🚀 go-pugleaf

In <1992Dec9.045940@avsht.sph.spb.su> avsht@sph.spb.su (Alex V. Shturm) writes:

>Trying to recompile my Windows project under BC 3.1, I was wondering
>very much when compiler suddenly reported me that he doesn't know
>the message WM_PAINTICON. I looked into windows.h and didn't find it!!!
>Although nearest win30.h file (former windows.h from BC 3.0)
>defines it.
>
>1. Is it Borland mistake or mine?
>2. What is the best way to avoid it:
>   - to feed bcc the option -DWM_PAINTICON=0x0026
>   - to change windows.h by adding #define WM_PAINTICON 0x0026
>   - another way

According to the Fall issue of Microsoft Develop Network News, Microsoft
deliberately removed WM_PAINTICON because "[t]his unnecessary message was
extremely confusing to developers and caused some version compatibility
problems for Windows."

They suggest that you (if you don't want to just register the icon under
RegisterClass()) use the WM_PAINT message, and check IsIconic(hWnd) to
see if it's an icon or not.  Their sample code suggests that you'd have
something like:

    case WM_PAINT: {
        PAINTSTRUCT ps;
        if (IsIconic(hWnd)) {
            BeginPaint(hWnd, &ps);
            DefWindowProc(hWnd, WM_ICONERASEBKGND, (WORD) ps.hdc, 0L);
            DrawIcon(ps.hdc, 0, 0, hIcon);
            EndPaint(hWnd, &ps);
            return 0;  /* microsoft's sample didn't have this "return", */
                       /* but we want it, don't we?                     */
        } else {
            return DefWindowProc(hWnd, message, wParam, lParam);
        }
     }

     case WM_ERASEBKGND:
        if (IsIconic(hWnd))
            return TRUE;
        else
            return DefWindowProc(hWnd, message, wParam, lParam);

     case WM_QUERYDRAGICON:
        return (LONG) (WORD)hIcon;


They also point out that (a) you should register a NULL icon with
RegisterClass if you're doing it yourself; and (b) "You might also
want to use the new Windows v3.1 DDE capabilities of the Program
Manager to get the icon the user has associated with you application.
Doing this will give you changeable icons, just as MS-DOS applications
do."

Hope this helps.  In answer to your question of how to get your code
to use WM_PAINTICON, the answer is, unfortunately, change you code so
you don't use WM_PAINTICON.  Given that it's no longer supported, you
aren't guaranteed that later version of Windows will even have this
message.  It looks like v3.1 still does (though undocumented), but
you shouldn't rely on it.

-- 
 Rob Ryan
    rryan@panix.com