Element: graphic_window.double_buffering

Type

numeric

Description

Whether graphic drawing in graphic_window is to be double buffered.

Without double buffering the window is cleared before its contents, i.e. entity graphics, get redrawn. This can be irritating to some users as the window tends to "flash" while the window is cleared, but it has the advantage that the rendering of individual entity graphics can be seen during the redraw process.

This element has a positive value when double buffering is enabled, and 0 when double buffering is not enabled. A value of 1 indicates the default double buffering behavior whereby a new image simply replaces the old, but various transition styles are available including wipes and fades for presentation-type transitions. Such variations are invoked when a full window repaint is done, for example on a change of viewing extents. See here for a description of all available transition styles.

Double buffering the output computes the new image off-screen before displaying it when complete. This gives the effect of a smooth transition but is not always desirable as some complex graphics require time-consuming repaints, therefore a longer delay between completed images.

When double buffering is enabled it uses window "save under" facilities. Therefore window.save_under is set unless it was already set.

Turning this value on will perform an immediate repaint of the window.

See Also