OpenEuphoria

Re: win32lib bug in getFontSize

• Posted by CChris <christian.cuvier at agricult??e.gouv.fr> Nov 29, 2007
• 487 views

George Walters wrote:
> 
> I posted this once in "Analyze this" but I suspect that no one probably 
> noticed.
> 
> I've discovered that win32lib getFontSize is wrong..at least in my opinion.
> 
> Look at this link which has a drawing of characters explaining the vars used.
> 
> <a
> href="http://msdn2.microsoft.com/en-us/library/ms534015.aspx">http://msdn2.microsoft.com/en-us/library/ms534015.aspx</a>
> 

From the illustration posted on that page, I'd replace one of the
 tmInternalLeading by tmExternalLeading. But I'm not very experienced in
 typesetting, so please anyone prove me wrong.

CChris

> Then look at the winlib32 code below. "tmInternalLeading" is actually added
> twice. It's first contained in "tmHeight" then getFontSize adds it again.
> I think that "tmInternalLeading" should be removed from the char heigth. 
> I've rem'd it out on my copy and my list boxes have the correct height since
> I'm sizing them by character heights. If I'm wrong please explain.
> 
> 
> global function getFontSize( integer id )
> 
>     -- get metrics for current font
> 
>     integer width, height, maxwidth
>     atom tm
> 
>     -- text metric structure
>     tm  = w32acquire_mem(0, SIZEOF_TEXTMETRIC )
> 
>     -- get the metrics of the font (queryFont will prepend the DC)
>     if not queryFont( id, xGetTextMetrics, {tm} ) then
>         warnErr( Err_GETFONTSIZE )
>     end if
> 
>     -- assign values
>     width   = w32fetch(tm,tmAveCharWidth)
>     maxwidth   = w32fetch(tm,tmMaxCharWidth)
>     height  = w32fetch(tm,tmHeight) +
>                 w32fetch(tm,tmInternalLeading) + <----------- remove this 
>                 w32fetch(tm,tmExternalLeading)
> 
>     -- release
>     w32release_mem( tm )
> 
>     -- return results
>     return { width, height, maxwidth }
> 
> end function