#include <wx/scrolwin.h>
The wxScrolled 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.
There are two commonly used (but not the only possible!) specializations of this class:
Starting from version 2.4 of wxWidgets, there are several ways to use a wxScrolledWindow (and now wxScrolled). In particular, there are three ways to set the size of the scrolling area:
One way is to set the scrollbars directly using a call to with wxWindow::SetSizer(). The scrolling area will be set to the size requested by the sizer and the scrollbars will be assigned for each orientation according to the need for them and the scrolling increment set by SetScrollRate(). As above, scrolling is only enabled in orientations with a non-zero increment. You can influence the minimum size of the scrolled area controlled by a sizer by calling wxWindow::SetVirtualSizeHints(). (Calling SetScrollbars() has analogous effects in wxWidgets 2.4 – in later versions it may not continue to override the sizer.)
Note that if maximum size hints are still supported by wxWindow::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 wxWindow::SetVirtualSizeHints() with wxWindow::SetMinVirtualSize() or similar and remove it entirely in future.
As with all windows, an application can draw onto a wxScrolled using a device context.
You have the option of handling the OnPaint handler or overriding the wxScrolled::OnDraw() function, which is passed a pre-scrolled device context (prepared by wxScrolled::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 wxScrolled).
This class supports the following styles:
The following event handler macros redirect the events to member function handlers 'func' with prototypes like:
Event macros for events emitted by this class:
wxEVT_SCROLLWIN_TOPscroll-to-top events.
wxEVT_SCROLLWIN_BOTTOMscroll-to-bottom events.
wxEVT_SCROLLWIN_LINEUPline up events.
wxEVT_SCROLLWIN_LINEDOWNline down events.
wxEVT_SCROLLWIN_PAGEUPpage up events.
wxEVT_SCROLLWIN_PAGEDOWNpage down events.
wxEVT_SCROLLWIN_THUMBTRACKthumbtrack events (frequent events sent as the user drags the thumbtrack).
wxEVT_SCROLLWIN_THUMBRELEASEthumb release events.
Default constructor.
Constructor..
wxPerl Note: In wxPerl this method takes two parameters and returns a 2-element list (xx,.
wxPerl Note: In wxPerl this method takes two parameters and returns a 2-element list (xx, yy).
Creates the window for two-step construction.
Derived classes should call or replace this function. If it is not replaced, bear in mind that it calls T::Create() through the global function wxCreateScrolled() so if T::Create() has a different signature than wxScrolled::Create() you should implement overloaded wxCreateScrolled() which would call T::Create() in the correct manner.
Disable use of keyboard keys for scrolling.
By default cursor movement keys (including Home, End, Page Up and Down) are used to scroll the window appropriately. If the derived class uses these keys for something else, e.g. changing the currently selected item, this function can be used to disable this behaviour as it's not only not necessary then but can actually be actively harmful if another object forwards a keyboard event corresponding to one of the above keys to us using ProcessWindowEvent() because the event will always be processed which can be undesirable.
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
wxEVT_PAINT event handler, so your OnDraw() override will be passed an already 'pre-scrolled' device context. However, if you wish to draw from outside of OnDraw() (e.g. from your own
wxEVT_PAINT handler), you must call this function yourself.
For example:
Notice that the function sets the origin by moving it relatively to the current origin position, so you shouldn't change the origin before calling DoPrepareDC() or, if you do, reset it to (0, 0) later. If you call DoPrepareDC() immediately after device context creation, as in the example above, this problem doesn't arise, of course, so it is customary to do it like this.
Enable or disable use of wxWindow::ScrollWindow() for scrolling.
By default, when a scrolled window is logically scrolled, wxWindow::ScrollWindow() is called on the underlying window which scrolls the window contents and only invalidates the part of the window newly brought into view. If false is passed as an argument, then this "physical scrolling" is disabled and the window is entirely invalidated whenever it is scrolled by calling wxWindow::Refresh().
It should be rarely necessary to disable physical scrolling, so this method shouldn't be called in normal circumstances.
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.
wxPerl Note: In wxPerl this method takes no parameters and returns a 2-element list (xUnit, yUnit).
Function which must be overridden to implement the size available for the scroll target for the given size of the main window.
This method must be overridden if SetTargetWindow() is used (it is never called otherwise). The implementation should decrease the size to account for the size of the non-scrollable parts of the main window and return only the size available for the scrollable window itself. E.g. in the example given in SetTargetWindow() documentation the function would subtract the height of the header window from the vertical component of size.
Get the position at which the visible portion of the window starts.
wxPerl Note: In wxPerl this method takes no parameters and returns a 2-element list (x, y).
This is a simple overload of GetViewStart(int*,int*); see that function for more info.
Gets the size in device units of the scrollable window area (as opposed to the client size, which is the area of the window currently visible).
wxPerl Note: In wxPerl this method takes no parameters and returns a 2-element list (xUnit, yUnit).
Are we generating the autoscroll events?
Motif only: true if the window has a backing bitmap.
Called by the default paint event handler to allow the application to define painting behaviour without having to worry about calling DoPrepareDC().
Instead of overriding this function you may also just process the paint event in the derived class as usual, but then you will have to call DoPrepareDC() yourself.
This function is for backwards compatibility only and simply calls DoPrepareDC() now.
Notice that it is not called by the default paint event handle (DoPrepareDC() is), so overriding this method in your derived class is useless.
Scrolls a window so the view start is at the given point.
This is an overload of Scroll(int,int); see that function for more info.
This method can be overridden in a derived class to forbid sending the auto scroll events - note that unlike StopAutoScrolling() it doesn't stop the timer, so it will be called repeatedly and will typically return different values depending on the current mouse position.
The base class version just returns true.
Sets up vertical and/or horizontal scrollbars.:
wxScrolled.
Set the horizontal and vertical scrolling increment only.
See the pixelsPerUnit parameter in SetScrollbars().
Call this function to tell wxScrolled to perform the actual scrolling on a different window (and not on itself).
This method is useful when only a part of the window should be scrolled. A typical example is a control consisting of a fixed header and the scrollable contents window: the scrollbars are attached to the main window itself, hence it, and not the contents window must be derived from wxScrolled, but only the contents window scrolls when the scrollbars are used. To implement such setup, you need to call this method with the contents window as argument.
Notice that if this method is used, GetSizeAvailableForScrollTarget() method must be overridden.
This method can be overridden in a derived class to prevent scrolling the child window into view automatically when it gets focus.
The default behaviour is to scroll this window to show its currently focused child automatically, to ensure that the user can interact with it. This is usually helpful, but can be undesirable for some windows, in which case this method can be overridden to return false for them to prevent any scrolling from taking place when such windows get focus.
Set the scrollbar visibility.
By default the scrollbar in the corresponding direction is only shown if it is needed, i.e. if the virtual size of the scrolled window in this direction is greater than the current physical window size. Using this function the scrollbar visibility can be changed to be:
Note that the window must be created before calling this method.
Stop generating the scroll events when mouse is held outside the window.