Draws images that are optimized for every screen they cross.

void DeviceLoop (
     drawingRgn, 
    DeviceLoopDrawingUPP drawingProc, 
    SInt32 userData, 
    DeviceLoopFlags flags
);

Parameter descriptions

drawingRgn

A handle to the region in which you will draw; this drawing region uses coordinates that are local to its graphics port.

drawingProc

A pointer to your own drawing function.

userData

Any additional data that you wish to supply to your drawing function.

flags

One or more members of the set of flags defined by the “Device Loop Flags” data type. if you want to use the default behavior of DeviceLoop, specify an empty set ([]) in this parameter.

DISCUSSION

The DeviceLoop function searches for graphics devices that intersect your window’s drawing region, and it calls your drawing function for each dissimilar video device it finds.

Because DeviceLoop provides your drawing function with the pixel depth and other attributes of each video device, your drawing function can optimize its drawing for each video device.

See DeviceLoopDrawingProcPtr for a description of the drawing function you must provide for the drawingProc parameter.

SPECIAL CONSIDERATIONS

The DeviceLoop function may move or purge memory blocks in the application heap; do not call this function at interrupt time.

AVAILABILITY

Supported in Carbon. Available in Carbon 1.0.2 and later when running Mac OS 8.1 or later.

© 2000 Apple Computer, Inc. (Last Updated 6/30/2000)