Home | History | Annotate | Download | only in gle2 
      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      */
     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      */
     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      */
     56     public void dispose() {
     57     }
     58 
     59     /**
     60      * Paints the overlay.
     61      *
     62      * @param gc The SWT {@link GC} object to draw into.
     63      */
     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 */
     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      */
     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      */
     88     public void setHiding(boolean hiding) {
     89         mHiding = hiding;
     90     }
     91 }
     92