commit 3e5965f3184a828a1b7ee2b5bd5d5c2177807a35
author Alec Mouri <alecmouri@google.com> Fri Apr 07 18:00:58 2023 +0000
committer Alec Mouri <alecmouri@google.com> Tue Apr 25 22:28:10 2023 +0000
tree 9e437e8f7ab0350753552acbf457c005a25e6e31
parent 8aedbf30dd4123c3050a040ce1c1b6e9d07b96ec

Support screenshots of HDR content

Previously screenshots always rendered to either an SDR or a wide gamut
colorspace. For screenshotting HDR content, this is only appropriate
when the resulting screenshot (a) never leaves the device and (b) the
relevant code has workarounds for the display to appropriately handle
its luminance range.

HDR screenshots will now have two paths:
* A standard path for rendering to HLG. HLG was chosen because the OOTF
  shape is less hand-wavey than PQ's, does not require metadata, and
  bands less at 8-bits of color.
* A special path for "display-native" screenshots. This is for
  use-cases like screen rotation where there are stricter color accuracy
  requirements for round-tripping.

Skia already encodes the resulting screenshot by supplying an HLG CICP
alongside a backwards-compatible transfer function, so it's only
sufficient to change how SurfaceFlinger renders.

Bug: 242324609
Bug: 276812775
Test: screencap binary
Test: rotation animation
Test: swiping in Recents
Change-Id: Ic9edb92391d3beb38d076fba8f15e3fdcc2b8f50

services/surfaceflinger/RenderArea.h

diff --git a/services/surfaceflinger/RenderArea.h b/services/surfaceflinger/RenderArea.h
index 910fce0..71b85bd 100644
--- a/services/surfaceflinger/RenderArea.h
+++ b/services/surfaceflinger/RenderArea.h
@@ -25,12 +25,14 @@
     static float getCaptureFillValue(CaptureFill captureFill);
 
     RenderArea(ui::Size reqSize, CaptureFill captureFill, ui::Dataspace reqDataSpace,
-               bool allowSecureLayers = false, RotationFlags rotation = ui::Transform::ROT_0)
+               bool hintForSeamlessTransition, bool allowSecureLayers = false,
+               RotationFlags rotation = ui::Transform::ROT_0)
           : mAllowSecureLayers(allowSecureLayers),
             mReqSize(reqSize),
             mReqDataSpace(reqDataSpace),
             mCaptureFill(captureFill),
-            mRotationFlags(rotation) {}
+            mRotationFlags(rotation),
+            mHintForSeamlessTransition(hintForSeamlessTransition) {}
 
     static std::function<std::vector<std::pair<Layer*, sp<LayerFE>>>()> fromTraverseLayersLambda(
             std::function<void(const LayerVector::Visitor&)> traverseLayers) {
@@ -90,6 +92,10 @@
     // capture operation.
     virtual sp<Layer> getParentLayer() const { return nullptr; }
 
+    // Returns whether the render result may be used for system animations that
+    // must preserve the exact colors of the display.
+    bool getHintForSeamlessTransition() const { return mHintForSeamlessTransition; }
+
 protected:
     const bool mAllowSecureLayers;
 
@@ -98,7 +104,7 @@
     const ui::Dataspace mReqDataSpace;
     const CaptureFill mCaptureFill;
     const RotationFlags mRotationFlags;
-    const Rect mLayerStackSpaceRect;
+    const bool mHintForSeamlessTransition;
 };
 
 } // namespace android