graphics/java/android/graphics/drawable/ShapeDrawable.java - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2007 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package android.graphics.drawable;

 import android.content.res.ColorStateList;
 import android.content.res.Resources;
 import android.content.res.TypedArray;
 import android.graphics.Canvas;
 import android.graphics.ColorFilter;
 import android.graphics.Outline;
 import android.graphics.Paint;
 import android.graphics.PixelFormat;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuff.Mode;
 import android.graphics.PorterDuffColorFilter;
 import android.graphics.Rect;
 import android.graphics.Shader;
 import android.graphics.drawable.shapes.Shape;
 import android.content.res.Resources.Theme;
 import android.util.AttributeSet;

 import com.android.internal.R;
 import org.xmlpull.v1.XmlPullParser;
 import org.xmlpull.v1.XmlPullParserException;

 import java.io.IOException;

 /**
  * A Drawable object that draws primitive shapes. A ShapeDrawable takes a
  * {@link android.graphics.drawable.shapes.Shape} object and manages its
  * presence on the screen. If no Shape is given, then the ShapeDrawable will
  * default to a {@link android.graphics.drawable.shapes.RectShape}.
  * <p>
  * This object can be defined in an XML file with the <code>&lt;shape></code>
  * element.
  * </p>
  * <div class="special reference"> <h3>Developer Guides</h3>
  * <p>
  * For more information about how to use ShapeDrawable, read the <a
  * href="{@docRoot}guide/topics/graphics/2d-graphics.html#shape-drawable">
  * Canvas and Drawables</a> document. For more information about defining a
  * ShapeDrawable in XML, read the
  * <a href="{@docRoot}guide/topics/resources/drawable-resource.html#Shape">
  * Drawable Resources</a> document.
  * </p>
  * </div>
  *
  * @attr ref android.R.styleable#ShapeDrawablePadding_left
  * @attr ref android.R.styleable#ShapeDrawablePadding_top
  * @attr ref android.R.styleable#ShapeDrawablePadding_right
  * @attr ref android.R.styleable#ShapeDrawablePadding_bottom
  * @attr ref android.R.styleable#ShapeDrawable_color
  * @attr ref android.R.styleable#ShapeDrawable_width
  * @attr ref android.R.styleable#ShapeDrawable_height
  */
 public class ShapeDrawable extends Drawable {
     private ShapeState mShapeState;
     private PorterDuffColorFilter mTintFilter;
     private boolean mMutated;

     /**
      * ShapeDrawable constructor.
      */
     public ShapeDrawable() {
         this(new ShapeState(null), null);
     }

     /**
      * Creates a ShapeDrawable with a specified Shape.
      *
      * @param s the Shape that this ShapeDrawable should be
      */
     public ShapeDrawable(Shape s) {
         this(new ShapeState(null), null);

         mShapeState.mShape = s;
     }

     /**
      * Returns the Shape of this ShapeDrawable.
      */
     public Shape getShape() {
         return mShapeState.mShape;
     }

     /**
      * Sets the Shape of this ShapeDrawable.
      */
     public void setShape(Shape s) {
         mShapeState.mShape = s;
         updateShape();
     }

     /**
      * Sets a ShaderFactory to which requests for a
      * {@link android.graphics.Shader} object will be made.
      *
      * @param fact an instance of your ShaderFactory implementation
      */
     public void setShaderFactory(ShaderFactory fact) {
         mShapeState.mShaderFactory = fact;
     }

     /**
      * Returns the ShaderFactory used by this ShapeDrawable for requesting a
      * {@link android.graphics.Shader}.
      */
     public ShaderFactory getShaderFactory() {
         return mShapeState.mShaderFactory;
     }

     /**
      * Returns the Paint used to draw the shape.
      */
     public Paint getPaint() {
         return mShapeState.mPaint;
     }

     /**
      * Sets padding for the shape.
      *
      * @param left padding for the left side (in pixels)
      * @param top padding for the top (in pixels)
      * @param right padding for the right side (in pixels)
      * @param bottom padding for the bottom (in pixels)
      */
     public void setPadding(int left, int top, int right, int bottom) {
         if ((left | top | right | bottom) == 0) {
             mShapeState.mPadding = null;
         } else {
             if (mShapeState.mPadding == null) {
                 mShapeState.mPadding = new Rect();
             }
             mShapeState.mPadding.set(left, top, right, bottom);
         }
         invalidateSelf();
     }

     /**
      * Sets padding for this shape, defined by a Rect object. Define the padding
      * in the Rect object as: left, top, right, bottom.
      */
     public void setPadding(Rect padding) {
         if (padding == null) {
             mShapeState.mPadding = null;
         } else {
             if (mShapeState.mPadding == null) {
                 mShapeState.mPadding = new Rect();
             }
             mShapeState.mPadding.set(padding);
         }
         invalidateSelf();
     }

     /**
      * Sets the intrinsic (default) width for this shape.
      *
      * @param width the intrinsic width (in pixels)
      */
     public void setIntrinsicWidth(int width) {
         mShapeState.mIntrinsicWidth = width;
         invalidateSelf();
     }

     /**
      * Sets the intrinsic (default) height for this shape.
      *
      * @param height the intrinsic height (in pixels)
      */
     public void setIntrinsicHeight(int height) {
         mShapeState.mIntrinsicHeight = height;
         invalidateSelf();
     }

     @Override
     public int getIntrinsicWidth() {
         return mShapeState.mIntrinsicWidth;
     }

     @Override
     public int getIntrinsicHeight() {
         return mShapeState.mIntrinsicHeight;
     }

     @Override
     public boolean getPadding(Rect padding) {
         if (mShapeState.mPadding != null) {
             padding.set(mShapeState.mPadding);
             return true;
         } else {
             return super.getPadding(padding);
         }
     }

     private static int modulateAlpha(int paintAlpha, int alpha) {
         int scale = alpha + (alpha >>> 7); // convert to 0..256
         return paintAlpha * scale >>> 8;
     }

     /**
      * Called from the drawable's draw() method after the canvas has been set to
      * draw the shape at (0,0). Subclasses can override for special effects such
      * as multiple layers, stroking, etc.
      */
     protected void onDraw(Shape shape, Canvas canvas, Paint paint) {
         shape.draw(canvas, paint);
     }

     @Override
     public void draw(Canvas canvas) {
         final Rect r = getBounds();
         final ShapeState state = mShapeState;
         final Paint paint = state.mPaint;

         final int prevAlpha = paint.getAlpha();
         paint.setAlpha(modulateAlpha(prevAlpha, state.mAlpha));

         // only draw shape if it may affect output
         if (paint.getAlpha() != 0 || paint.getXfermode() != null || paint.hasShadowLayer()) {
             final boolean clearColorFilter;
             if (mTintFilter != null && paint.getColorFilter() == null) {
                 paint.setColorFilter(mTintFilter);
                 clearColorFilter = true;
             } else {
                 clearColorFilter = false;
             }

             if (state.mShape != null) {
                 // need the save both for the translate, and for the (unknown)
                 // Shape
                 final int count = canvas.save();
                 canvas.translate(r.left, r.top);
                 onDraw(state.mShape, canvas, paint);
                 canvas.restoreToCount(count);
             } else {
                 canvas.drawRect(r, paint);
             }

             if (clearColorFilter) {
                 paint.setColorFilter(null);
             }
         }

         // restore
         paint.setAlpha(prevAlpha);
     }

     @Override
     public int getChangingConfigurations() {
         return super.getChangingConfigurations()
                 | mShapeState.mChangingConfigurations;
     }

     /**
      * Set the alpha level for this drawable [0..255]. Note that this drawable
      * also has a color in its paint, which has an alpha as well. These two
      * values are automatically combined during drawing. Thus if the color's
      * alpha is 75% (i.e. 192) and the drawable's alpha is 50% (i.e. 128), then
      * the combined alpha that will be used during drawing will be 37.5% (i.e.
      * 96).
      */
     @Override
     public void setAlpha(int alpha) {
         mShapeState.mAlpha = alpha;
         invalidateSelf();
     }

     @Override
     public int getAlpha() {
         return mShapeState.mAlpha;
     }

     @Override
     public void setTintList(ColorStateList tint) {
         mShapeState.mTint = tint;
         mTintFilter = updateTintFilter(mTintFilter, tint, mShapeState.mTintMode);
         invalidateSelf();
     }

     @Override
     public void setTintMode(PorterDuff.Mode tintMode) {
         mShapeState.mTintMode = tintMode;
         mTintFilter = updateTintFilter(mTintFilter, mShapeState.mTint, tintMode);
         invalidateSelf();
     }

     @Override
     public void setColorFilter(ColorFilter cf) {
         mShapeState.mPaint.setColorFilter(cf);
         invalidateSelf();
     }

     @Override
     public int getOpacity() {
         if (mShapeState.mShape == null) {
             final Paint p = mShapeState.mPaint;
             if (p.getXfermode() == null) {
                 final int alpha = p.getAlpha();
                 if (alpha == 0) {
                     return PixelFormat.TRANSPARENT;
                 }
                 if (alpha == 255) {
                     return PixelFormat.OPAQUE;
                 }
             }
         }
         // not sure, so be safe
         return PixelFormat.TRANSLUCENT;
     }

     @Override
     public void setDither(boolean dither) {
         mShapeState.mPaint.setDither(dither);
         invalidateSelf();
     }

     @Override
     protected void onBoundsChange(Rect bounds) {
         super.onBoundsChange(bounds);
         updateShape();
     }

     @Override
     protected boolean onStateChange(int[] stateSet) {
         final ShapeState state = mShapeState;
         if (state.mTint != null && state.mTintMode != null) {
             mTintFilter = updateTintFilter(mTintFilter, state.mTint, state.mTintMode);
             return true;
         }
         return false;
     }

     @Override
     public boolean isStateful() {
         final ShapeState s = mShapeState;
         return super.isStateful() || (s.mTint != null && s.mTint.isStateful());
     }

     /**
      * Subclasses override this to parse custom subelements. If you handle it,
      * return true, else return <em>super.inflateTag(...)</em>.
      */
     protected boolean inflateTag(String name, Resources r, XmlPullParser parser,
             AttributeSet attrs) {

         if ("padding".equals(name)) {
             TypedArray a = r.obtainAttributes(attrs,
                     com.android.internal.R.styleable.ShapeDrawablePadding);
             setPadding(
                     a.getDimensionPixelOffset(
                             com.android.internal.R.styleable.ShapeDrawablePadding_left, 0),
                     a.getDimensionPixelOffset(
                             com.android.internal.R.styleable.ShapeDrawablePadding_top, 0),
                     a.getDimensionPixelOffset(
                             com.android.internal.R.styleable.ShapeDrawablePadding_right, 0),
                     a.getDimensionPixelOffset(
                             com.android.internal.R.styleable.ShapeDrawablePadding_bottom, 0));
             a.recycle();
             return true;
         }

         return false;
     }

     @Override
     public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme)
             throws XmlPullParserException, IOException {
         super.inflate(r, parser, attrs, theme);

         final TypedArray a = obtainAttributes(r, theme, attrs, R.styleable.ShapeDrawable);
         updateStateFromTypedArray(a);
         a.recycle();

         int type;
         final int outerDepth = parser.getDepth();
         while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
                 && (type != XmlPullParser.END_TAG || parser.getDepth() > outerDepth)) {
             if (type != XmlPullParser.START_TAG) {
                 continue;
             }

             final String name = parser.getName();
             // call our subclass
             if (!inflateTag(name, r, parser, attrs)) {
                 android.util.Log.w("drawable", "Unknown element: " + name +
                         " for ShapeDrawable " + this);
             }
         }

         // Update local properties.
         initializeWithState(mShapeState, r);
     }

     @Override
     public void applyTheme(Theme t) {
         super.applyTheme(t);

         final ShapeState state = mShapeState;
         if (state == null || state.mThemeAttrs == null) {
             return;
         }

         final TypedArray a = t.resolveAttributes(state.mThemeAttrs, R.styleable.ShapeDrawable);
         updateStateFromTypedArray(a);
         a.recycle();

         // Update local properties.
         initializeWithState(state, t.getResources());
     }

     private void updateStateFromTypedArray(TypedArray a) {
         final ShapeState state = mShapeState;
         final Paint paint = state.mPaint;

         // Account for any configuration changes.
         state.mChangingConfigurations |= a.getChangingConfigurations();

         // Extract the theme attributes, if any.
         state.mThemeAttrs = a.extractThemeAttrs();

         int color = paint.getColor();
         color = a.getColor(R.styleable.ShapeDrawable_color, color);
         paint.setColor(color);

         boolean dither = paint.isDither();
         dither = a.getBoolean(R.styleable.ShapeDrawable_dither, dither);
         paint.setDither(dither);

         setIntrinsicWidth((int) a.getDimension(
                 R.styleable.ShapeDrawable_width, state.mIntrinsicWidth));
         setIntrinsicHeight((int) a.getDimension(
                 R.styleable.ShapeDrawable_height, state.mIntrinsicHeight));

         final int tintMode = a.getInt(R.styleable.ShapeDrawable_tintMode, -1);
         if (tintMode != -1) {
             state.mTintMode = Drawable.parseTintMode(tintMode, Mode.SRC_IN);
         }

         final ColorStateList tint = a.getColorStateList(R.styleable.ShapeDrawable_tint);
         if (tint != null) {
             state.mTint = tint;
         }
     }

     private void updateShape() {
         if (mShapeState.mShape != null) {
             final Rect r = getBounds();
             final int w = r.width();
             final int h = r.height();

             mShapeState.mShape.resize(w, h);
             if (mShapeState.mShaderFactory != null) {
                 mShapeState.mPaint.setShader(mShapeState.mShaderFactory.resize(w, h));
             }
         }
         invalidateSelf();
     }

     @Override
     public void getOutline(Outline outline) {
         if (mShapeState.mShape != null) {
             mShapeState.mShape.getOutline(outline);
             outline.setAlpha(getAlpha() / 255.0f);
         }
     }

     @Override
     public ConstantState getConstantState() {
         mShapeState.mChangingConfigurations = getChangingConfigurations();
         return mShapeState;
     }

     @Override
     public Drawable mutate() {
         if (!mMutated && super.mutate() == this) {
             if (mShapeState.mPaint != null) {
                 mShapeState.mPaint = new Paint(mShapeState.mPaint);
             } else {
                 mShapeState.mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
             }
             if (mShapeState.mPadding != null) {
                 mShapeState.mPadding = new Rect(mShapeState.mPadding);
             } else {
                 mShapeState.mPadding = new Rect();
             }
             try {
                 mShapeState.mShape = mShapeState.mShape.clone();
             } catch (CloneNotSupportedException e) {
                 return null;
             }
             mMutated = true;
         }
         return this;
     }

     /**
      * @hide
      */
     public void clearMutated() {
         super.clearMutated();
         mMutated = false;
     }

     /**
      * Defines the intrinsic properties of this ShapeDrawable's Shape.
      */
     final static class ShapeState extends ConstantState {
         int[] mThemeAttrs;
         int mChangingConfigurations;
         Paint mPaint;
         Shape mShape;
         ColorStateList mTint = null;
         Mode mTintMode = DEFAULT_TINT_MODE;
         Rect mPadding;
         int mIntrinsicWidth;
         int mIntrinsicHeight;
         int mAlpha = 255;
         ShaderFactory mShaderFactory;

         ShapeState(ShapeState orig) {
             if (orig != null) {
                 mThemeAttrs = orig.mThemeAttrs;
                 mPaint = orig.mPaint;
                 mShape = orig.mShape;
                 mTint = orig.mTint;
                 mTintMode = orig.mTintMode;
                 mPadding = orig.mPadding;
                 mIntrinsicWidth = orig.mIntrinsicWidth;
                 mIntrinsicHeight = orig.mIntrinsicHeight;
                 mAlpha = orig.mAlpha;
                 mShaderFactory = orig.mShaderFactory;
             } else {
                 mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
             }
         }

         @Override
         public boolean canApplyTheme() {
             return mThemeAttrs != null;
         }

         @Override
         public Drawable newDrawable() {
             return new ShapeDrawable(this, null);
         }

         @Override
         public Drawable newDrawable(Resources res) {
             return new ShapeDrawable(this, res);
         }

         @Override
         public int getChangingConfigurations() {
             return mChangingConfigurations;
         }
     }

     /**
      * The one constructor to rule them all. This is called by all public
      * constructors to set the state and initialize local properties.
      */
     private ShapeDrawable(ShapeState state, Resources res) {
         mShapeState = state;

         initializeWithState(state, res);
     }

     /**
      * Initializes local dynamic properties from state. This should be called
      * after significant state changes, e.g. from the One True Constructor and
      * after inflating or applying a theme.
      */
     private void initializeWithState(ShapeState state, Resources res) {
         mTintFilter = updateTintFilter(mTintFilter, state.mTint, state.mTintMode);
     }

     /**
      * Base class defines a factory object that is called each time the drawable
      * is resized (has a new width or height). Its resize() method returns a
      * corresponding shader, or null. Implement this class if you'd like your
      * ShapeDrawable to use a special {@link android.graphics.Shader}, such as a
      * {@link android.graphics.LinearGradient}.
      */
     public static abstract class ShaderFactory {
         /**
          * Returns the Shader to be drawn when a Drawable is drawn. The
          * dimensions of the Drawable are passed because they may be needed to
          * adjust how the Shader is configured for drawing. This is called by
          * ShapeDrawable.setShape().
          *
          * @param width the width of the Drawable being drawn
          * @param height the heigh of the Drawable being drawn
          * @return the Shader to be drawn
          */
         public abstract Shader resize(int width, int height);
     }

     // other subclass could wack the Shader's localmatrix based on the
     // resize params (e.g. scaletofit, etc.). This could be used to scale
     // a bitmap to fill the bounds without needing any other special casing.
 }
	/*
	* Copyright (C) 2007 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package android.graphics.drawable;

	import android.content.res.ColorStateList;
	import android.content.res.Resources;
	import android.content.res.TypedArray;
	import android.graphics.Canvas;
	import android.graphics.ColorFilter;
	import android.graphics.Outline;
	import android.graphics.Paint;
	import android.graphics.PixelFormat;
	import android.graphics.PorterDuff;
	import android.graphics.PorterDuff.Mode;
	import android.graphics.PorterDuffColorFilter;
	import android.graphics.Rect;
	import android.graphics.Shader;
	import android.graphics.drawable.shapes.Shape;
	import android.content.res.Resources.Theme;
	import android.util.AttributeSet;

	import com.android.internal.R;
	import org.xmlpull.v1.XmlPullParser;
	import org.xmlpull.v1.XmlPullParserException;

	import java.io.IOException;

	/**
	* A Drawable object that draws primitive shapes. A ShapeDrawable takes a
	* {@link android.graphics.drawable.shapes.Shape} object and manages its
	* presence on the screen. If no Shape is given, then the ShapeDrawable will
	* default to a {@link android.graphics.drawable.shapes.RectShape}.
	* <p>
	* This object can be defined in an XML file with the <code><shape></code>
	* element.
	* </p>
	* <div class="special reference"> <h3>Developer Guides</h3>
	* <p>
	* For more information about how to use ShapeDrawable, read the <a
	* href="{@docRoot}guide/topics/graphics/2d-graphics.html#shape-drawable">
	* Canvas and Drawables</a> document. For more information about defining a
	* ShapeDrawable in XML, read the
	* <a href="{@docRoot}guide/topics/resources/drawable-resource.html#Shape">
	* Drawable Resources</a> document.
	* </p>
	* </div>
	*
	* @attr ref android.R.styleable#ShapeDrawablePadding_left
	* @attr ref android.R.styleable#ShapeDrawablePadding_top
	* @attr ref android.R.styleable#ShapeDrawablePadding_right
	* @attr ref android.R.styleable#ShapeDrawablePadding_bottom
	* @attr ref android.R.styleable#ShapeDrawable_color
	* @attr ref android.R.styleable#ShapeDrawable_width
	* @attr ref android.R.styleable#ShapeDrawable_height
	*/
	public class ShapeDrawable extends Drawable {
	private ShapeState mShapeState;
	private PorterDuffColorFilter mTintFilter;
	private boolean mMutated;

	/**
	* ShapeDrawable constructor.
	*/
	public ShapeDrawable() {
	this(new ShapeState(null), null);
	}

	/**
	* Creates a ShapeDrawable with a specified Shape.
	*
	* @param s the Shape that this ShapeDrawable should be
	*/
	public ShapeDrawable(Shape s) {
	this(new ShapeState(null), null);

	mShapeState.mShape = s;
	}

	/**
	* Returns the Shape of this ShapeDrawable.
	*/
	public Shape getShape() {
	return mShapeState.mShape;
	}

	/**
	* Sets the Shape of this ShapeDrawable.
	*/
	public void setShape(Shape s) {
	mShapeState.mShape = s;
	updateShape();
	}

	/**
	* Sets a ShaderFactory to which requests for a
	* {@link android.graphics.Shader} object will be made.
	*
	* @param fact an instance of your ShaderFactory implementation
	*/
	public void setShaderFactory(ShaderFactory fact) {
	mShapeState.mShaderFactory = fact;
	}

	/**
	* Returns the ShaderFactory used by this ShapeDrawable for requesting a
	* {@link android.graphics.Shader}.
	*/
	public ShaderFactory getShaderFactory() {
	return mShapeState.mShaderFactory;
	}

	/**
	* Returns the Paint used to draw the shape.
	*/
	public Paint getPaint() {
	return mShapeState.mPaint;
	}

	/**
	* Sets padding for the shape.
	*
	* @param left padding for the left side (in pixels)
	* @param top padding for the top (in pixels)
	* @param right padding for the right side (in pixels)
	* @param bottom padding for the bottom (in pixels)
	*/
	public void setPadding(int left, int top, int right, int bottom) {
	if ((left \| top \| right \| bottom) == 0) {
	mShapeState.mPadding = null;
	} else {
	if (mShapeState.mPadding == null) {
	mShapeState.mPadding = new Rect();
	}
	mShapeState.mPadding.set(left, top, right, bottom);
	}
	invalidateSelf();
	}

	/**
	* Sets padding for this shape, defined by a Rect object. Define the padding
	* in the Rect object as: left, top, right, bottom.
	*/
	public void setPadding(Rect padding) {
	if (padding == null) {
	mShapeState.mPadding = null;
	} else {
	if (mShapeState.mPadding == null) {
	mShapeState.mPadding = new Rect();
	}
	mShapeState.mPadding.set(padding);
	}
	invalidateSelf();
	}

	/**
	* Sets the intrinsic (default) width for this shape.
	*
	* @param width the intrinsic width (in pixels)
	*/
	public void setIntrinsicWidth(int width) {
	mShapeState.mIntrinsicWidth = width;
	invalidateSelf();
	}

	/**
	* Sets the intrinsic (default) height for this shape.
	*
	* @param height the intrinsic height (in pixels)
	*/
	public void setIntrinsicHeight(int height) {
	mShapeState.mIntrinsicHeight = height;
	invalidateSelf();
	}

	@Override
	public int getIntrinsicWidth() {
	return mShapeState.mIntrinsicWidth;
	}

	@Override
	public int getIntrinsicHeight() {
	return mShapeState.mIntrinsicHeight;
	}

	@Override
	public boolean getPadding(Rect padding) {
	if (mShapeState.mPadding != null) {
	padding.set(mShapeState.mPadding);
	return true;
	} else {
	return super.getPadding(padding);
	}
	}

	private static int modulateAlpha(int paintAlpha, int alpha) {
	int scale = alpha + (alpha >>> 7); // convert to 0..256
	return paintAlpha * scale >>> 8;
	}

	/**
	* Called from the drawable's draw() method after the canvas has been set to
	* draw the shape at (0,0). Subclasses can override for special effects such
	* as multiple layers, stroking, etc.
	*/
	protected void onDraw(Shape shape, Canvas canvas, Paint paint) {
	shape.draw(canvas, paint);
	}

	@Override
	public void draw(Canvas canvas) {
	final Rect r = getBounds();
	final ShapeState state = mShapeState;
	final Paint paint = state.mPaint;

	final int prevAlpha = paint.getAlpha();
	paint.setAlpha(modulateAlpha(prevAlpha, state.mAlpha));

	// only draw shape if it may affect output
	if (paint.getAlpha() != 0 \|\| paint.getXfermode() != null \|\| paint.hasShadowLayer()) {
	final boolean clearColorFilter;
	if (mTintFilter != null && paint.getColorFilter() == null) {
	paint.setColorFilter(mTintFilter);
	clearColorFilter = true;
	} else {
	clearColorFilter = false;
	}

	if (state.mShape != null) {
	// need the save both for the translate, and for the (unknown)
	// Shape
	final int count = canvas.save();
	canvas.translate(r.left, r.top);
	onDraw(state.mShape, canvas, paint);
	canvas.restoreToCount(count);
	} else {
	canvas.drawRect(r, paint);
	}

	if (clearColorFilter) {
	paint.setColorFilter(null);
	}
	}

	// restore
	paint.setAlpha(prevAlpha);
	}

	@Override
	public int getChangingConfigurations() {
	return super.getChangingConfigurations()
	\| mShapeState.mChangingConfigurations;
	}

	/**
	* Set the alpha level for this drawable [0..255]. Note that this drawable
	* also has a color in its paint, which has an alpha as well. These two
	* values are automatically combined during drawing. Thus if the color's
	* alpha is 75% (i.e. 192) and the drawable's alpha is 50% (i.e. 128), then
	* the combined alpha that will be used during drawing will be 37.5% (i.e.
	* 96).
	*/
	@Override
	public void setAlpha(int alpha) {
	mShapeState.mAlpha = alpha;
	invalidateSelf();
	}

	@Override
	public int getAlpha() {
	return mShapeState.mAlpha;
	}

	@Override
	public void setTintList(ColorStateList tint) {
	mShapeState.mTint = tint;
	mTintFilter = updateTintFilter(mTintFilter, tint, mShapeState.mTintMode);
	invalidateSelf();
	}

	@Override
	public void setTintMode(PorterDuff.Mode tintMode) {
	mShapeState.mTintMode = tintMode;
	mTintFilter = updateTintFilter(mTintFilter, mShapeState.mTint, tintMode);
	invalidateSelf();
	}

	@Override
	public void setColorFilter(ColorFilter cf) {
	mShapeState.mPaint.setColorFilter(cf);
	invalidateSelf();
	}

	@Override
	public int getOpacity() {
	if (mShapeState.mShape == null) {
	final Paint p = mShapeState.mPaint;
	if (p.getXfermode() == null) {
	final int alpha = p.getAlpha();
	if (alpha == 0) {
	return PixelFormat.TRANSPARENT;
	}
	if (alpha == 255) {
	return PixelFormat.OPAQUE;
	}
	}
	}
	// not sure, so be safe
	return PixelFormat.TRANSLUCENT;
	}

	@Override
	public void setDither(boolean dither) {
	mShapeState.mPaint.setDither(dither);
	invalidateSelf();
	}

	@Override
	protected void onBoundsChange(Rect bounds) {
	super.onBoundsChange(bounds);
	updateShape();
	}

	@Override
	protected boolean onStateChange(int[] stateSet) {
	final ShapeState state = mShapeState;
	if (state.mTint != null && state.mTintMode != null) {
	mTintFilter = updateTintFilter(mTintFilter, state.mTint, state.mTintMode);
	return true;
	}
	return false;
	}

	@Override
	public boolean isStateful() {
	final ShapeState s = mShapeState;
	return super.isStateful() \|\| (s.mTint != null && s.mTint.isStateful());
	}

	/**
	* Subclasses override this to parse custom subelements. If you handle it,
	* return true, else return <em>super.inflateTag(...)</em>.
	*/
	protected boolean inflateTag(String name, Resources r, XmlPullParser parser,
	AttributeSet attrs) {

	if ("padding".equals(name)) {
	TypedArray a = r.obtainAttributes(attrs,
	com.android.internal.R.styleable.ShapeDrawablePadding);
	setPadding(
	a.getDimensionPixelOffset(
	com.android.internal.R.styleable.ShapeDrawablePadding_left, 0),
	a.getDimensionPixelOffset(
	com.android.internal.R.styleable.ShapeDrawablePadding_top, 0),
	a.getDimensionPixelOffset(
	com.android.internal.R.styleable.ShapeDrawablePadding_right, 0),
	a.getDimensionPixelOffset(
	com.android.internal.R.styleable.ShapeDrawablePadding_bottom, 0));
	a.recycle();
	return true;
	}

	return false;
	}

	@Override
	public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme)
	throws XmlPullParserException, IOException {
	super.inflate(r, parser, attrs, theme);

	final TypedArray a = obtainAttributes(r, theme, attrs, R.styleable.ShapeDrawable);
	updateStateFromTypedArray(a);
	a.recycle();

	int type;
	final int outerDepth = parser.getDepth();
	while ((type = parser.next()) != XmlPullParser.END_DOCUMENT
	&& (type != XmlPullParser.END_TAG \|\| parser.getDepth() > outerDepth)) {
	if (type != XmlPullParser.START_TAG) {
	continue;
	}

	final String name = parser.getName();
	// call our subclass
	if (!inflateTag(name, r, parser, attrs)) {
	android.util.Log.w("drawable", "Unknown element: " + name +
	" for ShapeDrawable " + this);
	}
	}

	// Update local properties.
	initializeWithState(mShapeState, r);
	}

	@Override
	public void applyTheme(Theme t) {
	super.applyTheme(t);

	final ShapeState state = mShapeState;
	if (state == null \|\| state.mThemeAttrs == null) {
	return;
	}

	final TypedArray a = t.resolveAttributes(state.mThemeAttrs, R.styleable.ShapeDrawable);
	updateStateFromTypedArray(a);
	a.recycle();

	// Update local properties.
	initializeWithState(state, t.getResources());
	}

	private void updateStateFromTypedArray(TypedArray a) {
	final ShapeState state = mShapeState;
	final Paint paint = state.mPaint;

	// Account for any configuration changes.
	state.mChangingConfigurations \|= a.getChangingConfigurations();

	// Extract the theme attributes, if any.
	state.mThemeAttrs = a.extractThemeAttrs();

	int color = paint.getColor();
	color = a.getColor(R.styleable.ShapeDrawable_color, color);
	paint.setColor(color);

	boolean dither = paint.isDither();
	dither = a.getBoolean(R.styleable.ShapeDrawable_dither, dither);
	paint.setDither(dither);

	setIntrinsicWidth((int) a.getDimension(
	R.styleable.ShapeDrawable_width, state.mIntrinsicWidth));
	setIntrinsicHeight((int) a.getDimension(
	R.styleable.ShapeDrawable_height, state.mIntrinsicHeight));

	final int tintMode = a.getInt(R.styleable.ShapeDrawable_tintMode, -1);
	if (tintMode != -1) {
	state.mTintMode = Drawable.parseTintMode(tintMode, Mode.SRC_IN);
	}

	final ColorStateList tint = a.getColorStateList(R.styleable.ShapeDrawable_tint);
	if (tint != null) {
	state.mTint = tint;
	}
	}

	private void updateShape() {
	if (mShapeState.mShape != null) {
	final Rect r = getBounds();
	final int w = r.width();
	final int h = r.height();

	mShapeState.mShape.resize(w, h);
	if (mShapeState.mShaderFactory != null) {
	mShapeState.mPaint.setShader(mShapeState.mShaderFactory.resize(w, h));
	}
	}
	invalidateSelf();
	}

	@Override
	public void getOutline(Outline outline) {
	if (mShapeState.mShape != null) {
	mShapeState.mShape.getOutline(outline);
	outline.setAlpha(getAlpha() / 255.0f);
	}
	}

	@Override
	public ConstantState getConstantState() {
	mShapeState.mChangingConfigurations = getChangingConfigurations();
	return mShapeState;
	}

	@Override
	public Drawable mutate() {
	if (!mMutated && super.mutate() == this) {
	if (mShapeState.mPaint != null) {
	mShapeState.mPaint = new Paint(mShapeState.mPaint);
	} else {
	mShapeState.mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
	}
	if (mShapeState.mPadding != null) {
	mShapeState.mPadding = new Rect(mShapeState.mPadding);
	} else {
	mShapeState.mPadding = new Rect();
	}
	try {
	mShapeState.mShape = mShapeState.mShape.clone();
	} catch (CloneNotSupportedException e) {
	return null;
	}
	mMutated = true;
	}
	return this;
	}

	/**
	* @hide
	*/
	public void clearMutated() {
	super.clearMutated();
	mMutated = false;
	}

	/**
	* Defines the intrinsic properties of this ShapeDrawable's Shape.
	*/
	final static class ShapeState extends ConstantState {
	int[] mThemeAttrs;
	int mChangingConfigurations;
	Paint mPaint;
	Shape mShape;
	ColorStateList mTint = null;
	Mode mTintMode = DEFAULT_TINT_MODE;
	Rect mPadding;
	int mIntrinsicWidth;
	int mIntrinsicHeight;
	int mAlpha = 255;
	ShaderFactory mShaderFactory;

	ShapeState(ShapeState orig) {
	if (orig != null) {
	mThemeAttrs = orig.mThemeAttrs;
	mPaint = orig.mPaint;
	mShape = orig.mShape;
	mTint = orig.mTint;
	mTintMode = orig.mTintMode;
	mPadding = orig.mPadding;
	mIntrinsicWidth = orig.mIntrinsicWidth;
	mIntrinsicHeight = orig.mIntrinsicHeight;
	mAlpha = orig.mAlpha;
	mShaderFactory = orig.mShaderFactory;
	} else {
	mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
	}
	}

	@Override
	public boolean canApplyTheme() {
	return mThemeAttrs != null;
	}

	@Override
	public Drawable newDrawable() {
	return new ShapeDrawable(this, null);
	}

	@Override
	public Drawable newDrawable(Resources res) {
	return new ShapeDrawable(this, res);
	}

	@Override
	public int getChangingConfigurations() {
	return mChangingConfigurations;
	}
	}

	/**
	* The one constructor to rule them all. This is called by all public
	* constructors to set the state and initialize local properties.
	*/
	private ShapeDrawable(ShapeState state, Resources res) {
	mShapeState = state;

	initializeWithState(state, res);
	}

	/**
	* Initializes local dynamic properties from state. This should be called
	* after significant state changes, e.g. from the One True Constructor and
	* after inflating or applying a theme.
	*/
	private void initializeWithState(ShapeState state, Resources res) {
	mTintFilter = updateTintFilter(mTintFilter, state.mTint, state.mTintMode);
	}

	/**
	* Base class defines a factory object that is called each time the drawable
	* is resized (has a new width or height). Its resize() method returns a
	* corresponding shader, or null. Implement this class if you'd like your
	* ShapeDrawable to use a special {@link android.graphics.Shader}, such as a
	* {@link android.graphics.LinearGradient}.
	*/
	public static abstract class ShaderFactory {
	/**
	* Returns the Shader to be drawn when a Drawable is drawn. The
	* dimensions of the Drawable are passed because they may be needed to
	* adjust how the Shader is configured for drawing. This is called by
	* ShapeDrawable.setShape().
	*
	* @param width the width of the Drawable being drawn
	* @param height the heigh of the Drawable being drawn
	* @return the Shader to be drawn
	*/
	public abstract Shader resize(int width, int height);
	}

	// other subclass could wack the Shader's localmatrix based on the
	// resize params (e.g. scaletofit, etc.). This could be used to scale
	// a bitmap to fill the bounds without needing any other special casing.
	}