How do I avoid a window to be resized horizontally while maximizing?

[xanatose]

I want to make a window that can be resized vertically but not horizontally.

I am handling WM_SIZING to avoid the user to resize using the border, but got problems when the window is maximized.

What will be the message to handle?

[Gunner]

Check to see if the window is maximized with IsZoomed and bale if it is.

[dedndave]

you can set the min and max size by handling WM_GETMINMAXINFO

when you handle WM_SIZE, check the value of wParam   :U
you can handle maximize/minimize sizing seperately and also use it to detect when they switch

[Tedd]

Or just remove the ability to maximize - set the window style to:

WS_OVERLAPPEDWINDOW and (not WS_MAXIMIZEBOX)

(or whatever you're using, and mask out WS_MAXIMIZEBOX)

[dedndave]

not sure that will work, Tedd
the user can also maximize a window with the sysmenu or by double-clicking the title bar

i knew i had seen it someplace   :bg

When the system receives a command to maximize or restore a minimized window, it sends the window a WM_QUERYOPEN message. If the window procedure returns FALSE, the system ignores the maximize or restore command.

The system automatically sets the size and position of a maximized window to the system-defined defaults for a maximized window. To override these defaults, an application can either call the SetWindowPlacement function or process the WM_GETMINMAXINFO message that is received by a window when the system is about to maximize the window. WM_GETMINMAXINFO includes a pointer to a MINMAXINFO structure containing values the system uses to set the maximized size and position. Replacing these values overrides the defaults.

http://msdn.microsoft.com/en-us/library/ms632599%28v=vs.85%29.aspx#min_max

there is probably a way to create a window that cannot be maximized - maybe when you register the class
i think i read someplace you can access the sysmenu handle to disable it, there

[MichaelW]

When changing the style to disable the maximize button, you can force an update of the menu bar to match the new style.

Code Select Expand


;==============================================================================
    include \masm32\include\masm32rt.inc
;==============================================================================
    .data
        rc RECT <>
    .code
;==============================================================================
DlgProc proc hwndDlg:dword, uMsg:dword, wParam:dword, lParam:dword
    SWITCH uMsg
      CASE WM_INITDIALOG
        invoke GetWindowRect, hwndDlg, addr rc
      CASE WM_COMMAND
        .if wParam == 1000
          invoke GetWindowLong, hwndDlg, GWL_STYLE
          xor eax, WS_MAXIMIZEBOX
          invoke SetWindowLong, hwndDlg, GWL_STYLE, eax
          invoke DrawMenuBar, hwndDlg
        .endif
      CASE WM_SIZING
        mov edx, lParam
        push rc.left
        pop [edx].RECT.left
        push rc.right
        pop [edx].RECT.right
        return 1
      CASE WM_COMMAND
        SWITCH wParam
          CASE IDCANCEL
            invoke EndDialog, hwndDlg, 0
        ENDSW
      CASE WM_CLOSE
        invoke EndDialog, hwndDlg, 0
    ENDSW
    xor eax, eax
    ret
DlgProc endp
;==============================================================================
start:
;==============================================================================
    Dialog "Test", "MS Sans Serif",10, \
           WS_OVERLAPPEDWINDOW or DS_CENTER, \
           1,0,0,100,75,1024
    DlgButton "Swap Style",0,0,0,40,12,1000

    invoke GetModuleHandle, NULL
    CallModalDialog eax,0,DlgProc,NULL
    exit
;==============================================================================
end start


Edit: Modified the code making it possible to switch between the two styles.

[drizz]

The message is WM_SYSCOMMAND.
Set your own size and return "message handled".

Code Select Expand

Main_WM_SYSCOMMAND proc hWnd,wParam,lParam
mov eax,wParam
and eax,0FFF0h
.if eax == SC_MAXIMIZE
invoke MessageBox,hWnd,T("You are about to maximize a window. Are you sure you want to do that?"),T('Clippy'),MB_YESNO or MB_ICONQUESTION
cmp eax,IDNO
je @F
.endif
invoke DefWindowProc,hWnd,WM_SYSCOMMAND,wParam,lParam
@@:
return 0
Main_WM_SYSCOMMAND endp

[xanatose]

Thank you, WM_GETMINMAXINFO worked.

[dedndave]

well - that will work
but, i think a better way is to disable the maximize function on the menu with MF_GRAYED
this code can be in the WM_CREATE handler...

Code Select Expand

       INVOKE  GetSystemMenu,hWnd,FALSE
;now, the system menu handle is in EAX
;the control ID's are as listed in WM_SYSCOMMAND documentation
;we want to disable SC_MAXIMIZE, so...
       INVOKE  EnableMenuItem,eax,SC_MAXIMIZE,MF_BYCOMMAND or MF_GRAYED

well - that does not work as i expected - lol
let me see if i can figure out why

[dedndave]

ok - this works...

Code Select Expand

        INVOKE  GetSystemMenu,hWnd,FALSE
        INVOKE  RemoveMenu,eax,SC_MAXIMIZE,MF_BYCOMMAND
by god, if i can't disable it, i'll remove it altogether - lol
it also disabled the ability to maximize by double-clicking on the title bar   :U

if you use Tedd's idea to get rid of the max box, they have no way to maximize

[MichaelW]

Once you have removed the WS_MAXIMIZEBOX style, a call to DrawMenuBar will update the menu, disabling the Maximize command.

[dedndave]

ok - well - i haven't been able to get rid of the box yet - lol

[dedndave]

ok - got it   :U
i forgot that the AND preceeds the OR in order of operation

Code Select Expand

WS_OVERLAPPEDWINDOW or WS_VISIBLE or WS_CLIPCHILDREN and (not WS_MAXIMIZEBOX)
(WS_OVERLAPPEDWINDOW or WS_VISIBLE or WS_CLIPCHILDREN) and (not WS_MAXIMIZEBOX)
the first one did not work - the second one does
i guess this would be simpler

Code Select Expand

WS_OVERLAPPEDWINDOW and (not WS_MAXIMIZEBOX) or WS_VISIBLE or WS_CLIPCHILDREN

[Tedd]

Works fine for me (WinXP sp3)

The maximize button is disabled (but still visible), it's also disabled in the system-menu, and double-clicking the titlebar does nothing.

[dedndave]

i was playing with this a little more
oddly enough, if you also remove the minimize box, you get only the close box - weird (no grayed boxes)
i suppose if you wanted to go further, you could create your own class for the title bar and make it however you wanted