Finding the EXACT width of a line of text

[Mike Trader]

Is there anyway to determine the exact width of a line of text that is to be displayed in a dialog box?

I guess it could be in Dialog units or Pixels cos I can convert it but so far all the methods i have read and tried in Poffs are not exact.

bu& = GetDialogBaseUnits()
UnitW = CLNG(LOWRD(bu&)) ' get width of system font
UnitH = CLNG(HIWRD(bu&)) ' get height of system font

returns 8 as the "average" system font width. I had to dive that by 2 !!! to get anything close to a real world number.

Obviously I takes lee space than W. so is it possible to go through the string to be displayed and calculate a sum in pixel i guess, of all the letters that is dead nuts accurate?



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Kind Regards
Mike

[Lance Edmonds]

GetTextExtentPoint32()



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Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Jules Marchildon]

Mike;

AS Lance points out, GetTextExtentPoint32() is the required function.
Code fragment from working example...

        CASE %WM_PAINT
 
            hdc = BeginPaint(hWnd,ps)
            Call GetTextMetrics(hdc,tm)
            linespacing = tm.tmHeight + tm.tmInternalLeading
 
            For entry = 0 to %NUMENTRIES -1
                ColStart = 0
                For i = 0 to %NUMCOLS-1
                    select case i
                             case 0
                                sztext = Info(entry).title
                                exit select
                             case 1
                                sztext = Info(entry).author
                                exit select
                             case 2
                                sztext = Info(entry).publisher
                                exit select
                             case 3
                                sztext = Info(entry).date
                                exit select
                    end select
             Call GetTextExtentPoint32(hdc,sztext,len(sztext),sz)
 
            j= 2
            while ((Columns(i) - %SPACING) < sz.cx)
                  chrs = Columns(i) / tm.tmAveCharWidth
 
                  sOld$=sztext
                  sNew$=left$(sOld$,chrs-j) + "..."
                  sztext=sNew$
   
                  Call GetTextExtentPoint32(hdc,szText,len(szText),sz)
                  incr j
            wend
 
            Call TextOut(hdc,ColStart + %SPACING, _
                         HeaderHeight +(entry*linespacing), _
                         sztext,len(sztext))
 
            ColStart = ColStart + Columns(i)
 
          Next
 
       Next
 
            Call EndPaint(hWnd, ps)

HTH
Regards,
Jules

[Mike Trader]

OK.
What do i use for hdc befor I have even created a dialog box?

I need to calculate how big the dlg box is based on a line of text BEFOR i create the dialog.

I guess I could create it and resize it in the CASE %WM_INITDIALOG. Is that how its done?

In that case would hdc = CBHNDL ?

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Kind Regards
Mike

[Borje Hagsten]

One very important thing when it comes to using GetTextExtentPoint32
is that one must select correct font into DC, otherwise System font
is used in calculation, which may give wrong result if Ansi font is
used in control or dialog. Following gives rather good result:

'********************************************************************
' Get physical width of text string
'********************************************************************
FUNCTION GetTextWidth(BYVAL hWnd AS LONG, BYVAL txt AS STRING) AS LONG
  LOCAL hDc AS LONG, hFont AS LONG, lpSize AS SIZEL
 
  hDc = GetDc(hWnd)                               'get handle for proper device context
    hFont = SendMessage(hWnd, %WM_GETFONT, 0, 0)  'must select hWnd's font into DC,
    hFont = SelectObject(hDC, hFont)              'otherwise System font is used..
    CALL GetTextExtentPoint32(hDc, BYVAL STRPTR(txt), LEN(txt), lpSize)
    SelectObject hDC, hFont                       'select original font back
  ReleaseDC hWnd, hDc                             'and release DC
 
  'FUNCTION = lpSize.cy                           '<- for textheight..
  FUNCTION = lpSize.cx                            '<- function returns the textwidth
END FUNCTION

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[Borje Hagsten]

Resizing dialog or controls can be done in WM_INITDIALOG, or even in
PBMAIN/WINMAIN, right after dialog/control has been created. Using the
function above, just send control's handle + text to get textwidth back
in pixels. Then use DIALOG PIXELS hDlg&, x&, y& TO UNITS xx&, yy&
if you want use DIALOG SET SIZE.., or return value directly if you use
MoveWindow or SetWindowPos to resize and position dialog.


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[Mike Trader]

Thx Borje,
I get it, but why doesnt this work?

#COMPILE EXE
#REGISTER NONE
#DIM ALL
#INCLUDE "win32api.INC"
'-------------------------------------------------------------------------
CALLBACK FUNCTION DlgProc
STATIC hFont AS LONG
LOCAL El AS STRING, lpSize AS SizeL, WdPix AS LONG, HtPix AS LONG, hWnd AS LONG, hdc AS LONG
El = "***This is a TEST string***"
SELECT CASE CBMSG
CASE %WM_INITDIALOG
CONTROL ADD LABEL, CBHNDL, 100, "", 1, 1, 600, 200
hWnd = GetDlgItem( CBHNDL, 100 )
hDC = GetDC(hWnd)
GetTextExtentPoint32 hdc, BYVAL STRPTR(EL), LEN(El), lpSize
WdPix = lpSize.cx
HtPix = lpSize.cy + 60
DIALOG PIXELS CBHNDL, WdPix, HtPix TO UNITS WdPix, HtPix
DIALOG SET SIZE CBHNDL, WdPix, HtPix ' should set the Width
CONTROL SET TEXT CBHNDL, 100, EL + $CRLF + $CRLF + FORMAT$(WdPix) + " Dlg Units"
ReleaseDC hWnd, hDC
CASE %WM_DESTROY
END SELECT
END FUNCTION

'-----------------------------------------------------------------------------
FUNCTION PBMAIN
LOCAL hDlg AS LONG
DIALOG NEW 0, "", ,, 600, 200, %WS_CAPTION OR %WS_SYSMENU TO hDlg
DIALOG SHOW MODAL hDlg CALL DlgProc
END FUNCTION


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Kind Regards
Mike

[Borje Hagsten]

Because of the font problem I mentioned. The DC you get via GetDc uses
System font initially for calculations, but DDT dialogs and controls
is set to use ANSI font for size calculations, etc. Therefore, one must
select DDT control's or dialog's font into the DC first. Following in
%WM_INITDIALOG gives much better result:

            hDC  = GetDC(hWnd)
               hFont = SendMessage(hWnd, %WM_GETFONT, 0, 0)  'must select hWnd's font into DC,
               hFont = SelectObject(hDC, hFont)              'otherwise System font is used..
               GetTextExtentPoint32 hdc, BYVAL STRPTR(EL), LEN(El), lpSize
               SelectObject hDC, hFont                       'select original font back
            ReleaseDC hWnd, hDC

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Forgot: If dialog has 3D borders, one need to include those in size.
Usually 4-5 pixels extra per side, but other border widths may exist.
If you add like 10 pixels extra to width and height you get from
GetTextExtentPoint32, size should be enough..


[This message has been edited by Borje Hagsten (edited May 11, 2001).]

[Mike Trader]

aaaaaaaaaaaaaaaaaaaaaaaaaaaah!

I assumed the Dialog used the system font. duh.

thx so much Borje

------------------
Kind Regards
Mike

[Borje Hagsten]

Just for fun: it's actually possible to do this before creating a dialog too,
and resize directly at creation by using the desktop's DC. When this can be
useful? Well, for own tooltips-like messages, for example. Silly sample:

#COMPILE EXE
#INCLUDE "win32api.INC"
'-------------------------------------------------------------------------
CALLBACK FUNCTION DlgProc
  select case cbmsg
      CASE %WM_CTLCOLORDLG, %WM_CTLCOLORSTATIC
         SetBkColor cbwparam, GetSysColor(%COLOR_INFOBK) 'make it look like tooltips..
         function = GetSysColorBrush(%COLOR_INFOBK)
 
      CASE %WM_KEYUP, %WM_SYSKEYUP, %WM_MOUSEMOVE, %WM_KILLFOCUS
         DIALOG END cbhndl  'kill dialog at these..
 
      CASE %WM_DESTROY
         PostQuitMessage 0  'make sure dialog is destroyed properly at WM_KILLFOCUS..
 
   END SELECT
END FUNCTION
 
'-----------------------------------------------------------------------------
FUNCTION PBMAIN
   LOCAL hDlg AS LONG, hFont AS LONG, hdc AS LONG, WdPix AS LONG, HtPix AS LONG, _
         El AS STRING, lpSize AS SIZEL
 
   El = "***This is a TEST string***"
   hDC  = GetDC(%HWND_DESKTOP)
     hFont = GetStockObject(%ANSI_VAR_FONT)
     hFont = SelectObject(hDC, hFont)              'otherwise System font is used..
     GetTextExtentPoint32 hDC, BYVAL STRPTR(EL), LEN(El), lpSize
     SelectObject hDC, hFont                       'select original font back
   ReleaseDC %HWND_DESKTOP, hDC
 
   WdPix = lpSize.cx + 6
   HtPix = (lpSize.cy + 1) * 3  'in this sample, make room for three lines
 
   DIALOG NEW 0, "", ,, 0, 0, %WS_POPUP or %WS_BORDER TO hDlg
   DIALOG PIXELS hDlg, WdPix, HtPix TO UNITS WdPix, HtPix
   DIALOG SET SIZE hDlg, WdPix, HtPix
 
   El = El + $CRLF + $CRLF + FORMAT$(WdPix) + " Dlg Units wide"
   CONTROL ADD LABEL, hDlg, 100, El, -1, 0, WdPix, HtPix, %SS_CENTER
 
   DIALOG SHOW MODAL hDlg CALL DlgProc
END FUNCTION

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[mark smit]

Hello Mike,

I personally use the DrawText API to figure out the bounding RECT for my text string.

DIM rcBound AS RECT
DIM szText AS ASCIIZ * 256
DIM hDC AS LONG
 
szText = "Here is some example text"
 
DrawText hDC, szText, LEN(szText), rcBound, %DT_CALCRECT or %DT_LEFT

rcBound.nTop = 0
rcBound.nLeft = 0
rcBound.nRight = Text Width
rcBound.nBottom = Text Height

DT_CALCRECT Determines the width and height of the rectangle. If there are multiple lines of text, DrawText uses the width of the rectangle pointed to by the rcBound parameter and extends the base of the rectangle to bound the last line of text. If there is only one line of text, DrawText modifies the right side of the rectangle so that it bounds the last character in the line. In either case, DrawText returns the height of the formatted text but does not draw the text.

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Cheers!



[This message has been edited by mark smit (edited May 12, 2001).]

[Mike Trader]

THanks Mark,

Now that I know the fonts are different I will give it another try.

Sometines the simplist things give me the most trouble. These little functions are a minefield. Figuring out these things for the first time often feels like the following test:


Time limit: 2 hours. Begin immediately.

HISTORY
Describe the history of the Papacy from its origins to the present day,
concentrating especially , but not exclusively, on its social, political,
economic, religious and philosophical impact on Europe, Asia, America, and
Africa. Be brief, concise and specific.

MEDICINE
You have been provided with a razor blade, a piece of gauze, and a bottle of
scotch. Remove your appendix. Do not suture until your work has been
inspected. You have fifteen minutes.

PUBLIC SPEAKING
2500 riot-crazed aborigines are storming the classroom. Calm them. You may
use any ancient language except Latin or Greek.

BIOLOGY
Create life. Estimate the differences in subsequent human culture if this
form of life had developed 500 million years earlier, with special attention
to its affect on the English Parliamentary System. Prove your thesis.

MUSIC
Write a piano concerto. Orchestrate and perform it with flute and drum.
You will find a piano under your seat.

PSYCHOLOGY
Based on your knowledge of their works, evaluate the emotional stability,
degree of adjustment, and the repressed frustrations of each of the
following: Alexander of Aphrodisis, Ramses II, Hammurabi. Support your
evaluation with quotations from each man's work, making appropriate
references. It is not necessary to translate.

SOCIOLOGY
Estimate the social problems which might accompany the end of the world.
Construct an experiment to test your theory.

ENGINEERING
The disassembled parts of a high-powered rifle have been placed on your
desk. You will also find an instruction manual, printed in Swahili. In 10
minutes, a hungry Bengal tiger will be admitted to the room Take whatever
action you feel necessary. Be prepared to justify your decision.

ECONOMICS
Develop a realistic plan for refinancing the national debt. Trace the
possible effects of your plan in the following areas: Cubism, the Donatist
Controversy, and the Wave Theory of Light. Outline a method for preventing
these effects. Criticize this method from all possible points of view.
Point out the deficiencies in your point of view, as demonstrated in your
answer to the last question.

POLITICAL SCIENCE
There is a red telephone on the desk beside you. Start World War III.
Report at length on its socio-political effects, if any.

EPISTEMOLOGY
Take a position for or against truth. Prove the validity of your stand.

PHYSICS
Explain the nature of matter. Include in your answer an evaluation of the
impact of the development of mathematics on science.

PHILOSOPHY
Sketch the development of human thought. Estimate its significance. Compare
with the development of any other kind of thought.

ASTRONOMY
You have been given limitless supplies of hydrogen and helium and smaller
quantities of the heavy metals. Create the universe. Note: This is a
take-home question. Return project in six days.

(author unknown)


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Kind Regards
Mike