Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!boulder!sunybcs!acsu.buffalo.edu!volaski
From: volaski@acsu.buffalo.edu
Newsgroups: comp.sys.mac.programmer
Subject: RE:LDEF with multiple fonts
Message-ID: <13915@eerie.acsu.Buffalo.EDU>
Date: 29 Nov 89 15:21:06 GMT
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From: volaski@acsu.buffalo.edu ()
Path: acsu.buffalo.edu!volaski
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Subject: LDEF with styled textedit
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From: volaski@acsu.buffalo.edu ()
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Subject: LDEF with multiple fonts-more
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Newsgroups: comp.sys.mac.programmer
Subject: Re: LDEF with multiple fonts
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In article <9104@hoptoad.uucp> tim@hoptoad.UUCP (Tim Maroney) writes:
>In article <13748@eerie.acsu.Buffalo.EDU> volaski@acsu.buffalo.edu () writes:
>>I'm still curious as to why my TextFont doesn't work. Here's my code:
>>
>>procedure DrawList;
>>  begin
>>   with lhandle^^ do
>>    begin
>>     theChar := cells^^[lDataOffset];
>>     aStr := theChar;
>>     Textfont(6);	{this line is ignored; everything appears in Geneva}
>>     with lRect do
>>     moveTo(left, bottom);
>>     drawstring(aStr);
>>    end;
>>  end;
>
>I'm curious too.  Is it possible you don't have London font (font 6)
>installed?  Also, why aren't you doing a TextSize, since London doesn't
>come in the default 12 point size?  This omission makes me wonder, is
>this your real and complete code?  It also makes me wonder if, on
>getting the bad font size, the system would use Geneva instead of
>scaling the font down, but I don't see why it would.  Here's an example
>of some code in an LDEF of mine that draws in a nonstandard font.
>
>	TextFont(newYork); TextSize(9); TextFace(0); GetFontInfo(&info);
>	w1 = TextWidth(p->humanName + 1, 0, p->humanName[0]) + 2;
>	MoveTo(r.left + 4, r.bottom - (1 + info.leading + info.descent));
>	DrawText(p->humanName + 1, 0, p->humanName[0]);
>
>Since it works, so should yours.

I'll definitely have to try it with other fonts. I know I don't have London
installed. I wanted to get it to work, so I put in 6 as an arbitrary
number. Obviously, 6 isn't a good idea. I'll add a TextSize to make it 
more complete. The code has changed somewhat since I first started with it. It may
or may not have been the code I originally had. I did over again for the posting.

>One more note.  You are using unsafe "with" statements.  It is unsafe
>to use a with statement involving a relocatable handle if anything
>within the with statement could cause memory to be moved.  TextFont can
>cause memory to be moved, so it could cause the previous dereference of
>lhandle to become invalid, and so you would be reading from invalid
>memory.  This wouldn't cause your problem, but it could cause a problem
>in various conditions.  You should just bite the bullet and say
>"lhandle^^" before every field reference.  (Actually, looking at
>your code, it probably won't cause a problem, but it would be easy
>to forget and add a new statement after TextFont that uses the implicit
>reference to lHandle -- it's fragile code, in other words.)

Now that you mention this, how does one know if a handle is relocatable,
and how does one know when to lock handles down? For example, can the list
handle be locked down, and if not, then why? For example, I believe I once
tried locking down a pichandle and this resulted in a crash. 

Maurice Volaski
Dept. of Physiology
University at Buffalo