diff --git a/libs/gui/ScreenCaptureResults.cpp b/libs/gui/ScreenCaptureResults.cpp
index 601a5f9..2de023e 100644
--- a/libs/gui/ScreenCaptureResults.cpp
+++ b/libs/gui/ScreenCaptureResults.cpp
@@ -40,6 +40,13 @@
     SAFE_PARCEL(parcel->writeBool, capturedSecureLayers);
     SAFE_PARCEL(parcel->writeBool, capturedHdrLayers);
     SAFE_PARCEL(parcel->writeUint32, static_cast<uint32_t>(capturedDataspace));
+    if (optionalGainMap != nullptr) {
+        SAFE_PARCEL(parcel->writeBool, true);
+        SAFE_PARCEL(parcel->write, *optionalGainMap);
+    } else {
+        SAFE_PARCEL(parcel->writeBool, false);
+    }
+    SAFE_PARCEL(parcel->writeFloat, hdrSdrRatio);
     return NO_ERROR;
 }
 
@@ -68,6 +75,14 @@
     uint32_t dataspace = 0;
     SAFE_PARCEL(parcel->readUint32, &dataspace);
     capturedDataspace = static_cast<ui::Dataspace>(dataspace);
+
+    bool hasGainmap;
+    SAFE_PARCEL(parcel->readBool, &hasGainmap);
+    if (hasGainmap) {
+        optionalGainMap = new GraphicBuffer();
+        SAFE_PARCEL(parcel->read, *optionalGainMap);
+    }
+    SAFE_PARCEL(parcel->readFloat, &hdrSdrRatio);
     return NO_ERROR;
 }
 
diff --git a/libs/gui/aidl/android/gui/CaptureArgs.aidl b/libs/gui/aidl/android/gui/CaptureArgs.aidl
index 2bbed2b..4920344 100644
--- a/libs/gui/aidl/android/gui/CaptureArgs.aidl
+++ b/libs/gui/aidl/android/gui/CaptureArgs.aidl
@@ -69,5 +69,10 @@
     // exact colorspace is not an appropriate intermediate result.
     // Note that if the caller is requesting a specific dataspace, this hint does nothing.
     boolean hintForSeamlessTransition = false;
+
+    // Allows the screenshot to attach a gainmap, which allows for a per-pixel
+    // transformation of the screenshot to another luminance range, typically
+    // mapping an SDR base image into HDR.
+    boolean attachGainmap = false;
 }
 
diff --git a/libs/gui/aidl/android/gui/ScreenCaptureResults.aidl b/libs/gui/aidl/android/gui/ScreenCaptureResults.aidl
index 97a9035..f4ef16d 100644
--- a/libs/gui/aidl/android/gui/ScreenCaptureResults.aidl
+++ b/libs/gui/aidl/android/gui/ScreenCaptureResults.aidl
@@ -16,4 +16,4 @@
 
 package android.gui;
 
-parcelable ScreenCaptureResults cpp_header "gui/ScreenCaptureResults.h" rust_type "gui_aidl_types_rs::ScreenCaptureResults";
\ No newline at end of file
+parcelable ScreenCaptureResults cpp_header "gui/ScreenCaptureResults.h" rust_type "gui_aidl_types_rs::ScreenCaptureResults";
diff --git a/libs/gui/include/gui/ScreenCaptureResults.h b/libs/gui/include/gui/ScreenCaptureResults.h
index 6e17791..f176f48 100644
--- a/libs/gui/include/gui/ScreenCaptureResults.h
+++ b/libs/gui/include/gui/ScreenCaptureResults.h
@@ -36,6 +36,11 @@
     bool capturedSecureLayers{false};
     bool capturedHdrLayers{false};
     ui::Dataspace capturedDataspace{ui::Dataspace::V0_SRGB};
+    // A gainmap that can be used to "lift" the screenshot into HDR
+    sp<GraphicBuffer> optionalGainMap;
+    // HDR/SDR ratio value that fully applies the gainmap.
+    // Note that we use 1/64 epsilon offsets to eliminate precision issues
+    float hdrSdrRatio{1.0f};
 };
 
 } // namespace android::gui
diff --git a/libs/renderengine/Android.bp b/libs/renderengine/Android.bp
index 7639fab..d248ea0 100644
--- a/libs/renderengine/Android.bp
+++ b/libs/renderengine/Android.bp
@@ -100,6 +100,7 @@
         "skia/debug/SkiaCapture.cpp",
         "skia/debug/SkiaMemoryReporter.cpp",
         "skia/filters/BlurFilter.cpp",
+        "skia/filters/GainmapFactory.cpp",
         "skia/filters/GaussianBlurFilter.cpp",
         "skia/filters/KawaseBlurDualFilter.cpp",
         "skia/filters/KawaseBlurFilter.cpp",
diff --git a/libs/renderengine/RenderEngine.cpp b/libs/renderengine/RenderEngine.cpp
index bc3976d..907590a 100644
--- a/libs/renderengine/RenderEngine.cpp
+++ b/libs/renderengine/RenderEngine.cpp
@@ -21,6 +21,7 @@
 #include "skia/GraphiteVkRenderEngine.h"
 #include "skia/SkiaGLRenderEngine.h"
 #include "threaded/RenderEngineThreaded.h"
+#include "ui/GraphicTypes.h"
 
 #include <com_android_graphics_surfaceflinger_flags.h>
 #include <cutils/properties.h>
@@ -101,17 +102,34 @@
                                                   base::unique_fd&& bufferFence) {
     const auto resultPromise = std::make_shared<std::promise<FenceResult>>();
     std::future<FenceResult> resultFuture = resultPromise->get_future();
-    updateProtectedContext(layers, buffer);
+    updateProtectedContext(layers, {buffer.get()});
     drawLayersInternal(std::move(resultPromise), display, layers, buffer, std::move(bufferFence));
     return resultFuture;
 }
 
+ftl::Future<FenceResult> RenderEngine::drawGainmap(
+        const std::shared_ptr<ExternalTexture>& sdr, base::borrowed_fd&& sdrFence,
+        const std::shared_ptr<ExternalTexture>& hdr, base::borrowed_fd&& hdrFence,
+        float hdrSdrRatio, ui::Dataspace dataspace,
+        const std::shared_ptr<ExternalTexture>& gainmap) {
+    const auto resultPromise = std::make_shared<std::promise<FenceResult>>();
+    std::future<FenceResult> resultFuture = resultPromise->get_future();
+    updateProtectedContext({}, {sdr.get(), hdr.get(), gainmap.get()});
+    drawGainmapInternal(std::move(resultPromise), sdr, std::move(sdrFence), hdr,
+                        std::move(hdrFence), hdrSdrRatio, dataspace, gainmap);
+    return resultFuture;
+}
+
 void RenderEngine::updateProtectedContext(const std::vector<LayerSettings>& layers,
-                                          const std::shared_ptr<ExternalTexture>& buffer) {
+                                          vector<const ExternalTexture*> buffers) {
     const bool needsProtectedContext =
-            (buffer && (buffer->getUsage() & GRALLOC_USAGE_PROTECTED)) ||
-            std::any_of(layers.begin(), layers.end(), [](const LayerSettings& layer) {
-                const std::shared_ptr<ExternalTexture>& buffer = layer.source.buffer.buffer;
+            std::any_of(layers.begin(), layers.end(),
+                        [](const LayerSettings& layer) {
+                            const std::shared_ptr<ExternalTexture>& buffer =
+                                    layer.source.buffer.buffer;
+                            return buffer && (buffer->getUsage() & GRALLOC_USAGE_PROTECTED);
+                        }) ||
+            std::any_of(buffers.begin(), buffers.end(), [](const ExternalTexture* buffer) {
                 return buffer && (buffer->getUsage() & GRALLOC_USAGE_PROTECTED);
             });
     useProtectedContext(needsProtectedContext);
diff --git a/libs/renderengine/include/renderengine/DisplaySettings.h b/libs/renderengine/include/renderengine/DisplaySettings.h
index b640983..280ec19 100644
--- a/libs/renderengine/include/renderengine/DisplaySettings.h
+++ b/libs/renderengine/include/renderengine/DisplaySettings.h
@@ -102,6 +102,9 @@
         Local,
     };
     TonemapStrategy tonemapStrategy = TonemapStrategy::Libtonemap;
+
+    // For now, meaningful primarily when the TonemappingStrategy is Local
+    float targetHdrSdrRatio = 1.f;
 };
 
 static inline bool operator==(const DisplaySettings& lhs, const DisplaySettings& rhs) {
diff --git a/libs/renderengine/include/renderengine/RenderEngine.h b/libs/renderengine/include/renderengine/RenderEngine.h
index 9bc2c48..1954fc5 100644
--- a/libs/renderengine/include/renderengine/RenderEngine.h
+++ b/libs/renderengine/include/renderengine/RenderEngine.h
@@ -208,6 +208,13 @@
                                                 const std::shared_ptr<ExternalTexture>& buffer,
                                                 base::unique_fd&& bufferFence);
 
+    virtual ftl::Future<FenceResult> drawGainmap(const std::shared_ptr<ExternalTexture>& sdr,
+                                                 base::borrowed_fd&& sdrFence,
+                                                 const std::shared_ptr<ExternalTexture>& hdr,
+                                                 base::borrowed_fd&& hdrFence, float hdrSdrRatio,
+                                                 ui::Dataspace dataspace,
+                                                 const std::shared_ptr<ExternalTexture>& gainmap);
+
     // Clean-up method that should be called on the main thread after the
     // drawFence returned by drawLayers fires. This method will free up
     // resources used by the most recently drawn frame. If the frame is still
@@ -285,8 +292,7 @@
 
     // Update protectedContext mode depending on whether or not any layer has a protected buffer.
     void updateProtectedContext(const std::vector<LayerSettings>&,
-                                const std::shared_ptr<ExternalTexture>&);
-
+                                std::vector<const ExternalTexture*>);
     // Attempt to switch RenderEngine into and out of protectedContext mode
     virtual void useProtectedContext(bool useProtectedContext) = 0;
 
@@ -294,6 +300,13 @@
             const std::shared_ptr<std::promise<FenceResult>>&& resultPromise,
             const DisplaySettings& display, const std::vector<LayerSettings>& layers,
             const std::shared_ptr<ExternalTexture>& buffer, base::unique_fd&& bufferFence) = 0;
+
+    virtual void drawGainmapInternal(
+            const std::shared_ptr<std::promise<FenceResult>>&& resultPromise,
+            const std::shared_ptr<ExternalTexture>& sdr, base::borrowed_fd&& sdrFence,
+            const std::shared_ptr<ExternalTexture>& hdr, base::borrowed_fd&& hdrFence,
+            float hdrSdrRatio, ui::Dataspace dataspace,
+            const std::shared_ptr<ExternalTexture>& gainmap) = 0;
 };
 
 struct RenderEngineCreationArgs {
diff --git a/libs/renderengine/include/renderengine/mock/RenderEngine.h b/libs/renderengine/include/renderengine/mock/RenderEngine.h
index a8c242a..fb8331d 100644
--- a/libs/renderengine/include/renderengine/mock/RenderEngine.h
+++ b/libs/renderengine/include/renderengine/mock/RenderEngine.h
@@ -46,6 +46,17 @@
                  ftl::Future<FenceResult>(const DisplaySettings&, const std::vector<LayerSettings>&,
                                           const std::shared_ptr<ExternalTexture>&,
                                           base::unique_fd&&));
+    MOCK_METHOD7(drawGainmap,
+                 ftl::Future<FenceResult>(const std::shared_ptr<ExternalTexture>&,
+                                          base::borrowed_fd&&,
+                                          const std::shared_ptr<ExternalTexture>&,
+                                          base::borrowed_fd&&, float, ui::Dataspace,
+                                          const std::shared_ptr<ExternalTexture>&));
+    MOCK_METHOD8(drawGainmapInternal,
+                 void(const std::shared_ptr<std::promise<FenceResult>>&&,
+                      const std::shared_ptr<ExternalTexture>&, base::borrowed_fd&&,
+                      const std::shared_ptr<ExternalTexture>&, base::borrowed_fd&&, float,
+                      ui::Dataspace, const std::shared_ptr<ExternalTexture>&));
     MOCK_METHOD5(drawLayersInternal,
                  void(const std::shared_ptr<std::promise<FenceResult>>&&, const DisplaySettings&,
                       const std::vector<LayerSettings>&, const std::shared_ptr<ExternalTexture>&,
diff --git a/libs/renderengine/skia/SkiaRenderEngine.cpp b/libs/renderengine/skia/SkiaRenderEngine.cpp
index d58f303..426ccd6 100644
--- a/libs/renderengine/skia/SkiaRenderEngine.cpp
+++ b/libs/renderengine/skia/SkiaRenderEngine.cpp
@@ -75,6 +75,7 @@
 #include "ColorSpaces.h"
 #include "compat/SkiaGpuContext.h"
 #include "filters/BlurFilter.h"
+#include "filters/GainmapFactory.h"
 #include "filters/GaussianBlurFilter.h"
 #include "filters/KawaseBlurDualFilter.h"
 #include "filters/KawaseBlurFilter.h"
@@ -238,12 +239,22 @@
 static inline SkPoint3 getSkPoint3(const android::vec3& vector) {
     return SkPoint3::Make(vector.x, vector.y, vector.z);
 }
+
 } // namespace
 
 namespace android {
 namespace renderengine {
 namespace skia {
 
+namespace {
+void trace(sp<Fence> fence) {
+    if (SFTRACE_ENABLED()) {
+        static gui::FenceMonitor sMonitor("RE Completion");
+        sMonitor.queueFence(std::move(fence));
+    }
+}
+} // namespace
+
 using base::StringAppendF;
 
 std::future<void> SkiaRenderEngine::primeCache(PrimeCacheConfig config) {
@@ -544,13 +555,15 @@
         const auto usingLocalTonemap =
                 parameters.display.tonemapStrategy == DisplaySettings::TonemapStrategy::Local &&
                 hdrType != HdrRenderType::SDR &&
-                shader->isAImage((SkMatrix*)nullptr, (SkTileMode*)nullptr);
-
+                shader->isAImage((SkMatrix*)nullptr, (SkTileMode*)nullptr) &&
+                (hdrType != HdrRenderType::DISPLAY_HDR ||
+                 parameters.display.targetHdrSdrRatio < parameters.layerDimmingRatio);
         if (usingLocalTonemap) {
-            static MouriMap kMapper;
-            const float ratio =
+            const float inputRatio =
                     hdrType == HdrRenderType::GENERIC_HDR ? 1.0f : parameters.layerDimmingRatio;
-            shader = kMapper.mouriMap(getActiveContext(), shader, ratio);
+            static MouriMap kMapper;
+            shader = kMapper.mouriMap(getActiveContext(), shader, inputRatio,
+                                      parameters.display.targetHdrSdrRatio);
         }
 
         // disable tonemapping if we already locally tonemapped
@@ -1187,11 +1200,48 @@
 
     LOG_ALWAYS_FATAL_IF(activeSurface != dstSurface);
     auto drawFence = sp<Fence>::make(flushAndSubmit(context, dstSurface));
+    trace(drawFence);
+    resultPromise->set_value(std::move(drawFence));
+}
 
-    if (SFTRACE_ENABLED()) {
-        static gui::FenceMonitor sMonitor("RE Completion");
-        sMonitor.queueFence(drawFence);
-    }
+void SkiaRenderEngine::drawGainmapInternal(
+        const std::shared_ptr<std::promise<FenceResult>>&& resultPromise,
+        const std::shared_ptr<ExternalTexture>& sdr, base::borrowed_fd&& sdrFence,
+        const std::shared_ptr<ExternalTexture>& hdr, base::borrowed_fd&& hdrFence,
+        float hdrSdrRatio, ui::Dataspace dataspace,
+        const std::shared_ptr<ExternalTexture>& gainmap) {
+    std::lock_guard<std::mutex> lock(mRenderingMutex);
+    auto context = getActiveContext();
+    auto surfaceTextureRef = getOrCreateBackendTexture(gainmap->getBuffer(), true);
+    sk_sp<SkSurface> dstSurface =
+            surfaceTextureRef->getOrCreateSurface(ui::Dataspace::V0_SRGB_LINEAR);
+
+    waitFence(context, sdrFence);
+    const auto sdrTextureRef = getOrCreateBackendTexture(sdr->getBuffer(), false);
+    const auto sdrImage = sdrTextureRef->makeImage(dataspace, kPremul_SkAlphaType);
+    const auto sdrShader =
+            sdrImage->makeShader(SkTileMode::kClamp, SkTileMode::kClamp,
+                                 SkSamplingOptions({SkFilterMode::kLinear, SkMipmapMode::kNone}),
+                                 nullptr);
+    waitFence(context, hdrFence);
+    const auto hdrTextureRef = getOrCreateBackendTexture(hdr->getBuffer(), false);
+    const auto hdrImage = hdrTextureRef->makeImage(dataspace, kPremul_SkAlphaType);
+    const auto hdrShader =
+            hdrImage->makeShader(SkTileMode::kClamp, SkTileMode::kClamp,
+                                 SkSamplingOptions({SkFilterMode::kLinear, SkMipmapMode::kNone}),
+                                 nullptr);
+
+    static GainmapFactory kGainmapFactory;
+    const auto gainmapShader = kGainmapFactory.createSkShader(sdrShader, hdrShader, hdrSdrRatio);
+
+    const auto canvas = dstSurface->getCanvas();
+    SkPaint paint;
+    paint.setShader(gainmapShader);
+    paint.setBlendMode(SkBlendMode::kSrc);
+    canvas->drawPaint(paint);
+
+    auto drawFence = sp<Fence>::make(flushAndSubmit(context, dstSurface));
+    trace(drawFence);
     resultPromise->set_value(std::move(drawFence));
 }
 
diff --git a/libs/renderengine/skia/SkiaRenderEngine.h b/libs/renderengine/skia/SkiaRenderEngine.h
index 224a1ca..faa3fb5 100644
--- a/libs/renderengine/skia/SkiaRenderEngine.h
+++ b/libs/renderengine/skia/SkiaRenderEngine.h
@@ -143,6 +143,13 @@
                             const std::vector<LayerSettings>& layers,
                             const std::shared_ptr<ExternalTexture>& buffer,
                             base::unique_fd&& bufferFence) override final;
+    void drawGainmapInternal(const std::shared_ptr<std::promise<FenceResult>>&& resultPromise,
+                             const std::shared_ptr<ExternalTexture>& sdr,
+                             base::borrowed_fd&& sdrFence,
+                             const std::shared_ptr<ExternalTexture>& hdr,
+                             base::borrowed_fd&& hdrFence, float hdrSdrRatio,
+                             ui::Dataspace dataspace,
+                             const std::shared_ptr<ExternalTexture>& gainmap) override final;
 
     void dump(std::string& result) override final;
 
diff --git a/libs/renderengine/skia/filters/GainmapFactory.cpp b/libs/renderengine/skia/filters/GainmapFactory.cpp
new file mode 100644
index 0000000..e4d4fe9
--- /dev/null
+++ b/libs/renderengine/skia/filters/GainmapFactory.cpp
@@ -0,0 +1,72 @@
+/*
+ * Copyright 2024 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 "GainmapFactory.h"
+
+#include <log/log.h>
+
+namespace android {
+namespace renderengine {
+namespace skia {
+namespace {
+
+sk_sp<SkRuntimeEffect> makeEffect(const SkString& sksl) {
+    auto [effect, error] = SkRuntimeEffect::MakeForShader(sksl);
+    LOG_ALWAYS_FATAL_IF(!effect, "RuntimeShader error: %s", error.c_str());
+    return effect;
+}
+
+// Please refer to https://developer.android.com/media/platform/hdr-image-format#gain_map-generation
+static const SkString kGainmapShader = SkString(R"(
+    uniform shader sdr;
+    uniform shader hdr;
+    uniform float mapMaxLog2;
+
+    const float mapMinLog2 = 0.0;
+    const float mapGamma = 1.0;
+    const float offsetSdr = 0.015625;
+    const float offsetHdr = 0.015625;
+
+    float luminance(vec3 linearColor) {
+        return 0.2126 * linearColor.r + 0.7152 * linearColor.g + 0.0722 * linearColor.b;
+    }
+
+    vec4 main(vec2 xy) {
+        float sdrY = luminance(toLinearSrgb(sdr.eval(xy).rgb));
+        float hdrY = luminance(toLinearSrgb(hdr.eval(xy).rgb));
+        float pixelGain = (hdrY + offsetHdr) / (sdrY + offsetSdr);
+        float logRecovery = (log2(pixelGain) - mapMinLog2) / (mapMaxLog2 - mapMinLog2);
+        return vec4(pow(clamp(logRecovery, 0.0, 1.0), mapGamma));
+    }
+)");
+} // namespace
+
+const float INTERPOLATION_STRENGTH_VALUE = 0.7f;
+
+GainmapFactory::GainmapFactory() : mEffect(makeEffect(kGainmapShader)) {}
+
+sk_sp<SkShader> GainmapFactory::createSkShader(const sk_sp<SkShader>& sdr,
+                                               const sk_sp<SkShader>& hdr, float hdrSdrRatio) {
+    SkRuntimeShaderBuilder shaderBuilder(mEffect);
+    shaderBuilder.child("sdr") = sdr;
+    shaderBuilder.child("hdr") = hdr;
+    shaderBuilder.uniform("mapMaxLog2") = std::log2(hdrSdrRatio);
+    return shaderBuilder.makeShader();
+}
+
+} // namespace skia
+} // namespace renderengine
+} // namespace android
diff --git a/libs/renderengine/skia/filters/GainmapFactory.h b/libs/renderengine/skia/filters/GainmapFactory.h
new file mode 100644
index 0000000..7aea5e2
--- /dev/null
+++ b/libs/renderengine/skia/filters/GainmapFactory.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2024 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 <SkRuntimeEffect.h>
+#include <SkShader.h>
+
+namespace android {
+namespace renderengine {
+namespace skia {
+
+/**
+ * Generates a shader for computing a gainmap, given an SDR base image and its idealized HDR
+ * rendition. The shader follows the procedure in the UltraHDR spec:
+ * https://developer.android.com/media/platform/hdr-image-format#gain_map-generation, but makes some
+ * simplifying assumptions about metadata typical for RenderEngine's usage.
+ */
+class GainmapFactory {
+public:
+    GainmapFactory();
+    // Generates the gainmap shader. The hdrSdrRatio is the max_content_boost in the UltraHDR
+    // specification.
+    sk_sp<SkShader> createSkShader(const sk_sp<SkShader>& sdr, const sk_sp<SkShader>& hdr,
+                                   float hdrSdrRatio);
+
+private:
+    sk_sp<SkRuntimeEffect> mEffect;
+};
+} // namespace skia
+} // namespace renderengine
+} // namespace android
diff --git a/libs/renderengine/skia/filters/MouriMap.cpp b/libs/renderengine/skia/filters/MouriMap.cpp
index b458939..b099bcf 100644
--- a/libs/renderengine/skia/filters/MouriMap.cpp
+++ b/libs/renderengine/skia/filters/MouriMap.cpp
@@ -67,7 +67,7 @@
         float result = 0.0;
         for (int y = -2; y <= 2; y++) {
             for (int x = -2; x <= 2; x++) {
-            result += C[y + 2] * C[x + 2] * bitmap.eval(xy + vec2(x, y)).r;
+                result += C[y + 2] * C[x + 2] * bitmap.eval(xy + vec2(x, y)).r;
             }
         }
         return float4(float3(exp2(result)), 1.0);
@@ -78,18 +78,20 @@
     uniform shader lux;
     uniform float scaleFactor;
     uniform float hdrSdrRatio;
+    uniform float targetHdrSdrRatio;
     vec4 main(vec2 xy) {
         float localMax = lux.eval(xy * scaleFactor).r;
         float4 rgba = image.eval(xy);
         float3 linear = toLinearSrgb(rgba.rgb) * hdrSdrRatio;
 
-        if (localMax <= 1.0) {
+        if (localMax <= targetHdrSdrRatio) {
             return float4(fromLinearSrgb(linear), rgba.a);
         }
 
         float maxRGB = max(linear.r, max(linear.g, linear.b));
         localMax = max(localMax, maxRGB);
-        float gain = (1 + maxRGB / (localMax * localMax)) / (1 + maxRGB);
+        float gain = (1 + maxRGB * (targetHdrSdrRatio / (localMax * localMax)))
+                / (1 + maxRGB / targetHdrSdrRatio);
         return float4(fromLinearSrgb(linear * gain), rgba.a);
     }
 )");
@@ -114,10 +116,10 @@
         mTonemap(makeEffect(kTonemap)) {}
 
 sk_sp<SkShader> MouriMap::mouriMap(SkiaGpuContext* context, sk_sp<SkShader> input,
-                                   float hdrSdrRatio) {
+                                   float hdrSdrRatio, float targetHdrSdrRatio) {
     auto downchunked = downchunk(context, input, hdrSdrRatio);
     auto localLux = blur(context, downchunked.get());
-    return tonemap(input, localLux.get(), hdrSdrRatio);
+    return tonemap(input, localLux.get(), hdrSdrRatio, targetHdrSdrRatio);
 }
 
 sk_sp<SkImage> MouriMap::downchunk(SkiaGpuContext* context, sk_sp<SkShader> input,
@@ -166,8 +168,8 @@
     LOG_ALWAYS_FATAL_IF(!blurSurface, "%s: Failed to create surface!", __func__);
     return makeImage(blurSurface.get(), blurBuilder);
 }
-sk_sp<SkShader> MouriMap::tonemap(sk_sp<SkShader> input, SkImage* localLux,
-                                  float hdrSdrRatio) const {
+sk_sp<SkShader> MouriMap::tonemap(sk_sp<SkShader> input, SkImage* localLux, float hdrSdrRatio,
+                                  float targetHdrSdrRatio) const {
     static constexpr float kScaleFactor = 1.0f / 128.0f;
     SkRuntimeShaderBuilder tonemapBuilder(mTonemap);
     tonemapBuilder.child("image") = input;
@@ -176,8 +178,9 @@
                                     SkSamplingOptions(SkFilterMode::kLinear, SkMipmapMode::kNone));
     tonemapBuilder.uniform("scaleFactor") = kScaleFactor;
     tonemapBuilder.uniform("hdrSdrRatio") = hdrSdrRatio;
+    tonemapBuilder.uniform("targetHdrSdrRatio") = targetHdrSdrRatio;
     return tonemapBuilder.makeShader();
 }
 } // namespace skia
 } // namespace renderengine
-} // namespace android
\ No newline at end of file
+} // namespace android
diff --git a/libs/renderengine/skia/filters/MouriMap.h b/libs/renderengine/skia/filters/MouriMap.h
index 3c0df8a..9ba2b6f 100644
--- a/libs/renderengine/skia/filters/MouriMap.h
+++ b/libs/renderengine/skia/filters/MouriMap.h
@@ -64,13 +64,16 @@
     // Apply the MouriMap tonemmaping operator to the input.
     // The HDR/SDR ratio describes the luminace range of the input. 1.0 means SDR. Anything larger
     // then 1.0 means that there is headroom above the SDR region.
-    sk_sp<SkShader> mouriMap(SkiaGpuContext* context, sk_sp<SkShader> input, float hdrSdrRatio);
+    // Similarly, the target HDR/SDR ratio describes the luminance range of the output.
+    sk_sp<SkShader> mouriMap(SkiaGpuContext* context, sk_sp<SkShader> input, float inputHdrSdrRatio,
+                             float targetHdrSdrRatio);
 
 private:
     sk_sp<SkImage> downchunk(SkiaGpuContext* context, sk_sp<SkShader> input,
                              float hdrSdrRatio) const;
     sk_sp<SkImage> blur(SkiaGpuContext* context, SkImage* input) const;
-    sk_sp<SkShader> tonemap(sk_sp<SkShader> input, SkImage* localLux, float hdrSdrRatio) const;
+    sk_sp<SkShader> tonemap(sk_sp<SkShader> input, SkImage* localLux, float hdrSdrRatio,
+                            float targetHdrSdrRatio) const;
     const sk_sp<SkRuntimeEffect> mCrosstalkAndChunk16x16;
     const sk_sp<SkRuntimeEffect> mChunk8x8;
     const sk_sp<SkRuntimeEffect> mBlur;
@@ -78,4 +81,4 @@
 };
 } // namespace skia
 } // namespace renderengine
-} // namespace android
\ No newline at end of file
+} // namespace android
diff --git a/libs/renderengine/threaded/RenderEngineThreaded.cpp b/libs/renderengine/threaded/RenderEngineThreaded.cpp
index f5a90fd..c187f93 100644
--- a/libs/renderengine/threaded/RenderEngineThreaded.cpp
+++ b/libs/renderengine/threaded/RenderEngineThreaded.cpp
@@ -249,6 +249,16 @@
     return;
 }
 
+void RenderEngineThreaded::drawGainmapInternal(
+        const std::shared_ptr<std::promise<FenceResult>>&& resultPromise,
+        const std::shared_ptr<ExternalTexture>& sdr, base::borrowed_fd&& sdrFence,
+        const std::shared_ptr<ExternalTexture>& hdr, base::borrowed_fd&& hdrFence,
+        float hdrSdrRatio, ui::Dataspace dataspace,
+        const std::shared_ptr<ExternalTexture>& gainmap) {
+    resultPromise->set_value(Fence::NO_FENCE);
+    return;
+}
+
 ftl::Future<FenceResult> RenderEngineThreaded::drawLayers(
         const DisplaySettings& display, const std::vector<LayerSettings>& layers,
         const std::shared_ptr<ExternalTexture>& buffer, base::unique_fd&& bufferFence) {
@@ -262,7 +272,7 @@
         mFunctionCalls.push(
                 [resultPromise, display, layers, buffer, fd](renderengine::RenderEngine& instance) {
                     SFTRACE_NAME("REThreaded::drawLayers");
-                    instance.updateProtectedContext(layers, buffer);
+                    instance.updateProtectedContext(layers, {buffer.get()});
                     instance.drawLayersInternal(std::move(resultPromise), display, layers, buffer,
                                                 base::unique_fd(fd));
                 });
@@ -271,6 +281,30 @@
     return resultFuture;
 }
 
+ftl::Future<FenceResult> RenderEngineThreaded::drawGainmap(
+        const std::shared_ptr<ExternalTexture>& sdr, base::borrowed_fd&& sdrFence,
+        const std::shared_ptr<ExternalTexture>& hdr, base::borrowed_fd&& hdrFence,
+        float hdrSdrRatio, ui::Dataspace dataspace,
+        const std::shared_ptr<ExternalTexture>& gainmap) {
+    SFTRACE_CALL();
+    const auto resultPromise = std::make_shared<std::promise<FenceResult>>();
+    std::future<FenceResult> resultFuture = resultPromise->get_future();
+    {
+        std::lock_guard lock(mThreadMutex);
+        mNeedsPostRenderCleanup = true;
+        mFunctionCalls.push([resultPromise, sdr, sdrFence = std::move(sdrFence), hdr,
+                             hdrFence = std::move(hdrFence), hdrSdrRatio, dataspace,
+                             gainmap](renderengine::RenderEngine& instance) mutable {
+            SFTRACE_NAME("REThreaded::drawGainmap");
+            instance.updateProtectedContext({}, {sdr.get(), hdr.get(), gainmap.get()});
+            instance.drawGainmapInternal(std::move(resultPromise), sdr, std::move(sdrFence), hdr,
+                                         std::move(hdrFence), hdrSdrRatio, dataspace, gainmap);
+        });
+    }
+    mCondition.notify_one();
+    return resultFuture;
+}
+
 int RenderEngineThreaded::getContextPriority() {
     std::promise<int> resultPromise;
     std::future<int> resultFuture = resultPromise.get_future();
diff --git a/libs/renderengine/threaded/RenderEngineThreaded.h b/libs/renderengine/threaded/RenderEngineThreaded.h
index d4997d6..cb6e924 100644
--- a/libs/renderengine/threaded/RenderEngineThreaded.h
+++ b/libs/renderengine/threaded/RenderEngineThreaded.h
@@ -55,6 +55,12 @@
                                         const std::vector<LayerSettings>& layers,
                                         const std::shared_ptr<ExternalTexture>& buffer,
                                         base::unique_fd&& bufferFence) override;
+    ftl::Future<FenceResult> drawGainmap(const std::shared_ptr<ExternalTexture>& sdr,
+                                         base::borrowed_fd&& sdrFence,
+                                         const std::shared_ptr<ExternalTexture>& hdr,
+                                         base::borrowed_fd&& hdrFence, float hdrSdrRatio,
+                                         ui::Dataspace dataspace,
+                                         const std::shared_ptr<ExternalTexture>& gainmap) override;
 
     int getContextPriority() override;
     bool supportsBackgroundBlur() override;
@@ -71,6 +77,13 @@
                             const std::vector<LayerSettings>& layers,
                             const std::shared_ptr<ExternalTexture>& buffer,
                             base::unique_fd&& bufferFence) override;
+    void drawGainmapInternal(const std::shared_ptr<std::promise<FenceResult>>&& resultPromise,
+                             const std::shared_ptr<ExternalTexture>& sdr,
+                             base::borrowed_fd&& sdrFence,
+                             const std::shared_ptr<ExternalTexture>& hdr,
+                             base::borrowed_fd&& hdrFence, float hdrSdrRatio,
+                             ui::Dataspace dataspace,
+                             const std::shared_ptr<ExternalTexture>& gainmap) override;
 
 private:
     void threadMain(CreateInstanceFactory factory);