Anchor logic

[Edwin Knoppert]

Winforms (.NET) has a great feature.. an anchor property for controls.
When properly set it will reposition or size controls on a logic location.

I wrote something for my designer which almost works but i have trouble with the previous size for dialog client area.
The previous size is required to calculate the current (right-side) offset.

Minimizing the form and restoring it makes it currently messing things up.
I was able to prevent it a little but i find it unstable.
Any idea how to use this on WM_SIZE and still being able to reliably measure the right side offset for a control which should be anhor'd right+bottom ?

Here is an executable, it's almost good.
The button and tab control resizes well, even when you maximize the form, minimize it and restore it.

http://www.hellobasic.com/trials/Anchortest1.zip

The tab control is set to resize to all sides, problem will arise when the form get's to small.
The buttons do well.
On form3 the groupbox is in fact very small.
Due unpredictable resizing it fails to maintain the size.

Thanks!

[Kev Peel]

I didn't check the demo, but it sounds as if you should be checking fwSizeType of WM_SIZE and not resize the controls under certain values. Obviously if you don't process the parent's WM_SIZE then it won't work.

[Edwin Knoppert]

I have updated the exe.
It works better now but i seen .NET winforms behaving better on critical sizes.
I suspect they maintain a last known good offset and use that when the control can be resized properly again.

Check out the exe, it's fun to see

[Michael Mattias]

Real Men use MoveWindow() on WM_SIZE

[Edwin Knoppert]

The controls *are* moved on WM_SIZE

[Patrice Terrier]

Edwin

Here is how i am doing it myself:

' ANCHOR Flags:
  %ANCHOR_NONE                = 0
  %ANCHOR_LEFT                = %ANCHOR_NONE
  %ANCHOR_WIDTH               = 1
  %ANCHOR_RIGHT               = 2
  %ANCHOR_CENTER_HORZ         = 3
  %ANCHOR_HEIGHT              = 4
  %ANCHOR_HEIGHT_WIDTH        = 5
  %ANCHOR_HEIGHT_RIGHT        = 6
  %ANCHOR_BOTTOM              = 7
  %ANCHOR_BOTTOM_WIDTH        = 8
  %ANCHOR_BOTTOM_RIGHT        = 9
  %ANCHOR_CENTER_HORZ_BOTTOM  = 10
  %ANCHOR_CENTER_VERT         = 11
  %ANCHOR_CENTER_VERT_RIGHT   = 12
  %ANCHOR_CENTER              = 13
'****************************************************************************

TYPE ZIMAGEPROP
    hWnd        AS LONG
    anchor      AS LONG
    rc          AS RECT
    TiledBitmap AS LONG
'// order       AS STRING * 512  '//3.02 Before it was 128 objects and now 256 objects
    order       AS STRING * 2048 '//3.57 Before it was 256 and now 1024 objects
    ordersize   AS LONG

    WMBit(25)   AS LONG          '//4.02
    WMCodePtr(25*32) AS DWORD    '//4.02
END TYPE

GLOBAL WinProp() AS ZIMAGEPROP

FUNCTION zPropertyItem(BYVAL hWnd AS LONG) AS LONG
    IF UBOUND(WinProp) > 0 THEN
       ARRAY SCAN WinProp(), FROM 1 TO 4, = MKL$(hWnd), TO Item&
    END IF
    FUNCTION = Item&
END FUNCTION

FUNCTION ZI_SetAnchorMode ALIAS "ZI_SetAnchorMode" (BYVAL hWnd AS LONG, BYVAL AnchorMode AS LONG) EXPORT AS LONG
    LOCAL pZP AS LONG
    IF IsWindow(hWnd) THEN
       LOCAL rc AS RECT, pr AS RECT, p AS POINTAPI

       pZP = zPropertyItem(hWnd)
       IF pZP = 0 THEN ' If the object already exist then we ReUse it
          pZP = MAX&(UBOUND(WinProp) + 1, 1)
          REDIM PRESERVE WinProp(1 TO pZP) AS ZIMAGEPROP
       END IF
       WinProp(pZP).hWnd = hWnd
       CALL GetWindowRect(hWnd, rc)
       p.X = rc.nLeft: p.Y = rc.nTop
       CALL ScreenToClient(Getparent(hWnd), p)
       CALL GetClientRect(Getparent(hWnd), pr)
       WinProp(pZP).anchor     = MIN&(MAX&(AnchorMode, %ANCHOR_NONE), %ANCHOR_CENTER)
       WinProp(pZP).rc.nLeft   = p.X
       WinProp(pZP).rc.nTop    = p.Y
       WinProp(pZP).rc.nRight  = pr.nRight - (rc.nRight - rc.nLeft + p.X)
       WinProp(pZP).rc.nBottom = pr.nBottom - (rc.nBottom - rc.nTop + p.Y)
       FUNCTION = -1
    END IF
END FUNCTION

FUNCTION EnumChildProc(BYVAL hWnd AS LONG, BYVAL lParam AS LONG) AS LONG
    LOCAL zChildClass AS ASCIIZ * 32
    LOCAL pr AS RECT, rc AS RECT, pZP AS LONG

    IF GetClassName(hWnd, zChildClass, SIZEOF(zChildClass)) THEN
       pZP = zPropertyItem(hWnd)
       IF pZP THEN
          IF WinProp(pZP).anchor > %ANCHOR_NONE THEN
             CALL GetWindowRect(hWnd, rc)
             WidthIs&  = rc.nRight - rc.nLeft
             HeightIs& = rc.nBottom - rc.nTop
             CALL GetClientRect(GetParent(hWnd), pr)
             x& = 0: y& = 0: xW& = 0: yH& = 0
             SELECT CASE LONG WinProp(pZP).anchor
            'CASE %ANCHOR_NONE                '= 0
             CASE %ANCHOR_WIDTH               '= 1
                  x&  = WinProp(pZP).rc.nLeft
                  y&  = WinProp(pZP).rc.nTop
                  xW& = MAX&(pr.nRight - WinProp(pZP).rc.nLeft - WinProp(pZP).rc.nRight, 0)
                  yH& = HeightIs&
             CASE %ANCHOR_RIGHT               '= 2
                  x&  = pr.nRight - WidthIs& - WinProp(pZP).rc.nRight
                  y&  = WinProp(pZP).rc.nTop
                  xW& = WidthIs&
                  yH& = HeightIs&
             CASE %ANCHOR_CENTER_HORZ         '= 3
                  x&  = (pr.nRight - WidthIs&) \ 2
                  y&  = WinProp(pZP).rc.nTop
                  xW& = WidthIs&
                  yH& = HeightIs&
             CASE %ANCHOR_HEIGHT              '= 4
                  x&  = WinProp(pZP).rc.nLeft
                  y&  = WinProp(pZP).rc.nTop
                  xW& = WidthIs&
                  yH& = MAX&(pr.nBottom - WinProp(pZP).rc.nTop - WinProp(pZP).rc.nBottom, 0)
             CASE %ANCHOR_HEIGHT_WIDTH        '= 5
                  x& = WinProp(pZP).rc.nLeft
                  y& = WinProp(pZP).rc.nTop
                  xW& = MAX&(pr.nRight - WinProp(pZP).rc.nLeft - WinProp(pZP).rc.nRight, 0)
                  yH& = MAX&(pr.nBottom - WinProp(pZP).rc.nTop - WinProp(pZP).rc.nBottom, 0)
             CASE %ANCHOR_HEIGHT_RIGHT        '= 6
                  x&  = pr.nRight - WidthIs& - WinProp(pZP).rc.nRight
                  y&  = WinProp(pZP).rc.nTop
                  xW& = WidthIs&
                  yH& = MAX&(pr.nBottom - WinProp(pZP).rc.nTop - WinProp(pZP).rc.nBottom, 0)
             CASE %ANCHOR_BOTTOM              '= 7
                  x&  = WinProp(pZP).rc.nLeft
                  y&  = pr.nBottom - WinProp(pZP).rc.nBottom - HeightIs&
                  xW& = WidthIs&
                  yH& = HeightIs&
             CASE %ANCHOR_BOTTOM_WIDTH        '= 8
                  x&  = WinProp(pZP).rc.nLeft
                  y&  = pr.nBottom - WinProp(pZP).rc.nBottom - HeightIs&
                  xW& = MAX&(pr.nRight - WinProp(pZP).rc.nLeft - WinProp(pZP).rc.nRight, 0)
                  yH& = HeightIs&
             CASE %ANCHOR_BOTTOM_RIGHT        '= 9
                  x&  = pr.nRight - WidthIs& - WinProp(pZP).rc.nRight
                  y&  = pr.nBottom - WinProp(pZP).rc.nBottom - HeightIs&
                  xW& = WidthIs&
                  yH& = HeightIs&
             CASE %ANCHOR_CENTER_HORZ_BOTTOM  '= 10
                  x&  = (pr.nRight - WidthIs&) \ 2
                  y&  = pr.nBottom - WinProp(pZP).rc.nBottom - HeightIs&
                  xW& = WidthIs&
                  yH& = HeightIs&
             CASE %ANCHOR_CENTER_VERT         '= 11
                  x&  = WinProp(pZP).rc.nLeft
                  y&  = (pr.nBottom - HeightIs&) \ 2
                  xW& = WidthIs&
                  yH& = HeightIs&
             CASE %ANCHOR_CENTER_VERT_RIGHT   '= 12
                  x&  = pr.nRight - WidthIs& - WinProp(pZP).rc.nRight
                  y&  = (pr.nBottom - HeightIs&) \ 2
                  xW& = WidthIs&
                  yH& = HeightIs&
             CASE %ANCHOR_CENTER              '= 13
                  x&  = (pr.nRight - WidthIs&) \ 2
                  y&  = (pr.nBottom - HeightIs&) \ 2
                  xW& = WidthIs&
                  yH& = HeightIs&
             END SELECT
             CALL MoveWindow(hWnd, x&, y&, xW&, yH&, 1)
          END IF
       END IF
    END IF
    FUNCTION = %TRUE ' Continue enumeration of children..
END FUNCTION

FUNCTION zGetMsgProc(BYVAL nCode AS LONG, BYVAL wParam AS LONG, BYVAL lParam AS LONG) AS LONG
    LOCAL pCWP AS CWPSTRUCT PTR
    IF nCode = 0 THEN
       IF lParam THEN
          pCWP = lParam
          IF LOWRD(@pCWP.message) = %WM_SIZE THEN
             CALL EnumChildWindows(@pCWP.hWnd, CODEPTR(EnumChildProc), 0)
          END IF
       END IF
    END IF
    FUNCTION = CallNextHookEx(gChildHookPtr, nCode, wParam, lParam)
END FUNCTION

Note: i am using a HOOK procedure to monitor the %WM_SIZE message and the EnumChildProc callback to move the controls to their new location.


Added (the Hook management)

' LIBMAIN
FUNCTION DllMain (BYVAL DllInstance AS LONG, BYVAL Reason AS LONG, BYVAL Reserved AS LONG) EXPORT AS LONG

    LOCAL Ret AS LONG

    Ret = %TRUE

    IF Reason& = %DLL_PROCESS_ATTACH THEN

       IF gChildHookPtr = 0 THEN gChildHookPtr = SetWindowsHookEx (%WH_CALLWNDPROC, CODEPTR(zGetMsgProc), 0&, GetCurrentThreadID)
       IF gKeybHookPtr = 0 THEN gKeybHookPtr = SetWindowsHookEx(%WH_KEYBOARD, CODEPTR(zKeybProc), 0&, GetCurrentThreadID)


    ELSEIF Reason& = %DLL_PROCESS_DETACH THEN

       IF gChildHookPtr THEN CALL UnhookWindowsHookEx(gChildHookPtr): gChildHookPtr = 0
       IF gKeybHookPtr THEN CALL UnhookWindowsHookEx(gKeybHookPtr): gKeybHookPtr = 0

    END IF

    FUNCTION = Ret

END FUNCTION

[Michael Mattias]

IF gChildHookPtr = 0 THEN gChildHookPtr = [B]SetWindowsHookEx[/B] (....

SetWindowsHookEx in USER32.DLL; USER32.DLL <> KERNEL32.DLL; Not supposed to be used on DLL_PROCESS_ATTACH.

Probably safe if this library loaded dynamically, as I cannot imagine any program NOT loading USER32.DLL.

MCM

[Patrice Terrier]

http://msdn.microsoft.com/en-us/library/ms644990(VS.85).aspx

http://msdn.microsoft.com/en-us/library/ms644960(VS.85).aspx

[Michael Mattias]

Nice links: they reinforce what I cautioned:

An alternative method for installing a global hook procedure is to provide an installation function in the DLL, along with the hook procedure [italics mine]...

Note: Separate installation function recommended!