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17.5 Buffering of Graphics Output

To improve performance of graphics output, most graphics devices provide some form of buffering. By default, Scheme’s graphics procedures flush this buffer after every drawing operation. The procedures in this section allow the user to control the flushing of the output buffer.

procedure: graphics-enable-buffering graphics-device

Enables buffering for graphics-device. In other words, after this procedure is called, graphics operations are permitted to buffer their drawing requests. This usually means that the drawing is delayed until the buffer is flushed explicitly by the user, or until it fills up and is flushed by the system.

procedure: graphics-disable-buffering graphics-device

Disables buffering for graphics-device. By default, all graphics devices are initialized with buffering disabled. After this procedure is called, all drawing operations perform their output immediately, before returning.

Note: graphics-disable-buffering flushes the output buffer if necessary.

procedure: graphics-flush graphics-device

Flushes the graphics output buffer for graphics-device. This operation has no effect for devices that do not support buffering, or if buffering is disabled for the device.