Fun with Fonts...

[Bern Ertl]

Hi everyone,

Now that I've got my header / footer function working
without crashing, I need to correctly determine the height (in
device units) of any given header / footer that I will be
making.

I'm assuming that I will need to create a 10 point Arial font
(my preference for now), select it into the supplied hDC (device
context is initialized by a DLL), and then somehow calculate the
height based upon how many lines of text I require. Is there a
standard way of doing this?



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Bernard Ertl

[jcfuller]

Bern,
DrawText using %DT_CALCRECT I believe.

James

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[Chris Boss]

Bern;

To start, here is how you calculate the font height using a
Point size , to be used with the CreateFont API call :

FUNCTION FHeight(BYVAL PSize&) AS LONG
hDC = GetDC(%HWND_DESKTOP)
PSY&=GetDeviceCaps(hDC, %LOGPIXELSY)
ReleaseDC %HWND_DESKTOP, hDC      
FUNCTION=-MulDiv(PSize&, PSY&, 72)
END FUNCTION

The code above will autoscale the font based on the end users system
wide font setting (small fonts/large fonts), which is the proper way
to do it. The MulDiv (API) function is the proper way suggested by
Microsoft to do the conversion from Point size to Font height.
The function returns a negative value since that will force the
CreateFont function to use the value as the Character height and not
the cell height.

The code above used the Desktop DC, so it is assumed the device units
are pixels (MM_TEXT). If you are using a DC which does not use pixels
as device units, then use that DC in the calculation rather than the
desktop DC.

This should give you a start !




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[Bern Ertl]

James,

Yes, thanks. That was exactly what I was looking for.

Onwards to the next "problem". My header / footer callback
function needs to scale the font(s) for the header/footer
according to the current "zoom status" of the preview control.

The control is providing a bounding RECT for the header/footer
which is sized according to the current zoom status. It also
provides a bounding RECT for the header/footer according to the
printer device. The docs claim I should be able to scale the
fonts based upon that info only.

I've tried :

'Get 10 pt font for Printer Device
tFont.lfHeight = -MulDiv( 10, GetDeviceCaps( hPrinterDC&, %LOGPIXELSY), 72)
'Scale font????
'CurrentRect = Preview RECT
tFont.lfHeight = (CSNG(tFont.lfHeight) *  _
                 ((CurrentRect.nBottom - CurrentRect.nTop) / _
                 (@ptrPrintInfo.RectPrinter.nBottom - @ptrPrintInfo.RectPrinter.nTop)))
hFont = CreateFontIndirect( tFont)
'SelectObject, Drawtext, etc.

and it did not affect the font at all. Are there any other LOGFONT
elements that need to be adjusted in order to change the font size?

Am I doing something obviously wrong?




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Bernard Ertl

[Bern Ertl]

A little bit of progress...

I found that resetting the tFont.lfWidth to zero forced the fonts
to be resized according to the lfHeight.

Now I'm just trying yo figure out how I'm supposed to calculate
the correct scaling.

Farpoint sent me this advice:

The parameters RectPreview helps you to scale your fonts when
previewing the Spread. You can use the GetDeviceCaps() API to get the HORZRES and
VERTRES of the printer and then use the RectPreview to calculate a scale to use
in your fonts in the PrintHeader and PrintFooter when previewing the
Spread.

I don't have a clue as to how the printer device's HORZRES and
VERTRES correlate to the Preview Control's RECT....



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Bernard Ertl

[Ian Cairns]

bern, a good place to start might be:
getphyspagesize
and the printpage() function in this print source code:
printing with dialogs
regards,

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[email protected]

[Bern Ertl]

hi ian,

thanks for the tip. i think i figured it out. i posted my
solution here:
http://www.powerbasic.com/support/pb...ad.php?t=25733

thanks everyone!



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bernard ertl