diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 0aad282..7590d98 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -7060,7 +7060,8 @@
                                                  displayWeak, options),
                         getLayerSnapshotsFn, reqSize,
                         static_cast<ui::PixelFormat>(captureArgs.pixelFormat),
-                        captureArgs.allowProtected, captureArgs.grayscale, captureListener);
+                        captureArgs.allowProtected, captureArgs.grayscale,
+                        captureArgs.attachGainmap, captureListener);
 }
 
 void SurfaceFlinger::captureDisplay(DisplayId displayId, const CaptureArgs& args,
@@ -7117,7 +7118,7 @@
                                                  static_cast<ui::Dataspace>(args.dataspace),
                                                  displayWeak, options),
                         getLayerSnapshotsFn, size, static_cast<ui::PixelFormat>(args.pixelFormat),
-                        kAllowProtected, kGrayscale, captureListener);
+                        kAllowProtected, kGrayscale, args.attachGainmap, captureListener);
 }
 
 ScreenCaptureResults SurfaceFlinger::captureLayersSync(const LayerCaptureArgs& args) {
@@ -7228,7 +7229,8 @@
                                                  options),
                         getLayerSnapshotsFn, reqSize,
                         static_cast<ui::PixelFormat>(captureArgs.pixelFormat),
-                        captureArgs.allowProtected, captureArgs.grayscale, captureListener);
+                        captureArgs.allowProtected, captureArgs.grayscale,
+                        captureArgs.attachGainmap, captureListener);
 }
 
 // Creates a Future release fence for a layer and keeps track of it in a list to
@@ -7281,7 +7283,7 @@
 void SurfaceFlinger::captureScreenCommon(RenderAreaBuilderVariant renderAreaBuilder,
                                          GetLayerSnapshotsFunction getLayerSnapshotsFn,
                                          ui::Size bufferSize, ui::PixelFormat reqPixelFormat,
-                                         bool allowProtected, bool grayscale,
+                                         bool allowProtected, bool grayscale, bool attachGainmap,
                                          const sp<IScreenCaptureListener>& captureListener) {
     SFTRACE_CALL();
 
@@ -7327,9 +7329,9 @@
                 renderengine::impl::ExternalTexture>(buffer, getRenderEngine(),
                                                      renderengine::impl::ExternalTexture::Usage::
                                                              WRITEABLE);
-        auto futureFence =
-                captureScreenshot(renderAreaBuilder, texture, false /* regionSampling */, grayscale,
-                                  isProtected, captureListener, displayState, layerFEs);
+        auto futureFence = captureScreenshot(renderAreaBuilder, texture, false /* regionSampling */,
+                                             grayscale, isProtected, attachGainmap, captureListener,
+                                             displayState, layerFEs);
         futureFence.get();
 
     } else {
@@ -7364,7 +7366,7 @@
                                                              WRITEABLE);
         auto futureFence = captureScreenshotLegacy(renderAreaBuilder, getLayerSnapshotsFn, texture,
                                                    false /* regionSampling */, grayscale,
-                                                   isProtected, captureListener);
+                                                   isProtected, attachGainmap, captureListener);
         futureFence.get();
     }
 }
@@ -7418,7 +7420,8 @@
 ftl::SharedFuture<FenceResult> SurfaceFlinger::captureScreenshot(
         const RenderAreaBuilderVariant& renderAreaBuilder,
         const std::shared_ptr<renderengine::ExternalTexture>& buffer, bool regionSampling,
-        bool grayscale, bool isProtected, const sp<IScreenCaptureListener>& captureListener,
+        bool grayscale, bool isProtected, bool attachGainmap,
+        const sp<IScreenCaptureListener>& captureListener,
         std::optional<OutputCompositionState>& displayState, std::vector<sp<LayerFE>>& layerFEs) {
     SFTRACE_CALL();
 
@@ -7435,19 +7438,87 @@
         }
         return ftl::yield<FenceResult>(base::unexpected(NO_ERROR)).share();
     }
+    float displayBrightnessNits = displayState.value().displayBrightnessNits;
+    float sdrWhitePointNits = displayState.value().sdrWhitePointNits;
 
     // Empty vector needed to pass into renderScreenImpl for legacy path
     std::vector<std::pair<Layer*, sp<android::LayerFE>>> layers;
     ftl::SharedFuture<FenceResult> renderFuture =
-            renderScreenImpl(std::move(renderArea), buffer, regionSampling, grayscale, isProtected,
-                             captureResults, displayState, layers, layerFEs);
+            renderScreenImpl(renderArea.get(), buffer, regionSampling, grayscale, isProtected,
+                             attachGainmap, captureResults, displayState, layers, layerFEs);
+
+    if (captureResults.capturedHdrLayers && attachGainmap &&
+        FlagManager::getInstance().true_hdr_screenshots()) {
+        sp<GraphicBuffer> hdrBuffer =
+                getFactory().createGraphicBuffer(buffer->getWidth(), buffer->getHeight(),
+                                                 HAL_PIXEL_FORMAT_RGBA_FP16, 1 /* layerCount */,
+                                                 buffer->getUsage(), "screenshot-hdr");
+        sp<GraphicBuffer> gainmapBuffer =
+                getFactory().createGraphicBuffer(buffer->getWidth(), buffer->getHeight(),
+                                                 buffer->getPixelFormat(), 1 /* layerCount */,
+                                                 buffer->getUsage(), "screenshot-gainmap");
+
+        const status_t bufferStatus = hdrBuffer->initCheck();
+        const status_t gainmapBufferStatus = gainmapBuffer->initCheck();
+
+        if (bufferStatus != OK) {
+            ALOGW("%s: Buffer failed to allocate for hdr: %d. Screenshoting SDR instead.", __func__,
+                  bufferStatus);
+        } else if (gainmapBufferStatus != OK) {
+            ALOGW("%s: Buffer failed to allocate for gainmap: %d. Screenshoting SDR instead.",
+                  __func__, gainmapBufferStatus);
+        } else {
+            captureResults.optionalGainMap = gainmapBuffer;
+            const auto hdrTexture = std::make_shared<
+                    renderengine::impl::ExternalTexture>(hdrBuffer, getRenderEngine(),
+                                                         renderengine::impl::ExternalTexture::
+                                                                 Usage::WRITEABLE);
+            const auto gainmapTexture = std::make_shared<
+                    renderengine::impl::ExternalTexture>(gainmapBuffer, getRenderEngine(),
+                                                         renderengine::impl::ExternalTexture::
+                                                                 Usage::WRITEABLE);
+            ScreenCaptureResults unusedResults;
+            ftl::SharedFuture<FenceResult> hdrRenderFuture =
+                    renderScreenImpl(renderArea.get(), hdrTexture, regionSampling, grayscale,
+                                     isProtected, attachGainmap, unusedResults, displayState,
+                                     layers, layerFEs);
+
+            renderFuture =
+                    ftl::Future(std::move(renderFuture))
+                            .then([&, hdrRenderFuture = std::move(hdrRenderFuture),
+                                   displayBrightnessNits, sdrWhitePointNits,
+                                   dataspace = captureResults.capturedDataspace, buffer, hdrTexture,
+                                   gainmapTexture](FenceResult fenceResult) -> FenceResult {
+                                if (!fenceResult.ok()) {
+                                    return fenceResult;
+                                }
+
+                                auto hdrFenceResult = hdrRenderFuture.get();
+
+                                if (!hdrFenceResult.ok()) {
+                                    return hdrFenceResult;
+                                }
+
+                                return getRenderEngine()
+                                        .drawGainmap(buffer, fenceResult.value()->get(), hdrTexture,
+                                                     hdrFenceResult.value()->get(),
+                                                     displayBrightnessNits / sdrWhitePointNits,
+                                                     static_cast<ui::Dataspace>(dataspace),
+                                                     gainmapTexture)
+                                        .get();
+                            })
+                            .share();
+        };
+    }
 
     if (captureListener) {
         // Defer blocking on renderFuture back to the Binder thread.
         return ftl::Future(std::move(renderFuture))
-                .then([captureListener, captureResults = std::move(captureResults)](
-                              FenceResult fenceResult) mutable -> FenceResult {
+                .then([captureListener, captureResults = std::move(captureResults),
+                       displayBrightnessNits,
+                       sdrWhitePointNits](FenceResult fenceResult) mutable -> FenceResult {
                     captureResults.fenceResult = std::move(fenceResult);
+                    captureResults.hdrSdrRatio = displayBrightnessNits / sdrWhitePointNits;
                     captureListener->onScreenCaptureCompleted(captureResults);
                     return base::unexpected(NO_ERROR);
                 })
@@ -7459,7 +7530,8 @@
 ftl::SharedFuture<FenceResult> SurfaceFlinger::captureScreenshotLegacy(
         RenderAreaBuilderVariant renderAreaBuilder, GetLayerSnapshotsFunction getLayerSnapshotsFn,
         const std::shared_ptr<renderengine::ExternalTexture>& buffer, bool regionSampling,
-        bool grayscale, bool isProtected, const sp<IScreenCaptureListener>& captureListener) {
+        bool grayscale, bool isProtected, bool attachGainmap,
+        const sp<IScreenCaptureListener>& captureListener) {
     SFTRACE_CALL();
 
     auto takeScreenshotFn = [=, this, renderAreaBuilder = std::move(renderAreaBuilder)]() REQUIRES(
@@ -7488,8 +7560,8 @@
 
         auto layerFEs = extractLayerFEs(layers);
         ftl::SharedFuture<FenceResult> renderFuture =
-                renderScreenImpl(std::move(renderArea), buffer, regionSampling, grayscale,
-                                 isProtected, captureResults, displayState, layers, layerFEs);
+                renderScreenImpl(renderArea.get(), buffer, regionSampling, grayscale, isProtected,
+                                 attachGainmap, captureResults, displayState, layers, layerFEs);
 
         if (captureListener) {
             // Defer blocking on renderFuture back to the Binder thread.
@@ -7519,10 +7591,9 @@
 }
 
 ftl::SharedFuture<FenceResult> SurfaceFlinger::renderScreenImpl(
-        std::unique_ptr<const RenderArea> renderArea,
-        const std::shared_ptr<renderengine::ExternalTexture>& buffer, bool regionSampling,
-        bool grayscale, bool isProtected, ScreenCaptureResults& captureResults,
-        std::optional<OutputCompositionState>& displayState,
+        const RenderArea* renderArea, const std::shared_ptr<renderengine::ExternalTexture>& buffer,
+        bool regionSampling, bool grayscale, bool isProtected, bool attachGainmap,
+        ScreenCaptureResults& captureResults, std::optional<OutputCompositionState>& displayState,
         std::vector<std::pair<Layer*, sp<LayerFE>>>& layers, std::vector<sp<LayerFE>>& layerFEs) {
     SFTRACE_CALL();