workspace/ksmserver/fadeeffect.h

   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
  32 class QWidget;
  33 class QPixmap;
  34 class 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  */
  43 class FadeEffect : public LogoutEffect
  44 {
  45     Q_OBJECT
  46
  47 public:
  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
  79 private slots:
  80     /** @internal */
  81     void grabImageSection();
  82
  83     /** @internal */
  84     void nextFrame();
  85
  86 private:
  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