Fix empty region if the scale is smaller than 1

It may be used by Layer of SurfaceFlinger to calculate
touchable region. It should be able to scale a window
to a smaller size.

Bug: 111440400
Test: manual - An input-associated surface with a scaling
      matrix that has dsdx, dsdy < 1. Use "dumpsys input"
      to observe its touchable region.

Change-Id: I495bd16acec77f913fd39dcac90404eddc71cabb

1 files changed, 7 insertions, 4 deletions

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 81456dfea9..58fd86618e 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -2069,10 +2069,13 @@ InputWindowInfo Layer::fillInputInfo(const Rect& screenBounds) {
     info.frameBottom = screenBounds.bottom - info.surfaceInset;
 
     ui::Transform t = getTransform();
-    info.windowXScale *= 1.0f / t.sx();
-    info.windowYScale *= 1.0f / t.sy();
-
-    info.touchableRegion.scaleSelf(t.sx(), t.sy());
+    const float xScale = t.sx();
+    const float yScale = t.sy();
+    if (xScale != 1.0f || yScale != 1.0f) {
+        info.windowXScale *= 1.0f / xScale;
+        info.windowYScale *= 1.0f / yScale;
+        info.touchableRegion.scaleSelf(xScale, yScale);
+    }
 
     info.touchableRegion = info.touchableRegion.translate(
             screenBounds.left,