Merge "SurfaceFlinger: Inherit non-transform Scaling from parent." into oc-dev am: 08260b881a
am: 6bbe40abf9

Change-Id: Ifb0f16bf0484e0f7cfa58a93f1e94dab4f123f04
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index ef4c7b1..15accc8 100755
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -2617,6 +2617,21 @@
     const auto& p = getParent();
     if (p != nullptr) {
         t = p->getTransform();
+
+        // If the parent is not using NATIVE_WINDOW_SCALING_MODE_FREEZE (e.g.
+        // it isFixedSize) then there may be additional scaling not accounted
+        // for in the transform. We need to mirror this scaling in child surfaces
+        // or we will break the contract where WM can treat child surfaces as
+        // pixels in the parent surface.
+        if (p->isFixedSize()) {
+            float sx = p->getDrawingState().active.w /
+                    static_cast<float>(p->mActiveBuffer->getWidth());
+            float sy = p->getDrawingState().active.h /
+                    static_cast<float>(p->mActiveBuffer->getHeight());
+            Transform extraParentScaling;
+            extraParentScaling.set(sx, 0, 0, sy);
+            t = t * extraParentScaling;
+        }
     }
     return t * getDrawingState().active.transform;
 }
diff --git a/services/surfaceflinger/tests/Transaction_test.cpp b/services/surfaceflinger/tests/Transaction_test.cpp
index 441fc7e..7a8b4ab 100644
--- a/services/surfaceflinger/tests/Transaction_test.cpp
+++ b/services/surfaceflinger/tests/Transaction_test.cpp
@@ -909,4 +909,36 @@
     }
 }
 
+TEST_F(ChildLayerTest, ChildrenInheritNonTransformScalingFromParent) {
+    SurfaceComposerClient::openGlobalTransaction();
+    mChild->show();
+    mChild->setPosition(0, 0);
+    mFGSurfaceControl->setPosition(0, 0);
+    SurfaceComposerClient::closeGlobalTransaction(true);
+
+    {
+        ScreenCapture::captureScreen(&mCapture);
+        // We've positioned the child in the top left.
+        mCapture->expectChildColor(0, 0);
+        // But it's only 10x10.
+        mCapture->expectFGColor(10, 10);
+    }
+
+    SurfaceComposerClient::openGlobalTransaction();
+    mFGSurfaceControl->setOverrideScalingMode(NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW);
+    // We cause scaling by 2.
+    mFGSurfaceControl->setSize(128, 128);
+    SurfaceComposerClient::closeGlobalTransaction();
+
+    {
+        ScreenCapture::captureScreen(&mCapture);
+        // We've positioned the child in the top left.
+        mCapture->expectChildColor(0, 0);
+        mCapture->expectChildColor(10, 10);
+        mCapture->expectChildColor(19, 19);
+        // And now it should be scaled all the way to 20x20
+        mCapture->expectFGColor(20, 20);
+    }
+}
+
 }