Merge "Add clamp to Layer and update Transform inverse." into lmp-mr1-dev

2 files changed, 29 insertions, 17 deletions

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index c3e1a76..5e3dfab 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -332,8 +332,12 @@ FloatRect Layer::computeCrop(const sp<const DisplayDevice>& hw) const {
     activeCrop.intersect(hw->getViewport(), &activeCrop);
     activeCrop = s.transform.inverse().transform(activeCrop);
 
-    // paranoia: make sure the window-crop is constrained in the
-    // window's bounds
+    // This needs to be here as transform.transform(Rect) computes the
+    // transformed rect and then takes the bounding box of the result before
+    // returning. This means
+    // transform.inverse().transform(transform.transform(Rect)) != Rect
+    // in which case we need to make sure the final rect is clipped to the
+    // display bounds.
     activeCrop.intersect(Rect(s.active.w, s.active.h), &activeCrop);
 
     // subtract the transparent region and snap to the bounds
@@ -432,6 +436,13 @@ void Layer::setGeometry(
         activeCrop = s.transform.transform(activeCrop);
         activeCrop.intersect(hw->getViewport(), &activeCrop);
         activeCrop = s.transform.inverse().transform(activeCrop);
+        // This needs to be here as transform.transform(Rect) computes the
+        // transformed rect and then takes the bounding box of the result before
+        // returning. This means
+        // transform.inverse().transform(transform.transform(Rect)) != Rect
+        // in which case we need to make sure the final rect is clipped to the
+        // display bounds.
+        activeCrop.intersect(Rect(s.active.w, s.active.h), &activeCrop);
         // mark regions outside the crop as transparent
         activeTransparentRegion.orSelf(Rect(0, 0, s.active.w, activeCrop.top));
         activeTransparentRegion.orSelf(Rect(0, activeCrop.bottom,
diff --git a/services/surfaceflinger/Transform.cpp b/services/surfaceflinger/Transform.cpp
index 3456abf..35e7e7d 100644
--- a/services/surfaceflinger/Transform.cpp
+++ b/services/surfaceflinger/Transform.cpp
@@ -301,16 +301,16 @@ Transform Transform::inverse() const {
     // (T*M)^-1 = M^-1 * T^-1
     Transform result;
     if (mType <= TRANSLATE) {
-        // 1 0 x
-        // 0 1 y
-        // 0 0 1
+        // 1 0 0
+        // 0 1 0
+        // x y 1
         result = *this;
         result.mMatrix[2][0] = -result.mMatrix[2][0];
         result.mMatrix[2][1] = -result.mMatrix[2][1];
     } else {
-        // a c x
-        // b d y
-        // 0 0 1
+        // a c 0
+        // b d 0
+        // x y 1
         const mat33& M(mMatrix);
         const float a = M[0][0];
         const float b = M[1][0];
@@ -319,16 +319,17 @@ Transform Transform::inverse() const {
         const float x = M[2][0];
         const float y = M[2][1];
 
-        Transform R, T;
         const float idet = 1.0 / (a*d - b*c);
-        R.mMatrix[0][0] =  d*idet;    R.mMatrix[0][1] = -c*idet;
-        R.mMatrix[1][0] = -b*idet;    R.mMatrix[1][1] =  a*idet;
-        R.mType = mType &= ~TRANSLATE;
-
-        T.mMatrix[2][0] = -x;
-        T.mMatrix[2][1] = -y;
-        T.mType = TRANSLATE;
-        result =  R * T;
+        result.mMatrix[0][0] =  d*idet;
+        result.mMatrix[0][1] = -c*idet;
+        result.mMatrix[1][0] = -b*idet;
+        result.mMatrix[1][1] =  a*idet;
+        result.mType = mType;
+
+        vec2 T(-x, -y);
+        T = result.transform(T);
+        result.mMatrix[2][0] = T[0];
+        result.mMatrix[2][1] = T[1];
     }
     return result;
 }