Cache widget previews in a DB

- Smoother All Apps scroll performance

Change-Id: Id2d31a45e71c63d05a46f580667ad94403730616

7 files changed, 682 insertions, 310 deletions

diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index c14b63ed8..f3ef6c8c1 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -134,7 +134,16 @@
                 <action android:name="android.intent.action.USER_INITIALIZE" />
             </intent-filter>
         </receiver>
-        
+
+        <receiver android:name="com.android.launcher2.PackageChangedReceiver" >
+            <intent-filter>
+                <action android:name="android.intent.action.PACKAGE_CHANGED"/>
+                <action android:name="android.intent.action.PACKAGE_REPLACED"/>
+                <action android:name="android.intent.action.PACKAGE_REMOVED"/>
+                <data android:scheme="package"></data>
+            </intent-filter>
+        </receiver>
+
         <!-- The settings provider contains Home's data, like the workspace favorites -->
         <provider
             android:name="com.android.launcher2.LauncherProvider"
diff --git a/src/com/android/launcher2/AppsCustomizePagedView.java b/src/com/android/launcher2/AppsCustomizePagedView.java
index 1817c824f..bfc2db02c 100644
--- a/src/com/android/launcher2/AppsCustomizePagedView.java
+++ b/src/com/android/launcher2/AppsCustomizePagedView.java
@@ -30,17 +30,9 @@ import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.content.res.TypedArray;
 import android.graphics.Bitmap;
-import android.graphics.Bitmap.Config;
 import android.graphics.Canvas;
-import android.graphics.ColorMatrix;
-import android.graphics.ColorMatrixColorFilter;
-import android.graphics.Matrix;
-import android.graphics.Paint;
-import android.graphics.PorterDuff;
+import android.graphics.Point;
 import android.graphics.Rect;
-import android.graphics.RectF;
-import android.graphics.Shader;
-import android.graphics.drawable.BitmapDrawable;
 import android.graphics.drawable.Drawable;
 import android.os.AsyncTask;
 import android.os.Build;
@@ -62,7 +54,6 @@ import android.widget.Toast;
 import com.android.launcher.R;
 import com.android.launcher2.DropTarget.DragObject;
 
-import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
@@ -83,16 +74,6 @@ class AsyncTaskPageData {
         LoadWidgetPreviewData
     }
 
-    AsyncTaskPageData(int p, ArrayList<Object> l, ArrayList<Bitmap> si, AsyncTaskCallback bgR,
-            AsyncTaskCallback postR) {
-        page = p;
-        items = l;
-        sourceImages = si;
-        generatedImages = new ArrayList<Bitmap>();
-        maxImageWidth = maxImageHeight = -1;
-        doInBackgroundCallback = bgR;
-        postExecuteCallback = postR;
-    }
     AsyncTaskPageData(int p, ArrayList<Object> l, int cw, int ch, AsyncTaskCallback bgR,
             AsyncTaskCallback postR) {
         page = p;
@@ -105,18 +86,10 @@ class AsyncTaskPageData {
     }
     void cleanup(boolean cancelled) {
         // Clean up any references to source/generated bitmaps
-        if (sourceImages != null) {
-            if (cancelled) {
-                for (Bitmap b : sourceImages) {
-                    b.recycle();
-                }
-            }
-            sourceImages.clear();
-        }
         if (generatedImages != null) {
             if (cancelled) {
-                for (Bitmap b : generatedImages) {
-                    b.recycle();
+                for (int i = 0; i < generatedImages.size(); i++) {
+                    WidgetPreviewLoader.releaseBitmap(items.get(i), generatedImages.get(i));
                 }
             }
             generatedImages.clear();
@@ -167,64 +140,6 @@ class AppsCustomizeAsyncTask extends AsyncTask<AsyncTaskPageData, Void, AsyncTas
     int threadPriority;
 }
 
-abstract class WeakReferenceThreadLocal<T> {
-    private ThreadLocal<WeakReference<T>> mThreadLocal;
-    public WeakReferenceThreadLocal() {
-        mThreadLocal = new ThreadLocal<WeakReference<T>>();
-    }
-
-    abstract T initialValue();
-
-    public void set(T t) {
-        mThreadLocal.set(new WeakReference<T>(t));
-    }
-
-    public T get() {
-        WeakReference<T> reference = mThreadLocal.get();
-        T obj;
-        if (reference == null) {
-            obj = initialValue();
-            mThreadLocal.set(new WeakReference<T>(obj));
-            return obj;
-        } else {
-            obj = reference.get();
-            if (obj == null) {
-                obj = initialValue();
-                mThreadLocal.set(new WeakReference<T>(obj));
-            }
-            return obj;
-        }
-    }
-}
-
-class CanvasCache extends WeakReferenceThreadLocal<Canvas> {
-    @Override
-    protected Canvas initialValue() {
-        return new Canvas();
-    }
-}
-
-class PaintCache extends WeakReferenceThreadLocal<Paint> {
-    @Override
-    protected Paint initialValue() {
-        return null;
-    }
-}
-
-class BitmapCache extends WeakReferenceThreadLocal<Bitmap> {
-    @Override
-    protected Bitmap initialValue() {
-        return null;
-    }
-}
-
-class RectCache extends WeakReferenceThreadLocal<Rect> {
-    @Override
-    protected Rect initialValue() {
-        return new Rect();
-    }
-}
-
 /**
  * The Apps/Customize page that displays all the applications, widgets, and shortcuts.
  */
@@ -267,11 +182,9 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
 
     // Dimens
     private int mContentWidth;
-    private int mAppIconSize;
     private int mMaxAppCellCountX, mMaxAppCellCountY;
     private int mWidgetCountX, mWidgetCountY;
     private int mWidgetWidthGap, mWidgetHeightGap;
-    private final float sWidgetPreviewIconPaddingPercentage = 0.25f;
     private PagedViewCellLayout mWidgetSpacingLayout;
     private int mNumAppsPages;
     private int mNumWidgetPages;
@@ -323,6 +236,8 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
     RectCache mCachedAppWidgetPreviewDestRect = new RectCache();
     PaintCache mCachedAppWidgetPreviewPaint = new PaintCache();
 
+    WidgetPreviewLoader mWidgetPreviewLoader;
+
     public AppsCustomizePagedView(Context context, AttributeSet attrs) {
         super(context, attrs);
         mLayoutInflater = LayoutInflater.from(context);
@@ -334,9 +249,6 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
         mRunningTasks = new ArrayList<AppsCustomizeAsyncTask>();
 
         // Save the default widget preview background
-        Resources resources = context.getResources();
-        mAppIconSize = resources.getDimensionPixelSize(R.dimen.app_icon_size);
-
         TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.AppsCustomizePagedView, 0, 0);
         mMaxAppCellCountX = a.getInt(R.styleable.AppsCustomizePagedView_maxAppCellCountX, -1);
         mMaxAppCellCountY = a.getInt(R.styleable.AppsCustomizePagedView_maxAppCellCountY, -1);
@@ -769,6 +681,8 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
         Bitmap preview;
         Bitmap outline;
         float scale = 1f;
+        Point previewPadding = null;
+
         if (createItemInfo instanceof PendingAddWidgetInfo) {
             // This can happen in some weird cases involving multi-touch. We can't start dragging
             // the widget if this is null, so we break out.
@@ -788,19 +702,25 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
             int maxWidth, maxHeight;
             maxWidth = Math.min((int) (previewDrawable.getIntrinsicWidth() * minScale), size[0]);
             maxHeight = Math.min((int) (previewDrawable.getIntrinsicHeight() * minScale), size[1]);
-            preview = getWidgetPreview(createWidgetInfo.componentName, createWidgetInfo.previewImage,
-                    createWidgetInfo.icon, spanX, spanY, maxWidth, maxHeight);
-
-            // Determine the image view drawable scale relative to the preview
-            float[] mv = new float[9];
-            Matrix m = new Matrix();
-            m.setRectToRect(
-                    new RectF(0f, 0f, (float) preview.getWidth(), (float) preview.getHeight()),
-                    new RectF(0f, 0f, (float) previewDrawable.getIntrinsicWidth(),
-                            (float) previewDrawable.getIntrinsicHeight()),
-                    Matrix.ScaleToFit.START);
-            m.getValues(mv);
-            scale = (float) mv[0];
+
+            int[] previewSizeBeforeScale = new int[1];
+
+            preview = mWidgetPreviewLoader.generateWidgetPreview(createWidgetInfo.componentName,
+                    createWidgetInfo.previewImage, createWidgetInfo.icon, spanX, spanY,
+                    maxWidth, maxHeight, null, previewSizeBeforeScale);
+
+            // Compare the size of the drag preview to the preview in the AppsCustomize tray
+            int previewWidthInAppsCustomize = Math.min(previewSizeBeforeScale[0],
+                    mWidgetPreviewLoader.maxWidthForWidgetPreview(spanX));
+            scale = previewWidthInAppsCustomize / (float) preview.getWidth();
+
+            // The bitmap in the AppsCustomize tray is always the the same size, so there
+            // might be extra pixels around the preview itself - this accounts for that
+            if (previewWidthInAppsCustomize < previewDrawable.getIntrinsicWidth()) {
+                int padding =
+                        (previewDrawable.getIntrinsicWidth() - previewWidthInAppsCustomize) / 2;
+                previewPadding = new Point(padding, 0);
+            }
         } else {
             PendingAddShortcutInfo createShortcutInfo = (PendingAddShortcutInfo) v.getTag();
             Drawable icon = mIconCache.getFullResIcon(createShortcutInfo.shortcutActivityInfo);
@@ -809,7 +729,7 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
 
             mCanvas.setBitmap(preview);
             mCanvas.save();
-            renderDrawableToBitmap(icon, preview, 0, 0,
+            WidgetPreviewLoader.renderDrawableToBitmap(icon, preview, 0, 0,
                     icon.getIntrinsicWidth(), icon.getIntrinsicHeight());
             mCanvas.restore();
             mCanvas.setBitmap(null);
@@ -828,7 +748,7 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
         mLauncher.lockScreenOrientation();
         mLauncher.getWorkspace().onDragStartedWithItem(createItemInfo, outline, clipAlpha);
         mDragController.startDrag(image, preview, this, createItemInfo,
-                DragController.DRAG_ACTION_COPY, null, scale);
+                DragController.DRAG_ACTION_COPY, previewPadding, scale);
         outline.recycle();
         preview.recycle();
         return true;
@@ -1215,181 +1135,6 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
         layout.measure(widthSpec, heightSpec);
     }
 
-    private void renderDrawableToBitmap(Drawable d, Bitmap bitmap, int x, int y, int w, int h) {
-        renderDrawableToBitmap(d, bitmap, x, y, w, h, 1f);
-    }
-
-    private void renderDrawableToBitmap(Drawable d, Bitmap bitmap, int x, int y, int w, int h,
-            float scale) {
-        if (bitmap != null) {
-            Canvas c = new Canvas(bitmap);
-            c.scale(scale, scale);
-            Rect oldBounds = d.copyBounds();
-            d.setBounds(x, y, x + w, y + h);
-            d.draw(c);
-            d.setBounds(oldBounds); // Restore the bounds
-            c.setBitmap(null);
-        }
-    }
-
-    private Bitmap getShortcutPreview(ResolveInfo info, int maxWidth, int maxHeight) {
-        Bitmap tempBitmap = mCachedShortcutPreviewBitmap.get();
-        final Canvas c = mCachedShortcutPreviewCanvas.get();
-        if (tempBitmap == null ||
-                tempBitmap.getWidth() != maxWidth ||
-                tempBitmap.getHeight() != maxHeight) {
-            tempBitmap = Bitmap.createBitmap(maxWidth, maxHeight, Config.ARGB_8888);
-            mCachedShortcutPreviewBitmap.set(tempBitmap);
-        } else {
-            c.setBitmap(tempBitmap);
-            c.drawColor(0, PorterDuff.Mode.CLEAR);
-            c.setBitmap(null);
-        }
-        // Render the icon
-        Drawable icon = mIconCache.getFullResIcon(info);
-
-        int paddingTop =
-                getResources().getDimensionPixelOffset(R.dimen.shortcut_preview_padding_top);
-        int paddingLeft =
-                getResources().getDimensionPixelOffset(R.dimen.shortcut_preview_padding_left);
-        int paddingRight =
-                getResources().getDimensionPixelOffset(R.dimen.shortcut_preview_padding_right);
-
-        int scaledIconWidth = (maxWidth - paddingLeft - paddingRight);
-
-        renderDrawableToBitmap(
-                icon, tempBitmap, paddingLeft, paddingTop, scaledIconWidth, scaledIconWidth);
-
-        Bitmap preview = Bitmap.createBitmap(maxWidth, maxHeight, Config.ARGB_8888);
-        c.setBitmap(preview);
-        Paint p = mCachedShortcutPreviewPaint.get();
-        if (p == null) {
-            p = new Paint();
-            ColorMatrix colorMatrix = new ColorMatrix();
-            colorMatrix.setSaturation(0);
-            p.setColorFilter(new ColorMatrixColorFilter(colorMatrix));
-            p.setAlpha((int) (255 * 0.06f));
-            //float density = 1f;
-            //p.setMaskFilter(new BlurMaskFilter(15*density, BlurMaskFilter.Blur.NORMAL));
-            mCachedShortcutPreviewPaint.set(p);
-        }
-        c.drawBitmap(tempBitmap, 0, 0, p);
-        c.setBitmap(null);
-
-        renderDrawableToBitmap(icon, preview, 0, 0, mAppIconSize, mAppIconSize);
-
-        return preview;
-    }
-
-    private Bitmap getWidgetPreview(ComponentName provider, int previewImage,
-            int iconId, int cellHSpan, int cellVSpan, int maxWidth,
-            int maxHeight) {
-        // Load the preview image if possible
-        String packageName = provider.getPackageName();
-        if (maxWidth < 0) maxWidth = Integer.MAX_VALUE;
-        if (maxHeight < 0) maxHeight = Integer.MAX_VALUE;
-
-        Drawable drawable = null;
-        if (previewImage != 0) {
-            drawable = mPackageManager.getDrawable(packageName, previewImage, null);
-            if (drawable == null) {
-                Log.w(TAG, "Can't load widget preview drawable 0x" +
-                        Integer.toHexString(previewImage) + " for provider: " + provider);
-            }
-        }
-
-        int bitmapWidth;
-        int bitmapHeight;
-        Bitmap defaultPreview = null;
-        boolean widgetPreviewExists = (drawable != null);
-        if (widgetPreviewExists) {
-            bitmapWidth = drawable.getIntrinsicWidth();
-            bitmapHeight = drawable.getIntrinsicHeight();
-        } else {
-            // Generate a preview image if we couldn't load one
-            if (cellHSpan < 1) cellHSpan = 1;
-            if (cellVSpan < 1) cellVSpan = 1;
-
-            BitmapDrawable previewDrawable = (BitmapDrawable) getResources()
-                    .getDrawable(R.drawable.widget_preview_tile);
-            final int previewDrawableWidth = previewDrawable
-                    .getIntrinsicWidth();
-            final int previewDrawableHeight = previewDrawable
-                    .getIntrinsicHeight();
-            bitmapWidth = previewDrawableWidth * cellHSpan; // subtract 2 dips
-            bitmapHeight = previewDrawableHeight * cellVSpan;
-
-            defaultPreview = Bitmap.createBitmap(bitmapWidth, bitmapHeight,
-                    Config.ARGB_8888);
-            final Canvas c = mCachedAppWidgetPreviewCanvas.get();
-            c.setBitmap(defaultPreview);
-            previewDrawable.setBounds(0, 0, bitmapWidth, bitmapHeight);
-            previewDrawable.setTileModeXY(Shader.TileMode.REPEAT,
-                    Shader.TileMode.REPEAT);
-            previewDrawable.draw(c);
-            c.setBitmap(null);
-
-            // Draw the icon in the top left corner
-            int minOffset = (int) (mAppIconSize * sWidgetPreviewIconPaddingPercentage);
-            int smallestSide = Math.min(bitmapWidth, bitmapHeight);
-            float iconScale = Math.min((float) smallestSide
-                    / (mAppIconSize + 2 * minOffset), 1f);
-
-            try {
-                Drawable icon = null;
-                int hoffset =
-                        (int) ((previewDrawableWidth - mAppIconSize * iconScale) / 2);
-                int yoffset =
-                        (int) ((previewDrawableHeight - mAppIconSize * iconScale) / 2);
-                if (iconId > 0)
-                    icon = mIconCache.getFullResIcon(packageName, iconId);
-                if (icon != null) {
-                    renderDrawableToBitmap(icon, defaultPreview, hoffset,
-                            yoffset, (int) (mAppIconSize * iconScale),
-                            (int) (mAppIconSize * iconScale));
-                }
-            } catch (Resources.NotFoundException e) {
-            }
-        }
-
-        // Scale to fit width only - let the widget preview be clipped in the
-        // vertical dimension
-        float scale = 1f;
-        if (bitmapWidth > maxWidth) {
-            scale = maxWidth / (float) bitmapWidth;
-        }
-        if (scale != 1f) {
-            bitmapWidth = (int) (scale * bitmapWidth);
-            bitmapHeight = (int) (scale * bitmapHeight);
-        }
-
-        Bitmap preview = Bitmap.createBitmap(bitmapWidth, bitmapHeight,
-                Config.ARGB_8888);
-
-        // Draw the scaled preview into the final bitmap
-        if (widgetPreviewExists) {
-            renderDrawableToBitmap(drawable, preview, 0, 0, bitmapWidth,
-                    bitmapHeight);
-        } else {
-            final Canvas c = mCachedAppWidgetPreviewCanvas.get();
-            final Rect src = mCachedAppWidgetPreviewSrcRect.get();
-            final Rect dest = mCachedAppWidgetPreviewDestRect.get();
-            c.setBitmap(preview);
-            src.set(0, 0, defaultPreview.getWidth(), defaultPreview.getHeight());
-            dest.set(0, 0, preview.getWidth(), preview.getHeight());
-
-            Paint p = mCachedAppWidgetPreviewPaint.get();
-            if (p == null) {
-                p = new Paint();
-                p.setFilterBitmap(true);
-                mCachedAppWidgetPreviewPaint.set(p);
-            }
-            c.drawBitmap(defaultPreview, src, dest, p);
-            c.setBitmap(null);
-        }
-        return preview;
-    }
-
     public void syncWidgetPageItems(final int page, final boolean immediate) {
         int numItemsPerPage = mWidgetCountX * mWidgetCountY;
 
@@ -1475,6 +1220,11 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
                     maxPreviewWidth = maxSize[0];
                     maxPreviewHeight = maxSize[1];
                 }
+
+                if (mWidgetPreviewLoader == null) {
+                    mWidgetPreviewLoader = new WidgetPreviewLoader(
+                            maxPreviewWidth, maxPreviewHeight, mLauncher, mWidgetSpacingLayout);
+                }
                 if (immediate) {
                     AsyncTaskPageData data = new AsyncTaskPageData(page, items,
                             maxPreviewWidth, maxPreviewHeight, null, null);
@@ -1513,23 +1263,7 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
                 task.syncThreadPriority();
             }
 
-            Object rawInfo = items.get(i);
-            if (rawInfo instanceof AppWidgetProviderInfo) {
-                AppWidgetProviderInfo info = (AppWidgetProviderInfo) rawInfo;
-                int[] cellSpans = Launcher.getSpanForWidget(mLauncher, info);
-
-                int maxWidth = Math.min(data.maxImageWidth,
-                        mWidgetSpacingLayout.estimateCellWidth(cellSpans[0]));
-                int maxHeight = Math.min(data.maxImageHeight,
-                        mWidgetSpacingLayout.estimateCellHeight(cellSpans[1]));
-                Bitmap b = getWidgetPreview(info.provider, info.previewImage, info.icon,
-                        cellSpans[0], cellSpans[1], maxWidth, maxHeight);
-                images.add(b);
-            } else if (rawInfo instanceof ResolveInfo) {
-                // Fill in the shortcuts information
-                ResolveInfo info = (ResolveInfo) rawInfo;
-                images.add(getShortcutPreview(info, data.maxImageWidth, data.maxImageHeight));
-            }
+            images.add(mWidgetPreviewLoader.getPreview(items.get(i)));
         }
     }
 
@@ -1707,8 +1441,6 @@ public class AppsCustomizePagedView extends PagedViewWithDraggableItems implemen
             }
         }
 
-        int newLeft = -1;
-        int newRight = -1;
         for (int i = 0; i < screenCount; i++) {
             final View layout = (View) getPageAt(i);
 
diff --git a/src/com/android/launcher2/DragController.java b/src/com/android/launcher2/DragController.java
index 4c4295319..3e586bf61 100644
--- a/src/com/android/launcher2/DragController.java
+++ b/src/com/android/launcher2/DragController.java
@@ -175,16 +175,18 @@ public class DragController {
      *          Makes dragging feel more precise, e.g. you can clip out a transparent border
      */
     public void startDrag(View v, Bitmap bmp, DragSource source, Object dragInfo, int dragAction,
-            Rect dragRegion, float initialDragViewScale) {
+            Point extraPadding, float initialDragViewScale) {
         int[] loc = mCoordinatesTemp;
         mLauncher.getDragLayer().getLocationInDragLayer(v, loc);
-        int dragLayerX = loc[0] + v.getPaddingLeft() +
+        int viewExtraPaddingLeft = extraPadding != null ? extraPadding.x : 0;
+        int viewExtraPaddingTop = extraPadding != null ? extraPadding.y : 0;
+        int dragLayerX = loc[0] + v.getPaddingLeft() + viewExtraPaddingLeft +
                 (int) ((initialDragViewScale * bmp.getWidth() - bmp.getWidth()) / 2);
-        int dragLayerY = loc[1] + v.getPaddingTop() +
+        int dragLayerY = loc[1] + v.getPaddingTop() + viewExtraPaddingTop +
                 (int) ((initialDragViewScale * bmp.getHeight() - bmp.getHeight()) / 2);
 
-        startDrag(bmp, dragLayerX, dragLayerY, source, dragInfo, dragAction, null, dragRegion,
-                initialDragViewScale);
+        startDrag(bmp, dragLayerX, dragLayerY, source, dragInfo, dragAction, null,
+                null, initialDragViewScale);
 
         if (dragAction == DRAG_ACTION_MOVE) {
             v.setVisibility(View.GONE);
diff --git a/src/com/android/launcher2/LauncherModel.java b/src/com/android/launcher2/LauncherModel.java
index ccf83282c..9a5bd47b3 100644
--- a/src/com/android/launcher2/LauncherModel.java
+++ b/src/com/android/launcher2/LauncherModel.java
@@ -1988,6 +1988,7 @@ public class LauncherModel extends BroadcastReceiver {
                     for (int i=0; i<N; i++) {
                         if (DEBUG_LOADERS) Log.d(TAG, "mAllAppsList.updatePackage " + packages[i]);
                         mBgAllAppsList.updatePackage(context, packages[i]);
+                        WidgetPreviewLoader.removeFromDb(context, packages[i]);
                     }
                     break;
                 case OP_REMOVE:
@@ -1995,6 +1996,7 @@ public class LauncherModel extends BroadcastReceiver {
                     for (int i=0; i<N; i++) {
                         if (DEBUG_LOADERS) Log.d(TAG, "mAllAppsList.removePackage " + packages[i]);
                         mBgAllAppsList.removePackage(packages[i]);
+                        WidgetPreviewLoader.removeFromDb(context, packages[i]);
                     }
                     break;
             }
diff --git a/src/com/android/launcher2/PackageChangedReceiver.java b/src/com/android/launcher2/PackageChangedReceiver.java
new file mode 100644
index 000000000..ce08b3acd
--- /dev/null
+++ b/src/com/android/launcher2/PackageChangedReceiver.java
@@ -0,0 +1,18 @@
+package com.android.launcher2;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+
+public class PackageChangedReceiver extends BroadcastReceiver {
+    @Override
+    public void onReceive(final Context context, Intent intent) {
+        final String packageName = intent.getData().getSchemeSpecificPart();
+
+        if (packageName == null || packageName.length() == 0) {
+            // they sent us a bad intent
+            return;
+        }
+        WidgetPreviewLoader.removeFromDb(context, packageName);
+    }
+}
diff --git a/src/com/android/launcher2/PagedViewWidget.java b/src/com/android/launcher2/PagedViewWidget.java
index b804ab0a2..1ee1c4ac0 100644
--- a/src/com/android/launcher2/PagedViewWidget.java
+++ b/src/com/android/launcher2/PagedViewWidget.java
@@ -46,6 +46,7 @@ public class PagedViewWidget extends LinearLayout {
     static PagedViewWidget sShortpressTarget = null;
     boolean mIsAppWidget;
     private final Rect mOriginalImagePadding = new Rect();
+    private Object mInfo;
 
     public PagedViewWidget(Context context) {
         this(context, null);
@@ -88,8 +89,8 @@ public class PagedViewWidget extends LinearLayout {
             final ImageView image = (ImageView) findViewById(R.id.widget_preview);
             if (image != null) {
                 FastBitmapDrawable preview = (FastBitmapDrawable) image.getDrawable();
-                if (preview != null && preview.getBitmap() != null) {
-                    preview.getBitmap().recycle();
+                if (mInfo != null && preview != null && preview.getBitmap() != null) {
+                    WidgetPreviewLoader.releaseBitmap(mInfo, preview.getBitmap());
                 }
                 image.setImageDrawable(null);
             }
@@ -99,6 +100,7 @@ public class PagedViewWidget extends LinearLayout {
     public void applyFromAppWidgetProviderInfo(AppWidgetProviderInfo info,
             int maxWidth, int[] cellSpan) {
         mIsAppWidget = true;
+        mInfo = info;
         final ImageView image = (ImageView) findViewById(R.id.widget_preview);
         if (maxWidth > -1) {
             image.setMaxWidth(maxWidth);
@@ -116,6 +118,7 @@ public class PagedViewWidget extends LinearLayout {
 
     public void applyFromResolveInfo(PackageManager pm, ResolveInfo info) {
         mIsAppWidget = false;
+        mInfo = info;
         CharSequence label = info.loadLabel(pm);
         final ImageView image = (ImageView) findViewById(R.id.widget_preview);
         image.setContentDescription(label);
diff --git a/src/com/android/launcher2/WidgetPreviewLoader.java b/src/com/android/launcher2/WidgetPreviewLoader.java
new file mode 100644
index 000000000..2d1096778
--- /dev/null
+++ b/src/com/android/launcher2/WidgetPreviewLoader.java
@@ -0,0 +1,606 @@
+package com.android.launcher2;
+
+import android.appwidget.AppWidgetProviderInfo;
+import android.content.ComponentName;
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.content.pm.ResolveInfo;
+import android.content.res.Resources;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+import android.graphics.Bitmap;
+import android.graphics.Bitmap.Config;
+import android.graphics.BitmapFactory;
+import android.graphics.Canvas;
+import android.graphics.ColorMatrix;
+import android.graphics.ColorMatrixColorFilter;
+import android.graphics.Paint;
+import android.graphics.PorterDuff;
+import android.graphics.Rect;
+import android.graphics.Shader;
+import android.graphics.drawable.BitmapDrawable;
+import android.graphics.drawable.Drawable;
+import android.os.AsyncTask;
+import android.util.Log;
+
+import com.android.launcher.R;
+
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.lang.ref.SoftReference;
+import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+
+abstract class SoftReferenceThreadLocal<T> {
+    private ThreadLocal<SoftReference<T>> mThreadLocal;
+    public SoftReferenceThreadLocal() {
+        mThreadLocal = new ThreadLocal<SoftReference<T>>();
+    }
+
+    abstract T initialValue();
+
+    public void set(T t) {
+        mThreadLocal.set(new SoftReference<T>(t));
+    }
+
+    public T get() {
+        SoftReference<T> reference = mThreadLocal.get();
+        T obj;
+        if (reference == null) {
+            obj = initialValue();
+            mThreadLocal.set(new SoftReference<T>(obj));
+            return obj;
+        } else {
+            obj = reference.get();
+            if (obj == null) {
+                obj = initialValue();
+                mThreadLocal.set(new SoftReference<T>(obj));
+            }
+            return obj;
+        }
+    }
+}
+
+class CanvasCache extends SoftReferenceThreadLocal<Canvas> {
+    @Override
+    protected Canvas initialValue() {
+        return new Canvas();
+    }
+}
+
+class PaintCache extends SoftReferenceThreadLocal<Paint> {
+    @Override
+    protected Paint initialValue() {
+        return null;
+    }
+}
+
+class BitmapCache extends SoftReferenceThreadLocal<Bitmap> {
+    @Override
+    protected Bitmap initialValue() {
+        return null;
+    }
+}
+
+class RectCache extends SoftReferenceThreadLocal<Rect> {
+    @Override
+    protected Rect initialValue() {
+        return new Rect();
+    }
+}
+
+class BitmapFactoryOptionsCache extends SoftReferenceThreadLocal<BitmapFactory.Options> {
+    @Override
+    protected BitmapFactory.Options initialValue() {
+        return new BitmapFactory.Options();
+    }
+}
+
+public class WidgetPreviewLoader {
+    static final String TAG = "WidgetPreviewLoader";
+
+    private int mPreviewBitmapMaxWidth;
+    private int mPreviewBitmapMaxHeight;
+    private String mSize;
+    private Context mContext;
+    private Launcher mLauncher;
+    private PackageManager mPackageManager;
+    private PagedViewCellLayout mWidgetSpacingLayout;
+
+    // Used for drawing shortcut previews
+    private BitmapCache mCachedShortcutPreviewBitmap = new BitmapCache();
+    private PaintCache mCachedShortcutPreviewPaint = new PaintCache();
+    private CanvasCache mCachedShortcutPreviewCanvas = new CanvasCache();
+
+    // Used for drawing widget previews
+    private CanvasCache mCachedAppWidgetPreviewCanvas = new CanvasCache();
+    private RectCache mCachedAppWidgetPreviewSrcRect = new RectCache();
+    private RectCache mCachedAppWidgetPreviewDestRect = new RectCache();
+    private PaintCache mCachedAppWidgetPreviewPaint = new PaintCache();
+    private String mCachedSelectQuery;
+    private BitmapFactoryOptionsCache mCachedBitmapFactoryOptions = new BitmapFactoryOptionsCache();
+
+    private int mAppIconSize;
+    private IconCache mIconCache;
+
+    private final float sWidgetPreviewIconPaddingPercentage = 0.25f;
+
+    private WidgetPreviewCacheDb mDb;
+
+    private static HashMap<String, WeakReference<Bitmap>> sLoadedPreviews;
+    private static ArrayList<SoftReference<Bitmap>> sUnusedBitmaps;
+    private static HashSet<String> sInvalidPackages;
+
+    static {
+        sLoadedPreviews = new HashMap<String, WeakReference<Bitmap>>();
+        sUnusedBitmaps = new ArrayList<SoftReference<Bitmap>>();
+        sInvalidPackages = new HashSet<String>();
+    }
+
+    public WidgetPreviewLoader(int previewWidth, int previewHeight,
+            Launcher launcher, PagedViewCellLayout widgetSpacingLayout) {
+        mPreviewBitmapMaxWidth = previewWidth;
+        mPreviewBitmapMaxHeight = previewHeight;
+        mSize = previewWidth + "x" + previewHeight;
+        mContext = mLauncher = launcher;
+        mPackageManager = mContext.getPackageManager();
+        mAppIconSize = mContext.getResources().getDimensionPixelSize(R.dimen.app_icon_size);
+        mIconCache = ((LauncherApplication) launcher.getApplicationContext()).getIconCache();
+        mWidgetSpacingLayout = widgetSpacingLayout;
+        mDb = new WidgetPreviewCacheDb(mContext);
+    }
+
+    public Bitmap getPreview(final Object o) {
+        String name = getObjectName(o);
+        // check if the package is valid
+        boolean packageValid = true;
+        synchronized(sInvalidPackages) {
+            packageValid = !sInvalidPackages.contains(getObjectPackage(o));
+        }
+        if (!packageValid) {
+            return null;
+        }
+        if (packageValid) {
+            synchronized(sLoadedPreviews) {
+                // check if it exists in our existing cache
+                if (sLoadedPreviews.containsKey(name) && sLoadedPreviews.get(name).get() != null) {
+                    return sLoadedPreviews.get(name).get();
+                }
+            }
+        }
+
+        Bitmap unusedBitmap = null;
+        synchronized(sUnusedBitmaps) {
+            // not in cache; we need to load it from the db
+            while ((unusedBitmap == null || !unusedBitmap.isMutable())
+                    && sUnusedBitmaps.size() > 0) {
+                unusedBitmap = sUnusedBitmaps.remove(0).get();
+            }
+            if (unusedBitmap != null) {
+                final Canvas c = mCachedAppWidgetPreviewCanvas.get();
+                c.setBitmap(unusedBitmap);
+                c.drawColor(0, PorterDuff.Mode.CLEAR);
+                c.setBitmap(null);
+            }
+        }
+
+        if (unusedBitmap == null) {
+            unusedBitmap = Bitmap.createBitmap(mPreviewBitmapMaxWidth, mPreviewBitmapMaxHeight,
+                    Bitmap.Config.ARGB_8888);
+        }
+
+        Bitmap preview = null;
+
+        if (packageValid) {
+            preview = readFromDb(name, unusedBitmap);
+        }
+
+        if (preview != null) {
+            synchronized(sLoadedPreviews) {
+                sLoadedPreviews.put(name, new WeakReference<Bitmap>(preview));
+            }
+            return preview;
+        } else {
+            // it's not in the db... we need to generate it
+            final Bitmap generatedPreview = generatePreview(o, unusedBitmap);
+            preview = generatedPreview;
+            if (preview != unusedBitmap) {
+                throw new RuntimeException("generatePreview is not recycling the bitmap " + o);
+            }
+
+            synchronized(sLoadedPreviews) {
+                sLoadedPreviews.put(name, new WeakReference<Bitmap>(preview));
+            }
+
+            // write to db on a thread pool... this can be done lazily and improves the performance
+            // of the first time widget previews are loaded
+            new AsyncTask<Void, Void, Void>() {
+                public Void doInBackground(Void ... args) {
+                    writeToDb(o, generatedPreview);
+                    return null;
+                }
+            }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, (Void) null);
+
+            return preview;
+        }
+    }
+
+    public static void releaseBitmap(Object o, Bitmap bitmapToFree) {
+        // enable this code when doDecode doesn't force Bitmaps to become immutable
+        String name = getObjectName(o);
+        synchronized(sLoadedPreviews) {
+            synchronized(sUnusedBitmaps) {
+                Bitmap b = sLoadedPreviews.get(name).get();
+                if (b == bitmapToFree) {
+                    sLoadedPreviews.remove(name);
+                    if (bitmapToFree.isMutable()) {
+                        sUnusedBitmaps.add(new SoftReference<Bitmap>(b));
+                    }
+                } else {
+                    throw new RuntimeException("Bitmap passed in doesn't match up");
+                }
+            }
+        }
+    }
+
+    static class WidgetPreviewCacheDb extends SQLiteOpenHelper {
+        final static int DB_VERSION = 1;
+        final static String DB_NAME = "widgetpreviews.db";
+        final static String TABLE_NAME = "shortcut_and_widget_previews";
+        final static String COLUMN_NAME = "name";
+        final static String COLUMN_SIZE = "size";
+        final static String COLUMN_PREVIEW_BITMAP = "preview_bitmap";
+        Context mContext;
+
+        public WidgetPreviewCacheDb(Context context) {
+            super(context, new File(context.getCacheDir(), DB_NAME).getPath(), null, DB_VERSION);
+            // Store the context for later use
+            mContext = context;
+        }
+
+        @Override
+        public void onCreate(SQLiteDatabase database) {
+            database.execSQL("CREATE TABLE " + TABLE_NAME + " (" +
+                    COLUMN_NAME + " TEXT NOT NULL, " +
+                    COLUMN_SIZE + " TEXT NOT NULL, " +
+                    COLUMN_PREVIEW_BITMAP + " BLOB NOT NULL, " +
+                    "PRIMARY KEY (" + COLUMN_NAME + ", " + COLUMN_SIZE + ") " +
+                    ");");
+        }
+
+        @Override
+        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+            // We are still only on version 1
+        }
+    }
+
+    private static final String WIDGET_PREFIX = "Widget:";
+    private static final String SHORTCUT_PREFIX = "Shortcut:";
+
+    private static String getObjectName(Object o) {
+        // should cache the string builder
+        StringBuilder sb = new StringBuilder();
+        String output;
+        if (o instanceof AppWidgetProviderInfo) {
+            sb.append(WIDGET_PREFIX);
+            sb.append(((AppWidgetProviderInfo) o).provider.flattenToString());
+            output = sb.toString();
+            sb.setLength(0);
+        } else {
+            sb.append(SHORTCUT_PREFIX);
+
+            ResolveInfo info = (ResolveInfo) o;
+            sb.append(new ComponentName(info.activityInfo.packageName,
+                    info.activityInfo.name).flattenToString());
+            output = sb.toString();
+            sb.setLength(0);
+        }
+        return output;
+    }
+
+    private String getObjectPackage(Object o) {
+        if (o instanceof AppWidgetProviderInfo) {
+            return ((AppWidgetProviderInfo) o).provider.getPackageName();
+        } else {
+            ResolveInfo info = (ResolveInfo) o;
+            return info.activityInfo.packageName;
+        }
+    }
+
+    private void writeToDb(Object o, Bitmap preview) {
+        String name = getObjectName(o);
+        SQLiteDatabase db = mDb.getWritableDatabase();
+        ContentValues values = new ContentValues();
+
+        values.put(WidgetPreviewCacheDb.COLUMN_NAME, name);
+        ByteArrayOutputStream stream = new ByteArrayOutputStream();
+        preview.compress(Bitmap.CompressFormat.PNG, 100, stream);
+        values.put(WidgetPreviewCacheDb.COLUMN_PREVIEW_BITMAP, stream.toByteArray());
+        values.put(WidgetPreviewCacheDb.COLUMN_SIZE, mSize);
+        db.insert(WidgetPreviewCacheDb.TABLE_NAME, null, values);
+    }
+
+    public static void removeFromDb(final Context mContext, final String packageName) {
+        synchronized(sInvalidPackages) {
+            sInvalidPackages.add(packageName);
+        }
+        new AsyncTask<Void, Void, Void>() {
+            public Void doInBackground(Void ... args) {
+                SQLiteDatabase db = new WidgetPreviewCacheDb(mContext).getWritableDatabase();
+                db.delete(WidgetPreviewCacheDb.TABLE_NAME,
+                        WidgetPreviewCacheDb.COLUMN_NAME + " LIKE ? OR " +
+                        WidgetPreviewCacheDb.COLUMN_NAME + " LIKE ?", // SELECT query
+                        new String[] {
+                            WIDGET_PREFIX + packageName + "/%",
+                            SHORTCUT_PREFIX + packageName + "/%"} // args to SELECT query
+                            );
+                db.close();
+                synchronized(sInvalidPackages) {
+                    sInvalidPackages.remove(packageName);
+                }
+                return null;
+            }
+        }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, (Void) null);
+    }
+
+    private Bitmap readFromDb(String name, Bitmap b) {
+        if (mCachedSelectQuery == null) {
+            mCachedSelectQuery = WidgetPreviewCacheDb.COLUMN_NAME + " = ? AND " +
+                    WidgetPreviewCacheDb.COLUMN_SIZE + " = ?";
+        }
+        SQLiteDatabase db = mDb.getReadableDatabase();
+        Cursor result = db.query(WidgetPreviewCacheDb.TABLE_NAME,
+                new String[] { WidgetPreviewCacheDb.COLUMN_PREVIEW_BITMAP }, // cols to return
+                mCachedSelectQuery, // select query
+                new String[] { name, mSize }, // args to select query
+                null,
+                null,
+                null,
+                null);
+        if (result.getCount() > 0) {
+            result.moveToFirst();
+            byte[] blob = result.getBlob(0);
+            result.close();
+            final BitmapFactory.Options opts = mCachedBitmapFactoryOptions.get();
+            opts.inBitmap = b;
+            opts.inSampleSize = 1;
+            Bitmap out = BitmapFactory.decodeByteArray(blob, 0, blob.length, opts);
+            return out;
+        } else {
+            result.close();
+            return null;
+        }
+    }
+
+    public Bitmap generatePreview(Object info, Bitmap preview) {
+        if (preview != null &&
+                (preview.getWidth() != mPreviewBitmapMaxWidth ||
+                preview.getHeight() != mPreviewBitmapMaxHeight)) {
+            throw new RuntimeException("Improperly sized bitmap passed as argument");
+        }
+        if (info instanceof AppWidgetProviderInfo) {
+            return generateWidgetPreview((AppWidgetProviderInfo) info, preview);
+        } else {
+            return generateShortcutPreview(
+                    (ResolveInfo) info, mPreviewBitmapMaxWidth, mPreviewBitmapMaxHeight, preview);
+        }
+    }
+
+    public Bitmap generateWidgetPreview(AppWidgetProviderInfo info, Bitmap preview) {
+        // should just read what's in the DB, and return it
+        // what's the method that's used?
+        // going to have to track down more or less how the DB stuff works
+        // when you long click on something, we're going to have to load the bigger preview at that
+        // time (worry about it later)
+        int[] cellSpans = Launcher.getSpanForWidget(mLauncher, info);
+        int maxWidth = maxWidthForWidgetPreview(cellSpans[0]);
+        int maxHeight = maxHeightForWidgetPreview(cellSpans[1]);
+        return generateWidgetPreview(info.provider, info.previewImage, info.icon,
+                cellSpans[0], cellSpans[1], maxWidth, maxHeight, preview, null);
+    }
+
+    public int maxWidthForWidgetPreview(int spanX) {
+        return Math.min(mPreviewBitmapMaxWidth,
+                mWidgetSpacingLayout.estimateCellWidth(spanX));
+    }
+
+    public int maxHeightForWidgetPreview(int spanY) {
+        return Math.min(mPreviewBitmapMaxHeight,
+                mWidgetSpacingLayout.estimateCellHeight(spanY));
+    }
+
+    public Bitmap generateWidgetPreview(ComponentName provider, int previewImage,
+            int iconId, int cellHSpan, int cellVSpan, int maxPreviewWidth, int maxPreviewHeight,
+            Bitmap preview, int[] preScaledWidthOut) {
+        // Load the preview image if possible
+        String packageName = provider.getPackageName();
+        if (maxPreviewWidth < 0) maxPreviewWidth = Integer.MAX_VALUE;
+        if (maxPreviewHeight < 0) maxPreviewHeight = Integer.MAX_VALUE;
+
+        Drawable drawable = null;
+        if (previewImage != 0) {
+            drawable = mPackageManager.getDrawable(packageName, previewImage, null);
+            if (drawable == null) {
+                Log.w(TAG, "Can't load widget preview drawable 0x" +
+                        Integer.toHexString(previewImage) + " for provider: " + provider);
+            }
+        }
+
+        int previewWidth;
+        int previewHeight;
+        Bitmap defaultPreview = null;
+        boolean widgetPreviewExists = (drawable != null);
+        if (widgetPreviewExists) {
+            previewWidth = drawable.getIntrinsicWidth();
+            previewHeight = drawable.getIntrinsicHeight();
+        } else {
+            // Generate a preview image if we couldn't load one
+            if (cellHSpan < 1) cellHSpan = 1;
+            if (cellVSpan < 1) cellVSpan = 1;
+
+            BitmapDrawable previewDrawable = (BitmapDrawable) mContext.getResources()
+                    .getDrawable(R.drawable.widget_preview_tile);
+            final int previewDrawableWidth = previewDrawable
+                    .getIntrinsicWidth();
+            final int previewDrawableHeight = previewDrawable
+                    .getIntrinsicHeight();
+            previewWidth = previewDrawableWidth * cellHSpan; // subtract 2 dips
+            previewHeight = previewDrawableHeight * cellVSpan;
+
+            defaultPreview = Bitmap.createBitmap(previewWidth, previewHeight,
+                    Config.ARGB_8888);
+            final Canvas c = mCachedAppWidgetPreviewCanvas.get();
+            c.setBitmap(defaultPreview);
+            previewDrawable.setBounds(0, 0, previewWidth, previewHeight);
+            previewDrawable.setTileModeXY(Shader.TileMode.REPEAT,
+                    Shader.TileMode.REPEAT);
+            previewDrawable.draw(c);
+            c.setBitmap(null);
+
+            // Draw the icon in the top left corner
+            int minOffset = (int) (mAppIconSize * sWidgetPreviewIconPaddingPercentage);
+            int smallestSide = Math.min(previewWidth, previewHeight);
+            float iconScale = Math.min((float) smallestSide
+                    / (mAppIconSize + 2 * minOffset), 1f);
+
+            try {
+                Drawable icon = null;
+                int hoffset =
+                        (int) ((previewDrawableWidth - mAppIconSize * iconScale) / 2);
+                int yoffset =
+                        (int) ((previewDrawableHeight - mAppIconSize * iconScale) / 2);
+                if (iconId > 0)
+                    icon = mIconCache.getFullResIcon(packageName, iconId);
+                if (icon != null) {
+                    renderDrawableToBitmap(icon, defaultPreview, hoffset,
+                            yoffset, (int) (mAppIconSize * iconScale),
+                            (int) (mAppIconSize * iconScale));
+                }
+            } catch (Resources.NotFoundException e) {
+            }
+        }
+
+        // Scale to fit width only - let the widget preview be clipped in the
+        // vertical dimension
+        float scale = 1f;
+        if (preScaledWidthOut != null) {
+            preScaledWidthOut[0] = previewWidth;
+        }
+        if (previewWidth > maxPreviewWidth) {
+            scale = maxPreviewWidth / (float) previewWidth;
+        }
+        if (scale != 1f) {
+            previewWidth = (int) (scale * previewWidth);
+            previewHeight = (int) (scale * previewHeight);
+        }
+
+        // If a bitmap is passed in, we use it; otherwise, we create a bitmap of the right size
+        if (preview == null) {
+            preview = Bitmap.createBitmap(previewWidth, previewHeight, Config.ARGB_8888);
+        }
+
+        // Draw the scaled preview into the final bitmap
+        int x = (preview.getWidth() - previewWidth) / 2;
+        if (widgetPreviewExists) {
+            renderDrawableToBitmap(drawable, preview, x, 0, previewWidth,
+                    previewHeight);
+        } else {
+            final Canvas c = mCachedAppWidgetPreviewCanvas.get();
+            final Rect src = mCachedAppWidgetPreviewSrcRect.get();
+            final Rect dest = mCachedAppWidgetPreviewDestRect.get();
+            c.setBitmap(preview);
+            src.set(0, 0, defaultPreview.getWidth(), defaultPreview.getHeight());
+            dest.set(x, 0, previewWidth, previewHeight);
+
+            Paint p = mCachedAppWidgetPreviewPaint.get();
+            if (p == null) {
+                p = new Paint();
+                p.setFilterBitmap(true);
+                mCachedAppWidgetPreviewPaint.set(p);
+            }
+            c.drawBitmap(defaultPreview, src, dest, p);
+            c.setBitmap(null);
+        }
+        return preview;
+    }
+
+    private Bitmap generateShortcutPreview(
+            ResolveInfo info, int maxWidth, int maxHeight, Bitmap preview) {
+        Bitmap tempBitmap = mCachedShortcutPreviewBitmap.get();
+        final Canvas c = mCachedShortcutPreviewCanvas.get();
+        if (tempBitmap == null ||
+                tempBitmap.getWidth() != maxWidth ||
+                tempBitmap.getHeight() != maxHeight) {
+            tempBitmap = Bitmap.createBitmap(maxWidth, maxHeight, Config.ARGB_8888);
+            mCachedShortcutPreviewBitmap.set(tempBitmap);
+        } else {
+            c.setBitmap(tempBitmap);
+            c.drawColor(0, PorterDuff.Mode.CLEAR);
+            c.setBitmap(null);
+        }
+        // Render the icon
+        Drawable icon = mIconCache.getFullResIcon(info);
+
+        int paddingTop = mContext.
+                getResources().getDimensionPixelOffset(R.dimen.shortcut_preview_padding_top);
+        int paddingLeft = mContext.
+                getResources().getDimensionPixelOffset(R.dimen.shortcut_preview_padding_left);
+        int paddingRight = mContext.
+                getResources().getDimensionPixelOffset(R.dimen.shortcut_preview_padding_right);
+
+        int scaledIconWidth = (maxWidth - paddingLeft - paddingRight);
+
+        renderDrawableToBitmap(
+                icon, tempBitmap, paddingLeft, paddingTop, scaledIconWidth, scaledIconWidth);
+
+        if (preview != null &&
+                (preview.getWidth() != maxWidth || preview.getHeight() != maxHeight)) {
+            throw new RuntimeException("Improperly sized bitmap passed as argument");
+        } else if (preview == null) {
+            preview = Bitmap.createBitmap(maxWidth, maxHeight, Config.ARGB_8888);
+        }
+
+        c.setBitmap(preview);
+        // Draw a desaturated/scaled version of the icon in the background as a watermark
+        Paint p = mCachedShortcutPreviewPaint.get();
+        if (p == null) {
+            p = new Paint();
+            ColorMatrix colorMatrix = new ColorMatrix();
+            colorMatrix.setSaturation(0);
+            p.setColorFilter(new ColorMatrixColorFilter(colorMatrix));
+            p.setAlpha((int) (255 * 0.06f));
+            mCachedShortcutPreviewPaint.set(p);
+        }
+        c.drawBitmap(tempBitmap, 0, 0, p);
+        c.setBitmap(null);
+
+        renderDrawableToBitmap(icon, preview, 0, 0, mAppIconSize, mAppIconSize);
+
+        return preview;
+    }
+
+
+    public static void renderDrawableToBitmap(
+            Drawable d, Bitmap bitmap, int x, int y, int w, int h) {
+        renderDrawableToBitmap(d, bitmap, x, y, w, h, 1f);
+    }
+
+    private static void renderDrawableToBitmap(
+            Drawable d, Bitmap bitmap, int x, int y, int w, int h,
+            float scale) {
+        if (bitmap != null) {
+            Canvas c = new Canvas(bitmap);
+            c.scale(scale, scale);
+            Rect oldBounds = d.copyBounds();
+            d.setBounds(x, y, x + w, y + h);
+            d.draw(c);
+            d.setBounds(oldBounds); // Restore the bounds
+            c.setBitmap(null);
+        }
+    }
+
+}