commit 883dffaa0095ac9ac2be70915f620af9f429dc4b
author Mathias Agopian <mathias@google.com> Mon Oct 25 18:29:35 2010 -0700
committer Mathias Agopian <mathias@google.com> Wed Oct 27 18:04:11 2010 -0700
tree 710a42b881befb78a0ecb2c5143602331e06c7ef
parent 069ba0b5f24d5e42b6cde863baf0304c08b21f06

really fix [3118445] Transform * Transform does not work as expected

Two bugs were counter acting each other.
- rotation matrices are on the left-hand side of multiplies
- the transform of the overlay is applied before that of the layer

Change-Id: Ia79bd368e9b719235c89ecf244ea263f01ce906a

services/surfaceflinger/Transform.cpp

diff --git a/services/surfaceflinger/Transform.cpp b/services/surfaceflinger/Transform.cpp
index f128429..0467a14 100644
--- a/services/surfaceflinger/Transform.cpp
+++ b/services/surfaceflinger/Transform.cpp
@@ -28,26 +28,40 @@
 
 // ---------------------------------------------------------------------------
 
-template <typename T> inline T min(T a, T b) {
+template <typename T>
+static inline T min(T a, T b) {
     return a<b ? a : b;
 }
-template <typename T> inline T min(T a, T b, T c) {
+template <typename T>
+static inline T min(T a, T b, T c) {
     return min(a, min(b, c));
 }
-template <typename T> inline T min(T a, T b, T c, T d) {
+template <typename T>
+static inline T min(T a, T b, T c, T d) {
     return min(a, b, min(c, d));
 }
 
-template <typename T> inline T max(T a, T b) {
+template <typename T>
+static inline T max(T a, T b) {
     return a>b ? a : b;
 }
-template <typename T> inline T max(T a, T b, T c) {
+template <typename T>
+static inline T max(T a, T b, T c) {
     return max(a, max(b, c));
 }
-template <typename T> inline T max(T a, T b, T c, T d) {
+template <typename T>
+static inline T max(T a, T b, T c, T d) {
     return max(a, b, max(c, d));
 }
 
+template <typename T>
+static inline
+void swap(T& a, T& b) {
+    T t(a);
+    a = b;
+    b = t;
+}
+
 // ---------------------------------------------------------------------------
 
 Transform::Transform() {
@@ -160,6 +174,11 @@
     }
 
     Transform H, V, R;
+    if (flags & ROT_90) {
+        // w & h are inverted when rotating by 90 degrees
+        swap(w, h);
+    }
+
     if (flags & FLIP_H) {
         H.mType = (FLIP_H << 8) | SCALE;
         H.mType |= isZero(w) ? IDENTITY : TRANSLATE;
@@ -177,14 +196,15 @@
     }
 
     if (flags & ROT_90) {
+        const float original_w = h;
         R.mType = (ROT_90 << 8) | ROTATE;
-        R.mType |= isZero(w) ? IDENTITY : TRANSLATE;
+        R.mType |= isZero(original_w) ? IDENTITY : TRANSLATE;
         mat33& M(R.mMatrix);
-        M[0][0] = 0;    M[1][0] =-1;    M[2][0] = w;
+        M[0][0] = 0;    M[1][0] =-1;    M[2][0] = original_w;
         M[0][1] = 1;    M[1][1] = 0;
     }
 
-    *this = ((H*V)*R);
+    *this = (R*(H*V));
     return NO_ERROR;
 }
 
@@ -282,8 +302,8 @@
             }
         } else if (isZero(a) && isZero(d)) {
             flags |= ROT_90;
-            if (b>0)    flags |= FLIP_H;
-            if (c<0)    flags |= FLIP_V;
+            if (b>0)    flags |= FLIP_V;
+            if (c<0)    flags |= FLIP_H;
             if (!absIsOne(b) || !absIsOne(c)) {
                 scale = true;
             }