Fix brightness change during screenrotation

When doing a layer capture for seamless transitions
avoid clamping the max HDR headroom.

Fixes: 288063548
Test: repro steps in bug
Change-Id: Ic90c8b4478ad90b1776c455cbe696ec22182496d
(cherry picked from commit 1dadaa6b78f2939e717451303cd29d8f683e5f08)

1 files changed, 4 insertions, 1 deletions

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 1c646869a5..f4f4bccc7e 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -7424,7 +7424,10 @@ ftl::SharedFuture<FenceResult> SurfaceFlinger::renderScreenImpl(
                                       renderArea->getHintForSeamlessTransition());
             sdrWhitePointNits = state.sdrWhitePointNits;
             displayBrightnessNits = state.displayBrightnessNits;
-            if (sdrWhitePointNits > 1.0f) {
+            // 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;