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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.launcher2;
     18 
     19 import android.content.Context;
     20 import android.content.res.Resources;
     21 import android.graphics.Bitmap;
     22 import android.graphics.Canvas;
     23 import android.graphics.PorterDuff;
     24 import android.graphics.drawable.StateListDrawable;
     25 import android.widget.ImageView;
     26 
     27 public class HolographicViewHelper {
     28 
     29     private final Canvas mTempCanvas = new Canvas();
     30 
     31     private boolean mStatesUpdated;
     32     private int mHighlightColor;
     33 
     34     public HolographicViewHelper(Context context) {
     35         Resources res = context.getResources();
     36         mHighlightColor = res.getColor(android.R.color.holo_blue_light);
     37     }
     38 
     39     /**
     40      * Generate the pressed/focused states if necessary.
     41      */
     42     void generatePressedFocusedStates(ImageView v) {
     43         if (!mStatesUpdated && v != null) {
     44             mStatesUpdated = true;
     45             Bitmap outline = createPressImage(v, mTempCanvas);
     46             FastBitmapDrawable d = new FastBitmapDrawable(outline);
     47 
     48             StateListDrawable states = new StateListDrawable();
     49             states.addState(new int[] {android.R.attr.state_pressed}, d);
     50             states.addState(new int[] {android.R.attr.state_focused}, d);
     51             states.addState(new int[] {}, v.getDrawable());
     52             v.setImageDrawable(states);
     53         }
     54     }
     55 
     56     /**
     57      * Invalidates the pressed/focused states.
     58      */
     59     void invalidatePressedFocusedStates(ImageView v) {
     60         mStatesUpdated = false;
     61         if (v != null) {
     62             v.invalidate();
     63         }
     64     }
     65 
     66     /**
     67      * Creates a new press state image which is the old image with a blue overlay.
     68      * Responsibility for the bitmap is transferred to the caller.
     69      */
     70     private Bitmap createPressImage(ImageView v, Canvas canvas) {
     71         final int padding = HolographicOutlineHelper.MAX_OUTER_BLUR_RADIUS;
     72         final Bitmap b = Bitmap.createBitmap(
     73                 v.getWidth() + padding, v.getHeight() + padding, Bitmap.Config.ARGB_8888);
     74 
     75         canvas.setBitmap(b);
     76         canvas.save();
     77             v.getDrawable().draw(canvas);
     78         canvas.restore();
     79         canvas.drawColor(mHighlightColor, PorterDuff.Mode.SRC_IN);
     80         canvas.setBitmap(null);
     81 
     82         return b;
     83     }
     84 }
     85