src/ui/QFingerScrollArea.h

   1 /* Shopper
   2  * Copyright (C) 2008 David Greaves <david@dgreaves.com>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library 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 GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA 02110-1301, USA.
  18  */
  19 #ifndef SHOPPER_UI_QFINGERSCROLLAREA_H
  20 #define SHOPPER_UI_QFINGERSCROLLAREA_H
  21
  22 #include <QScrollArea>
  23 #include <QTime>
  24 #include <QBasicTimer>
  25
  26 class QFingerScrollArea: public QScrollArea
  27         {
  28                 Q_OBJECT;
  29
  30         public:
  31                 QFingerScrollArea(QWidget * parent = 0);
  32
  33                 // New interface
  34                 void setScrollConstraints(bool AllowHoriz, bool AllowVert);
  35                 void setKinetic(bool kinetic);              // Continue moving after release
  36 //              bool kinetic();
  37                 void setScrollPaper(bool scrollPaper);      // true then simulate finger dragging the widget
  38 //              bool scrollPaper();                         // false then scroll like a scrollbar
  39
  40
  41                 // Operational
  42                 bool eventFilter(QObject *obj, QEvent *event);
  43
  44                 // constants
  45                 static const int SENSITIVITY, KINETIC_REFRESH, VSCALE,
  46                         DECEL_DURATION, DEBOUNCE;
  47                 static const double DECEL;
  48         public:
  49                 void registerChildrenForFingerScrolling(QObject *top);
  50                 void deregisterChildrenForFingerScrolling(QObject *top);
  51                 void mousePressEvent ( QMouseEvent * event );
  52                 void mouseMoveEvent ( QMouseEvent * event );
  53                 void mouseReleaseEvent ( QMouseEvent * event );
  54                 void childEvent ( QChildEvent * event );
  55
  56         private:
  57                 bool allowHoriz, allowVert; // Should we scroll horiz and/or vert
  58                 bool scrollPaper;
  59                 int direction;               // +1/-1
  60                 bool scrolling;              // State: are we scrolling?
  61                 bool recently_scrolling;     // were we scrolling?
  62                 bool scrolling_setup;        // are we setup for scrolling?
  63                 int scroll_start_x, scroll_start_y;    // scrollbar value at fingerdown to establish base position
  64                 int start_x, start_y;        // global event x,y at start
  65                 int curr_x, curr_y;          // current x,y (kept to allow velocity calc)
  66
  67                 int max_x, max_y;            // screen size for scaling
  68                 int scroll_range_x;          // scroll range horiz
  69                 int scroll_range_y;          // scroll range vert
  70                 int scale_x, scale_y;        // scale (ie scroll by pixels or by scrollbar)
  71                 bool kinetic;                // Should we be a little kinetic
  72                 QTime event_time;
  73                 int last_x, last_y;          // global event x,y at start
  74                 int vel_x, vel_y;            // Velocity
  75                 int vel_x1, vel_y1;          // Velocity before
  76                 int last_ev_time, curr_time; // timer for velocity
  77
  78                 int kineticTimer;
  79                 int debounceTimer;
  80                 void timerEvent(QTimerEvent *event);
  81                 int kinetic_cycles;          // how long do we slow down for
  82
  83                 void setupEvent ( QMouseEvent * event );
  84
  85 //              bool event ( QEvent * e);
  86         };
  87
  88 #endif // SHOPPER_UI_QFINGERSCROLLAREA_H