src/com/android/launcher3/folder/PreviewBackground.java - platform/packages/apps/Launcher3 - Git at Google

 /*
  * Copyright (C) 2017 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 com.android.launcher3.folder;

 import android.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.ObjectAnimator;
 import android.animation.ValueAnimator;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Matrix;
 import android.graphics.Paint;
 import android.graphics.Path;
 import android.graphics.PorterDuff;
 import android.graphics.PorterDuffXfermode;
 import android.graphics.RadialGradient;
 import android.graphics.Region;
 import android.graphics.Shader;
 import android.support.v4.graphics.ColorUtils;
 import android.util.Property;
 import android.view.View;

 import com.android.launcher3.CellLayout;
 import com.android.launcher3.DeviceProfile;
 import com.android.launcher3.Launcher;
 import com.android.launcher3.LauncherAnimUtils;
 import com.android.launcher3.util.Themes;

 /**
  * This object represents a FolderIcon preview background. It stores drawing / measurement
  * information, handles drawing, and animation (accept state <--> rest state).
  */
 public class PreviewBackground {

     private static final int CONSUMPTION_ANIMATION_DURATION = 100;

     private final PorterDuffXfermode mClipPorterDuffXfermode
             = new PorterDuffXfermode(PorterDuff.Mode.DST_IN);
     // Create a RadialGradient such that it draws a black circle and then extends with
     // transparent. To achieve this, we keep the gradient to black for the range [0, 1) and
     // just at the edge quickly change it to transparent.
     private final RadialGradient mClipShader = new RadialGradient(0, 0, 1,
             new int[] {Color.BLACK, Color.BLACK, Color.TRANSPARENT },
             new float[] {0, 0.999f, 1},
             Shader.TileMode.CLAMP);

     private final PorterDuffXfermode mShadowPorterDuffXfermode
             = new PorterDuffXfermode(PorterDuff.Mode.DST_OUT);
     private RadialGradient mShadowShader = null;

     private final Matrix mShaderMatrix = new Matrix();
     private final Path mPath = new Path();

     private final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

     float mScale = 1f;
     private float mColorMultiplier = 1f;
     private int mBgColor;
     private float mStrokeWidth;
     private int mStrokeAlpha = MAX_BG_OPACITY;
     private int mShadowAlpha = 255;
     private View mInvalidateDelegate;

     int previewSize;
     int basePreviewOffsetX;
     int basePreviewOffsetY;

     private CellLayout mDrawingDelegate;
     public int delegateCellX;
     public int delegateCellY;

     // When the PreviewBackground is drawn under an icon (for creating a folder) the border
     // should not occlude the icon
     public boolean isClipping = true;

     // Drawing / animation configurations
     private static final float ACCEPT_SCALE_FACTOR = 1.20f;
     private static final float ACCEPT_COLOR_MULTIPLIER = 1.5f;

     // Expressed on a scale from 0 to 255.
     private static final int BG_OPACITY = 160;
     private static final int MAX_BG_OPACITY = 225;
     private static final int SHADOW_OPACITY = 40;

     private ValueAnimator mScaleAnimator;
     private ObjectAnimator mStrokeAlphaAnimator;
     private ObjectAnimator mShadowAnimator;

     private static final Property<PreviewBackground, Integer> STROKE_ALPHA =
             new Property<PreviewBackground, Integer>(Integer.class, "strokeAlpha") {
                 @Override
                 public Integer get(PreviewBackground previewBackground) {
                     return previewBackground.mStrokeAlpha;
                 }

                 @Override
                 public void set(PreviewBackground previewBackground, Integer alpha) {
                     previewBackground.mStrokeAlpha = alpha;
                     previewBackground.invalidate();
                 }
             };

     private static final Property<PreviewBackground, Integer> SHADOW_ALPHA =
             new Property<PreviewBackground, Integer>(Integer.class, "shadowAlpha") {
                 @Override
                 public Integer get(PreviewBackground previewBackground) {
                     return previewBackground.mShadowAlpha;
                 }

                 @Override
                 public void set(PreviewBackground previewBackground, Integer alpha) {
                     previewBackground.mShadowAlpha = alpha;
                     previewBackground.invalidate();
                 }
             };

     public void setup(Launcher launcher, View invalidateDelegate,
                       int availableSpaceX, int topPadding) {
         mInvalidateDelegate = invalidateDelegate;
         mBgColor = Themes.getAttrColor(launcher, android.R.attr.colorPrimary);

         DeviceProfile grid = launcher.getDeviceProfile();
         previewSize = grid.folderIconSizePx;

         basePreviewOffsetX = (availableSpaceX - previewSize) / 2;
         basePreviewOffsetY = topPadding + grid.folderIconOffsetYPx;

         // Stroke width is 1dp
         mStrokeWidth = launcher.getResources().getDisplayMetrics().density;

         float radius = getScaledRadius();
         float shadowRadius = radius + mStrokeWidth;
         int shadowColor = Color.argb(SHADOW_OPACITY, 0, 0, 0);
         mShadowShader = new RadialGradient(0, 0, 1,
                 new int[] {shadowColor, Color.TRANSPARENT},
                 new float[] {radius / shadowRadius, 1},
                 Shader.TileMode.CLAMP);

         invalidate();
     }

     int getRadius() {
         return previewSize / 2;
     }

     int getScaledRadius() {
         return (int) (mScale * getRadius());
     }

     int getOffsetX() {
         return basePreviewOffsetX - (getScaledRadius() - getRadius());
     }

     int getOffsetY() {
         return basePreviewOffsetY - (getScaledRadius() - getRadius());
     }

     /**
      * Returns the progress of the scale animation, where 0 means the scale is at 1f
      * and 1 means the scale is at ACCEPT_SCALE_FACTOR.
      */
     float getScaleProgress() {
         return (mScale - 1f) / (ACCEPT_SCALE_FACTOR - 1f);
     }

     void invalidate() {
         if (mInvalidateDelegate != null) {
             mInvalidateDelegate.invalidate();
         }

         if (mDrawingDelegate != null) {
             mDrawingDelegate.invalidate();
         }
     }

     void setInvalidateDelegate(View invalidateDelegate) {
         mInvalidateDelegate = invalidateDelegate;
         invalidate();
     }

     public int getBgColor() {
         int alpha = (int) Math.min(MAX_BG_OPACITY, BG_OPACITY * mColorMultiplier);
         return ColorUtils.setAlphaComponent(mBgColor, alpha);
     }

     public int getBadgeColor() {
         return mBgColor;
     }

     public void drawBackground(Canvas canvas) {
         mPaint.setStyle(Paint.Style.FILL);
         mPaint.setColor(getBgColor());

         drawCircle(canvas, 0 /* deltaRadius */);

         drawShadow(canvas);
     }

     public void drawShadow(Canvas canvas) {
         if (mShadowShader == null) {
             return;
         }

         float radius = getScaledRadius();
         float shadowRadius = radius + mStrokeWidth;
         mPaint.setStyle(Paint.Style.FILL);
         mPaint.setColor(Color.BLACK);
         int offsetX = getOffsetX();
         int offsetY = getOffsetY();
         final int saveCount;
         if (canvas.isHardwareAccelerated()) {
             saveCount = canvas.saveLayer(offsetX - mStrokeWidth, offsetY,
                     offsetX + radius + shadowRadius, offsetY + shadowRadius + shadowRadius, null);

         } else {
             saveCount = canvas.save();
             canvas.clipPath(getClipPath(), Region.Op.DIFFERENCE);
         }

         mShaderMatrix.setScale(shadowRadius, shadowRadius);
         mShaderMatrix.postTranslate(radius + offsetX, shadowRadius + offsetY);
         mShadowShader.setLocalMatrix(mShaderMatrix);
         mPaint.setAlpha(mShadowAlpha);
         mPaint.setShader(mShadowShader);
         canvas.drawPaint(mPaint);
         mPaint.setAlpha(255);
         mPaint.setShader(null);
         if (canvas.isHardwareAccelerated()) {
             mPaint.setXfermode(mShadowPorterDuffXfermode);
             canvas.drawCircle(radius + offsetX, radius + offsetY, radius, mPaint);
             mPaint.setXfermode(null);
         }

         canvas.restoreToCount(saveCount);
     }

     public void fadeInBackgroundShadow() {
         if (mShadowAnimator != null) {
             mShadowAnimator.cancel();
         }
         mShadowAnimator = ObjectAnimator
                 .ofInt(this, SHADOW_ALPHA, 0, 255)
                 .setDuration(100);
         mShadowAnimator.addListener(new AnimatorListenerAdapter() {
             @Override
             public void onAnimationEnd(Animator animation) {
                 mShadowAnimator = null;
             }
         });
         mShadowAnimator.start();
     }

     public void animateBackgroundStroke() {
         if (mStrokeAlphaAnimator != null) {
             mStrokeAlphaAnimator.cancel();
         }
         mStrokeAlphaAnimator = ObjectAnimator
                 .ofInt(this, STROKE_ALPHA, MAX_BG_OPACITY / 2, MAX_BG_OPACITY)
                 .setDuration(100);
         mStrokeAlphaAnimator.addListener(new AnimatorListenerAdapter() {
             @Override
             public void onAnimationEnd(Animator animation) {
                 mStrokeAlphaAnimator = null;
             }
         });
         mStrokeAlphaAnimator.start();
     }

     public void drawBackgroundStroke(Canvas canvas) {
         mPaint.setColor(ColorUtils.setAlphaComponent(mBgColor, mStrokeAlpha));
         mPaint.setStyle(Paint.Style.STROKE);
         mPaint.setStrokeWidth(mStrokeWidth);
         drawCircle(canvas, 1 /* deltaRadius */);
     }

     public void drawLeaveBehind(Canvas canvas) {
         float originalScale = mScale;
         mScale = 0.5f;

         mPaint.setStyle(Paint.Style.FILL);
         mPaint.setColor(Color.argb(160, 245, 245, 245));
         drawCircle(canvas, 0 /* deltaRadius */);

         mScale = originalScale;
     }

     private void drawCircle(Canvas canvas,float deltaRadius) {
         float radius = getScaledRadius();
         canvas.drawCircle(radius + getOffsetX(), radius + getOffsetY(),
                 radius - deltaRadius, mPaint);
     }

     public Path getClipPath() {
         mPath.reset();
         float r = getScaledRadius();
         mPath.addCircle(r + getOffsetX(), r + getOffsetY(), r, Path.Direction.CW);
         return mPath;
     }

     // It is the callers responsibility to save and restore the canvas layers.
     void clipCanvasHardware(Canvas canvas) {
         mPaint.setColor(Color.BLACK);
         mPaint.setStyle(Paint.Style.FILL);
         mPaint.setXfermode(mClipPorterDuffXfermode);

         float radius = getScaledRadius();
         mShaderMatrix.setScale(radius, radius);
         mShaderMatrix.postTranslate(radius + getOffsetX(), radius + getOffsetY());
         mClipShader.setLocalMatrix(mShaderMatrix);
         mPaint.setShader(mClipShader);
         canvas.drawPaint(mPaint);
         mPaint.setXfermode(null);
         mPaint.setShader(null);
     }

     private void delegateDrawing(CellLayout delegate, int cellX, int cellY) {
         if (mDrawingDelegate != delegate) {
             delegate.addFolderBackground(this);
         }

         mDrawingDelegate = delegate;
         delegateCellX = cellX;
         delegateCellY = cellY;

         invalidate();
     }

     private void clearDrawingDelegate() {
         if (mDrawingDelegate != null) {
             mDrawingDelegate.removeFolderBackground(this);
         }

         mDrawingDelegate = null;
         isClipping = true;
         invalidate();
     }

     boolean drawingDelegated() {
         return mDrawingDelegate != null;
     }

     private void animateScale(float finalScale, float finalMultiplier,
                               final Runnable onStart, final Runnable onEnd) {
         final float scale0 = mScale;
         final float scale1 = finalScale;

         final float bgMultiplier0 = mColorMultiplier;
         final float bgMultiplier1 = finalMultiplier;

         if (mScaleAnimator != null) {
             mScaleAnimator.cancel();
         }

         mScaleAnimator = LauncherAnimUtils.ofFloat(0f, 1.0f);

         mScaleAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
             @Override
             public void onAnimationUpdate(ValueAnimator animation) {
                 float prog = animation.getAnimatedFraction();
                 mScale = prog * scale1 + (1 - prog) * scale0;
                 mColorMultiplier = prog * bgMultiplier1 + (1 - prog) * bgMultiplier0;
                 invalidate();
             }
         });
         mScaleAnimator.addListener(new AnimatorListenerAdapter() {
             @Override
             public void onAnimationStart(Animator animation) {
                 if (onStart != null) {
                     onStart.run();
                 }
             }

             @Override
             public void onAnimationEnd(Animator animation) {
                 if (onEnd != null) {
                     onEnd.run();
                 }
                 mScaleAnimator = null;
             }
         });

         mScaleAnimator.setDuration(CONSUMPTION_ANIMATION_DURATION);
         mScaleAnimator.start();
     }

     public void animateToAccept(final CellLayout cl, final int cellX, final int cellY) {
         Runnable onStart = new Runnable() {
             @Override
             public void run() {
                 delegateDrawing(cl, cellX, cellY);
             }
         };
         animateScale(ACCEPT_SCALE_FACTOR, ACCEPT_COLOR_MULTIPLIER, onStart, null);
     }

     public void animateToRest() {
         // This can be called multiple times -- we need to make sure the drawing delegate
         // is saved and restored at the beginning of the animation, since cancelling the
         // existing animation can clear the delgate.
         final CellLayout cl = mDrawingDelegate;
         final int cellX = delegateCellX;
         final int cellY = delegateCellY;

         Runnable onStart = new Runnable() {
             @Override
             public void run() {
                 delegateDrawing(cl, cellX, cellY);
             }
         };
         Runnable onEnd = new Runnable() {
             @Override
             public void run() {
                 clearDrawingDelegate();
             }
         };
         animateScale(1f, 1f, onStart, onEnd);
     }

     public int getBackgroundAlpha() {
         return (int) Math.min(MAX_BG_OPACITY, BG_OPACITY * mColorMultiplier);
     }

     public float getStrokeWidth() {
         return mStrokeWidth;
     }
 }
	/*
	* Copyright (C) 2017 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 com.android.launcher3.folder;

	import android.animation.Animator;
	import android.animation.AnimatorListenerAdapter;
	import android.animation.ObjectAnimator;
	import android.animation.ValueAnimator;
	import android.graphics.Canvas;
	import android.graphics.Color;
	import android.graphics.Matrix;
	import android.graphics.Paint;
	import android.graphics.Path;
	import android.graphics.PorterDuff;
	import android.graphics.PorterDuffXfermode;
	import android.graphics.RadialGradient;
	import android.graphics.Region;
	import android.graphics.Shader;
	import android.support.v4.graphics.ColorUtils;
	import android.util.Property;
	import android.view.View;

	import com.android.launcher3.CellLayout;
	import com.android.launcher3.DeviceProfile;
	import com.android.launcher3.Launcher;
	import com.android.launcher3.LauncherAnimUtils;
	import com.android.launcher3.util.Themes;

	/**
	* This object represents a FolderIcon preview background. It stores drawing / measurement
	* information, handles drawing, and animation (accept state <--> rest state).
	*/
	public class PreviewBackground {

	private static final int CONSUMPTION_ANIMATION_DURATION = 100;

	private final PorterDuffXfermode mClipPorterDuffXfermode
	= new PorterDuffXfermode(PorterDuff.Mode.DST_IN);
	// Create a RadialGradient such that it draws a black circle and then extends with
	// transparent. To achieve this, we keep the gradient to black for the range [0, 1) and
	// just at the edge quickly change it to transparent.
	private final RadialGradient mClipShader = new RadialGradient(0, 0, 1,
	new int[] {Color.BLACK, Color.BLACK, Color.TRANSPARENT },
	new float[] {0, 0.999f, 1},
	Shader.TileMode.CLAMP);

	private final PorterDuffXfermode mShadowPorterDuffXfermode
	= new PorterDuffXfermode(PorterDuff.Mode.DST_OUT);
	private RadialGradient mShadowShader = null;

	private final Matrix mShaderMatrix = new Matrix();
	private final Path mPath = new Path();

	private final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

	float mScale = 1f;
	private float mColorMultiplier = 1f;
	private int mBgColor;
	private float mStrokeWidth;
	private int mStrokeAlpha = MAX_BG_OPACITY;
	private int mShadowAlpha = 255;
	private View mInvalidateDelegate;

	int previewSize;
	int basePreviewOffsetX;
	int basePreviewOffsetY;

	private CellLayout mDrawingDelegate;
	public int delegateCellX;
	public int delegateCellY;

	// When the PreviewBackground is drawn under an icon (for creating a folder) the border
	// should not occlude the icon
	public boolean isClipping = true;

	// Drawing / animation configurations
	private static final float ACCEPT_SCALE_FACTOR = 1.20f;
	private static final float ACCEPT_COLOR_MULTIPLIER = 1.5f;

	// Expressed on a scale from 0 to 255.
	private static final int BG_OPACITY = 160;
	private static final int MAX_BG_OPACITY = 225;
	private static final int SHADOW_OPACITY = 40;

	private ValueAnimator mScaleAnimator;
	private ObjectAnimator mStrokeAlphaAnimator;
	private ObjectAnimator mShadowAnimator;

	private static final Property<PreviewBackground, Integer> STROKE_ALPHA =
	new Property<PreviewBackground, Integer>(Integer.class, "strokeAlpha") {
	@Override
	public Integer get(PreviewBackground previewBackground) {
	return previewBackground.mStrokeAlpha;
	}

	@Override
	public void set(PreviewBackground previewBackground, Integer alpha) {
	previewBackground.mStrokeAlpha = alpha;
	previewBackground.invalidate();
	}
	};

	private static final Property<PreviewBackground, Integer> SHADOW_ALPHA =
	new Property<PreviewBackground, Integer>(Integer.class, "shadowAlpha") {
	@Override
	public Integer get(PreviewBackground previewBackground) {
	return previewBackground.mShadowAlpha;
	}

	@Override
	public void set(PreviewBackground previewBackground, Integer alpha) {
	previewBackground.mShadowAlpha = alpha;
	previewBackground.invalidate();
	}
	};

	public void setup(Launcher launcher, View invalidateDelegate,
	int availableSpaceX, int topPadding) {
	mInvalidateDelegate = invalidateDelegate;
	mBgColor = Themes.getAttrColor(launcher, android.R.attr.colorPrimary);

	DeviceProfile grid = launcher.getDeviceProfile();
	previewSize = grid.folderIconSizePx;

	basePreviewOffsetX = (availableSpaceX - previewSize) / 2;
	basePreviewOffsetY = topPadding + grid.folderIconOffsetYPx;

	// Stroke width is 1dp
	mStrokeWidth = launcher.getResources().getDisplayMetrics().density;

	float radius = getScaledRadius();
	float shadowRadius = radius + mStrokeWidth;
	int shadowColor = Color.argb(SHADOW_OPACITY, 0, 0, 0);
	mShadowShader = new RadialGradient(0, 0, 1,
	new int[] {shadowColor, Color.TRANSPARENT},
	new float[] {radius / shadowRadius, 1},
	Shader.TileMode.CLAMP);

	invalidate();
	}

	int getRadius() {
	return previewSize / 2;
	}

	int getScaledRadius() {
	return (int) (mScale * getRadius());
	}

	int getOffsetX() {
	return basePreviewOffsetX - (getScaledRadius() - getRadius());
	}

	int getOffsetY() {
	return basePreviewOffsetY - (getScaledRadius() - getRadius());
	}

	/**
	* Returns the progress of the scale animation, where 0 means the scale is at 1f
	* and 1 means the scale is at ACCEPT_SCALE_FACTOR.
	*/
	float getScaleProgress() {
	return (mScale - 1f) / (ACCEPT_SCALE_FACTOR - 1f);
	}

	void invalidate() {
	if (mInvalidateDelegate != null) {
	mInvalidateDelegate.invalidate();
	}

	if (mDrawingDelegate != null) {
	mDrawingDelegate.invalidate();
	}
	}

	void setInvalidateDelegate(View invalidateDelegate) {
	mInvalidateDelegate = invalidateDelegate;
	invalidate();
	}

	public int getBgColor() {
	int alpha = (int) Math.min(MAX_BG_OPACITY, BG_OPACITY * mColorMultiplier);
	return ColorUtils.setAlphaComponent(mBgColor, alpha);
	}

	public int getBadgeColor() {
	return mBgColor;
	}

	public void drawBackground(Canvas canvas) {
	mPaint.setStyle(Paint.Style.FILL);
	mPaint.setColor(getBgColor());

	drawCircle(canvas, 0 /* deltaRadius */);

	drawShadow(canvas);
	}

	public void drawShadow(Canvas canvas) {
	if (mShadowShader == null) {
	return;
	}

	float radius = getScaledRadius();
	float shadowRadius = radius + mStrokeWidth;
	mPaint.setStyle(Paint.Style.FILL);
	mPaint.setColor(Color.BLACK);
	int offsetX = getOffsetX();
	int offsetY = getOffsetY();
	final int saveCount;
	if (canvas.isHardwareAccelerated()) {
	saveCount = canvas.saveLayer(offsetX - mStrokeWidth, offsetY,
	offsetX + radius + shadowRadius, offsetY + shadowRadius + shadowRadius, null);

	} else {
	saveCount = canvas.save();
	canvas.clipPath(getClipPath(), Region.Op.DIFFERENCE);
	}

	mShaderMatrix.setScale(shadowRadius, shadowRadius);
	mShaderMatrix.postTranslate(radius + offsetX, shadowRadius + offsetY);
	mShadowShader.setLocalMatrix(mShaderMatrix);
	mPaint.setAlpha(mShadowAlpha);
	mPaint.setShader(mShadowShader);
	canvas.drawPaint(mPaint);
	mPaint.setAlpha(255);
	mPaint.setShader(null);
	if (canvas.isHardwareAccelerated()) {
	mPaint.setXfermode(mShadowPorterDuffXfermode);
	canvas.drawCircle(radius + offsetX, radius + offsetY, radius, mPaint);
	mPaint.setXfermode(null);
	}

	canvas.restoreToCount(saveCount);
	}

	public void fadeInBackgroundShadow() {
	if (mShadowAnimator != null) {
	mShadowAnimator.cancel();
	}
	mShadowAnimator = ObjectAnimator
	.ofInt(this, SHADOW_ALPHA, 0, 255)
	.setDuration(100);
	mShadowAnimator.addListener(new AnimatorListenerAdapter() {
	@Override
	public void onAnimationEnd(Animator animation) {
	mShadowAnimator = null;
	}
	});
	mShadowAnimator.start();
	}

	public void animateBackgroundStroke() {
	if (mStrokeAlphaAnimator != null) {
	mStrokeAlphaAnimator.cancel();
	}
	mStrokeAlphaAnimator = ObjectAnimator
	.ofInt(this, STROKE_ALPHA, MAX_BG_OPACITY / 2, MAX_BG_OPACITY)
	.setDuration(100);
	mStrokeAlphaAnimator.addListener(new AnimatorListenerAdapter() {
	@Override
	public void onAnimationEnd(Animator animation) {
	mStrokeAlphaAnimator = null;
	}
	});
	mStrokeAlphaAnimator.start();
	}

	public void drawBackgroundStroke(Canvas canvas) {
	mPaint.setColor(ColorUtils.setAlphaComponent(mBgColor, mStrokeAlpha));
	mPaint.setStyle(Paint.Style.STROKE);
	mPaint.setStrokeWidth(mStrokeWidth);
	drawCircle(canvas, 1 /* deltaRadius */);
	}

	public void drawLeaveBehind(Canvas canvas) {
	float originalScale = mScale;
	mScale = 0.5f;

	mPaint.setStyle(Paint.Style.FILL);
	mPaint.setColor(Color.argb(160, 245, 245, 245));
	drawCircle(canvas, 0 /* deltaRadius */);

	mScale = originalScale;
	}

	private void drawCircle(Canvas canvas,float deltaRadius) {
	float radius = getScaledRadius();
	canvas.drawCircle(radius + getOffsetX(), radius + getOffsetY(),
	radius - deltaRadius, mPaint);
	}

	public Path getClipPath() {
	mPath.reset();
	float r = getScaledRadius();
	mPath.addCircle(r + getOffsetX(), r + getOffsetY(), r, Path.Direction.CW);
	return mPath;
	}

	// It is the callers responsibility to save and restore the canvas layers.
	void clipCanvasHardware(Canvas canvas) {
	mPaint.setColor(Color.BLACK);
	mPaint.setStyle(Paint.Style.FILL);
	mPaint.setXfermode(mClipPorterDuffXfermode);

	float radius = getScaledRadius();
	mShaderMatrix.setScale(radius, radius);
	mShaderMatrix.postTranslate(radius + getOffsetX(), radius + getOffsetY());
	mClipShader.setLocalMatrix(mShaderMatrix);
	mPaint.setShader(mClipShader);
	canvas.drawPaint(mPaint);
	mPaint.setXfermode(null);
	mPaint.setShader(null);
	}

	private void delegateDrawing(CellLayout delegate, int cellX, int cellY) {
	if (mDrawingDelegate != delegate) {
	delegate.addFolderBackground(this);
	}

	mDrawingDelegate = delegate;
	delegateCellX = cellX;
	delegateCellY = cellY;

	invalidate();
	}

	private void clearDrawingDelegate() {
	if (mDrawingDelegate != null) {
	mDrawingDelegate.removeFolderBackground(this);
	}

	mDrawingDelegate = null;
	isClipping = true;
	invalidate();
	}

	boolean drawingDelegated() {
	return mDrawingDelegate != null;
	}

	private void animateScale(float finalScale, float finalMultiplier,
	final Runnable onStart, final Runnable onEnd) {
	final float scale0 = mScale;
	final float scale1 = finalScale;

	final float bgMultiplier0 = mColorMultiplier;
	final float bgMultiplier1 = finalMultiplier;

	if (mScaleAnimator != null) {
	mScaleAnimator.cancel();
	}

	mScaleAnimator = LauncherAnimUtils.ofFloat(0f, 1.0f);

	mScaleAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
	@Override
	public void onAnimationUpdate(ValueAnimator animation) {
	float prog = animation.getAnimatedFraction();
	mScale = prog * scale1 + (1 - prog) * scale0;
	mColorMultiplier = prog * bgMultiplier1 + (1 - prog) * bgMultiplier0;
	invalidate();
	}
	});
	mScaleAnimator.addListener(new AnimatorListenerAdapter() {
	@Override
	public void onAnimationStart(Animator animation) {
	if (onStart != null) {
	onStart.run();
	}
	}

	@Override
	public void onAnimationEnd(Animator animation) {
	if (onEnd != null) {
	onEnd.run();
	}
	mScaleAnimator = null;
	}
	});

	mScaleAnimator.setDuration(CONSUMPTION_ANIMATION_DURATION);
	mScaleAnimator.start();
	}

	public void animateToAccept(final CellLayout cl, final int cellX, final int cellY) {
	Runnable onStart = new Runnable() {
	@Override
	public void run() {
	delegateDrawing(cl, cellX, cellY);
	}
	};
	animateScale(ACCEPT_SCALE_FACTOR, ACCEPT_COLOR_MULTIPLIER, onStart, null);
	}

	public void animateToRest() {
	// This can be called multiple times -- we need to make sure the drawing delegate
	// is saved and restored at the beginning of the animation, since cancelling the
	// existing animation can clear the delgate.
	final CellLayout cl = mDrawingDelegate;
	final int cellX = delegateCellX;
	final int cellY = delegateCellY;

	Runnable onStart = new Runnable() {
	@Override
	public void run() {
	delegateDrawing(cl, cellX, cellY);
	}
	};
	Runnable onEnd = new Runnable() {
	@Override
	public void run() {
	clearDrawingDelegate();
	}
	};
	animateScale(1f, 1f, onStart, onEnd);
	}

	public int getBackgroundAlpha() {
	return (int) Math.min(MAX_BG_OPACITY, BG_OPACITY * mColorMultiplier);
	}

	public float getStrokeWidth() {
	return mStrokeWidth;
	}
	}