Platform Package reference: Function EwBeginUpdateArea()

Description of the function EwBeginUpdateArea() available in all Platform Packages for ANSI C compatible target systems. This function is intended to be used when integrating the Embedded Wizard created GUI application with the underlying graphics subsystem, graphics hardware or other external GUI applications coexisting on the same system.

Declaration

XBitmap* EwBeginUpdateArea( XViewport* aViewport, XRect aArea )

Parameters

aViewport

Viewport to begin the drawing operations.

aArea

Area affected by the drawing operations relative to the top-left corner of the viewport.

Discussion

The function EwBeginUpdateArea() initiates the screen update cycle for the given viewport and provides access to the specified area of its framebuffer via the returned temporary bitmap. The returned bitmap covers the area of the framebuffer and can serve as the destination in all drawing operations until the function EwEndUpdate() is called. Due to the platform specific framebuffer limitations the returned bitmap may not be used as source in the drawing operations.

If successful, the function returns a temporary bitmap providing the access to the framebuffer of the viewport.