Q88192: INFO: WM_PAINTICON Message Removed from Windows SDK Docs
Article: Q88192
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.1
Operating System(s):
Keyword(s): kb16bitonly kbSDKPlatform kbWndw kbWndwMsg
Last Modified: 11-JUN-1999
3.10
WINDOWS
kbprg
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The information in this article applies to:
- Microsoft Windows Software Development Kit (SDK) 3.1
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SUMMARY
=======
The WM_PAINTICON message is not listed in the "Programmer's Reference, Volume 3:
Messages, Structures, and Macros" for version 3.1 of the Microsoft Windows
Software Development Kit (SDK). The text below explains this decision and
provides source code that enables an application to paint its own icon.
MORE INFORMATION
================
When an application for the Microsoft Windows operating system registers a
window class, it specifies a handle to an appropriate icon in the hIcon member
of the WNDCLASS data structure. This can be an application-specific icon loaded
from the application's resources or the default application icon provided with
Windows.
If the application includes its own icon, Windows sends a WM_PAINTICON message
when the user minimizes the application. If the application passes the
WM_PAINTICON message to the DefWindowProc function, Windows paints the icon in
the appropriate location.
If the application specifies the default icon or no icon, Windows does not send a
WM_PAINTICON message when the user minimizes the application; instead, it sends
a WM_PAINT message. When the application receives the WM_PAINT message, it can
either pass the message to DefWindowProc so that Windows will paint the default
icon, or the application can paint the icon dynamically.
Because the application cannot process the WM_PAINTICON message, except to pass
it to DefWindowProc, it has been removed from the documentation for version 3.1
of the Windows SDK.
The following code demonstrates how to process the WM_PAINT message to paint the
icon. Given a window handle, the IsIconic function indicates whether the window
is an icon:
case WM_PAINT:
{
PAINTSTRUCT ps;
BeginPaint(hWnd, &ps);
if (IsIconic(hWnd))
{
SendMessage(hWnd, WM_ICONERASEBKGND, (WORD)ps.hdc, 0);
DrawIcon(ps.hdc, 0, 0, hIcon);
}
EndPaint(hWnd, &ps);
}
break;
When the application processes the WM_QUERYDRAGICON message by returning the
handle to its icon, Windows converts the icon to a cursor when the user drags
the icon window with the mouse.
case WM_QUERYDRAGICON:
return hIcon;
Because the application paints the icon background when it processes the WM_PAINT
message, the following code prevents the screen from flashing:
case WM_ERASEBKGND:
if (IsIconic(hWnd))
return TRUE;
else
return DefWindowProc(...);
break;
DefWindowProc erases the background.
Additional query words: 3.10
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Keywords : kb16bitonly kbSDKPlatform kbWndw kbWndwMsg
Technology : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version : WINDOWS:3.1
Issue type : kbinfo
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