beginBatchDrawing();
The beginBatchDrawing method of the Window class marks the start of a batch mode operation.
During batch mode, drawing requests are collected into a drawing script (as normally occurs when the autoRedraw property is set to true), but are not drawn. No evaluation of whether previous script entries are redundant is performed (for example, does a filled rectangle totally cover a previously drawn line?).
Use of batch drawing mode can reduce flicker associated with consecutive drawing operations and improve performance by using the same window drawing environment for the entire script.
An exception is raised if the autoRedraw property for the window is not set to true when the beginBatchDrawing method is called.