workspace/plasma/containments/desktop/desktoplayout.h

   1 /*
   2   Copyright (c) 2008 Ambroz Bizjak <ambro@b4ever.net>
   3
   4   This program is free software; you can redistribute it and/or modify
   5   it under the terms of the GNU General Public License as published by
   6   the Free Software Foundation; either version 2 of the License, or
   7   (at your option) any later version.
   8 */
   9
  10 #ifndef _DESKTOPLAYOUT_H
  11 #define _DESKTOPLAYOUT_H
  12
  13 #include <QGraphicsLayout>
  14 #include <QHash>
  15 #include <QMap>
  16 #include <QList>
  17 #include <QObject>
  18
  19 #include "itemspace.h"
  20
  21 class QGraphicsItem;
  22
  23 class DesktopLayout : public QObject, public QGraphicsLayout
  24 {
  25     Q_OBJECT
  26
  27 public:
  28     DesktopLayout (QGraphicsLayoutItem *parent = 0);
  29
  30     /**
  31      * Adds a new item.
  32      * The item will be automatically positioned.
  33      *
  34      * @param item the item to add
  35      * @param pushBack if the item should attempt to always be in its preferred position;
  36      *                 if false, it will only move when pushed by other items or edges
  37      *                 of the working area
  38      * @param size the size initial size of the item; if invalid or not supplied,
  39      *             the PreferredSize hint will be used
  40      **/
  41     void addItem(QGraphicsLayoutItem *item, bool pushBack = true, const QSizeF &size = QSizeF());
  42
  43     /**
  44      * Adds a previously managed item.
  45      **/
  46     void addItem(QGraphicsLayoutItem *item, bool pushBack, const QRectF &preferredGeom, const QRectF &lastGeom = QRectF());
  47
  48     bool getPushBack(int index);
  49     QRectF getPreferredGeometry(int index);
  50     QRectF getLastGeometry(int index);
  51
  52     /**
  53      * Sets spacing required between an item and
  54      * the edge of the working area when a new item is positioned.
  55      **/
  56     void setPlacementSpacing(qreal spacing);
  57
  58     /**
  59      * Sets spacing between an item and the edge of
  60      * the working area when items are being pushed around
  61      * and when an item is moved by the user.
  62      **/
  63     void setScreenSpacing(qreal spacing);
  64
  65     /**
  66      * Sets spacing between items when items are being pushed around.
  67      **/
  68     void setShiftingSpacing(qreal spacing);
  69
  70     /**
  71      * Sets the tolerance for temporary placement in terms of surface
  72      * of the item concerned.
  73      **/
  74     void setVisibilityTolerance(qreal part);
  75
  76     /**
  77      * Sets whether the working area should always be
  78      * considered the geometry of the managed widget.
  79      * Default is on.
  80      **/
  81     void setAutoWorkingArea(bool value);
  82
  83     /**
  84      * Sets the area of the widget where items can be displayed.
  85      * If you turned off auto working area, you have to use
  86      * this function to adjust it manually every time it changes.
  87      **/
  88     void setWorkingArea(QRectF area);
  89
  90     /**
  91      * Sets the alignment.
  92      * This defines the sides of the working area where items are
  93      * pushed inside in case the working area shrinks.
  94      * Default is Qt::AlignTop|Qt::AlignLeft which pushes items on
  95      * the right and the bottom sides.
  96      **/
  97     void setAlignment(Qt::Alignment alignment);
  98
  99     /**
 100      * Enables or disables temporary placement.
 101      **/
 102     void setTemporaryPlacement(bool enabled);
 103
 104     /**
 105      * Checks if the specified item's geometry has been changed externally
 106      * and sets its preferred position to the current position.
 107      * Call this when an item has been manually moved or resized.
 108      **/
 109     void itemGeometryChanged(QGraphicsLayoutItem *layoutItem);
 110
 111     // inherited from QGraphicsLayout
 112     int count() const;
 113     QGraphicsLayoutItem *itemAt(int index) const;
 114     void removeAt(int index);
 115
 116     // inherited from QGraphicsLayoutItem
 117     void setGeometry(const QRectF &rect);
 118     QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF()) const;
 119
 120 private slots:
 121     void movementFinished(QGraphicsItem*);
 122
 123 private:
 124
 125     class DesktopLayoutItem
 126     {
 127       public:
 128         QGraphicsLayoutItem *item;
 129         QRectF temporaryGeometry;
 130     };
 131
 132     int newItemKey();
 133
 134     // layout status
 135
 136     /**
 137      * The ItemSpace where items are stored and calculations are done.
 138      * We use the 'user' item option as an identifier that survives
 139      * regrouping.
 140      **/
 141     ItemSpace itemSpace;
 142
 143     /**
 144      * Item-specific data that cannot be stored in the ItemSpace.
 145      * Maps integer IDs in the 'user' item field to their local data.
 146      **/
 147     QMap<int, DesktopLayoutItem> items;
 148
 149     QHash<QGraphicsItem*, int> m_animatingItems;
 150     QPointF workingStart;
 151
 152     // layout configuration
 153
 154     bool autoWorkingArea;
 155     bool temporaryPlacement;
 156
 157     qreal visibilityTolerance;
 158
 159     // item manipulation functions
 160     void performTemporaryPlacement(int group, int itemInGroup);
 161     void revertTemporaryPlacement(int group, int itemInGroup);
 162
 163     bool m_activated;
 164 };
 165
 166 #endif