Tweak some RenderNode API surfaces

* no-arg #start()
* remove no-op #destroy method
* fix a Java-imposed quirk that you can't draw a
  currently invalid RenderNode, forcing bottom-up
  recording for no particular reason

Test: builds
Change-Id: I28b41c83b4f7f9ddced843b0d57e9ac510d40ae5

apct-tests/perftests/core/src/android/graphics/perftests/RenderNodePerfTest.java

@@ -47,8 +47,7 @@ public class RenderNodePerfTest {
     public void testCreateRenderNodeNoName() {
         final BenchmarkState state = mPerfStatusReporter.getBenchmarkState();
         while (state.keepRunning()) {
-            RenderNode node = RenderNode.create(null, null);
-            node.destroy();
+            RenderNode.create(null, null);
         }
     }
 
@@ -56,8 +55,7 @@ public class RenderNodePerfTest {
     public void testCreateRenderNode() {
         final BenchmarkState state = mPerfStatusReporter.getBenchmarkState();
         while (state.keepRunning()) {
-            RenderNode node = RenderNode.create("LinearLayout", null);
-            node.destroy();
+            RenderNode.create("LinearLayout", null);
         }
     }
 

core/java/android/view/DisplayListCanvas.java

@@ -180,13 +180,12 @@ public final class DisplayListCanvas extends RecordingCanvas {
     ///////////////////////////////////////////////////////////////////////////
 
     /**
-     * Draws the specified display list onto this canvas. The display list can only
-     * be drawn if {@link android.view.RenderNode#isValid()} returns true.
+     * Draws the specified display list onto this canvas.
      *
      * @param renderNode The RenderNode to draw.
      */
     public void drawRenderNode(RenderNode renderNode) {
-        nDrawRenderNode(mNativeCanvasWrapper, renderNode.getNativeDisplayList());
+        nDrawRenderNode(mNativeCanvasWrapper, renderNode.mNativeRenderNode);
     }
 
     ///////////////////////////////////////////////////////////////////////////

core/java/android/view/RenderNode.java

@@ -139,7 +139,9 @@ public class RenderNode {
                 RenderNode.class.getClassLoader(), nGetNativeFinalizer(), 1024);
     }
 
-    // Do not access directly unless you are ThreadedRenderer
+    /** Not for general use; use only if you are ThreadedRenderer or DisplayListCanvas.
+     * @hide
+     */
     final long mNativeRenderNode;
     private final View mOwningView;
 
@@ -158,15 +160,6 @@ public class RenderNode {
         mOwningView = null;
     }
 
-    /**
-     * Immediately destroys the RenderNode
-     * Only suitable for testing/benchmarking where waiting for the GC/finalizer
-     * is not feasible.
-     */
-    public void destroy() {
-        // TODO: Removed temporarily
-    }
-
     /**
      * Creates a new RenderNode that can be used to record batches of
      * drawing operations, and store / apply render properties when drawn.
@@ -218,6 +211,14 @@ public class RenderNode {
         return DisplayListCanvas.obtain(this, width, height);
     }
 
+    /**
+     * Same as {@link #start(int, int)} but with the RenderNode's width & height
+     */
+    public DisplayListCanvas start() {
+        return DisplayListCanvas.obtain(this,
+                nGetWidth(mNativeRenderNode), nGetHeight(mNativeRenderNode));
+    }
+
     /**
      * Ends the recording for this display list. A display list cannot be
      * replayed if recording is not finished. Calling this method marks
@@ -251,13 +252,6 @@ public class RenderNode {
         return nIsValid(mNativeRenderNode);
     }
 
-    long getNativeDisplayList() {
-        if (!isValid()) {
-            throw new IllegalStateException("The display list is not valid.");
-        }
-        return mNativeRenderNode;
-    }
-
     ///////////////////////////////////////////////////////////////////////////
     // Matrix manipulation
     ///////////////////////////////////////////////////////////////////////////
@@ -463,7 +457,6 @@ public class RenderNode {
      * @see #setHasOverlappingRendering(boolean)
      */
     public boolean hasOverlappingRendering() {
-        //noinspection SimplifiableIfStatement
         return nHasOverlappingRendering(mNativeRenderNode);
     }
 
@@ -1009,4 +1002,8 @@ public class RenderNode {
     private static native float nGetPivotX(long renderNode);
     @CriticalNative
     private static native float nGetPivotY(long renderNode);
+    @CriticalNative
+    private static native int nGetWidth(long renderNode);
+    @CriticalNative
+    private static native int nGetHeight(long renderNode);
 }

core/java/android/view/ThreadedRenderer.java

@@ -850,7 +850,9 @@ public final class ThreadedRenderer {
 
 
     void buildLayer(RenderNode node) {
-        nBuildLayer(mNativeProxy, node.getNativeDisplayList());
+        if (node.isValid()) {
+            nBuildLayer(mNativeProxy, node.mNativeRenderNode);
+        }
     }
 
 
@@ -928,7 +930,7 @@ public final class ThreadedRenderer {
      * not the RenderNode from a View.
      **/
     public static Bitmap createHardwareBitmap(RenderNode node, int width, int height) {
-        return nCreateHardwareBitmap(node.getNativeDisplayList(), width, height);
+        return nCreateHardwareBitmap(node.mNativeRenderNode, width, height);
     }
 
     /**

core/java/android/view/ViewDebug.java

@@ -531,7 +531,6 @@ public class ViewDebug {
             throws IOException {
         RenderNode node = RenderNode.create("ViewDebug", null);
         profileViewAndChildren(view, node, out, true);
-        node.destroy();
     }
 
     private static void profileViewAndChildren(View view, RenderNode node, BufferedWriter out,

core/java/android/widget/Magnifier.java

@@ -611,7 +611,6 @@ public final class Magnifier {
                 mRenderer.destroy();
                 mSurfaceControl.destroy();
                 mSurfaceSession.kill();
-                mBitmapRenderNode.destroy();
                 mHandler.removeCallbacks(mMagnifierUpdater);
                 if (mBitmap != null) {
                     mBitmap.recycle();

core/jni/android_view_RenderNode.cpp

@@ -431,6 +431,14 @@ static jfloat android_view_RenderNode_getPivotY(jlong renderNodePtr) {
     return renderNode->stagingProperties().getPivotY();
 }
 
+static jint android_view_RenderNode_getWidth(jlong renderNodePtr) {
+    return reinterpret_cast<RenderNode*>(renderNodePtr)->stagingProperties().getWidth();
+}
+
+static jint android_view_RenderNode_getHeight(jlong renderNodePtr) {
+    return reinterpret_cast<RenderNode*>(renderNodePtr)->stagingProperties().getHeight();
+}
+
 // ----------------------------------------------------------------------------
 // RenderProperties - Animations
 // ----------------------------------------------------------------------------
@@ -648,6 +656,8 @@ static const JNINativeMethod gMethods[] = {
 
     { "nGetPivotX",                "(J)F",  (void*) android_view_RenderNode_getPivotX },
     { "nGetPivotY",                "(J)F",  (void*) android_view_RenderNode_getPivotY },
+    { "nGetWidth",                 "(J)I",  (void*) android_view_RenderNode_getWidth },
+    { "nGetHeight",                "(J)I",  (void*) android_view_RenderNode_getHeight },
 };
 
 int register_android_view_RenderNode(JNIEnv* env) {