1#-----------------------------------------------------------------------------
2# Name:        dragscroller.py
3# Purpose:     Scrolls a wx.ScrollWindow by dragging
4#
5# Author:      Riaan Booysen
6#
7# Created:     2006/09/05
8# Copyright:   (c) 2006
9# Licence:     wxPython
10#-----------------------------------------------------------------------------
11
12import wx
13
14class DragScroller:
15    """ Scrolls a wx.ScrollWindow in the direction and speed of a mouse drag.
16
17        Call Start with the position of the drag start.
18        Call Stop on the drag release. """
19
20    def __init__(self, scrollwin=None, rate=30, sensitivity=0.75):
21        self.scrollwin = scrollwin
22        self.rate = rate
23        self.sensitivity = sensitivity
24
25        self.pos = None
26        self.timer = None
27
28    def GetScrollWindow(self):
29        return self.scrollwin
30    def SetScrollWindow(self, scrollwin):
31        self.scrollwin = scrollwin
32
33    def GetUpdateRate(self):
34        return self.rate
35    def SetUpdateRate(self, rate):
36        self.rate = rate
37
38    def GetSensitivity(self):
39        return self.sensitivity
40    def SetSensitivity(self, sensitivity):
41        self.sensitivity = sensitivity
42
43    def Start(self, pos):
44        """ Start a drag scroll operation """
45        if not self.scrollwin:
46            raise Exception('No ScrollWindow defined')
47
48        self.pos = pos
49        self.scrollwin.SetCursor(wx.Cursor(wx.CURSOR_SIZING))
50        if not self.scrollwin.HasCapture():
51            self.scrollwin.CaptureMouse()
52
53        self.timer = wx.Timer(self.scrollwin)
54        self.scrollwin.Bind(wx.EVT_TIMER, self.OnTimerDoScroll, id=self.timer.GetId())
55        self.timer.Start(self.rate)
56
57    def Stop(self):
58        """ Stops a drag scroll operation """
59        if self.timer and self.scrollwin:
60            self.timer.Stop()
61            self.scrollwin.Disconnect(self.timer.GetId())
62            self.timer.Destroy()
63            self.timer = None
64
65            self.scrollwin.SetCursor(wx.STANDARD_CURSOR)
66            if self.scrollwin.HasCapture():
67                self.scrollwin.ReleaseMouse()
68
69    def OnTimerDoScroll(self, event):
70        if self.pos is None or not self.timer or not self.scrollwin:
71            return
72
73        new = self.scrollwin.ScreenToClient(wx.GetMousePosition())
74        dx = int((new.x-self.pos.x)*self.sensitivity)
75        dy = int((new.y-self.pos.y)*self.sensitivity)
76        spx = self.scrollwin.GetScrollPos(wx.HORIZONTAL)
77        spy = self.scrollwin.GetScrollPos(wx.VERTICAL)
78
79        self.scrollwin.Scroll(spx+dx, spy+dy)
80