Saving TFont

[aussieian]

I need to save the FONT properties of objects before changing them,
so tried the following:

var

   OldFont : TFont;

Begin

   OldFont.Name := '';

   or

   oldfont := TheImage.Canvas.Font

The compiler accepts the code, but when it executes, the following
error occurs:

" project xxx raised exception class external 'error SIGSEGV'"

The problem doesn't appear to happen if OldFont is a LOCAL variable, only when I try to make it a GLOBAL variable.

I'm using the Windows 64 version.

Any suggestions appreciated.

[typo]

Code: [Select]

var
   var
   OldFont : TFont;
Begin
   OldFont := TFont.Create;
   OldFont := Font;
   ShowMessage(OldFont.Name);
   OldFont.Free;
end;               

[Martin_fr]

lets make it more correct

Code: [Select]

   OldFont := TFont.Create;
   OldFont.assign(Font);
 
OldFont can be local or global or whatever. And you must free OldFont ourself or memory leaks.

Assign copies all the attributes from one font to another

Reason is:
"Font" is an object. and objects are internally pointers.

therefore:
MyFont := SomeFont;
SomeFont.Free;

Since MyFont simply points to the same memory as SomeFont, once SomeFont is gone MyFont points to random data.

[aussieian]

Thanks for the prompt suggestions from both typo and Martin_fr.

I'm obviously missing something because the suggested solutions don't work.

I have made the TFont variable a global variable.

I put in the FORMCREATE procedure

          OldFont.Create

However I still get the same error generated on the CREATE itself.

Am I possibly missing a directive or something less obvious?

[theo]

Am I possibly missing a directive or something less obvious?

You are probably missing the basics of Object Pascal ;-)
It's written above:
OldFont := TFont.Create;

not OldFont.Create

[aussieian]

Thanks very much Theo.

You are correct. Shows what happens if you rush and don't pay attention to the advice.

Cheers.