From 0b6586649fe827d6e7ce39fa71e93fa582640a03 Mon Sep 17 00:00:00 2001
From: Michael Jurka <mikejurka@google.com>
Date: Thu, 12 Jan 2012 05:48:19 -0800
Subject: [PATCH] Speeding up System UI pressed anim

No longer saving a layer in KeyButtonView.onDraw,
which prevents a framebuffer readback on some
drivers and cuts ~3ms from render time per frame
(on some frames, up to ~10ms)

Change-Id: I5df56c20098f35c8ae6c25e76c67d81e9b72d1f7
---
 .../systemui/statusbar/policy/KeyButtonView.java    | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/policy/KeyButtonView.java b/packages/SystemUI/src/com/android/systemui/statusbar/policy/KeyButtonView.java
index 5e5bc1a425ef2..975c372acb861 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/policy/KeyButtonView.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/policy/KeyButtonView.java
@@ -87,7 +87,7 @@ public class KeyButtonView extends ImageView {
 
         mGlowBG = a.getDrawable(R.styleable.KeyButtonView_glowBackground);
         if (mGlowBG != null) {
-            mDrawingAlpha = BUTTON_QUIESCENT_ALPHA;
+            setDrawingAlpha(BUTTON_QUIESCENT_ALPHA);
         }
         
         a.recycle();
@@ -107,17 +107,13 @@ public class KeyButtonView extends ImageView {
             final int h = getHeight();
             canvas.scale(mGlowScale, mGlowScale, w*0.5f, h*0.5f);
             mGlowBG.setBounds(0, 0, w, h);
-            mGlowBG.setAlpha((int)(mGlowAlpha * 255));
+            mGlowBG.setAlpha((int)(mDrawingAlpha * mGlowAlpha * 255));
             mGlowBG.draw(canvas);
             canvas.restore();
             mRect.right = w;
             mRect.bottom = h;
-            canvas.saveLayerAlpha(mRect, (int)(mDrawingAlpha * 255), Canvas.ALL_SAVE_FLAG);
         }
         super.onDraw(canvas);
-        if (mGlowBG != null) {
-            canvas.restore();
-        }
     }
 
     public float getDrawingAlpha() {
@@ -127,8 +123,11 @@ public class KeyButtonView extends ImageView {
 
     public void setDrawingAlpha(float x) {
         if (mGlowBG == null) return;
+        // Calling setAlpha(int), which is an ImageView-specific
+        // method that's different from setAlpha(float). This sets
+        // the alpha on this ImageView's drawable directly
+        setAlpha((int) (x * 255));
         mDrawingAlpha = x;
-        invalidate();
     }
 
     public float getGlowAlpha() {