workspace/libs/plasma/layouts/nodelayout.h

   1 /*
   2  *   Copyright (C) 2007 Ivan Cukic <ivan.cukic+kde@gmail.com>
   3  *
   4  *   This program is free software; you can redistribute it and/or modify
   5  *   it under the terms of the GNU Lesser General Public License
   6  *   version 2, or (at your option) any later version, as published by the
   7  *   Free Software Foundation
   8  *
   9  *   This program is distributed in the hope that it will be useful,
  10  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *   GNU General Public License for more details
  13  *
  14  *   You should have received a copy of the GNU Lesser General Public
  15  *   License along with this program; if not, write to the
  16  *   Free Software Foundation, Inc.,
  17  *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18  */
  19
  20 #ifndef PLASMA_NODE_LAYOUT
  21 #define PLASMA_NODE_LAYOUT
  22
  23 #include <QtCore/QMap>
  24 #include <cmath>
  25
  26 #include <QtGui/QGraphicsLayout>
  27
  28 #include <plasma/plasma_export.h>
  29 #include <plasma/plasma.h>
  30
  31 namespace Plasma {
  32
  33 /**
  34  * Node layout has an advanced layouting mechanism. Every item's position
  35  * is defined by two nodes - one for top-left corner, and the other one for
  36  * bottom-right corner.
  37  *
  38  * Each node is defined by a pair of relative (xr, yr) and a pair of
  39  * absolute (xa, ya) coordinates. The calculated node coordinates depend
  40  * on the size and position of the NodeLayout object in the following
  41  * manner:
  42  *   x = layoutLeft + (xr * layoutWidth)  + xa
  43  *   y = layoutTop  + (yr * layoutHeight) + ya
  44  *
  45  * Alternatively, the item's position can be defined by using one node and
  46  * one pair of relative coordinates (xr, yr). In that case, the item is sized
  47  * following the sizeHint(). The relative coordinates (this time they are
  48  * relative to the item's geometry, not the layout's) specify what point of
  49  * the item will be bound to the defined node.
  50  */
  51
  52 class PLASMA_EXPORT NodeLayout : public QGraphicsLayout {
  53 public:
  54     class PLASMA_EXPORT NodeCoordinate {
  55     public:
  56         /**
  57          * Position is calculated:
  58          * x = parentLeft + (xRelative * parentWidth)  + xAbsolute
  59          * y = parentTop  + (yRelative * parentHeight) + yAbsolute
  60          */
  61         explicit NodeCoordinate(qreal xRelative = 0, qreal yRelative = 0, qreal xAbsolute = 0, qreal yAbsolute = 0);
  62
  63         enum CoordinateType {
  64             Relative = 0,
  65             Absolute = 1,
  66             InnerRelative = 2 };
  67
  68         static NodeCoordinate simple(qreal x, qreal y, CoordinateType xType = Relative, CoordinateType yType = Relative);
  69
  70         float xr, xa;
  71         float yr, ya;
  72     };
  73
  74     explicit NodeLayout(QGraphicsLayoutItem * parent = 0);
  75     virtual ~NodeLayout();
  76
  77
  78
  79     /**
  80      * Adds item at top-left corner, with automatic sizing
  81      * (using sizeHint of the item)
  82      */
  83     void addItem (QGraphicsLayoutItem * item);
  84
  85     /**
  86      * Adds item with specified top-left and bottom right corners.
  87      */
  88     void addItem (QGraphicsLayoutItem * item,
  89             NodeCoordinate topLeft, NodeCoordinate bottomRight);
  90
  91     /**
  92      * Adds item with automatic sizing turned on. xr and yr specify
  93      * which point of the item is bound to node coordinate. Those
  94      * are relative coordinates so (0, 0) represent top left corner,
  95      * (0.5, 0.5) represent the center of the item etc.
  96      */
  97     void addItem (QGraphicsLayoutItem * item,
  98             NodeCoordinate node, qreal xr = 0, qreal yr = 0);
  99
 100     void removeItem (QGraphicsLayoutItem * item);
 101
 102     virtual int count() const;
 103     virtual int indexOf(QGraphicsLayoutItem * item) const;
 104     virtual QGraphicsLayoutItem * itemAt(int i) const;
 105     virtual QGraphicsLayoutItem * takeAt(int i);
 106
 107 protected:
 108     void relayout();
 109     QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF()) const;
 110
 111 private:
 112     class Private;
 113     Private * const d;
 114 };
 115
 116 }
 117
 118 #endif /* PLASMA_NODE_LAYOUT */