width;
+    mInfo.height = height;
+    mInfo.layerCount = 1;
+    mInfo.format = format;
+    mInfo.usage = static_cast<uint64_t>(BufferUsage::CPU_READ_OFTEN | BufferUsage::CPU_WRITE_OFTEN |
+                                        BufferUsage::COMPOSER_OVERLAY);
+
+    mAccessRegion.top = 0;
+    mAccessRegion.left = 0;
+    mAccessRegion.width = width;
+    mAccessRegion.height = height;
+
+    setSourceCrop({0, 0, (float)width, (float)height});
+}
+
+TestBufferLayer::~TestBufferLayer() {
+    if (mBufferHandle != nullptr) {
+        mGralloc->freeBuffer(mBufferHandle);
+    }
+}
+
+void TestBufferLayer::write(const std::shared_ptr<CommandWriterBase>& writer) {
+    TestLayer::write(writer);
+    writer->setLayerCompositionType(mComposition);
+    writer->setLayerDataspace(Dataspace::UNKNOWN);
+    writer->setLayerVisibleRegion(std::vector<IComposerClient::Rect>(1, mDisplayFrame));
+    if (mBufferHandle != nullptr) writer->setLayerBuffer(0, mBufferHandle, mFillFence);
+}
+
+void TestBufferLayer::fillBuffer(std::vector<IComposerClient::Color> expectedColors) {
+    void* bufData = mGralloc->lock(mBufferHandle, mInfo.usage, mAccessRegion, -1);
+    ASSERT_NO_FATAL_FAILURE(ReadbackHelper::fillBuffer(mInfo.width, mInfo.height, mStride, bufData,
+                                                       mInfo.format, expectedColors));
+    mFillFence = mGralloc->unlock(mBufferHandle);
+    if (mFillFence != -1) {
+        sync_wait(mFillFence, -1);
+        close(mFillFence);
+    }
+}
+void TestBufferLayer::setBuffer(std::vector<IComposerClient::Color> colors) {
+    if (mBufferHandle != nullptr) {
+        mGralloc->freeBuffer(mBufferHandle);
+        mBufferHandle = nullptr;
+    }
+    mBufferHandle = mGralloc->allocate(mInfo, /*import*/ true, &mStride);
+    ASSERT_NE(nullptr, mBufferHandle);
+    ASSERT_NO_FATAL_FAILURE(fillBuffer(colors));
+    ASSERT_NE(false, mGralloc->validateBufferSize(mBufferHandle, mInfo, mStride));
+}
+
+void TestBufferLayer::setToClientComposition(const std::shared_ptr<CommandWriterBase>& writer) {
+    writer->selectLayer(mLayer);
+    writer->setLayerCompositionType(IComposerClient::Composition::CLIENT);
+}
+
+}  // namespace vts
+}  // namespace V2_2
+}  // namespace composer
+}  // namespace graphics
+}  // namespace hardware
+}  // namespace android
diff --git a/graphics/composer/2.2/utils/vts/include/composer-vts/2.2/ReadbackVts.h b/graphics/composer/2.2/utils/vts/include/composer-vts/2.2/ReadbackVts.h
new file mode 100644
index 0000000..9ce4e39
--- /dev/null
+++ b/graphics/composer/2.2/utils/vts/include/composer-vts/2.2/ReadbackVts.h
@@ -0,0 +1,175 @@
+/*
+ * Copyright 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android-base/unique_fd.h>
+#include <android/hardware/graphics/composer/2.2/IComposerClient.h>
+#include <composer-command-buffer/2.2/ComposerCommandBuffer.h>
+#include <composer-vts/2.1/GraphicsComposerCallback.h>
+#include <composer-vts/2.1/TestCommandReader.h>
+#include <composer-vts/2.2/ComposerVts.h>
+#include <mapper-vts/2.1/MapperVts.h>
+
+namespace android {
+namespace hardware {
+namespace graphics {
+namespace composer {
+namespace V2_2 {
+namespace vts {
+
+using android::hardware::hidl_handle;
+using common::V1_1::BufferUsage;
+using common::V1_1::Dataspace;
+using common::V1_1::PixelFormat;
+using mapper::V2_1::IMapper;
+using mapper::V2_1::vts::Gralloc;
+using V2_1::Display;
+using V2_1::Layer;
+using V2_1::vts::TestCommandReader;
+
+static const IComposerClient::Color BLACK = {0, 0, 0, 0xff};
+static const IComposerClient::Color RED = {0xff, 0, 0, 0xff};
+static const IComposerClient::Color TRANSLUCENT_RED = {0xff, 0, 0, 0x33};
+static const IComposerClient::Color GREEN = {0, 0xff, 0, 0xff};
+static const IComposerClient::Color BLUE = {0, 0, 0xff, 0xff};
+
+class TestLayer {
+  public:
+    TestLayer(const std::shared_ptr<ComposerClient>& client, Display display)
+        : mLayer(client->createLayer(display, kBufferSlotCount)), mComposerClient(client) {}
+
+    // ComposerClient will take care of destroying layers, no need to explicitly
+    // call destroyLayers here
+    virtual ~TestLayer(){};
+
+    virtual void write(const std::shared_ptr<CommandWriterBase>& writer);
+
+    void setDisplayFrame(IComposerClient::Rect frame) { mDisplayFrame = frame; }
+    void setSourceCrop(IComposerClient::FRect crop) { mSourceCrop = crop; }
+    void setZOrder(uint32_t z) { mZOrder = z; }
+
+    void setSurfaceDamage(std::vector<IComposerClient::Rect> surfaceDamage) {
+        mSurfaceDamage = surfaceDamage;
+    }
+
+    void setTransform(Transform transform) { mTransform = transform; }
+    void setAlpha(float alpha) { mAlpha = alpha; }
+    void setBlendMode(IComposerClient::BlendMode blendMode) { mBlendMode = blendMode; }
+
+    static constexpr uint32_t kBufferSlotCount = 64;
+
+    IComposerClient::Rect mDisplayFrame = {0, 0, 0, 0};
+    uint32_t mZOrder = 0;
+    std::vector<IComposerClient::Rect> mSurfaceDamage;
+    Transform mTransform = static_cast<Transform>(0);
+    IComposerClient::FRect mSourceCrop = {0, 0, 0, 0};
+    float mAlpha = 1.0;
+    IComposerClient::BlendMode mBlendMode = IComposerClient::BlendMode::NONE;
+
+  protected:
+    Layer mLayer;
+
+  private:
+    std::shared_ptr<ComposerClient> const mComposerClient;
+};
+
+class TestColorLayer : public TestLayer {
+  public:
+    TestColorLayer(const std::shared_ptr<ComposerClient>& client, Display display)
+        : TestLayer{client, display} {}
+
+    void write(const std::shared_ptr<CommandWriterBase>& writer) override;
+
+    void setColor(IComposerClient::Color color) { mColor = color; }
+
+  private:
+    IComposerClient::Color mColor = {0xff, 0xff, 0xff, 0xff};
+};
+
+class TestBufferLayer : public TestLayer {
+  public:
+    TestBufferLayer(
+            const std::shared_ptr<ComposerClient>& client, const std::shared_ptr<Gralloc>& gralloc,
+            Display display, int32_t width, int32_t height, PixelFormat format,
+            IComposerClient::Composition composition = IComposerClient::Composition::DEVICE);
+
+    ~TestBufferLayer();
+
+    void write(const std::shared_ptr<CommandWriterBase>& writer) override;
+
+    void fillBuffer(std::vector<IComposerClient::Color> expectedColors);
+
+    void setBuffer(std::vector<IComposerClient::Color> colors);
+
+    void setToClientComposition(const std::shared_ptr<CommandWriterBase>& writer);
+
+    IMapper::BufferDescriptorInfo mInfo;
+    IMapper::Rect mAccessRegion;
+    uint32_t mStride;
+
+  protected:
+    IComposerClient::Composition mComposition;
+    std::shared_ptr<Gralloc> mGralloc;
+    int32_t mFillFence;
+    const native_handle_t* mBufferHandle = nullptr;
+};
+
+class ReadbackHelper : public ::testing::VtsHalHidlTargetTestBase {
+  public:
+    static int32_t GetBytesPerPixel(PixelFormat pixelFormat);
+
+    static void fillBuffer(int32_t width, int32_t height, uint32_t stride, void* bufferData,
+                           PixelFormat pixelFormat,
+                           std::vector<IComposerClient::Color> desiredPixelColors);
+
+    static void clearColors(std::vector<IComposerClient::Color>& expectedColors, int32_t width,
+                            int32_t height, int32_t displayWidth);
+
+    static void fillColorsArea(std::vector<IComposerClient::Color>& expectedColors, int32_t stride,
+                               IComposerClient::Rect area, IComposerClient::Color color);
+
+    static bool readbackSupported(const PixelFormat& pixelFormat, const Dataspace& dataspace,
+                                  const Error error);
+};
+
+class ReadbackBuffer {
+  public:
+    ReadbackBuffer(Display display, const std::shared_ptr<ComposerClient>& client,
+                   const std::shared_ptr<Gralloc>& gralloc, uint32_t width, uint32_t height,
+                   PixelFormat pixelFormat, Dataspace dataspace);
+    ~ReadbackBuffer();
+
+    void setReadbackBuffer();
+
+    void checkReadbackBuffer(std::vector<IComposerClient::Color> expectedColors);
+
+  protected:
+    IMapper::BufferDescriptorInfo mInfo;
+    IMapper::Rect mAccessRegion;
+    uint32_t mStride;
+    const native_handle_t* mBufferHandle = nullptr;
+    PixelFormat mPixelFormat;
+    Dataspace mDataspace;
+    Display mDisplay;
+    std::shared_ptr<Gralloc> mGralloc;
+    std::shared_ptr<ComposerClient> mComposerClient;
+};
+
+}  // namespace vts
+}  // namespace V2_2
+}  // namespace composer
+}  // namespace graphics
+}  // namespace hardware
+}  // namespace android
diff --git a/graphics/composer/2.2/vts/functional/VtsHalGraphicsComposerV2_2ReadbackTest.cpp b/graphics/composer/2.2/vts/functional/VtsHalGraphicsComposerV2_2ReadbackTest.cpp
index da8858e..2534196 100644
--- a/graphics/composer/2.2/vts/functional/VtsHalGraphicsComposerV2_2ReadbackTest.cpp
+++ b/graphics/composer/2.2/vts/functional/VtsHalGraphicsComposerV2_2ReadbackTest.cpp
@@ -18,13 +18,10 @@
 
 #include <VtsHalHidlTargetTestBase.h>
 #include <VtsHalHidlTargetTestEnvBase.h>
-#include <android-base/unique_fd.h>
-#include <android/hardware/graphics/composer/2.2/IComposerClient.h>
 #include <composer-command-buffer/2.2/ComposerCommandBuffer.h>
 #include <composer-vts/2.1/GraphicsComposerCallback.h>
 #include <composer-vts/2.1/TestCommandReader.h>
-#include <composer-vts/2.2/ComposerVts.h>
-#include <mapper-vts/2.1/MapperVts.h>
+#include <composer-vts/2.2/ReadbackVts.h>
 
 namespace android {
 namespace hardware {
@@ -44,12 +41,6 @@
 using V2_1::Layer;
 using V2_1::vts::TestCommandReader;
 
-static const IComposerClient::Color BLACK = {0, 0, 0, 0xff};
-static const IComposerClient::Color RED = {0xff, 0, 0, 0xff};
-static const IComposerClient::Color TRANSLUCENT_RED = {0xff, 0, 0, 0x33};
-static const IComposerClient::Color GREEN = {0, 0xff, 0, 0xff};
-static const IComposerClient::Color BLUE = {0, 0, 0xff, 0xff};
-
 // Test environment for graphics.composer
 class GraphicsComposerHidlEnvironment : public ::testing::VtsHalHidlTargetTestEnvBase {
    public:
@@ -65,92 +56,7 @@
     GTEST_DISALLOW_COPY_AND_ASSIGN_(GraphicsComposerHidlEnvironment);
 };
 
-class TestLayer {
-   public:
-    TestLayer(const std::shared_ptr<ComposerClient>& client, Display display)
-        : mLayer(client->createLayer(display, kBufferSlotCount)), mComposerClient(client) {}
-
-    // ComposerClient will take care of destroying layers, no need to explicitly
-    // call destroyLayers here
-    virtual ~TestLayer(){};
-
-    virtual void write(const std::shared_ptr<CommandWriterBase>& writer) {
-        writer->selectLayer(mLayer);
-        writer->setLayerDisplayFrame(mDisplayFrame);
-        writer->setLayerSourceCrop(mSourceCrop);
-        writer->setLayerZOrder(mZOrder);
-        writer->setLayerSurfaceDamage(mSurfaceDamage);
-        writer->setLayerTransform(mTransform);
-        writer->setLayerPlaneAlpha(mAlpha);
-        writer->setLayerBlendMode(mBlendMode);
-    }
-
-    void setDisplayFrame(IComposerClient::Rect frame) { mDisplayFrame = frame; }
-    void setSourceCrop(IComposerClient::FRect crop) { mSourceCrop = crop; }
-    void setZOrder(uint32_t z) { mZOrder = z; }
-
-    void setSurfaceDamage(std::vector<IComposerClient::Rect> surfaceDamage) {
-        mSurfaceDamage = surfaceDamage;
-    }
-
-    void setTransform(Transform transform) { mTransform = transform; }
-    void setAlpha(float alpha) { mAlpha = alpha; }
-    void setBlendMode(IComposerClient::BlendMode blendMode) { mBlendMode = blendMode; }
-
-    static constexpr uint32_t kBufferSlotCount = 64;
-
-    IComposerClient::Rect mDisplayFrame = {0, 0, 0, 0};
-    uint32_t mZOrder = 0;
-    std::vector<IComposerClient::Rect> mSurfaceDamage;
-    Transform mTransform = static_cast<Transform>(0);
-    IComposerClient::FRect mSourceCrop = {0, 0, 0, 0};
-    float mAlpha = 1.0;
-    IComposerClient::BlendMode mBlendMode = IComposerClient::BlendMode::NONE;
-
-   protected:
-    Layer mLayer;
-
-   private:
-    std::shared_ptr<ComposerClient> const mComposerClient;
-};
-
 class GraphicsComposerReadbackTest : public ::testing::VtsHalHidlTargetTestBase {
-   public:
-    static int32_t GetBytesPerPixel(PixelFormat pixelFormat) {
-        switch (pixelFormat) {
-            case PixelFormat::RGBA_8888:
-                return 4;
-            case PixelFormat::RGB_888:
-                return 3;
-            default:
-                return -1;
-        }
-    }
-
-    static void fillBuffer(int32_t width, int32_t height, uint32_t stride, void* bufferData,
-                           PixelFormat pixelFormat,
-                           std::vector<IComposerClient::Color> desiredPixelColors) {
-        ASSERT_TRUE(pixelFormat == PixelFormat::RGB_888 || pixelFormat == PixelFormat::RGBA_8888);
-        int32_t bytesPerPixel = GetBytesPerPixel(pixelFormat);
-        ASSERT_NE(-1, bytesPerPixel);
-        for (int row = 0; row < height; row++) {
-            for (int col = 0; col < width; col++) {
-                int pixel = row * width + col;
-                IComposerClient::Color srcColor = desiredPixelColors[pixel];
-
-                int offset = (row * stride + col) * bytesPerPixel;
-                uint8_t* pixelColor = (uint8_t*)bufferData + offset;
-                pixelColor[0] = srcColor.r;
-                pixelColor[1] = srcColor.g;
-                pixelColor[2] = srcColor.b;
-
-                if (bytesPerPixel == 4) {
-                    pixelColor[3] = srcColor.a;
-                }
-            }
-        }
-    }
-
    protected:
     using PowerMode = V2_1::IComposerClient::PowerMode;
     void SetUp() override {
@@ -183,12 +89,13 @@
         mGralloc = std::make_shared<Gralloc>();
 
         mComposerClient->getRaw()->getReadbackBufferAttributes(
-            mPrimaryDisplay,
-            [&](const auto& tmpError, const auto& tmpPixelFormat, const auto& tmpDataspace) {
-                mHasReadbackBuffer = readbackSupported(tmpPixelFormat, tmpDataspace, tmpError);
-                mPixelFormat = tmpPixelFormat;
-                mDataspace = tmpDataspace;
-            });
+                mPrimaryDisplay,
+                [&](const auto& tmpError, const auto& tmpPixelFormat, const auto& tmpDataspace) {
+                    mHasReadbackBuffer = ReadbackHelper::readbackSupported(tmpPixelFormat,
+                                                                           tmpDataspace, tmpError);
+                    mPixelFormat = tmpPixelFormat;
+                    mDataspace = tmpDataspace;
+                });
         ASSERT_NO_FATAL_FAILURE(mComposerClient->setPowerMode(mPrimaryDisplay, PowerMode::ON));
     }
 
@@ -209,10 +116,6 @@
         mReader->mErrors.clear();
     }
 
-    void execute() {
-        ASSERT_NO_FATAL_FAILURE(mComposerClient->execute(mReader.get(), mWriter.get()));
-    }
-
     void writeLayers(const std::vector<std::shared_ptr<TestLayer>>& layers) {
         for (auto layer : layers) {
             layer->write(mWriter);
@@ -220,42 +123,10 @@
         execute();
     }
 
-    void clearColors(std::vector<IComposerClient::Color>& expectedColors, int32_t width,
-                     int32_t height) {
-        for (int row = 0; row < height; row++) {
-            for (int col = 0; col < width; col++) {
-                int pixel = row * mDisplayWidth + col;
-                expectedColors[pixel] = BLACK;
-            }
-        }
+    void execute() {
+        ASSERT_NO_FATAL_FAILURE(mComposerClient->execute(mReader.get(), mWriter.get()));
     }
 
-    void fillColorsArea(std::vector<IComposerClient::Color>& expectedColors, int32_t stride,
-                        IComposerClient::Rect area, IComposerClient::Color color) {
-        for (int row = area.top; row < area.bottom; row++) {
-            for (int col = area.left; col < area.right; col++) {
-                int pixel = row * stride + col;
-                expectedColors[pixel] = color;
-            }
-        }
-    }
-
-    bool readbackSupported(const PixelFormat& pixelFormat, const Dataspace& dataspace,
-                           const Error error) {
-        if (error != Error::NONE) {
-            return false;
-        }
-        // TODO: add support for RGBA_1010102
-        if (pixelFormat != PixelFormat::RGB_888 && pixelFormat != PixelFormat::RGBA_8888) {
-            return false;
-        }
-        if (dataspace != Dataspace::V0_SRGB) {
-            return false;
-        }
-        return true;
-    }
-
-
     std::unique_ptr<Composer> mComposer;
     std::shared_ptr<ComposerClient> mComposerClient;
 
@@ -286,178 +157,6 @@
         }
     }
 };
-class ReadbackBuffer {
-   public:
-    ReadbackBuffer(Display display, const std::shared_ptr<ComposerClient>& client,
-                   const std::shared_ptr<Gralloc>& gralloc, uint32_t width, uint32_t height,
-                   PixelFormat pixelFormat, Dataspace dataspace) {
-        mDisplay = display;
-
-        mComposerClient = client;
-        mGralloc = gralloc;
-
-        mPixelFormat = pixelFormat;
-        mDataspace = dataspace;
-
-        mInfo.width = width;
-        mInfo.height = height;
-        mInfo.layerCount = 1;
-        mInfo.format = mPixelFormat;
-        mInfo.usage = static_cast<uint64_t>(BufferUsage::CPU_READ_OFTEN | BufferUsage::GPU_TEXTURE);
-
-        mAccessRegion.top = 0;
-        mAccessRegion.left = 0;
-        mAccessRegion.width = width;
-        mAccessRegion.height = height;
-    };
-
-    ~ReadbackBuffer() {
-        if (mBufferHandle != nullptr) {
-            mGralloc->freeBuffer(mBufferHandle);
-        }
-    }
-
-    void setReadbackBuffer() {
-        if (mBufferHandle != nullptr) {
-            mGralloc->freeBuffer(mBufferHandle);
-            mBufferHandle = nullptr;
-        }
-        mBufferHandle = mGralloc->allocate(mInfo, /*import*/ true, &mStride);
-        ASSERT_NE(false, mGralloc->validateBufferSize(mBufferHandle, mInfo, mStride));
-        ASSERT_NO_FATAL_FAILURE(mComposerClient->setReadbackBuffer(mDisplay, mBufferHandle, -1));
-    }
-
-    void checkReadbackBuffer(std::vector<IComposerClient::Color> expectedColors) {
-        // lock buffer for reading
-        int32_t fenceHandle;
-        ASSERT_NO_FATAL_FAILURE(mComposerClient->getReadbackBufferFence(mDisplay, &fenceHandle));
-
-        void* bufData = mGralloc->lock(mBufferHandle, mInfo.usage, mAccessRegion, fenceHandle);
-        ASSERT_TRUE(mPixelFormat == PixelFormat::RGB_888 || mPixelFormat == PixelFormat::RGBA_8888);
-        int32_t bytesPerPixel = GraphicsComposerReadbackTest::GetBytesPerPixel(mPixelFormat);
-        ASSERT_NE(-1, bytesPerPixel);
-        for (int row = 0; row < mInfo.height; row++) {
-            for (int col = 0; col < mInfo.width; col++) {
-                int pixel = row * mInfo.width + col;
-                int offset = (row * mStride + col) * bytesPerPixel;
-                uint8_t* pixelColor = (uint8_t*)bufData + offset;
-
-                ASSERT_EQ(expectedColors[pixel].r, pixelColor[0]);
-                ASSERT_EQ(expectedColors[pixel].g, pixelColor[1]);
-                ASSERT_EQ(expectedColors[pixel].b, pixelColor[2]);
-            }
-        }
-        int32_t unlockFence = mGralloc->unlock(mBufferHandle);
-        if (unlockFence != -1) {
-            sync_wait(unlockFence, -1);
-            close(unlockFence);
-        }
-    }
-
-   protected:
-    IMapper::BufferDescriptorInfo mInfo;
-    IMapper::Rect mAccessRegion;
-    uint32_t mStride;
-    const native_handle_t* mBufferHandle = nullptr;
-    PixelFormat mPixelFormat;
-    Dataspace mDataspace;
-    Display mDisplay;
-    std::shared_ptr<Gralloc> mGralloc;
-    std::shared_ptr<ComposerClient> mComposerClient;
-};
-
-class TestColorLayer : public TestLayer {
-   public:
-    TestColorLayer(const std::shared_ptr<ComposerClient>& client, Display display)
-        : TestLayer{client, display} {}
-
-    void write(const std::shared_ptr<CommandWriterBase>& writer) override {
-        TestLayer::write(writer);
-        writer->setLayerCompositionType(IComposerClient::Composition::SOLID_COLOR);
-        writer->setLayerColor(mColor);
-    }
-
-    void setColor(IComposerClient::Color color) { mColor = color; }
-
-   private:
-    IComposerClient::Color mColor = {0xff, 0xff, 0xff, 0xff};
-};
-
-class TestBufferLayer : public TestLayer {
-   public:
-    TestBufferLayer(const std::shared_ptr<ComposerClient>& client,
-                    const std::shared_ptr<Gralloc>& gralloc, Display display, int32_t width,
-                    int32_t height, PixelFormat format,
-                    IComposerClient::Composition composition = IComposerClient::Composition::DEVICE)
-        : TestLayer{client, display} {
-        mGralloc = gralloc;
-        mComposition = composition;
-        mInfo.width = width;
-        mInfo.height = height;
-        mInfo.layerCount = 1;
-        mInfo.format = format;
-        mInfo.usage =
-            static_cast<uint64_t>(BufferUsage::CPU_READ_OFTEN | BufferUsage::CPU_WRITE_OFTEN |
-                                  BufferUsage::COMPOSER_OVERLAY);
-
-        mAccessRegion.top = 0;
-        mAccessRegion.left = 0;
-        mAccessRegion.width = width;
-        mAccessRegion.height = height;
-
-        setSourceCrop({0, 0, (float)width, (float)height});
-    }
-
-    ~TestBufferLayer() {
-        if (mBufferHandle != nullptr) {
-            mGralloc->freeBuffer(mBufferHandle);
-        }
-    }
-
-    void write(const std::shared_ptr<CommandWriterBase>& writer) override {
-        TestLayer::write(writer);
-        writer->setLayerCompositionType(mComposition);
-        writer->setLayerDataspace(Dataspace::UNKNOWN);
-        writer->setLayerVisibleRegion(std::vector<IComposerClient::Rect>(1, mDisplayFrame));
-        if (mBufferHandle != nullptr) writer->setLayerBuffer(0, mBufferHandle, mFillFence);
-    }
-
-    void fillBuffer(std::vector<IComposerClient::Color> expectedColors) {
-        void* bufData = mGralloc->lock(mBufferHandle, mInfo.usage, mAccessRegion, -1);
-        ASSERT_NO_FATAL_FAILURE(GraphicsComposerReadbackTest::fillBuffer(
-            mInfo.width, mInfo.height, mStride, bufData, mInfo.format, expectedColors));
-        mFillFence = mGralloc->unlock(mBufferHandle);
-        if (mFillFence != -1) {
-            sync_wait(mFillFence, -1);
-            close(mFillFence);
-        }
-    }
-    void setBuffer(std::vector<IComposerClient::Color> colors) {
-        if (mBufferHandle != nullptr) {
-            mGralloc->freeBuffer(mBufferHandle);
-            mBufferHandle = nullptr;
-        }
-        mBufferHandle = mGralloc->allocate(mInfo, /*import*/ true, &mStride);
-        ASSERT_NE(nullptr, mBufferHandle);
-        ASSERT_NO_FATAL_FAILURE(fillBuffer(colors));
-        ASSERT_NE(false, mGralloc->validateBufferSize(mBufferHandle, mInfo, mStride));
-    }
-
-    void setToClientComposition(const std::shared_ptr<CommandWriterBase>& writer) {
-        writer->selectLayer(mLayer);
-        writer->setLayerCompositionType(IComposerClient::Composition::CLIENT);
-    }
-
-    IMapper::BufferDescriptorInfo mInfo;
-    IMapper::Rect mAccessRegion;
-    uint32_t mStride;
-
-   protected:
-    IComposerClient::Composition mComposition;
-    std::shared_ptr<Gralloc> mGralloc;
-    int32_t mFillFence;
-    const native_handle_t* mBufferHandle = nullptr;
-};
 
 TEST_F(GraphicsComposerReadbackTest, SingleSolidColorLayer) {
     if (!mHasReadbackBuffer) {
@@ -478,7 +177,7 @@
 
     // expected color for each pixel
     std::vector<IComposerClient::Color> expectedColors(mDisplayWidth * mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth, coloredSquare, BLUE);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth, coloredSquare, BLUE);
 
     ReadbackBuffer readbackBuffer(mPrimaryDisplay, mComposerClient, mGralloc, mDisplayWidth,
                                   mDisplayHeight, mPixelFormat, mDataspace);
@@ -515,11 +214,13 @@
                                   mDisplayHeight, mPixelFormat, mDataspace);
     ASSERT_NO_FATAL_FAILURE(readbackBuffer.setReadbackBuffer());
     std::vector<IComposerClient::Color> expectedColors(mDisplayWidth * mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth, {0, 0, mDisplayWidth, mDisplayHeight / 4}, RED);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {0, mDisplayHeight / 4, mDisplayWidth, mDisplayHeight / 2}, GREEN);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {0, mDisplayHeight / 2, mDisplayWidth, mDisplayHeight}, BLUE);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, 0, mDisplayWidth, mDisplayHeight / 4}, RED);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, mDisplayHeight / 4, mDisplayWidth, mDisplayHeight / 2},
+                                   GREEN);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, mDisplayHeight / 2, mDisplayWidth, mDisplayHeight}, BLUE);
 
     auto layer =
         std::make_shared<TestBufferLayer>(mComposerClient, mGralloc, mPrimaryDisplay, mDisplayWidth,
@@ -580,7 +281,7 @@
 
     // expected color for each pixel
     std::vector<IComposerClient::Color> expectedColors(mDisplayWidth * mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth, coloredSquare, BLUE);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth, coloredSquare, BLUE);
 
     ReadbackBuffer readbackBuffer(mPrimaryDisplay, mComposerClient, mGralloc, mDisplayWidth,
                                   mDisplayHeight, mPixelFormat, mDataspace);
@@ -611,11 +312,13 @@
     mWriter->selectDisplay(mPrimaryDisplay);
 
     std::vector<IComposerClient::Color> expectedColors(mDisplayWidth * mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth, {0, 0, mDisplayWidth, mDisplayHeight / 4}, RED);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {0, mDisplayHeight / 4, mDisplayWidth, mDisplayHeight / 2}, GREEN);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {0, mDisplayHeight / 2, mDisplayWidth, mDisplayHeight}, BLUE);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, 0, mDisplayWidth, mDisplayHeight / 4}, RED);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, mDisplayHeight / 4, mDisplayWidth, mDisplayHeight / 2},
+                                   GREEN);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, mDisplayHeight / 2, mDisplayWidth, mDisplayHeight}, BLUE);
 
     auto layer =
         std::make_shared<TestBufferLayer>(mComposerClient, mGralloc, mPrimaryDisplay, mDisplayWidth,
@@ -657,8 +360,9 @@
         void* clientBufData =
             mGralloc->lock(clientBufferHandle, clientInfo.usage, layer->mAccessRegion, -1);
 
-        ASSERT_NO_FATAL_FAILURE(fillBuffer(clientInfo.width, clientInfo.height, clientStride,
-                                           clientBufData, clientInfo.format, expectedColors));
+        ASSERT_NO_FATAL_FAILURE(ReadbackHelper::fillBuffer(clientInfo.width, clientInfo.height,
+                                                           clientStride, clientBufData,
+                                                           clientInfo.format, expectedColors));
         int clientFence = mGralloc->unlock(clientBufferHandle);
         if (clientFence != -1) {
             sync_wait(clientFence, -1);
@@ -695,9 +399,10 @@
         mComposerClient->setClientTargetSlotCount(mPrimaryDisplay, kClientTargetSlotCount));
 
     std::vector<IComposerClient::Color> expectedColors(mDisplayWidth * mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth, {0, 0, mDisplayWidth, mDisplayHeight / 2}, GREEN);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {0, mDisplayHeight / 2, mDisplayWidth, mDisplayHeight}, RED);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, 0, mDisplayWidth, mDisplayHeight / 2}, GREEN);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, mDisplayHeight / 2, mDisplayWidth, mDisplayHeight}, RED);
 
     ReadbackBuffer readbackBuffer(mPrimaryDisplay, mComposerClient, mGralloc, mDisplayWidth,
                                   mDisplayHeight, mPixelFormat, mDataspace);
@@ -708,10 +413,10 @@
                                           mDisplayHeight / 2, PixelFormat::RGBA_8888);
     std::vector<IComposerClient::Color> deviceColors(deviceLayer->mInfo.width *
                                                      deviceLayer->mInfo.height);
-    fillColorsArea(deviceColors, deviceLayer->mInfo.width,
-                   {0, 0, static_cast<int32_t>(deviceLayer->mInfo.width),
-                    static_cast<int32_t>(deviceLayer->mInfo.height)},
-                   GREEN);
+    ReadbackHelper::fillColorsArea(deviceColors, deviceLayer->mInfo.width,
+                                   {0, 0, static_cast<int32_t>(deviceLayer->mInfo.width),
+                                    static_cast<int32_t>(deviceLayer->mInfo.height)},
+                                   GREEN);
     deviceLayer->setDisplayFrame({0, 0, static_cast<int32_t>(deviceLayer->mInfo.width),
                                   static_cast<int32_t>(deviceLayer->mInfo.height)});
     deviceLayer->setZOrder(10);
@@ -749,9 +454,10 @@
     clientAccessRegion.height = mDisplayHeight;
     void* clientData = mGralloc->lock(clientBufferHandle, clientInfo.usage, clientAccessRegion, -1);
     std::vector<IComposerClient::Color> clientColors(clientInfo.width * clientInfo.height);
-    fillColorsArea(clientColors, clientInfo.width, clientFrame, RED);
-    ASSERT_NO_FATAL_FAILURE(fillBuffer(clientInfo.width, clientInfo.height, clientStride,
-                                       clientData, clientInfo.format, clientColors));
+    ReadbackHelper::fillColorsArea(clientColors, clientInfo.width, clientFrame, RED);
+    ASSERT_NO_FATAL_FAILURE(ReadbackHelper::fillBuffer(clientInfo.width, clientInfo.height,
+                                                       clientStride, clientData, clientInfo.format,
+                                                       clientColors));
     int clientFence = mGralloc->unlock(clientBufferHandle);
     if (clientFence != -1) {
         sync_wait(clientFence, -1);
@@ -787,7 +493,7 @@
     IComposerClient::Rect redRect = {0, 0, mDisplayWidth / 4, mDisplayHeight / 4};
 
     std::vector<IComposerClient::Color> expectedColors(mDisplayWidth * mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth, redRect, RED);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth, redRect, RED);
 
     auto layer =
         std::make_shared<TestBufferLayer>(mComposerClient, mGralloc, mPrimaryDisplay, mDisplayWidth,
@@ -820,8 +526,8 @@
 
     // update surface damage and recheck
     redRect = {mDisplayWidth / 4, mDisplayHeight / 4, mDisplayWidth / 2, mDisplayHeight / 2};
-    clearColors(expectedColors, mDisplayWidth, mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth, redRect, RED);
+    ReadbackHelper::clearColors(expectedColors, mDisplayWidth, mDisplayHeight, mDisplayWidth);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth, redRect, RED);
 
     ASSERT_NO_FATAL_FAILURE(layer->fillBuffer(expectedColors));
     layer->setSurfaceDamage(
@@ -895,9 +601,10 @@
     mWriter->selectDisplay(mPrimaryDisplay);
 
     std::vector<IComposerClient::Color> expectedColors(mDisplayWidth * mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth, {0, 0, mDisplayWidth, mDisplayHeight / 4}, RED);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {0, mDisplayHeight / 2, mDisplayWidth, mDisplayHeight}, BLUE);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, 0, mDisplayWidth, mDisplayHeight / 4}, RED);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, mDisplayHeight / 2, mDisplayWidth, mDisplayHeight}, BLUE);
 
     auto layer =
         std::make_shared<TestBufferLayer>(mComposerClient, mGralloc, mPrimaryDisplay, mDisplayWidth,
@@ -911,7 +618,8 @@
     std::vector<std::shared_ptr<TestLayer>> layers = {layer};
 
     // update expected colors to match crop
-    fillColorsArea(expectedColors, mDisplayWidth, {0, 0, mDisplayWidth, mDisplayHeight}, BLUE);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, 0, mDisplayWidth, mDisplayHeight}, BLUE);
     ReadbackBuffer readbackBuffer(mPrimaryDisplay, mComposerClient, mGralloc, mDisplayWidth,
                                   mDisplayHeight, mPixelFormat, mDataspace);
     ASSERT_NO_FATAL_FAILURE(readbackBuffer.setReadbackBuffer());
@@ -959,8 +667,8 @@
     redLayer->setZOrder(10);
 
     // fill blue first so that red will overwrite on overlap
-    fillColorsArea(expectedColors, mDisplayWidth, blueRect, BLUE);
-    fillColorsArea(expectedColors, mDisplayWidth, redRect, RED);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth, blueRect, BLUE);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth, redRect, RED);
 
     ReadbackBuffer readbackBuffer(mPrimaryDisplay, mComposerClient, mGralloc, mDisplayWidth,
                                   mDisplayHeight, mPixelFormat, mDataspace);
@@ -982,9 +690,9 @@
     ASSERT_NO_FATAL_FAILURE(readbackBuffer.checkReadbackBuffer(expectedColors));
 
     redLayer->setZOrder(1);
-    clearColors(expectedColors, mDisplayWidth, mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth, redRect, RED);
-    fillColorsArea(expectedColors, mDisplayWidth, blueRect, BLUE);
+    ReadbackHelper::clearColors(expectedColors, mDisplayWidth, mDisplayHeight, mDisplayWidth);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth, redRect, RED);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth, blueRect, BLUE);
 
     ASSERT_NO_FATAL_FAILURE(readbackBuffer.setReadbackBuffer());
 
@@ -1019,8 +727,8 @@
     void setUpLayers(IComposerClient::BlendMode blendMode) {
         mLayers.clear();
         std::vector<IComposerClient::Color> topLayerPixelColors(mDisplayWidth * mDisplayHeight);
-        fillColorsArea(topLayerPixelColors, mDisplayWidth, {0, 0, mDisplayWidth, mDisplayHeight},
-                       mTopLayerColor);
+        ReadbackHelper::fillColorsArea(topLayerPixelColors, mDisplayWidth,
+                                       {0, 0, mDisplayWidth, mDisplayHeight}, mTopLayerColor);
 
         auto backgroundLayer = std::make_shared<TestColorLayer>(mComposerClient, mPrimaryDisplay);
         backgroundLayer->setDisplayFrame({0, 0, mDisplayWidth, mDisplayHeight});
@@ -1043,7 +751,7 @@
 
     void setExpectedColors(std::vector<IComposerClient::Color>& expectedColors) {
         ASSERT_EQ(2, mLayers.size());
-        clearColors(expectedColors, mDisplayWidth, mDisplayHeight);
+        ReadbackHelper::clearColors(expectedColors, mDisplayWidth, mDisplayHeight, mDisplayWidth);
 
         auto layer = mLayers[1];
         IComposerClient::BlendMode blendMode = layer->mBlendMode;
@@ -1216,8 +924,8 @@
         mLayer->setZOrder(10);
 
         std::vector<IComposerClient::Color> baseColors(mSideLength * mSideLength);
-        fillColorsArea(baseColors, mSideLength, redRect, RED);
-        fillColorsArea(baseColors, mSideLength, blueRect, BLUE);
+        ReadbackHelper::fillColorsArea(baseColors, mSideLength, redRect, RED);
+        ReadbackHelper::fillColorsArea(baseColors, mSideLength, blueRect, BLUE);
         ASSERT_NO_FATAL_FAILURE(mLayer->setBuffer(baseColors));
 
         mLayers = {backgroundLayer, mLayer};
@@ -1240,10 +948,10 @@
     ASSERT_NO_FATAL_FAILURE(readbackBuffer.setReadbackBuffer());
     mLayer->setTransform(Transform::FLIP_H);
     std::vector<IComposerClient::Color> expectedColors(mDisplayWidth * mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {mSideLength / 2, 0, mSideLength, mSideLength / 2}, RED);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {0, mSideLength / 2, mSideLength / 2, mSideLength}, BLUE);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {mSideLength / 2, 0, mSideLength, mSideLength / 2}, RED);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, mSideLength / 2, mSideLength / 2, mSideLength}, BLUE);
 
     writeLayers(mLayers);
     ASSERT_EQ(0, mReader->mErrors.size());
@@ -1274,10 +982,10 @@
     mLayer->setTransform(Transform::FLIP_V);
 
     std::vector<IComposerClient::Color> expectedColors(mDisplayWidth * mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {0, mSideLength / 2, mSideLength / 2, mSideLength}, RED);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {mSideLength / 2, 0, mSideLength, mSideLength / 2}, BLUE);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, mSideLength / 2, mSideLength / 2, mSideLength}, RED);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {mSideLength / 2, 0, mSideLength, mSideLength / 2}, BLUE);
 
     writeLayers(mLayers);
     ASSERT_EQ(0, mReader->mErrors.size());
@@ -1307,9 +1015,11 @@
     mLayer->setTransform(Transform::ROT_180);
 
     std::vector<IComposerClient::Color> expectedColors(mDisplayWidth * mDisplayHeight);
-    fillColorsArea(expectedColors, mDisplayWidth,
-                   {mSideLength / 2, mSideLength / 2, mSideLength, mSideLength}, RED);
-    fillColorsArea(expectedColors, mDisplayWidth, {0, 0, mSideLength / 2, mSideLength / 2}, BLUE);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {mSideLength / 2, mSideLength / 2, mSideLength, mSideLength},
+                                   RED);
+    ReadbackHelper::fillColorsArea(expectedColors, mDisplayWidth,
+                                   {0, 0, mSideLength / 2, mSideLength / 2}, BLUE);
 
     writeLayers(mLayers);
     ASSERT_EQ(0, mReader->mErrors.size());