Inheritance diagram for wx.ScrolledWindow:
The wx.ScrolledWindow class manages scrolling for its client area, transforming the coordinates according to the scrollbar positions, and setting the scroll positions, thumb sizes and ranges according to the area in view.
Starting from version 2.4 of wxWidgets, there are several ways to use a wx.ScrolledWindow. In particular, there are now three ways to set the size of the scrolling area:
Note
If Maximum size hints are still supported by SetVirtualSizeHints, use them at your own dire risk. They may or may not have been removed for 2.4, but it really only makes sense to set minimum size hints here. We should probably replace SetVirtualSizeHints with SetMinVirtualSize or similar and remove it entirely in future.
As with all windows, an application can draw onto a wx.ScrolledWindow using a device context. You have the option of handling the OnPaint handler or overriding the OnDraw function, which is passed a pre-scrolled device context (prepared by DoPrepareDC).
If you don’t wish to calculate your own scrolling, you must call DoPrepareDC when not drawing from within OnDraw, to set the device origin for the device context according to the current scroll position.
A wx.ScrolledWindow will normally scroll itself and therefore its child windows as well. It might however be desired to scroll a different window than itself: e.g. when designing a spreadsheet, you will normally only have to scroll the (usually white) cell area, whereas the (usually grey) label area will scroll very differently. For this special purpose, you can call SetTargetWindow which means that pressing the scrollbars will scroll a different window.
Note
Note that the underlying system knows nothing about scrolling coordinates, so that all system functions (mouse events, expose events, refresh calls etc) as well as the position of subwindows are relative to the “physical” origin of the scrolled window. If the user insert a child window at position (10, 10) and scrolls the window down 100 pixels (moving the child window out of the visible area), the child window will report a position of (10, -90).
See also
| Window Style | Description |
|---|---|
| wx.RETAINED | Uses a backing pixmap to speed refreshes. Motif only. |
Use wx.ScrolledWindow for applications where the user scrolls by a fixed amount, and where a ‘page’ can be interpreted to be the current visible portion of the window. For more sophisticated applications, use the wx.ScrolledWindow implementation as a guide to build your own scroll behaviour.
Constructor.
Parameters:
Returns:
Note
The window is initially created without visible scrollbars. Call SetScrollbars to specify how big the virtual window size should be.
Parameters:
Returns:
int
Translates the logical coordinates to the device ones. For example, if a window is scrolled 10 pixels to the bottom, the device coordinates of the origin are (0, 0) (as always), but the logical coordinates are (0, 10) and so the call to CalcScrolledPosition(0, 10) will return 0 in yy.
Parameters:
Returns:
(xx, yy)
See also
Translates the device coordinates to the logical ones. For example, if a window is scrolled 10 pixels to the bottom, the device coordinates of the origin are (0, 0) (as always), but the logical coordinates are (0, 10) and so the call to CalcUnscrolledPosition(0, 0) will return 10 in yy.
Parameters:
Returns:
(xx, yy)
See also
Call this function to prepare the device context for drawing a scrolled image. It sets the device origin according to the current scroll position.
DoPrepareDC is called automatically within the default OnPaint event handler, so your OnDraw override will be passed a ‘pre-scrolled’ device context. However, if you wish to draw from outside of OnDraw (via OnPaint), or you wish to implement OnPaint yourself, you must call this function yourself. For example:
def OnEvent(self, event):
dc = wx.ClientDC(self)
self.DoPrepareDC(dc)
dc.SetPen(wx.BLACK_PEN)
xpos, ypos = event.GetPosition()
if (xpos > -1 and ypos > -1 and event.Dragging()):
dc.DrawLine(xpos, ypos, x, y)
Parameters:
Enable or disable physical scrolling in the given direction. Physical scrolling is the physical transfer of bits up or down the screen when a scroll event occurs. If the application scrolls by a variable amount (e.g. if there are different font sizes) then physical scrolling will not work, and you should switch it off.
Parameters:
Note
Physical scrolling may not be available on all platforms. Where it is available, it is enabled by default.
Note
Note that you will have to reposition child windows yourself, if physical scrolling is disabled.
Parameters:
Returns:
int
Get the number of pixels per scroll unit (line), in each direction, as set by SetScrollbars.
A value of zero indicates no scrolling in that direction.
Returns:
(xUnit, yUnit)
See also
Get the position at which the visible portion of the window starts.
Returns:
(xView, yView)
Note
If either of the scrollbars is not at the home position, xView and/or yView will be greater than zero. Combined with wx.Window.GetClientSize, the application can use this function to efficiently redraw only the visible portion of the window. The positions are in logical scroll units, not pixels, so to convert to pixels you will have to multiply by the number of pixels per scroll increment.
See also
Note
Use wx.DC.DeviceToLogicalX and wx.DC.DeviceToLogicalY to translate these units to logical units.
See also
Scrolls a window so the view start is at the given point.
Parameters:
Note
The positions are in scroll units, not pixels, so to convert to pixels you will have to multiply by the number of pixels per scroll increment. If either parameter is -1, that position will be ignored (no change in that direction).
See also
Parameters:
Parameters:
Set the horizontal and vertical scrolling increment only. See the pixelsPerUnit parameter in SetScrollbars.
Parameters:
Sets up vertical and/or horizontal scrollbars.
Parameters:
The first pair of parameters give the number of pixels per ‘scroll step’, i.e. amount moved when the up or down scroll arrows are pressed. The second pair gives the length of scrollbar in scroll steps, which sets the size of the window. xPos and yPos optionally specify a position to scroll to immediately.
For example, the following gives a window horizontal and vertical scrollbars with 20 pixels per scroll step, and a size of 50 steps (1000 pixels) in each direction:
window.SetScrollbars(20, 20, 50, 50)
wx.ScrolledWindow manages the page size itself, using the current client window size as the page size.
Note
Note that for more sophisticated scrolling applications, for example where scroll steps may be variable according to the position in the document, it will be necessary to derive a new class from wx.Window, overriding OnSize and adjusting the scrollbars appropriately.
See also
