commit f15a83f5814219c167f87cb8aaea622fc8493499
author Jamie Gennis <jgennis@google.com> Thu May 10 20:43:55 2012 -0700
committer Jamie Gennis <jgennis@google.com> Fri May 11 03:16:02 2012 -0700
tree 131d3c92aa0f1e75b110b187b8ee6859be5d0bc5
parent f30fd01497a53cbff8692721026c3f7b6830158e

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

services/surfaceflinger/LayerBase.cpp

diff --git a/services/surfaceflinger/LayerBase.cpp b/services/surfaceflinger/LayerBase.cpp
index 694ecde..81031b1 100644
--- a/services/surfaceflinger/LayerBase.cpp
+++ b/services/surfaceflinger/LayerBase.cpp
@@ -93,6 +93,7 @@
     mCurrentState.flags         = layerFlags;
     mCurrentState.sequence      = 0;
     mCurrentState.transform.set(0, 0);
+    mCurrentState.crop.makeInvalid();
 
     // drawing state & current state are identical
     mDrawingState = mCurrentState;
@@ -172,6 +173,14 @@
     requestTransaction();
     return true;
 }
+bool LayerBase::setCrop(const Rect& crop) {
+    if (mCurrentState.crop == crop)
+        return false;
+    mCurrentState.sequence++;
+    mCurrentState.crop = crop;
+    requestTransaction();
+    return true;
+}
 
 Rect LayerBase::visibleBounds() const
 {
@@ -229,15 +238,18 @@
     const bool transformed = tr.transformed();
     const DisplayHardware& hw(graphicPlane(0).displayHardware());
     const uint32_t hw_h = hw.getHeight();
+    const Rect& crop(s.crop);
 
-    uint32_t w = s.w;
-    uint32_t h = s.h;
+    Rect win(s.w, s.h);
+    if (!crop.isEmpty()) {
+        win.intersect(crop, &win);
+    }
 
     mNumVertices = 4;
-    tr.transform(mVertices[0], 0, 0);
-    tr.transform(mVertices[1], 0, h);
-    tr.transform(mVertices[2], w, h);
-    tr.transform(mVertices[3], w, 0);
+    tr.transform(mVertices[0], win.left,  win.top);
+    tr.transform(mVertices[1], win.left,  win.bottom);
+    tr.transform(mVertices[2], win.right, win.bottom);
+    tr.transform(mVertices[3], win.right, win.top);
     for (size_t i=0 ; i<4 ; i++)
         mVertices[i][1] = hw_h - mVertices[i][1];
 
@@ -260,7 +272,7 @@
     mOrientation = tr.getOrientation();
     mPlaneOrientation = planeTransform.getOrientation();
     mTransform = tr;
-    mTransformedBounds = tr.makeBounds(w, h);
+    mTransformedBounds = tr.transform(win);
 }
 
 void LayerBase::lockPageFlip(bool& recomputeVisibleRegions) {
@@ -391,15 +403,27 @@
         GLfloat v;
     };
 
+    Rect crop(s.w, s.h);
+    if (!s.crop.isEmpty()) {
+        crop = s.crop;
+    }
+    GLfloat left = GLfloat(crop.left) / GLfloat(s.w);
+    GLfloat top = GLfloat(crop.top) / GLfloat(s.h);
+    GLfloat right = GLfloat(crop.right) / GLfloat(s.w);
+    GLfloat bottom = GLfloat(crop.bottom) / GLfloat(s.h);
+
     TexCoords texCoords[4];
-    texCoords[0].u = 0;
-    texCoords[0].v = 1;
-    texCoords[1].u = 0;
-    texCoords[1].v = 0;
-    texCoords[2].u = 1;
-    texCoords[2].v = 0;
-    texCoords[3].u = 1;
-    texCoords[3].v = 1;
+    texCoords[0].u = left;
+    texCoords[0].v = top;
+    texCoords[1].u = left;
+    texCoords[1].v = bottom;
+    texCoords[2].u = right;
+    texCoords[2].v = bottom;
+    texCoords[3].u = right;
+    texCoords[3].v = top;
+    for (int i = 0; i < 4; i++) {
+        texCoords[i].v = 1.0f - texCoords[i].v;
+    }
 
     glEnableClientState(GL_TEXTURE_COORD_ARRAY);
     glVertexPointer(2, GL_FLOAT, 0, mVertices);