1/*
2 * Copyright © 2008 Fredrik Höglund <fredrik@kde.org>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to deal
6 * in the Software without restriction, including without limitation the rights
7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 * copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17 * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
18 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
19 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
20*/
21
22#ifndef FADEEFFECT_H
23#define FADEEFFECT_H
24
25#include <QObject>
26#include <QTime>
27
28#include "logouteffect.h"
29#include <X11/Xlib.h>
30
31
32class QWidget;
33class QPixmap;
34class BlendingThread;
35
36
37/**
38 * This class implements an effect that will slowly fade the screen from color to grayscale.
39 *
40 * This class is X11 specific, and currently only works on little-endian systems where
41 * the root window has a 24/32 or 16 bit r5g6b5 pixel format.
42 */
43class FadeEffect : public LogoutEffect
44{
45 Q_OBJECT
46
47public:
48 /**
49 * Creates the FadeEffect.
50 *
51 * This effect will grab a screenshot and then slowly fade it to gray,
52 * rendering each frame on the pixmap you pass to the constructor.
53 * The animation will begin when you call start(), and each time the
54 * pixmap is updated, update() will be called in the @p parent widget,
55 * which must then paint the pixmap.
56 *
57 * The actual blending is done in a separate thread to keep the event
58 * loop alive.
59 *
60 * The FadeEffect can safely be deleted at any time, even while the
61 * effect is running, but it's important that the pixmap isn't deleted
62 * before the effect object.
63 *
64 * @param parent The parent widget, which will draw the pixmap.
65 * @param pixmap The pixmap the effect will be rendered to.
66 */
67 FadeEffect(QWidget *parent, QPixmap *pixmap);
68
69 /**
70 * Destroys the fade effect.
71 */
72 ~FadeEffect();
73
74 /**
75 * Starts the animation.
76 */
77 void start();
78
79private slots:
80 /** @internal */
81 void grabImageSection();
82
83 /** @internal */
84 void nextFrame();
85
86private:
87 BlendingThread *blender;
88 int alpha;
89 int currentY;
90 bool done;
91 XImage *image;
92 GC gc;
93 QTime time;
94};
95
96#endif
97
98