1/*
2 * Copyright (C) 2010 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 android.graphics;
18
19import com.android.layoutlib.bridge.impl.DelegateManager;
20import com.android.tools.layoutlib.annotations.LayoutlibDelegate;
21
22import android.graphics.PorterDuff.Mode;
23
24import java.awt.Graphics2D;
25import java.awt.image.BufferedImage;
26
27import static com.android.layoutlib.bridge.impl.PorterDuffUtility.getComposite;
28import static com.android.layoutlib.bridge.impl.PorterDuffUtility.getPorterDuffMode;
29
30/**
31 * Delegate implementing the native methods of android.graphics.PorterDuffColorFilter
32 *
33 * Through the layoutlib_create tool, the original native methods of PorterDuffColorFilter have
34 * been replaced by calls to methods of the same name in this delegate class.
35 *
36 * This class behaves like the original native implementation, but in Java, keeping previously
37 * native data into its own objects and mapping them to int that are sent back and forth between
38 * it and the original PorterDuffColorFilter class.
39 *
40 * Because this extends {@link ColorFilter_Delegate}, there's no need to use a
41 * {@link DelegateManager}, as all the Shader classes will be added to the manager
42 * owned by {@link ColorFilter_Delegate}.
43 *
44 * @see ColorFilter_Delegate
45 *
46 */
47public class PorterDuffColorFilter_Delegate extends ColorFilter_Delegate {
48
49    // ---- delegate data ----
50
51    private final int mSrcColor;
52    private final Mode mMode;
53
54
55    // ---- Public Helper methods ----
56
57    @Override
58    public boolean isSupported() {
59        return true;
60    }
61
62    @Override
63    public String getSupportMessage() {
64        return "PorterDuff Color Filter is not supported for mode: " + mMode.name() + ".";
65    }
66
67    @Override
68    public void applyFilter(Graphics2D g, int width, int height) {
69        BufferedImage image = createFilterImage(width, height);
70        g.setComposite(getComposite(mMode, 0xFF));
71        g.drawImage(image, 0, 0, null);
72    }
73
74    // ---- native methods ----
75
76    @LayoutlibDelegate
77    /*package*/ static long native_CreatePorterDuffFilter(int srcColor, int porterDuffMode) {
78        PorterDuffColorFilter_Delegate newDelegate =
79                new PorterDuffColorFilter_Delegate(srcColor, porterDuffMode);
80        return sManager.addNewDelegate(newDelegate);
81    }
82
83
84    // ---- Private delegate/helper methods ----
85
86    private PorterDuffColorFilter_Delegate(int srcColor, int mode) {
87        mSrcColor = srcColor;
88        mMode = getCompatibleMode(getPorterDuffMode(mode));
89    }
90
91    private BufferedImage createFilterImage(int width, int height) {
92        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
93        Graphics2D graphics = image.createGraphics();
94        try {
95            graphics.setColor(new java.awt.Color(mSrcColor, true /* hasAlpha */));
96            graphics.fillRect(0, 0, width, height);
97        } finally {
98            graphics.dispose();
99        }
100        return image;
101    }
102
103    // For filtering the colors, the src image should contain the "color" only for pixel values
104    // which are not transparent in the target image. But, we are using a simple rectangular image
105    // completely filled with color. Hence some Composite rules do not apply as intended. However,
106    // in such cases, they can usually be mapped to some other mode, which produces an
107    // equivalent result.
108    private Mode getCompatibleMode(Mode mode) {
109        Mode m = mode;
110        // Modes that are directly supported:
111        // CLEAR, DST, SRC_IN, DST_IN, DST_OUT, SRC_ATOP, DARKEN, LIGHTEN, MULTIPLY, SCREEN,
112        // ADD, OVERLAY
113        switch (mode) {
114        // Modes that can be mapped to one of the supported modes.
115        case SRC:
116            m = Mode.SRC_IN;
117            break;
118        case SRC_OVER:
119            m = Mode.SRC_ATOP;
120            break;
121        case DST_OVER:
122            m = Mode.DST;
123            break;
124        case SRC_OUT:
125            m = Mode.CLEAR;
126            break;
127        case DST_ATOP:
128            m = Mode.DST_IN;
129            break;
130        case XOR:
131            m = Mode.DST_OUT;
132            break;
133        }
134        return m;
135    }
136}
137