SysUI: Allow styling of battery text/charge blend mode

Not all battery meter modes are created equally and sometimes you
need to draw the text or charge indicator using a different blend
mode than XOR.  This patch adds a new attribute to the battery
meter style which allows the blend mode to be defined per battery
style.

Change-Id: I3d2eb38828abc7e5d93337fa815a414675df43a1
TICKET: NIGHTLIES-2981

3 files changed, 67 insertions, 9 deletions

diff --git a/packages/SystemUI/res/values/cm_attrs.xml b/packages/SystemUI/res/values/cm_attrs.xml
index 8c2cf91..36edac0 100644
--- a/packages/SystemUI/res/values/cm_attrs.xml
+++ b/packages/SystemUI/res/values/cm_attrs.xml
@@ -33,6 +33,43 @@
 
     <declare-styleable name="BatteryMeterViewDrawable">
         <attr name="android:gravity"/>
+        <!-- Blending mode used for drawing charging bolt and percentage text -->
+        <attr name="blendMode">
+            <!-- [0, 0] -->
+            <enum name="clear" value="0" />
+            <!-- [Sa, Sc] -->
+            <enum name="src" value="1" />
+            <!-- [Da, Dc] -->
+            <enum name="dst" value="2" />
+            <!-- [Sa + (1 - Sa)*Da, Rc = Sc + (1 - Sa)*Dc] -->
+            <enum name="src_over" value="3" />
+            <!-- [Sa + (1 - Sa)*Da, Rc = Dc + (1 - Da)*Sc] -->
+            <enum name="dst_over" value="4" />
+            <!-- [Sa * Da, Sc * Da] -->
+            <enum name="src_in" value="5" />
+            <!-- [Sa * Da, Sa * Dc] -->
+            <enum name="dst_in" value="6" />
+            <!-- [Sa * (1 - Da), Sc * (1 - Da)] -->
+            <enum name="src_out" value="7" />
+            <!-- [Da * (1 - Sa), Dc * (1 - Sa)] -->
+            <enum name="dst_out" value="8" />
+            <!-- [Da, Sc * Da + (1 - Sa) * Dc] -->
+            <enum name="src_atop" value="9" />
+            <!-- [Sa, Sa * Dc + Sc * (1 - Da)] -->
+            <enum name="dst_atop" value="10" />
+            <!-- [Sa + Da - 2 * Sa * Da, Sc * (1 - Da) + (1 - Sa) * Dc] -->
+            <enum name="xor" value="11" />
+            <!-- Saturate(S + D) -->
+            <enum name="add" value="12" />
+            <!-- [Sa * Da, Sc * Dc] -->
+            <enum name="multiply" value="13" />
+            <!-- [Sa + Da - Sa * Da, Sc + Dc - Sc * Dc] -->
+            <enum name="screen" value="14" />
+            <!-- Draw on top without any blending operations performed -->
+            <enum name="overlay" value="15" />
+            <!-- [Sa + Da - Sa*Da, Sc*(1 - Da) + Dc*(1 - Sa) + min(Sc, Dc)] -->
+            <enum name="darken" value="16" />
+        </attr>
     </declare-styleable>
 </resources>
 
diff --git a/packages/SystemUI/res/values/cm_styles.xml b/packages/SystemUI/res/values/cm_styles.xml
index 4fb216c..1e63418 100644
--- a/packages/SystemUI/res/values/cm_styles.xml
+++ b/packages/SystemUI/res/values/cm_styles.xml
@@ -45,10 +45,13 @@
     <style name="BatteryMeterViewDrawable">
         <!-- gravity used for positioning text within the battery meter -->
         <item name="android:gravity">center</item>
+        <item name="blendMode">clear</item>
     </style>
     <!-- Battery meter drawable styles -->
     <style name="BatteryMeterViewDrawable.Portrait"/>
     <style name="BatteryMeterViewDrawable.Landscape"/>
-    <style name="BatteryMeterViewDrawable.Circle"/>
+    <style name="BatteryMeterViewDrawable.Circle">
+        <item name="blendMode">overlay</item>
+    </style>
 
 </resources>
diff --git a/packages/SystemUI/src/com/android/systemui/BatteryMeterView.java b/packages/SystemUI/src/com/android/systemui/BatteryMeterView.java
index cfb8396..7440fc5 100755
--- a/packages/SystemUI/src/com/android/systemui/BatteryMeterView.java
+++ b/packages/SystemUI/src/com/android/systemui/BatteryMeterView.java
@@ -473,6 +473,7 @@ public class BatteryMeterView extends View implements DemoMode,
 
         private Paint mTextAndBoltPaint;
         private Paint mWarningTextPaint;
+        private Paint mClearPaint;
 
         private LayerDrawable mBatteryDrawable;
         private Drawable mFrameDrawable;
@@ -490,13 +491,16 @@ public class BatteryMeterView extends View implements DemoMode,
             mMode = mode;
             mDisposed = false;
 
-            // load text gravity
-            int[] textGravityAttr = new int[] {android.R.attr.gravity};
+            // load text gravity and blend mode
+            int[] attrs = new int[] {android.R.attr.gravity, R.attr.blendMode};
             int resId = getBatteryDrawableStyleResourceForMode(mode);
+            PorterDuff.Mode xferMode = PorterDuff.Mode.XOR;
             if (resId != 0) {
                 TypedArray a = getContext().obtainStyledAttributes(
-                        getBatteryDrawableStyleResourceForMode(mode), textGravityAttr);
+                        getBatteryDrawableStyleResourceForMode(mode), attrs);
                 mTextGravity = a.getInt(0, Gravity.CENTER);
+                xferMode = PorterDuff.intToMode(a.getInt(1,
+                        PorterDuff.modeToInt(PorterDuff.Mode.XOR)));
             } else {
                 mTextGravity = Gravity.CENTER;
             }
@@ -506,13 +510,16 @@ public class BatteryMeterView extends View implements DemoMode,
             Typeface font = Typeface.create("sans-serif-condensed", Typeface.BOLD);
             mTextAndBoltPaint.setTypeface(font);
             mTextAndBoltPaint.setTextAlign(getPaintAlignmentFromGravity(mTextGravity));
-            mTextAndBoltPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.XOR));
+            mTextAndBoltPaint.setXfermode(new PorterDuffXfermode(xferMode));
 
             mWarningTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
             mWarningTextPaint.setColor(mColors[1]);
             font = Typeface.create("sans-serif", Typeface.BOLD);
             mWarningTextPaint.setTypeface(font);
             mWarningTextPaint.setTextAlign(getPaintAlignmentFromGravity(mTextGravity));
+
+            mClearPaint = new Paint();
+            mClearPaint.setColor(0);
         }
 
         @Override
@@ -635,12 +642,24 @@ public class BatteryMeterView extends View implements DemoMode,
                 level = 100;
             }
 
+            mTextAndBoltPaint.setColor(getColorForLevel(level));
+
+            // Make sure we don't draw the charge indicator if not plugged in
+            Drawable d = mBatteryDrawable.findDrawableByLayerId(R.id.battery_charge_indicator);
+            if (d instanceof BitmapDrawable) {
+                // In case we are using a BitmapDrawable, which we should be unless something bad
+                // happened, we need to change the paint rather than the alpha in case the blendMode
+                // has been set to clear.  Clear always clears regardless of alpha level ;)
+                BitmapDrawable bd = (BitmapDrawable) d;
+                bd.getPaint().set(tracker.plugged ? mTextAndBoltPaint : mClearPaint);
+            } else {
+                d.setAlpha(tracker.plugged ? 255 : 0);
+            }
+
             // Now draw the level indicator
             // set the level and tint color of the fill drawable
             mLevelDrawable.setCurrentFraction(level / 100f);
             mLevelDrawable.setTint(getColorForLevel(level));
-            mBatteryDrawable.findDrawableByLayerId(R.id.battery_charge_indicator)
-                    .setAlpha(tracker.plugged ? 255 : 0);
             mBatteryDrawable.draw(canvas);
 
             // if chosen by options, draw percentage text in the middle
@@ -774,8 +793,7 @@ public class BatteryMeterView extends View implements DemoMode,
                 newBoltDrawable = new BitmapDrawable(getResources(), boltBitmap);
                 newBoltDrawable.setBounds(bounds);
             }
-            newBoltDrawable.getPaint().setXfermode(new PorterDuffXfermode(
-                    PorterDuff.Mode.XOR));
+            newBoltDrawable.getPaint().set(mTextAndBoltPaint);
             batteryDrawable.setDrawableByLayerId(R.id.battery_charge_indicator, newBoltDrawable);
         }