wm-paletteischanging.md

description	ms.assetid	title	ms.topic	ms.date
The WM\_PALETTEISCHANGING message informs applications that an application is going to realize its logical palette.	64ec1042-0ab5-496f-9a88-2f293b412704	WM_PALETTEISCHANGING message (Winuser.h)	reference	05/31/2018

WM_PALETTEISCHANGING message

The WM_PALETTEISCHANGING message informs applications that an application is going to realize its logical palette.

A window receives this message through its WindowProc function.

LRESULT CALLBACK WindowProc(
  HWND hwnd, 
  UINT  uMsg, 
  WPARAM wParam, 
  LPARAM lParam     
);

Parameters

wParam

A handle to the window that is going to realize its logical palette.

lParam

This parameter is not used.

Return value

If an application processes this message, it should return zero.

Remarks

The application changing its palette does not wait for acknowledgment of this message before changing the palette and sending the WM_PALETTECHANGED message. As a result, the palette may already be changed by the time an application receives this message.

If the application either ignores or fails to process this message and a second application realizes its palette while the first is using palette indexes, there is a strong possibility that the user will see unexpected colors during subsequent drawing operations.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Header	Winuser.h (include Windows.h)

See also

Colors Overview

Color Messages

WM_PALETTECHANGED

WM_QUERYNEWPALETTE