1 /*
2  * Copyright (C) 2010 The Android Open Source Project
3  *
4  * Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php
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.ide.eclipse.adt.internal.editors.layout.gle2;
18 
19 import org.eclipse.swt.graphics.Device;
20 import org.eclipse.swt.graphics.GC;
21 
22 /**
23  * An Overlay is a set of graphics which can be painted on top of the visual
24  * editor. Different {@link Gesture}s produce context specific overlays, such as
25  * swiping rectangles from the {@link MarqueeGesture} and guidelines from the
26  * {@link MoveGesture}.
27  */
28 public abstract class Overlay {
29     private Device mDevice;
30 
31     /** Whether the hover is hidden */
32     private boolean mHiding;
33 
34     /**
35      * Construct the overlay, using the given graphics context for painting.
36      */
Overlay()37     public Overlay() {
38         super();
39     }
40 
41     /**
42      * Initializes the overlay before the first use, if applicable. This is a
43      * good place to initialize resources like colors.
44      *
45      * @param device The device to allocate resources for; the parameter passed
46      *            to {@link #paint} will correspond to this device.
47      */
create(Device device)48     public void create(Device device) {
49         mDevice = device;
50     }
51 
52     /**
53      * Releases resources held by the overlay. Called by the editor when an
54      * overlay has been removed.
55      */
dispose()56     public void dispose() {
57     }
58 
59     /**
60      * Paints the overlay.
61      *
62      * @param gc The SWT {@link GC} object to draw into.
63      */
paint(GC gc)64     public void paint(GC gc) {
65         throw new IllegalArgumentException("paint() not implemented, probably done "
66                 + "with specialized paint signature");
67     }
68 
69     /** Returns the device associated with this overlay */
getDevice()70     public Device getDevice() {
71         return mDevice;
72     }
73 
74     /**
75      * Returns whether the overlay is hidden
76      *
77      * @return true if the selection overlay is hidden
78      */
isHiding()79     public boolean isHiding() {
80         return mHiding;
81     }
82 
83     /**
84      * Hides the overlay
85      *
86      * @param hiding true to hide the overlay, false to unhide it (default)
87      */
setHiding(boolean hiding)88     public void setHiding(boolean hiding) {
89         mHiding = hiding;
90     }
91 }
92