1 /*
2 * Copyright (c) 1996, 2009, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package sun.awt.windows;
26
27 import java.awt.*;
28 import java.awt.peer.*;
29 import java.lang.ref.WeakReference;
30 import java.lang.reflect.Method;
31 import sun.awt.AWTAccessor;
32 import sun.awt.ComponentAccessor;
33 import sun.awt.SunToolkit;
34 import sun.awt.Win32GraphicsDevice;
35 import sun.awt.PaintEventDispatcher;
36
37 class WCanvasPeer extends WComponentPeer implements CanvasPeer {
38
39 private boolean eraseBackground;
40
41 Method resetGCMethod;
42
43 // Toolkit & peer internals
44
45 WCanvasPeer(Component target) {
46 super(target);
47 }
48
49 /*
50 * From the DisplayChangedListener interface.
51 *
52 * Overrides WComponentPeer version because Canvases can be created with
53 * a non-defulat GraphicsConfiguration, which is no longer valid.
54 * Up-called for other windows peer instances (WPanelPeer, WWindowPeer).
55 */
56 public void displayChanged() {
57 clearLocalGC();
58 resetTargetGC();
59 super.displayChanged();
60 }
61
62 /*
63 * Reset the graphicsConfiguration member of our target Component.
64 * Component.resetGC() is a package-private method, so we have to call it
65 * through reflection.
66 */
67 public void resetTargetGC() {
68 ComponentAccessor.resetGC((Component)target);
69 }
70
71 /*
72 * Clears the peer's winGraphicsConfig member.
73 * Overridden by WWindowPeer, which shouldn't have a null winGraphicsConfig.
74 */
75 void clearLocalGC() {
76 winGraphicsConfig = null;
77 }
78
79 native void create(WComponentPeer parent);
80
81 void initialize() {
82 eraseBackground = !SunToolkit.getSunAwtNoerasebackground();
83 boolean eraseBackgroundOnResize = SunToolkit.getSunAwtErasebackgroundonresize();
84 // Optimization: the default value in the native code is true, so we
85 // call setNativeBackgroundErase only when the value changes to false
86 if (!PaintEventDispatcher.getPaintEventDispatcher().
87 shouldDoNativeBackgroundErase((Component)target)) {
88 eraseBackground = false;
89 }
90 setNativeBackgroundErase(eraseBackground, eraseBackgroundOnResize);
91 super.initialize();
92 Color bg = ((Component)target).getBackground();
93 if (bg != null) {
94 setBackground(bg);
95 }
96 }
97
98 public void paint(Graphics g) {
99 Dimension d = ((Component)target).getSize();
100 if (g instanceof Graphics2D ||
101 g instanceof sun.awt.Graphics2Delegate) {
102 // background color is setup correctly, so just use clearRect
103 g.clearRect(0, 0, d.width, d.height);
104 } else {
105 // emulate clearRect
106 g.setColor(((Component)target).getBackground());
107 g.fillRect(0, 0, d.width, d.height);
108 g.setColor(((Component)target).getForeground());
109 }
110 super.paint(g);
111 }
112
113 public void print(Graphics g) {
114 if (!(target instanceof Window) ||
115 AWTAccessor.getWindowAccessor().isOpaque((Window)target))
116 {
117 Dimension d = ((Component)target).getSize();
118 if (g instanceof Graphics2D ||
119 g instanceof sun.awt.Graphics2Delegate) {
120 // background color is setup correctly, so just use clearRect
121 g.clearRect(0, 0, d.width, d.height);
122 } else {
123 // emulate clearRect
124 g.setColor(((Component)target).getBackground());
125 g.fillRect(0, 0, d.width, d.height);
126 g.setColor(((Component)target).getForeground());
127 }
128 }
129 super.print(g);
130 }
131
132 public boolean shouldClearRectBeforePaint() {
133 return eraseBackground;
134 }
135
136 /*
137 * Disables background erasing for this canvas, both for resizing
138 * and not-resizing repaints.
139 */
140 void disableBackgroundErase() {
141 eraseBackground = false;
142 setNativeBackgroundErase(false, false);
143 }
144
145 /*
146 * Sets background erasing flags at the native level. If {@code
147 * doErase} is set to {@code true}, canvas background is erased on
148 * every repaint. If {@code doErase} is {@code false} and {@code
149 * doEraseOnResize} is {@code true}, then background is only erased
150 * on resizing repaints. If both {@code doErase} and {@code
151 * doEraseOnResize} are false, then background is never erased.
152 */
153 private native void setNativeBackgroundErase(boolean doErase,
154 boolean doEraseOnResize);
155 }