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

1 files changed, 16 insertions, 0 deletions

diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index a52f298e77..5922f3a876 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -1437,6 +1437,22 @@ SurfaceComposerClient::Transaction& SurfaceComposerClient::Transaction::setFrame
     return *this;
 }
 
+SurfaceComposerClient::Transaction& SurfaceComposerClient::Transaction::setFixedTransformHint(
+        const sp<SurfaceControl>& sc, int32_t fixedTransformHint) {
+    layer_state_t* s = getLayerState(sc);
+    if (!s) {
+        mStatus = BAD_INDEX;
+        return *this;
+    }
+
+    const ui::Transform::RotationFlags transform = fixedTransformHint == -1
+            ? ui::Transform::ROT_INVALID
+            : ui::Transform::toRotationFlags(static_cast<ui::Rotation>(fixedTransformHint));
+    s->what |= layer_state_t::eFixedTransformHintChanged;
+    s->fixedTransformHint = transform;
+    return *this;
+}
+
 // ---------------------------------------------------------------------------
 
 DisplayState& SurfaceComposerClient::Transaction::getDisplayState(const sp<IBinder>& token) {