ContrastControl (Compact 2013)

3/26/2014

This function is used to modify the display contrast. This function must be implemented by the driver developer when it is needed.

Syntax

BOOL ContrastControl(
    ULONG cmd,
    ULONG * pValue
);

Parameters

• cmd
  Specifies the command to perform that is related to display contrast. This can be one of the following:

  • CONTRAST_CMD_GET - indicates to retrieve the contrast value.
  • CONTRAST_CMD_SET - indicates to set the contrast value.
  • CONTRAST_CMD_INCREASE - indicates to increment the contrast value.
  • CONTRAST_CMD_DECREASE - indicates to decrement the contrast value.
  • CONTRAST_CMD_DEFAULT - indicates to set contrast to the default value provided by the OEM in OEM_INFO.

• pValue
  A buffer that varies based on the value passed in to cmd. If cmd is CONTRAST_CMD_GET, CONTRAST_CMD_INCREASE, or CONTRAST_CMD_DECREASE, then on return pValue contains the new contrast value. If cmd is CONTRAST_CMD_SET, then it is an [in] parameter that specifies the new contrast value to set.

Return Value

TRUE indicates success. Otherwise, FALSE is returned, and GetLastError can be used to obtain error information.

Remarks

GPE-based display drivers must implement this method in order to support user-controllable display contrast.

Requirements

See Also

Reference

Display Driver Functions