Drawtext output to screen is lost on minimize

[Timm Motl]

I've been trying to implement the DrawText function to display text in a dialog... no problem getting it to display, but getting it to stay there is another thing. I've recreated the problem in the following code example... after text has been displayed in the dialog using DrawText (or TextOut, for that matter) the text is lost when you minimize and restore the dialog. Is there something wrong with the code or is this the way it's supposed to be?

#COMPILE EXE
#REGISTER NONE
#INCLUDE "Win32Api.Inc"


GLOBAL PenColor AS LONG
GLOBAL BackColor AS LONG
GLOBAL StringVar AS ASCIIZ * 256


CALLBACK FUNCTION DlgProc
   SELECT CASE CBMSG
   CASE %WM_INITDIALOG
      DIM tRect AS GLOBAL RECT
      GetClientRect CBHNDL, tRect
      ' Set up initial position, colors and first text line to be displayed
      tRect.nLeft = tRect.nLeft + 10
      tRect.nTop = tRect.nTop + 10
      PenColor = RGB(0, 0, 200)
      BackColor = -1 ' This flag is used to force transparent background mode
      StringVar = "Type some text and press Enter..."
   CASE %WM_PAINT
      LOCAL hDC AS LONG
      LOCAL ps  AS PAINTSTRUCT
      hDC = BeginPaint(CBHNDL, ps)
         IF BackColor < 0 THEN
            Setbkmode hDC, %TRANSPARENT
         ELSE
            Setbkmode hDC, %OPAQUE
            SetBkColor hDC, BackColor
         END IF
         SetTextColor hDC, PenColor
         DrawText hDC, StringVar, LEN(StringVar), tRect, 0
      EndPaint CBHNDL, ps
      StringVar = ""
      FUNCTION = 0
   END SELECT
   
   SELECT CASE CBCTL
   CASE 200
      ' Display Text button was clicked (or Enter key was pressed)
      CONTROL GET TEXT CBHNDL, 100 TO StringVar
      IF LEN(StringVar) THEN
         tRect.nTop = tRect.nTop + 16
         IF tRect.nTop <= 266 THEN
            ' Initiate a WM_PAINT message so StringVar is displayed
            InvalidateRect CBHNDL, BYVAL 0, %FALSE
            UpdateWindow CBHNDL
         END IF
         CONTROL SET TEXT CBHNDL, 100, ""
      END IF
      CONTROL SET FOCUS CBHNDL, 100
   END SELECT
END FUNCTION


FUNCTION PBMAIN
   LOCAL hDlg AS LONG
   DIALOG NEW 0, "Minimizing & Restoring clears the text from this dialog... WHY?",,, 300, 200, _
              %WS_CAPTION + %WS_MINIMIZEBOX + %WS_SYSMENU TO hDlg
   CONTROL ADD TEXTBOX, hDlg, 100, "", 6, 180, 225, 13
   CONTROL ADD BUTTON, hDlg, 200, "Display Text", 236, 180, 58, 14, %BS_DEFAULT
   DIALOG SHOW MODAL hDlg CALL DlgProc
END FUNCTION

Thanks for any help.

Timm



[This message has been edited by Timm Motl (edited September 26, 2000).]

[Semen Matusovski]

Timm --
In %WM_PAINT you should draw whole text from the beginning.
I reconstructed your code a little.

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

   CallBack Function DlgProc
       Select Case CbMsg
          Case %WM_INITDIALOG
             Static StringVar As String
             StringVar = "Type some text and press Enter..."
          Case %WM_COMMAND
             Select Case CbCtl
                Case 200
                   Local Tmp As String
                   Control Get Text CbHndl, 100 To Tmp
                   If Len(Tmp) Then
                      StringVar = StringVar + $CRLF + Tmp
                      InvalidateRect CbHndl, ByVal 0, %FALSE
                      UpdateWindow CbHndl
                      Control Set Text CbHndl, 100, ""
                   End If
                   Control Set Focus CbHndl, 100
             End Select
             
          Case %WM_PAINT
             Dim tRect As RECT
             GetClientRect CbHndl, tRect
             tRect.nLeft = 0.05 * tRect.nRight
             tRect.nRight = 0.95 * tRect.nRight
             tRect.nTop = 0.05 * tRect.nBottom
             tRect.nBottom = 0.80 * tRect.nBottom
             Local ps As PAINTSTRUCT
             BeginPaint CbHndl, ps
             Setbkmode ps.hDC, %TRANSPARENT
             SetTextColor ps.hDC, Rgb(0, 0, 200)
             DrawText ps.hDC, ByCopy StringVar, Len(StringVar), tRect, 0
             EndPaint CbHndl, ps
         End Select

   End Function

   Function PbMain
      Local hDlg As Long
      Dialog New 0, "Test",,, 300, 200, %WS_CAPTION Or %WS_MINIMIZEBOX Or %WS_SYSMENU To hDlg
      Control Add TextBox, hDlg, 100, "", 6, 180, 225, 13
      Control Add Button, hDlg, 200, "Display Text", 236, 180, 58, 14, %BS_DEFAULT
      Dialog Show Modal hDlg Call DlgProc
   End Function

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E-MAIL: [email protected]

[Michael Mattias]

Not tested, but I would think you could add a STATIC control to the dialog, and use CONTROL SET TEXT at the appropriate time(s)....

MCM

[Timm Motl]

Semen...
Thanks for responding and "cleaning up" my code. Your changes helped me to understand that my WM_PAINT handler needs to redisplay all of the strings displayed with DrawText and TextOut commands... they are not automatically redrawn when a WM_PAINT message is processed. Please excuse my lack of understanding... I'm just now migrating from DOS programming to Windows and I'm slowly discovering the differences between the two. Semen, I watch for your postings here every day. Your code examples have taught me a great deal and I thank you!

Michael...
Thanks for the suggestion on using static controls. That's a definite option, but I was really trying to find out more about using DrawText and TextOut. I guess my initial posting wasn't very clear in that respect. I wasn't really trying to find a solution to a programming problem as much as I was trying to understand the use of those two commands. Thanks for responding though!

Timm


[This message has been edited by Timm Motl (edited September 27, 2000).]

[John Hutchins]

This may help.
The following function is like the dos
Locate nn:nn
Color n
print n$

all rolled into one.

FUNCTION SPRINT(BYVAL hDlg AS LONG,BYVAL Row AS LONG,BYVAL Col AS LONG,BYVAL Ink AS LONG,PrintStr AS ASCIIZ) AS LONG

LOCAL hDC AS LONG
LOCAL Trect AS Rect
LOCAL DiUnit AS DWORD
LOCAL HZDBU AS LONG
LOCAL VTDBU AS LONG
LOCAL ch AS LONG
LOCAL cv AS LONG
LOCAL hBkCol AS LONG
LOCAL STRINGPTR AS ASCIIZ PTR
LOCAL STRINGLEN AS LONG

GetDC hDlg TO hDC
SelectObject hDc,hFont
GetClientRect hDlg,Trect
GetDialogBaseUnits TO DiUnit
HZDBU = LOWRD(DiUnit)
VTDBU = HIWRD(DiUnit)
ch = (Col * HZDBU)+2
cv = (Row * VTDBU)+2
SetBkMode hDC, %OPAQUE'%TRANSPARENT
SetTextColor hDC,Ink
APGREY&=GetSysColor(%COLOR_ACTIVEBORDER)
SETBKCOLOR hDC,APGREY&
STRINGPTR = VARPTR(PrintStr)
STRINGLEN = LEN(PrintStr)
TextOut hDC,ch,cv,@STRINGPTR,STRINGLEN
ReleaseDC hDlg,hDC
FUNCTION = %TRUE
END FUNCTION

Use hFont = GetStockObject(%OEM_FIXED_FONT) to select a fixed
pitch font and you will not have problems with formatted text.

In order to repaint the text when the window is moved you must
maintain a buffer of the text you are writing to the window.
Write the buffer contents to the window on a WM_MOVE or WM_PAINT.

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[Timm Motl]

John...

Thanks for the code sample... the comment at the end of your response confirms what I gathered from Semen's code sample as well. The DrawText and TextOut commands (and WM_PAINT message) are much clearer to me now. Thanks for offering your assistance.

Timm