diff --git a/libs/tonemap/Android.bp b/libs/tonemap/Android.bp
new file mode 100644
index 0000000..231a342
--- /dev/null
+++ b/libs/tonemap/Android.bp
@@ -0,0 +1,37 @@
+// Copyright 2021 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.
+
+package {
+    // See: http://go/android-license-faq
+    // A large-scale-change added 'default_applicable_licenses' to import
+    // all of the 'license_kinds' from "frameworks_native_license"
+    // to get the below license kinds:
+    //   SPDX-license-identifier-Apache-2.0
+    default_applicable_licenses: ["frameworks_native_license"],
+}
+
+cc_library_static {
+    name: "libtonemap",
+    vendor_available: true,
+
+    export_include_dirs: ["include"],
+    local_include_dirs: ["include"],
+
+    shared_libs: [
+        "android.hardware.graphics.common-V3-ndk",
+    ],
+    srcs: [
+        "tonemap.cpp",
+    ],
+}
diff --git a/libs/tonemap/OWNERS b/libs/tonemap/OWNERS
new file mode 100644
index 0000000..6d91da3
--- /dev/null
+++ b/libs/tonemap/OWNERS
@@ -0,0 +1,4 @@
+alecmouri@google.com
+jreck@google.com
+sallyqi@google.com
+scroggo@google.com
\ No newline at end of file
diff --git a/libs/tonemap/TEST_MAPPING b/libs/tonemap/TEST_MAPPING
new file mode 100644
index 0000000..00f83ba
--- /dev/null
+++ b/libs/tonemap/TEST_MAPPING
@@ -0,0 +1,10 @@
+{
+  "presubmit": [
+    {
+      "name": "librenderengine_test"
+    },
+    {
+      "name": "libtonemap_test"
+    }
+  ]
+}
diff --git a/libs/tonemap/include/tonemap/tonemap.h b/libs/tonemap/include/tonemap/tonemap.h
new file mode 100644
index 0000000..d350e16
--- /dev/null
+++ b/libs/tonemap/include/tonemap/tonemap.h
@@ -0,0 +1,103 @@
+/*
+ * Copyright 2021 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.
+ */
+
+#pragma once
+
+#include <aidl/android/hardware/graphics/common/Dataspace.h>
+
+#include <string>
+#include <vector>
+
+namespace android::tonemap {
+
+// Describes a shader uniform
+// The shader uniform is intended to be passed into a SkRuntimeShaderBuilder, i.e.:
+//
+// SkRuntimeShaderBuilder builder;
+// builder.uniform(<uniform name>).set(<uniform value>.data(), <uniform value>.size());
+struct ShaderUniform {
+    // The name of the uniform, used for binding into a shader.
+    // The shader must contain a uniform whose name matches this.
+    std::string name;
+
+    // The value for the uniform, which should be bound to the uniform identified by <name>
+    std::vector<uint8_t> value;
+};
+
+// Describes metadata which may be used for constructing the shader uniforms.
+// This metadata should not be used for manipulating the source code of the shader program directly,
+// as otherwise caching by other system of these shaders may break.
+struct Metadata {
+    float displayMaxLuminance = 0.0;
+    float contentMaxLuminance = 0.0;
+};
+
+class ToneMapper {
+public:
+    virtual ~ToneMapper() {}
+    // Constructs a tonemap shader whose shader language is SkSL
+    //
+    // The returned shader string *must* contain a function with the following signature:
+    // float libtonemap_LookupTonemapGain(vec3 linearRGB, vec3 xyz);
+    //
+    // The arguments are:
+    // * linearRGB is the absolute nits of the RGB pixels in linear space
+    // * xyz is linearRGB converted into XYZ
+    //
+    // libtonemap_LookupTonemapGain() returns a float representing the amount by which to scale the
+    // absolute nits of the pixels. This function may be plugged into any existing SkSL shader, and
+    // is expected to look something like this:
+    //
+    // vec3 rgb = ...;
+    // // apply the EOTF based on the incoming dataspace to convert to linear nits.
+    // vec3 linearRGB = applyEOTF(rgb);
+    // // apply a RGB->XYZ matrix float3
+    // vec3 xyz = toXYZ(linearRGB);
+    // // Scale the luminance based on the content standard
+    // vec3 absoluteRGB = ScaleLuminance(linearRGB);
+    // vec3 absoluteXYZ = ScaleLuminance(xyz);
+    // float gain = libtonemap_LookupTonemapGain(absoluteRGB, absoluteXYZ);
+    // // Normalize the luminance back down to a [0, 1] range
+    // xyz = NormalizeLuminance(absoluteXYZ * gain);
+    // // apply a XYZ->RGB matrix and apply the output OETf.
+    // vec3 finalColor = applyOETF(ToRGB(xyz));
+    // ...
+    //
+    // Helper methods in this shader should be prefixed with "libtonemap_". Accordingly, libraries
+    // which consume this shader must *not* contain any methods prefixed with "libtonemap_" to
+    // guarantee that there are no conflicts in name resolution.
+    virtual std::string generateTonemapGainShaderSkSL(
+            aidl::android::hardware::graphics::common::Dataspace sourceDataspace,
+            aidl::android::hardware::graphics::common::Dataspace destinationDataspace) = 0;
+
+    // Constructs uniform descriptions that correspond to those that are generated for the tonemap
+    // shader. Uniforms must be prefixed with "in_libtonemap_". Libraries which consume this shader
+    // must not bind any new uniforms that begin with this prefix.
+    //
+    // Downstream shaders may assume the existence of the uniform in_libtonemap_displayMaxLuminance
+    // and in_libtonemap_inputMaxLuminance, in order to assist with scaling and normalizing
+    // luminance as described in the documentation for generateTonemapGainShaderSkSL(). That is,
+    // shaders plugging in a tone-mapping shader returned by generateTonemapGainShaderSkSL() may
+    // assume that there are predefined floats in_libtonemap_displayMaxLuminance and
+    // in_libtonemap_inputMaxLuminance inside of the body of the tone-mapping shader.
+    virtual std::vector<ShaderUniform> generateShaderSkSLUniforms(const Metadata& metadata) = 0;
+};
+
+// Retrieves a tonemapper instance.
+// This instance is globally constructed.
+ToneMapper* getToneMapper();
+
+} // namespace android::tonemap
\ No newline at end of file
diff --git a/libs/tonemap/tests/Android.bp b/libs/tonemap/tests/Android.bp
new file mode 100644
index 0000000..e58d519
--- /dev/null
+++ b/libs/tonemap/tests/Android.bp
@@ -0,0 +1,38 @@
+// Copyright 2021 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.
+
+package {
+    // See: http://go/android-license-faq
+    // A large-scale-change added 'default_applicable_licenses' to import
+    // all of the 'license_kinds' from "frameworks_native_license"
+    // to get the below license kinds:
+    //   SPDX-license-identifier-Apache-2.0
+    default_applicable_licenses: ["frameworks_native_license"],
+}
+
+cc_test {
+    name: "libtonemap_test",
+    test_suites: ["device-tests"],
+    srcs: [
+        "tonemap_test.cpp",
+    ],
+    shared_libs: [
+        "android.hardware.graphics.common-V3-ndk",
+    ],
+    static_libs: [
+        "libgmock",
+        "libgtest",
+        "libtonemap",
+    ],
+}
diff --git a/libs/tonemap/tests/tonemap_test.cpp b/libs/tonemap/tests/tonemap_test.cpp
new file mode 100644
index 0000000..7a7958f
--- /dev/null
+++ b/libs/tonemap/tests/tonemap_test.cpp
@@ -0,0 +1,76 @@
+/*
+ * Copyright 2021 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 <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <tonemap/tonemap.h>
+#include <cmath>
+
+namespace android {
+
+using testing::HasSubstr;
+
+struct TonemapTest : public ::testing::Test {};
+
+TEST_F(TonemapTest, generateShaderSkSLUniforms_containsDefaultUniforms) {
+    static const constexpr float kDisplayMaxLuminance = 1.f;
+    static const constexpr float kContentMaxLuminance = 2.f;
+    tonemap::Metadata metadata{.displayMaxLuminance = kDisplayMaxLuminance,
+                               .contentMaxLuminance = kContentMaxLuminance};
+    const auto uniforms = tonemap::getToneMapper()->generateShaderSkSLUniforms(metadata);
+
+    ASSERT_EQ(1, std::count_if(uniforms.cbegin(), uniforms.cend(), [](const auto& data) {
+                  return data.name == "in_libtonemap_displayMaxLuminance";
+              }));
+    ASSERT_EQ(1, std::count_if(uniforms.cbegin(), uniforms.cend(), [](const auto& data) {
+                  return data.name == "in_libtonemap_inputMaxLuminance";
+              }));
+
+    // Smoke check that metadata values are "real", specifically that they're non-zero and actually
+    // numbers. This is to help avoid shaders using these uniforms from dividing by zero or other
+    // catastrophic errors.
+    const auto& displayLum = std::find_if(uniforms.cbegin(), uniforms.cend(), [](const auto& data) {
+                                 return data.name == "in_libtonemap_displayMaxLuminance";
+                             })->value;
+
+    float displayLumFloat = 0.f;
+    std::memcpy(&displayLumFloat, displayLum.data(), displayLum.size());
+    EXPECT_FALSE(std::isnan(displayLumFloat));
+    EXPECT_GT(displayLumFloat, 0);
+
+    const auto& contentLum = std::find_if(uniforms.cbegin(), uniforms.cend(), [](const auto& data) {
+                                 return data.name == "in_libtonemap_inputMaxLuminance";
+                             })->value;
+
+    float contentLumFloat = 0.f;
+    std::memcpy(&contentLumFloat, contentLum.data(), contentLum.size());
+    EXPECT_FALSE(std::isnan(contentLumFloat));
+    EXPECT_GT(contentLumFloat, 0);
+}
+
+TEST_F(TonemapTest, generateTonemapGainShaderSkSL_containsEntryPoint) {
+    const auto shader =
+            tonemap::getToneMapper()
+                    ->generateTonemapGainShaderSkSL(aidl::android::hardware::graphics::common::
+                                                            Dataspace::BT2020_ITU_PQ,
+                                                    aidl::android::hardware::graphics::common::
+                                                            Dataspace::DISPLAY_P3);
+
+    // Other tests such as librenderengine_test will plug in the shader to check compilation.
+    EXPECT_THAT(shader, HasSubstr("float libtonemap_LookupTonemapGain(vec3 linearRGB, vec3 xyz)"));
+}
+
+} // namespace android
diff --git a/libs/tonemap/tonemap.cpp b/libs/tonemap/tonemap.cpp
new file mode 100644
index 0000000..350bca4
--- /dev/null
+++ b/libs/tonemap/tonemap.cpp
@@ -0,0 +1,256 @@
+/*
+ * Copyright 2021 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 <tonemap/tonemap.h>
+
+#include <cstdint>
+#include <mutex>
+#include <type_traits>
+
+namespace android::tonemap {
+
+namespace {
+
+// Flag containing the variant of tone map algorithm to use.
+enum class ToneMapAlgorithm {
+    AndroidO, // Default algorithm in place since Android O,
+};
+
+static const constexpr auto kToneMapAlgorithm = ToneMapAlgorithm::AndroidO;
+
+static const constexpr auto kTransferMask =
+        static_cast<int32_t>(aidl::android::hardware::graphics::common::Dataspace::TRANSFER_MASK);
+static const constexpr auto kTransferST2084 =
+        static_cast<int32_t>(aidl::android::hardware::graphics::common::Dataspace::TRANSFER_ST2084);
+static const constexpr auto kTransferHLG =
+        static_cast<int32_t>(aidl::android::hardware::graphics::common::Dataspace::TRANSFER_HLG);
+
+template <typename T, std::enable_if_t<std::is_trivially_copyable<T>::value, bool> = true>
+std::vector<uint8_t> buildUniformValue(T value) {
+    std::vector<uint8_t> result;
+    result.resize(sizeof(value));
+    std::memcpy(result.data(), &value, sizeof(value));
+    return result;
+}
+
+class ToneMapperO : public ToneMapper {
+public:
+    std::string generateTonemapGainShaderSkSL(
+            aidl::android::hardware::graphics::common::Dataspace sourceDataspace,
+            aidl::android::hardware::graphics::common::Dataspace destinationDataspace) override {
+        const int32_t sourceDataspaceInt = static_cast<int32_t>(sourceDataspace);
+        const int32_t destinationDataspaceInt = static_cast<int32_t>(destinationDataspace);
+
+        std::string program;
+        // Define required uniforms
+        program.append(R"(
+                uniform float in_libtonemap_displayMaxLuminance;
+                uniform float in_libtonemap_inputMaxLuminance;
+            )");
+        switch (sourceDataspaceInt & kTransferMask) {
+            case kTransferST2084:
+            case kTransferHLG:
+                switch (destinationDataspaceInt & kTransferMask) {
+                    case kTransferST2084:
+                        program.append(R"(
+                                    float libtonemap_ToneMapTargetNits(vec3 xyz) {
+                                        return xyz.y;
+                                    }
+                                )");
+                        break;
+                    case kTransferHLG:
+                        // PQ has a wider luminance range (10,000 nits vs. 1,000 nits) than HLG, so
+                        // we'll clamp the luminance range in case we're mapping from PQ input to
+                        // HLG output.
+                        program.append(R"(
+                                    float libtonemap_ToneMapTargetNits(vec3 xyz) {
+                                        return clamp(xyz.y, 0.0, 1000.0);
+                                    }
+                                )");
+                        break;
+                    default:
+                        // Here we're mapping from HDR to SDR content, so interpolate using a
+                        // Hermitian polynomial onto the smaller luminance range.
+                        program.append(R"(
+                                    float libtonemap_ToneMapTargetNits(vec3 xyz) {
+                                        float maxInLumi = in_libtonemap_inputMaxLuminance;
+                                        float maxOutLumi = in_libtonemap_displayMaxLuminance;
+
+                                        float nits = xyz.y;
+
+                                        // if the max input luminance is less than what we can
+                                        // output then no tone mapping is needed as all color
+                                        // values will be in range.
+                                        if (maxInLumi <= maxOutLumi) {
+                                            return xyz.y;
+                                        } else {
+
+                                            // three control points
+                                            const float x0 = 10.0;
+                                            const float y0 = 17.0;
+                                            float x1 = maxOutLumi * 0.75;
+                                            float y1 = x1;
+                                            float x2 = x1 + (maxInLumi - x1) / 2.0;
+                                            float y2 = y1 + (maxOutLumi - y1) * 0.75;
+
+                                            // horizontal distances between the last three
+                                            // control points
+                                            float h12 = x2 - x1;
+                                            float h23 = maxInLumi - x2;
+                                            // tangents at the last three control points
+                                            float m1 = (y2 - y1) / h12;
+                                            float m3 = (maxOutLumi - y2) / h23;
+                                            float m2 = (m1 + m3) / 2.0;
+
+                                            if (nits < x0) {
+                                                // scale [0.0, x0] to [0.0, y0] linearly
+                                                float slope = y0 / x0;
+                                                return nits * slope;
+                                            } else if (nits < x1) {
+                                                // scale [x0, x1] to [y0, y1] linearly
+                                                float slope = (y1 - y0) / (x1 - x0);
+                                                nits = y0 + (nits - x0) * slope;
+                                            } else if (nits < x2) {
+                                                // scale [x1, x2] to [y1, y2] using Hermite interp
+                                                float t = (nits - x1) / h12;
+                                                nits = (y1 * (1.0 + 2.0 * t) + h12 * m1 * t) *
+                                                        (1.0 - t) * (1.0 - t) +
+                                                        (y2 * (3.0 - 2.0 * t) +
+                                                        h12 * m2 * (t - 1.0)) * t * t;
+                                            } else {
+                                                // scale [x2, maxInLumi] to [y2, maxOutLumi] using
+                                                // Hermite interp
+                                                float t = (nits - x2) / h23;
+                                                nits = (y2 * (1.0 + 2.0 * t) + h23 * m2 * t) *
+                                                        (1.0 - t) * (1.0 - t) + (maxOutLumi *
+                                                        (3.0 - 2.0 * t) + h23 * m3 *
+                                                        (t - 1.0)) * t * t;
+                                            }
+                                        }
+
+                                        return nits;
+                                    }
+                                )");
+                        break;
+                }
+                break;
+            default:
+                switch (destinationDataspaceInt & kTransferMask) {
+                    case kTransferST2084:
+                    case kTransferHLG:
+                        // Map from SDR onto an HDR output buffer
+                        // Here we use a polynomial curve to map from [0, displayMaxLuminance] onto
+                        // [0, maxOutLumi] which is hard-coded to be 3000 nits.
+                        program.append(R"(
+                                    float libtonemap_ToneMapTargetNits(vec3 xyz) {
+                                        const float maxOutLumi = 3000.0;
+
+                                        const float x0 = 5.0;
+                                        const float y0 = 2.5;
+                                        float x1 = in_libtonemap_displayMaxLuminance * 0.7;
+                                        float y1 = maxOutLumi * 0.15;
+                                        float x2 = in_libtonemap_displayMaxLuminance * 0.9;
+                                        float y2 = maxOutLumi * 0.45;
+                                        float x3 = in_libtonemap_displayMaxLuminance;
+                                        float y3 = maxOutLumi;
+
+                                        float c1 = y1 / 3.0;
+                                        float c2 = y2 / 2.0;
+                                        float c3 = y3 / 1.5;
+
+                                        float nits = xyz.y;
+
+                                        if (nits <= x0) {
+                                            // scale [0.0, x0] to [0.0, y0] linearly
+                                            float slope = y0 / x0;
+                                            return nits * slope;
+                                        } else if (nits <= x1) {
+                                            // scale [x0, x1] to [y0, y1] using a curve
+                                            float t = (nits - x0) / (x1 - x0);
+                                            nits = (1.0 - t) * (1.0 - t) * y0 +
+                                                    2.0 * (1.0 - t) * t * c1 + t * t * y1;
+                                        } else if (nits <= x2) {
+                                            // scale [x1, x2] to [y1, y2] using a curve
+                                            float t = (nits - x1) / (x2 - x1);
+                                            nits = (1.0 - t) * (1.0 - t) * y1 +
+                                                    2.0 * (1.0 - t) * t * c2 + t * t * y2;
+                                        } else {
+                                            // scale [x2, x3] to [y2, y3] using a curve
+                                            float t = (nits - x2) / (x3 - x2);
+                                            nits = (1.0 - t) * (1.0 - t) * y2 +
+                                                    2.0 * (1.0 - t) * t * c3 + t * t * y3;
+                                        }
+
+                                        return nits;
+                                    }
+                                )");
+                        break;
+                    default:
+                        // For completeness, this is tone-mapping from SDR to SDR, where this is
+                        // just a no-op.
+                        program.append(R"(
+                                    float libtonemap_ToneMapTargetNits(vec3 xyz) {
+                                        return xyz.y;
+                                    }
+                                )");
+                        break;
+                }
+                break;
+        }
+
+        program.append(R"(
+            float libtonemap_LookupTonemapGain(vec3 linearRGB, vec3 xyz) {
+                if (xyz.y <= 0.0) {
+                    return 1.0;
+                }
+                return libtonemap_ToneMapTargetNits(xyz) / xyz.y;
+            }
+        )");
+        return program;
+    }
+
+    std::vector<ShaderUniform> generateShaderSkSLUniforms(const Metadata& metadata) override {
+        std::vector<ShaderUniform> uniforms;
+
+        uniforms.reserve(2);
+
+        uniforms.push_back({.name = "in_libtonemap_displayMaxLuminance",
+                            .value = buildUniformValue<float>(metadata.displayMaxLuminance)});
+        uniforms.push_back({.name = "in_libtonemap_inputMaxLuminance",
+                            .value = buildUniformValue<float>(metadata.contentMaxLuminance)});
+
+        return uniforms;
+    }
+};
+
+} // namespace
+
+ToneMapper* getToneMapper() {
+    static std::once_flag sOnce;
+    static std::unique_ptr<ToneMapper> sToneMapper;
+
+    std::call_once(sOnce, [&] {
+        switch (kToneMapAlgorithm) {
+            case ToneMapAlgorithm::AndroidO:
+                sToneMapper = std::unique_ptr<ToneMapper>(new ToneMapperO());
+                break;
+        }
+    });
+
+    return sToneMapper.get();
+}
+
+} // namespace android::tonemap
\ No newline at end of file