A memory device context provides a means to draw graphics onto a
bitmap. When drawing in to a mono-bitmap, using
WHITE_BRUSH will draw the background colour (i.e. 0) whereas all other
colours will draw the foreground colour (i.e. 1).
A bitmap must be selected into the new memory DC before it may be used for anything. Using the Bitmap#draw method with a block ensures that the DC is properly set up and disposed of, and it’s recommended you use that method to create a MemoryDC rather than instantiating it directly.
Selects the given bitmap into the device context, to use as the memory bitmap. Selecting the bitmap into a memory DC allows you to draw into the DC (and therefore the bitmap). and also to use Blit to copy the bitmap to a window. For simple drawing of Bitmaps onto a window’s DC, you may find DC#draw_icon easier to use instead.
If the argument is Wx::NULL_BITMAP (or some other uninitialised Bitmap) the current bitmap is selected out of the device context, and the original bitmap restored, allowing the current bitmap to be destroyed safely.
It is recommended that you use Bitmap#draw rather than creating a MemoryDC and calling select_object yourself.
[This page automatically generated from the Textile source at Wed Sep 09 02:21:17 +0100 2009]