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
17package com.android.launcher2;
18
19import android.content.Context;
20import android.content.res.Resources;
21import android.graphics.Bitmap;
22import android.graphics.Canvas;
23import android.graphics.PorterDuff;
24import android.graphics.drawable.Drawable;
25import android.graphics.drawable.StateListDrawable;
26import android.widget.ImageView;
27
28public class HolographicViewHelper {
29
30    private final Canvas mTempCanvas = new Canvas();
31
32    private boolean mStatesUpdated;
33    private int mHighlightColor;
34
35    public HolographicViewHelper(Context context) {
36        Resources res = context.getResources();
37        mHighlightColor = res.getColor(android.R.color.white);
38    }
39
40    /**
41     * Generate the pressed/focused states if necessary.
42     */
43    void generatePressedFocusedStates(ImageView v) {
44        if (!mStatesUpdated && v != null) {
45            mStatesUpdated = true;
46            Bitmap original = createOriginalImage(v, mTempCanvas);
47            Bitmap outline = createPressImage(v, mTempCanvas);
48            FastBitmapDrawable originalD = new FastBitmapDrawable(original);
49            FastBitmapDrawable outlineD = new FastBitmapDrawable(outline);
50
51            StateListDrawable states = new StateListDrawable();
52            states.addState(new int[] {android.R.attr.state_pressed}, outlineD);
53            states.addState(new int[] {android.R.attr.state_focused}, outlineD);
54            states.addState(new int[] {}, originalD);
55            v.setImageDrawable(states);
56        }
57    }
58
59    /**
60     * Invalidates the pressed/focused states.
61     */
62    void invalidatePressedFocusedStates(ImageView v) {
63        mStatesUpdated = false;
64        if (v != null) {
65            v.invalidate();
66        }
67    }
68
69    /**
70     * Creates a copy of the original image.
71     */
72    private Bitmap createOriginalImage(ImageView v, Canvas canvas) {
73        final Drawable d = v.getDrawable();
74        final Bitmap b = Bitmap.createBitmap(
75                d.getIntrinsicWidth(), d.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
76
77        canvas.setBitmap(b);
78        canvas.save();
79            d.draw(canvas);
80        canvas.restore();
81        canvas.setBitmap(null);
82
83        return b;
84    }
85
86    /**
87     * Creates a new press state image which is the old image with a blue overlay.
88     * Responsibility for the bitmap is transferred to the caller.
89     */
90    private Bitmap createPressImage(ImageView v, Canvas canvas) {
91        final Drawable d = v.getDrawable();
92        final Bitmap b = Bitmap.createBitmap(
93                d.getIntrinsicWidth(), d.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
94
95        canvas.setBitmap(b);
96        canvas.save();
97            d.draw(canvas);
98        canvas.restore();
99        canvas.drawColor(mHighlightColor, PorterDuff.Mode.SRC_IN);
100        canvas.setBitmap(null);
101
102        return b;
103    }
104}
105