SurfaceFlinger: add a crop to the layer state

This change adds a crop rectangle specified in window coordinates to the layer
state.  The all window pixels outside this crop rectangle are treated as though
they were fully transparent.  This change also adds the plumbing necessary for
WindowManager to set that crop.

Change-Id: I582bc445dc8c97d4c943d4db8d582a6ef5a66081
diff --git a/include/gui/ISurfaceComposer.h b/include/gui/ISurfaceComposer.h
index f3c0ecb..7320e4d 100644
--- a/include/gui/ISurfaceComposer.h
+++ b/include/gui/ISurfaceComposer.h
@@ -67,6 +67,7 @@
         eTransparentRegionChanged   = 0x00000020,
         eVisibilityChanged          = 0x00000040,
         eFreezeTintChanged          = 0x00000080,
+        eCropChanged                = 0x00000100,
     };
 
     enum {
diff --git a/include/gui/Surface.h b/include/gui/Surface.h
index 1f90c59..50bdf71 100644
--- a/include/gui/Surface.h
+++ b/include/gui/Surface.h
@@ -72,6 +72,7 @@
     status_t    setAlpha(float alpha=1.0f);
     status_t    setMatrix(float dsdx, float dtdx, float dsdy, float dtdy);
     status_t    setFreezeTint(uint32_t tint);
+    status_t    setCrop(const Rect& crop);
 
     static status_t writeSurfaceToParcel(
             const sp<SurfaceControl>& control, Parcel* parcel);
diff --git a/include/gui/SurfaceComposerClient.h b/include/gui/SurfaceComposerClient.h
index d971031..3bd10de 100644
--- a/include/gui/SurfaceComposerClient.h
+++ b/include/gui/SurfaceComposerClient.h
@@ -127,6 +127,7 @@
     status_t    setMatrix(SurfaceID id, float dsdx, float dtdx, float dsdy, float dtdy);
     status_t    setPosition(SurfaceID id, float x, float y);
     status_t    setSize(SurfaceID id, uint32_t w, uint32_t h);
+    status_t    setCrop(SurfaceID id, const Rect& crop);
     status_t    destroySurface(SurfaceID sid);
 
 private:
diff --git a/include/private/gui/LayerState.h b/include/private/gui/LayerState.h
index ca277e0..9151c11 100644
--- a/include/private/gui/LayerState.h
+++ b/include/private/gui/LayerState.h
@@ -23,6 +23,7 @@
 #include <utils/Errors.h>
 
 #include <ui/Region.h>
+#include <ui/Rect.h>
 #include <gui/ISurface.h>
 
 namespace android {
@@ -40,6 +41,7 @@
     {
         matrix.dsdx = matrix.dtdy = 1.0f;
         matrix.dsdy = matrix.dtdx = 0.0f;
+        crop.makeInvalid();
     }
 
     status_t    write(Parcel& output) const;
@@ -64,6 +66,7 @@
             uint8_t         mask;
             uint8_t         reserved;
             matrix22_t      matrix;
+            Rect            crop;
             // non POD must be last. see write/read
             Region          transparentRegion;
 };
diff --git a/include/ui/Rect.h b/include/ui/Rect.h
index bd82061..308da7b 100644
--- a/include/ui/Rect.h
+++ b/include/ui/Rect.h
@@ -147,7 +147,7 @@
     // a ROT90 then the output rectangle is defined in a space extending to
     // (height, width).  Otherwise the output rectangle is in the same space as
     // the input.
-    Rect transform(uint32_t xform, int32_t width, int32_t height);
+    Rect transform(uint32_t xform, int32_t width, int32_t height) const;
 };
 
 ANDROID_BASIC_TYPES_TRAITS(Rect)