Legacy Document

Inside Macintosh: Devices /

Chapter 6 - Power Manager / Power Manager Reference

Power Manager Dispatch Routines / Controlling the Dimming Timer

DimmingControl

You can use the DimmingControl function to turn the automatic dimming feature on and off.

void DimmingControl(Boolean enableDimming);

enableDimming

A Boolean that specifies whether to enable the automatic dimming feature. Set this parameter to true to enable automatic dimming.

DESCRIPTION

The DimmingControl function enables or disables the automatic dimming feature that causes the computer to dim the screen after a preset period of time. When enableDimming is set to true, the automatic dimming feature is enabled (this is the normal state). When enableDimming is set to false, the computer will not dim the screen.

SPECIAL CONSIDERATIONS

Calling DimmingControl with enableDimming set to false multiple times increments the auto dimming disable level so that it requires the same number of calls to DimmingControl with enableDimming set to true to reenable the auto dimming feature. If more than one piece of software makes this call, auto dimming may not be reenabled when you think it should be.

ASSEMBLY-LANGUAGE INFORMATION

The trap is _PowerMgrDispatch ($A09E). The selector value for DimmingControl is 31 ($1F) in the low word of register D0. The Boolean value is passed in the high word of register D0.

SEE ALSO

You can use the PMFeatures function (page 6-41) to determine whether the computer supports automatic dimming.