implement display projection clipping in h/w composer
- cropping to the projection's "viewport" is "simply"
accomplished by intersecting it with the window crop
expressed in layerstack space.
Bug: 7149437
Change-Id: I0e90b3f37945292314b5d78a8f134935967e8053
diff --git a/services/surfaceflinger/Transform.cpp b/services/surfaceflinger/Transform.cpp
index aca90e0..315720e 100644
--- a/services/surfaceflinger/Transform.cpp
+++ b/services/surfaceflinger/Transform.cpp
@@ -298,6 +298,44 @@
return mType;
}
+Transform Transform::inverse() const {
+ // our 3x3 matrix is always of the form of a 2x2 transformation
+ // followed by a translation: T*M, therefore:
+ // (T*M)^-1 = M^-1 * T^-1
+ Transform result;
+ if (mType <= TRANSLATE) {
+ // 1 0 x
+ // 0 1 y
+ // 0 0 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
+ const mat33& M(mMatrix);
+ const float a = M[0][0];
+ const float b = M[1][0];
+ const float c = M[0][1];
+ const float d = M[1][1];
+ 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;
+ }
+ return result;
+}
+
uint32_t Transform::getType() const {
return type() & 0xFF;
}