VB Cordinates to Dialog Units

[Gregery D Engle]

How would I translate VB Form Cordinates (I believe twips) to
Dialog Units, eg:

FORM1

Height = 3195
Left = 60
Top = 345
Width = 4680

---
TEXTBOX

Height = 495
LEFT = 120
Top = 1200
Width = 1455

How do I translate the above numbers to dialog units?

Thanks

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-Greg

[Semen Matusovski]

Greg --
As I understand, 1 twip = 1/20 of a point, or 1/1440 of an inch.
From another side, for a screen hDC
1 inch = GetDeviceCaps(hDC, %LOGPIXELSX) pixels (horz) or
1 inch = GetDeviceCaps(hDC, %LOGPIXELSY) pixels (vert).

This means that to translate (x, y) in twips to (xx, yy) in units:

   Sub TwipsToUnits (hDlg As Long, ByVal x As Long, ByVal y As Long, xx As Long, yy As Long)
      Dim hDC As Long
      hDC = CreateIC ("DISPLAY", ByVal 0&, ByVal 0&, ByVal 0&)
      Dialog Pixels hDlg, x * GetDeviceCaps(hDC, %LOGPIXELSX) / 1440, _
                          y * GetDeviceCaps(hDC, %LOGPIXELSY) / 1440 To Units xx, yy
      DeleteDc hDC
   End Sub

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E-MAIL: [email protected]

[Gregery D Engle]

Semen,

I don't see how that works. Running your code with these twip
values: 4800, 3600 I get: 213, 148

If I import that frm into a resource dialog in Visual Studio
6.0 I get this:

IDD_DIALOG1 DIALOG DISCARDABLE  0, 0, 208, 131
STYLE WS_MINIMIZEBOX | WS_MAXIMIZEBOX | WS_CAPTION | WS_SYSMENU
CAPTION "Form1"
FONT 8, "MS Sans Serif"
BEGIN
END

I have lined up the Visual Studio import and my original VB form
and everything lines up so the number 208,131 is correct.

Why can't I get it with your code? Am I doing something wrong?

Thanks


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-Greg

[Joseph W Murphy]

208 to 213 looks like a rounding problem
131 to 148 could be caption height ?

just guessing

Joe Murphy

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[Gregery D Engle]

I'm confused on why the Visual Studio import works perfectly.

There has to be a formula that is as accurate, any suggestions?

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-Greg

[Semen Matusovski]

Greg --
Take empty form in VB and run

Private Sub Form_Load()
   Me.ScaleWidth = 4800
   Me.ScaleHeight = 3600
End Sub

In PB

   #Compile Exe
   #Register None
   #Include "Win32Api.Inc"

   Sub TwipsToUnits (hDlg As Long, ByVal x As Long, ByVal y As Long, xx As Long, yy As Long)
      Dim hDC As Long
      hDC = CreateIC ("DISPLAY", ByVal 0&, ByVal 0&, ByVal 0&)
      Dialog Pixels hDlg, x * GetDeviceCaps(hDC, %LOGPIXELSX) / 1440, _
                          y * GetDeviceCaps(hDC, %LOGPIXELSY) / 1440 To Units xx, yy
      DeleteDc hDC
   End Sub

   Function PbMain
      Local hDlg As Long, xx As Long, yy As Long
      Dialog New 0, "", , , 0, 0, %WS_CAPTION Or %WS_THICKFRAME Or _
         %WS_SYSMENU Or %WS_MINIMIZEBOX Or %WS_MAXIMIZEBOX To hDlg
      TwipsToUnits hDlg, 4800, 3600, xx, yy
      Dialog Set Size hDlg, xx, yy
      SetWindowText hDlg, "Units: " + Str$(xx) + Str$(yy)
      Dialog Show Modal hDlg
   End Function

and visually compare two forms.
On my PC I see a small (very small) difference (VB is a little BIGGER).

99% sure that this is a result of VB & DDT conversions.
As I understand, in natural API there are no functions "Set the size of client area" and "Convert pixels to units". It's necessary to use combinations of some functions and here could be different rounding.

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E-MAIL: [email protected]

[Eric Pearson]

I haven't looked closely at this, but I agree with Joe... Those number look to me like one set is based on 0,0 at the top-left corner of the dialog, and the other is based on the top-left corner of the client area of the dialog.

-- Eric

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[Gregery D Engle]

Eric & Semen,

#COMPILE EXE
#REGISTER NONE
#INCLUDE "Win32Api.Inc"
GLOBAL gExit AS LONG

SUB TwipsToUnits (hDlg AS LONG, BYVAL x AS LONG, BYVAL y AS LONG, xx AS LONG, yy AS LONG)
      DIM hDC AS LONG
      hDC = CreateIC ("DISPLAY", BYVAL 0&, BYVAL 0&, BYVAL 0&)
      DIALOG PIXELS hDlg, x * GetDeviceCaps(hDC, %LOGPIXELSX) / 1440, _
                          y * GetDeviceCaps(hDC, %LOGPIXELSY) / 1440 TO UNITS xx, yy
      DeleteDc hDC
END SUB

CALLBACK FUNCTION Form1_DLGPROC
    SELECT CASE CBMSG
         CASE %WM_DESTROY
              gExit = 1
    END SELECT
END FUNCTION

CALLBACK FUNCTION Form2_DLGPROC
    SELECT CASE CBMSG
         CASE %WM_DESTROY
              gExit = 1
    END SELECT
END FUNCTION

SUB Test1()
    LOCAL hDlg AS LONG, xx AS LONG, yy AS LONG
      DIALOG NEW 0, "", , , 0, 0, %WS_CAPTION OR %WS_THICKFRAME OR _
         %WS_SYSMENU OR %WS_MINIMIZEBOX OR %WS_MAXIMIZEBOX TO hDlg
      TwipsToUnits hDlg, 2925, 5460, xx, yy
      DIALOG SET SIZE hDlg, xx, yy
      'SetWindowText hDlg, "Test1 - Units: " + STR$(xx) + STR$(yy)
      DIALOG SHOW MODELESS hDlg CALL Form1_DLGPROC
    DIALOG GET SIZE hDlg TO x&, y&
    SetWindowText hDlg, "Test1 - Units: " + STR$(x&) + STR$(y&)   

END SUB

SUB test2()
   LOCAL hDlg AS LONG, xx AS LONG, yy AS LONG
      DIALOG NEW 0, "", , , 0, 0, %WS_CAPTION OR %WS_THICKFRAME OR _
         %WS_SYSMENU OR %WS_MINIMIZEBOX OR %WS_MAXIMIZEBOX TO hDlg
      TwipsToUnits hDlg, 2925, 5460, xx, yy
     DIALOG END hDlg
      DIALOG NEW 0, "", , , xx, yy, %WS_CAPTION OR %WS_THICKFRAME OR _
         %WS_SYSMENU OR %WS_MINIMIZEBOX OR %WS_MAXIMIZEBOX TO hDlg
    'SetWindowText hDlg, "Test2 - Units: " + STR$(xx) + STR$(yy)
    DIALOG SHOW MODELESS hDlg CALL Form2_DLGPROC
    DIALOG GET SIZE hDlg TO x&, y&
    SetWindowText hDlg, "Test2 - Units: " + STR$(x&) + STR$(y&)   
END SUB

FUNCTION PBMAIN() AS LONG
test1
test2
DO WHILE NOT gExit = 1
   DIALOG DOEVENTS
LOOP
END FUNCTION

look at both dialogs, test2 is bigger then test1, the only difference
is that I call DIALOG SET SIZE hDlg, xx, yy in test1.

Is this what you are talking about Eric?


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-Greg

[This message has been edited by Gregery D Engle (edited December 11, 2000).]

[Semen Matusovski]

Greg --
Let's strictly divide following questions
1) How to convert twips to pixels
2) How to convert pixels to dialog units
3) How Dialog New and Dialog Set Size work.

About first. Let's make in VB6 empty form and run following.

Private Type RECT
        Left As Long
        Top As Long
        Right As Long
        Bottom As Long
End Type

Private Const LOGPIXELSX = 88        '  Logical pixels/inch in X
Private Const LOGPIXELSY = 90        '  Logical pixels/inch in Y

Private Declare Function GetWindowRect Lib "user32" (ByVal hwnd As Long, lpRect As RECT) As Long
Private Declare Function CreateIC Lib "gdi32" Alias "CreateICA" (ByVal lpDriverName As String, ByVal lpDeviceName As String, ByVal lpOutput As String, ByVal NotUsedHere As Long) As Long
Private Declare Function GetDeviceCaps Lib "gdi32" (ByVal hdc As Long, ByVal nIndex As Long) As Long
Private Declare Function DeleteDC Lib "gdi32" (ByVal hdc As Long) As Long

Private Sub Form_Load()
  Me.Height = 3600
  Me.Width = 4800
End Sub


Private Sub Form_Activate()
   Dim rc As RECT
   Dim hdc As Long
   
   hdc = CreateIC("DISPLAY", ByVal 0&, ByVal 0&, ByVal 0&)
   
   GetWindowRect Me.hwnd, rc
   MsgBox 1440 * (rc.Right - rc.Left) / GetDeviceCaps(hdc, LOGPIXELSX), , Me.Width
   MsgBox 1440 * (rc.Bottom - rc.Top) / GetDeviceCaps(hdc, LOGPIXELSY), , Me.Height
   
   DeleteDC hdc
End Sub

In my understanding this means:
a) formula is correct
b) Width/Height in VB (at least for form) are sizes of window area (not of a client area).

About second questions.
I have no idea, how PB converts pixels to units.
Probably is used MapDialogRect with reverse re-calculation.
Here it's possible to expect losing accuracy.

Dialog New ...
As Lance mentioned somehow, if there is %WS_CAPTION in DIALOG NEW, DDT accepts that sizes relate to client area.
Otherwise - to window.

Dialog Set Size...
From your sample, it looks that Dialog Set Size thinks about window coordinates, unlike %WS_CAPTION.
And this explains different results of Test1/Test2.




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E-MAIL: [email protected]

[Edwin Knoppert]

The FreeDDT tool on my site does this conversion too.
Take a look in the generated code..


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[email protected]

[Gregery D Engle]

Edwin,

I'm actually trying to make my own Visual Basic frm to DDT
conversion tool. Just for a learning experience I guess.


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-Greg

[Scott Hauser]

Greg,
I posted a little vb to ddt conversion utility a while back. It includes
source and samples. There are some problems with this utility (explained in the readme)
feel free to use it and tweak it in any way you choose. I still use it for quick and dirty
dialog building.

http://www.powerbasic.com/files/pub/pbwin/vb/

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[Gregery D Engle]

Thanks Scott

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-Greg