SetICMMode function

The SetICMMode function causes Image Color Management to be enabled, disabled, or queried on a given device context (DC).

Syntax

int SetICMMode(
  HDC hdc,
  int mode
);

Parameters

hdc

Identifies handle to the device context.

mode

Turns on and off image color management. This parameter can take one of the following constant values.

 

Value Meaning
ICM_ON
Turns on color management. Turns off old-style color correction of halftones.
ICM_OFF
Turns off color management. Turns on old-style color correction of halftones.
ICM_QUERY
Queries the current state of color management.
ICM_DONE_OUTSIDEDC
Turns off color management inside DC. Under Windows 2000, also turns off old-style color correction of halftones. Not supported under Windows 95.

Return Value

If this function succeeds, the return value is a nonzero value.

If this function fails, the return value is zero.

If ICM_QUERY is specified and the function succeeds, the nonzero value returned is ICM_ON or ICM_OFF to indicate the current mode.

Remarks

If the system cannot find an ICC color profile to match the state of the device, SetICMMode fails and returns zero.

Once WCS is enabled for a device context (DC), colors passed into the DC using most Win32 API functions are color matched. The primary exceptions are BitBlt and StretchBlt. The assumption is that when performing a bit block transfer (blit) from one DC to another, the two DCs are already compatible and need no color correction. If this is not the case, color correction may be performed. Specifically, if a device independent bitmap (DIB) is used as the source for a blit, and the blit is performed into a DC that has WCS enabled, color matching will be performed. If this is not what you want, turn WCS off for the destination DC by calling SetICMMode before calling BitBlt or StretchBlt.

If the CreateCompatibleDC function is used to create a bitmap in a DC, it is possible for the bitmap to be color matched twice, once when it is created and once when a blit is performed. The reason is that a bitmap in a DC created by the CreateCompatibleDC function acquires the current brush, pens, and palette of the source DC. However, WCS will be disabled by default for the new DC. If WCS is later enabled for the new DC by using the SetICMMode function, a color correction will be done. To prevent double color corrections through the use of the CreateCompatibleDC function, use the SetICMMode function to turn WCS off for the source DC before the CreateCompatibleDC function is called.

When a compatible DC is created from a printer's DC (see CreateCompatibleDC ), the default is for color matching to always be performed if it is enabled for the printer's DC. The default color profile for the printer is used when a blit is performed into the printer's DC using SetDIBitsToDevice or StretchDIBits. If this is not what you want, turn WCS off for the printer's DC by calling SetICMMode before calling SetDIBitsToDevice or StretchDIBits.

Also, when printing to a printer's DC with WCS turned on, the SetICMMode function needs to be called after every call to the StartPage function to turn back on WCS. The StartPage function calls the RestoreDC and SaveDC functions, which result in WCS being turned off for the printer's DC.

Requirements

   
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header wingdi.h
Library Gdi32.lib
DLL Gdi32.dll

See Also

Basic Color Management Concepts

BitBlt

CreateCompatibleDC

Functions

SetDIBitsToDevice

StartPage

StretchBlt

StretchDIBits