From 6213bd900145b9189c7d87aec8a2714a66c8d057 Mon Sep 17 00:00:00 2001
From: Vishnu Nair <vishnun@google.com>
Date: Fri, 8 May 2020 17:42:25 -0700
Subject: Provide a fixed transform hint if the layer is in a fixed orientation
 1/2

The transform hint is used to prevent allocating a buffer of a
different size when a layer is rotated. The producer can choose to
consume the hint and allocate the buffer with the same size.

Provide the graphic producer a transform hint if the layer and its
children are in an orientation different from the display's
orientation. The caller is responsible for clearing this transform
hint if the layer is no longer in a fixed orientation.

Bug: 152919661
Test: atest VulkanPreTransformTest
Test: confirm with winscope trace, buffers are allocated taking into
account the transform hint in fixed orientation scenarios
Test: go/wm-smoke

Change-Id: Iea9dcf909921802a5be5c44dd61be3274f36bbd8
---
 services/surfaceflinger/Layer.cpp | 33 ++++++++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 5 deletions(-)

(limited to 'services/surfaceflinger/Layer.cpp')

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 752407aedc..25929ed1d7 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -117,6 +117,7 @@ Layer::Layer(const LayerCreationArgs& args)
     mCurrentState.metadata = args.metadata;
     mCurrentState.shadowRadius = 0.f;
     mCurrentState.treeHasFrameRateVote = false;
+    mCurrentState.fixedTransformHint = ui::Transform::ROT_INVALID;
 
     // drawing state & current state are identical
     mDrawingState = mCurrentState;
@@ -1333,6 +1334,18 @@ bool Layer::setShadowRadius(float shadowRadius) {
     return true;
 }
 
+bool Layer::setFixedTransformHint(ui::Transform::RotationFlags fixedTransformHint) {
+    if (mCurrentState.fixedTransformHint == fixedTransformHint) {
+        return false;
+    }
+
+    mCurrentState.sequence++;
+    mCurrentState.fixedTransformHint = fixedTransformHint;
+    mCurrentState.modified = true;
+    setTransactionFlags(eTransactionNeeded);
+    return true;
+}
+
 void Layer::updateTreeHasFrameRateVote() {
     const auto traverseTree = [&](const LayerVector::Visitor& visitor) {
         auto parent = getParent();
@@ -1460,19 +1473,19 @@ uint32_t Layer::getEffectiveUsage(uint32_t usage) const {
 }
 
 void Layer::updateTransformHint(const sp<const DisplayDevice>& display) const {
-    uint32_t orientation = 0;
+    ui::Transform::RotationFlags transformHint = ui::Transform::ROT_0;
     // Disable setting transform hint if the debug flag is set.
     if (!mFlinger->mDebugDisableTransformHint) {
         // The transform hint is used to improve performance, but we can
         // only have a single transform hint, it cannot
         // apply to all displays.
         const ui::Transform& planeTransform = display->getTransform();
-        orientation = planeTransform.getOrientation();
-        if (orientation & ui::Transform::ROT_INVALID) {
-            orientation = 0;
+        transformHint = static_cast<ui::Transform::RotationFlags>(planeTransform.getOrientation());
+        if (transformHint & ui::Transform::ROT_INVALID) {
+            transformHint = ui::Transform::ROT_0;
         }
     }
-    setTransformHint(orientation);
+    setTransformHint(transformHint);
 }
 
 // ----------------------------------------------------------------------------
@@ -2076,6 +2089,16 @@ half Layer::getAlpha() const {
     return parentAlpha * getDrawingState().color.a;
 }
 
+ui::Transform::RotationFlags Layer::getFixedTransformHint() const {
+    ui::Transform::RotationFlags fixedTransformHint = mCurrentState.fixedTransformHint;
+    if (fixedTransformHint != ui::Transform::ROT_INVALID) {
+        return fixedTransformHint;
+    }
+    const auto& p = mCurrentParent.promote();
+    if (!p) return fixedTransformHint;
+    return p->getFixedTransformHint();
+}
+
 half4 Layer::getColor() const {
     const half4 color(getDrawingState().color);
     return half4(color.r, color.g, color.b, getAlpha());
-- 
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