commit b4814de15685275e1c57b6a5250418fd6ffddd60
author Alec Mouri <alecmouri@google.com> Mon Sep 11 22:09:03 2023 +0000
committer Alec Mouri <alecmouri@google.com> Tue Sep 12 21:44:31 2023 +0000
tree 5cda403b82ffa33ced1206e06200e84f8b0900f1
parent ce9c53fe99d19acb7d3e1251c42eb7c5329e8ac2

Don't dim screenshots when there's no HDR on-screen.

Dimming the screenshot:
* Is incorrect for screenshots that leave the device
* For transitions, requires disabling dimming which reports to DisplayManager that the screenshot is HDR, which costs power.

Bug: 293560925
Bug: 298492174
Bug: 299055884
Flag: Exempt
Test: screen rotation with and without HDR
Test: systemui jank suite
Change-Id: Id6de2c8d3987300a1c24bf79dc5b523f40420174

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 38dc435..6187537 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -7678,6 +7678,7 @@
     ATRACE_CALL();
 
     auto layers = getLayerSnapshots();
+
     for (auto& [_, layerFE] : layers) {
         frontend::LayerSnapshot* snapshot = layerFE->mSnapshot.get();
         captureResults.capturedSecureLayers |= (snapshot->isVisible && snapshot->isSecure);
@@ -7729,20 +7730,29 @@
                     pickBestDataspace(requestedDataspace, display, captureResults.capturedHdrLayers,
                                       renderArea->getHintForSeamlessTransition());
             sdrWhitePointNits = state.sdrWhitePointNits;
-            displayBrightnessNits = state.displayBrightnessNits;
-            // Only clamp the display brightness if this is not a seamless transition. Otherwise
-            // for seamless transitions it's important to match the current display state as the
-            // buffer will be shown under these same conditions, and we want to avoid any flickers
-            if (sdrWhitePointNits > 1.0f && !renderArea->getHintForSeamlessTransition()) {
-                // Restrict the amount of HDR "headroom" in the screenshot to avoid over-dimming
-                // the SDR portion. 2.0 chosen by experimentation
-                constexpr float kMaxScreenshotHeadroom = 2.0f;
-                displayBrightnessNits =
-                        std::min(sdrWhitePointNits * kMaxScreenshotHeadroom, displayBrightnessNits);
-            }
 
-            if (requestedDataspace == ui::Dataspace::UNKNOWN) {
-                renderIntent = state.renderIntent;
+             // TODO(b/298219334): Clean this up once we verify this doesn't break anything
+             static constexpr bool kScreenshotsDontDim = true;
+
+            if (kScreenshotsDontDim && !captureResults.capturedHdrLayers) {
+                displayBrightnessNits = sdrWhitePointNits;
+            } else {
+                displayBrightnessNits = state.displayBrightnessNits;
+                // Only clamp the display brightness if this is not a seamless transition. Otherwise
+                // for seamless transitions it's important to match the current display state as the
+                // buffer will be shown under these same conditions, and we want to avoid any
+                // flickers
+                if (sdrWhitePointNits > 1.0f && !renderArea->getHintForSeamlessTransition()) {
+                    // Restrict the amount of HDR "headroom" in the screenshot to avoid over-dimming
+                    // the SDR portion. 2.0 chosen by experimentation
+                    constexpr float kMaxScreenshotHeadroom = 2.0f;
+                    displayBrightnessNits = std::min(sdrWhitePointNits * kMaxScreenshotHeadroom,
+                                                     displayBrightnessNits);
+                }
+
+                if (requestedDataspace == ui::Dataspace::UNKNOWN) {
+                    renderIntent = state.renderIntent;
+                }
             }
         }
     }