Retrieves a Cairo context to be used to draw on the gdk.surface.Surface of context.
A call to gdk.draw_context.DrawContext.beginFrame with this context must have been done or this function will return null.
The returned context is guaranteed to be valid until gdk.draw_context.DrawContext.endFrame is called.
a Cairo context to draw on `GdkSurface
Retrieves a Cairo context to be used to draw on the gdk.surface.Surface of context.
A call to gdk.draw_context.DrawContext.beginFrame with this context must have been done or this function will return null.
The returned context is guaranteed to be valid until gdk.draw_context.DrawContext.endFrame is called.