Re: [XaraXtreme-dev] Current/default font

[Martin Wuerthner <lists@xxxxxxxxxxxxxxx>]

In message <44C8D7D6.6040902@xxxxxxxxxxx>
          Alex Bligh <alex@xxxxxxxxxxx> wrote:

> Martin Wuerthner wrote:
>> But if we do not always do it, why do it at all? Just to avoid a
>> single font attribute that contains the name of a font that is not
>> installed? We will have lots of them in the tree anyway simply by
>> loading a document containing fonts that are not installed. We do not
>> do "hard" font substition, just "soft" font substitution, i.e., the
>> text remains in the unknown font but when it is displayed the default
>> font is used instead.
> 
> I had been presuming the implementation time of either option would
> be the same.
> 
> IE (in PsuedoCode)
>    FixFontAttributeIfUnusedAndUninstalled(CurrentAttribute);
> becomes
>    FixFontAttributeIfUnusedAndUninstalled(CurrentAttribute);
>    FixFontAttributeIfUnusedAndUninstalled(DefaultAttribute);
> 
> Somewhere during the long discussion at GP it became obvious we needed
> to fix both. I now can't remember why. Anyone else? But if the
> implementation time is the same, why not, now we know it's harmless?

Because there are good reasons for changing the current font but I 
cannot see any reason for changing the default font attribute. The 
default font attribute nodes are just the in-memory manifestations of 
the implicit, fixed default attributes that are part of the file 
format. The default font attribute has been defined to be Times New 
Roman - some choice had to be made.

Yes, we can change the default attribute *node* in some specific 
cases. But why would we want to do it in the first place? And if there 
really is a good reason for doing it, then are we not going to be in 
trouble when we cannot do it? Or, the other way round, if we are happy 
without doing it when the circumstances do not allow, we might just as 
well never do it.

So far, the only reason given for doing it was that there should be no 
font attibutes in the tree for fonts that are not installed. As I 
wrote above, we have lots of them anyway (for all fonts found in 
loaded documents that do not happen to be installed), so why bother?

Martin