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

The problem wasn't in the multiply operator, but rather in the code
that built the transform from the HAL bitmask.

We now use the multiply operator to build the Transform from the bitmask,
which guarantees, it'll always be correct.

Also added a simple test for Transform.

Change-Id: I09bf3b0e51d92f59d83ea91c4cc94fc2aa0bf227

services/surfaceflinger/Transform.cpp

@@ -159,56 +159,32 @@ status_t Transform::set(uint32_t flags, float w, float h)
         return BAD_VALUE;
     }
 
-    mType = flags << 8;
-    float sx = (flags & FLIP_H) ? -1 : 1;
-    float sy = (flags & FLIP_V) ? -1 : 1;
-    float a=0, b=0, c=0, d=0, x=0, y=0;
-    int xmask = 0;
-
-    // computation of x,y
-    // x y
-    // 0 0  0
-    // w 0  ROT90
-    // w h  FLIPH|FLIPV
-    // 0 h  FLIPH|FLIPV|ROT90
-
-    if (flags & ROT_90) {
-        mType |= ROTATE;
-        b = -sy;
-        c = sx;
-        xmask = 1;
-    } else {
-        a = sx;
-        d = sy;
-    }
-
+    Transform H, V, R;
     if (flags & FLIP_H) {
-        mType ^= SCALE;
-        xmask ^= 1;
+        H.mType = (FLIP_H << 8) | SCALE;
+        H.mType |= isZero(w) ? IDENTITY : TRANSLATE;
+        mat33& M(H.mMatrix);
+        M[0][0] = -1;
+        M[2][0] = w;
     }
 
     if (flags & FLIP_V) {
-        mType ^= SCALE;
-        y = h;
+        V.mType = (FLIP_V << 8) | SCALE;
+        V.mType |= isZero(h) ? IDENTITY : TRANSLATE;
+        mat33& M(V.mMatrix);
+        M[1][1] = -1;
+        M[2][1] = h;
     }
 
-    if ((flags & ROT_180) == ROT_180) {
-        mType |= ROTATE;
+    if (flags & ROT_90) {
+        R.mType = (ROT_90 << 8) | ROTATE;
+        R.mType |= isZero(w) ? IDENTITY : TRANSLATE;
+        mat33& M(R.mMatrix);
+        M[0][0] = 0;    M[1][0] =-1;    M[2][0] = w;
+        M[0][1] = 1;    M[1][1] = 0;
     }
 
-    if (xmask) {
-        x = w;
-    }
-
-    if (!isZero(x) || !isZero(y)) {
-        mType |= TRANSLATE;
-    }
-
-    mat33& M(mMatrix);
-    M[0][0] = a;    M[1][0] = b;    M[2][0] = x;
-    M[0][1] = c;    M[1][1] = d;    M[2][1] = y;
-    M[0][2] = 0;    M[1][2] = 0;    M[2][2] = 1;
-
+    *this = ((H*V)*R);
     return NO_ERROR;
 }
 

services/surfaceflinger/Transform.h

@@ -23,6 +23,8 @@
 #include <ui/Point.h>
 #include <ui/Rect.h>
 
+#include <hardware/hardware.h>
+
 namespace android {
 
 class Region;
@@ -37,12 +39,11 @@ public:
            explicit Transform(uint32_t orientation);
                     ~Transform();
 
-            // FIXME: must match OVERLAY_TRANSFORM_*, pull from hardware.h
             enum orientation_flags {
                 ROT_0   = 0x00000000,
-                FLIP_H  = 0x00000001,
-                FLIP_V  = 0x00000002,
-                ROT_90  = 0x00000004,
+                FLIP_H  = HAL_TRANSFORM_FLIP_H,
+                FLIP_V  = HAL_TRANSFORM_FLIP_V,
+                ROT_90  = HAL_TRANSFORM_ROT_90,
                 ROT_180 = FLIP_H|FLIP_V,
                 ROT_270 = ROT_180|ROT_90,
                 ROT_INVALID = 0x80

services/surfaceflinger/tests/transform/Android.mk

@@ -0,0 +1,19 @@
+LOCAL_PATH:= $(call my-dir)
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES:= \
+	TransformTest.cpp \
+	../../Transform.cpp
+
+LOCAL_SHARED_LIBRARIES := \
+	libcutils \
+	libutils \
+	libui \
+
+LOCAL_MODULE:= test-transform
+
+LOCAL_MODULE_TAGS := tests
+
+LOCAL_C_INCLUDES += ../..
+
+include $(BUILD_EXECUTABLE)

services/surfaceflinger/tests/transform/TransformTest.cpp

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <utils/Errors.h>
+#include "../../Transform.h"
+
+using namespace android;
+
+int main(int argc, char **argv)
+{
+    Transform tr90(Transform::ROT_90);
+    Transform trFH(Transform::FLIP_H);
+    Transform trFV(Transform::FLIP_V);
+
+    Transform tr90FH(Transform::ROT_90 | Transform::FLIP_H);
+    Transform tr90FV(Transform::ROT_90 | Transform::FLIP_V);
+
+    tr90.dump("tr90");
+    trFH.dump("trFH");
+    trFV.dump("trFV");
+
+    tr90FH.dump("tr90FH");
+    tr90FV.dump("tr90FV");
+
+    (trFH*tr90).dump("trFH*tr90");
+    (trFV*tr90).dump("trFV*tr90");
+
+    (tr90*trFH).dump("tr90*trFH");
+    (tr90*trFV).dump("tr90*trFV");
+
+    return 0;
+}