Hide layers that have irreversible transforms
Surface API doesn't prohibit putting interesting values in transforms.
It's especially possible to scale something to 0 at the begining or the
end of an animation, but we should guard SF against ill-intentioned
apps.
Bug: 210837722
Test: KeyguardTests#testDismissKeyguardActivity doesn't crash SF on CF
PC and the warning log is in logcat.
Change-Id: Idaa1cdb0676102a580c4478c860327796c8213f3
diff --git a/libs/ui/Transform.cpp b/libs/ui/Transform.cpp
index b34d906..42dd85e 100644
--- a/libs/ui/Transform.cpp
+++ b/libs/ui/Transform.cpp
@@ -134,6 +134,10 @@
return mMatrix[1][1];
}
+float Transform::det() const {
+ return mMatrix[0][0] * mMatrix[1][1] - mMatrix[0][1] * mMatrix[1][0];
+}
+
float Transform::getScaleX() const {
return sqrt((dsdx() * dsdx()) + (dtdx() * dtdx()));
}
@@ -390,7 +394,7 @@
const float x = M[2][0];
const float y = M[2][1];
- const float idet = 1.0f / (a*d - b*c);
+ const float idet = 1.0f / det();
result.mMatrix[0][0] = d*idet;
result.mMatrix[0][1] = -c*idet;
result.mMatrix[1][0] = -b*idet;