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/**
- @wxheader{scrolwin.h}
The wxScrolled class manages scrolling for its client area, transforming
the coordinates according to the scrollbar positions, and setting the
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
+ DoPrepareDC() is called automatically within the default @c 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() (via OnPaint()), or you wish to implement OnPaint()
- yourself, you must call this function yourself.
+ outside of OnDraw() (e.g. from your own @c wxEVT_PAINT handler), you
+ must call this function yourself.
For example:
@code
}
@endcode
+ 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.
*/
void DoPrepareDC(wxDC& dc);