Smarter font selection for Command::TTF_TEXT

[he-la]

This is not a bug report but a feature request/discussion.

Currently, when creating a new TTF_TEXT object, the font defaults to arial.ttf (see here). Especially on linux systems (such as mine), arial.ttf may not be present. This means that every time I create a new TTF_TEXT object, I need to manually scroll down the list and select a suitable sans-serif font, which is rather tedious.

To resolve this issue, the default font should be selected in such a way that it actually exists. I can see primarily three options here:

1.) Require arial.ttf as a dependency. This is a simple solution and enables cross-platform compatability. However, it is very much against the GPL philosophy (see the arial licensing info).

1.1.) Require/bundle something like FreeSans as a dependency and use it by default.

2.) Use pango to perform automatic font selection. This mean the user gets to see their default sans-serif font being used. However, the font may not be present on other systems opening the save file, or, if only the 'sans-serif' directive is stored in the save file, may look different on other systems.

3.) Persist the last selected font and use it as default when creating a new TTF_TEXT object. The obvious downside is that if the user intents to change the font only for a specific object, he will need to go through the process of scrolling down the list again.

I'm very much willing to create a pull request solving this issue, but I was hoping for some guidance as to which direction to go. Personally, I would prefer the solution 1.1, as it reduces the problem to a one-off issue when first installing solvespace.

[whitequark]

Sure, let's add FreeSans (or maybe Bitstream Vera Sans) as a default TTF font.

[he-la]

I'm supposed to be on holiday, but since this seems like a quick fix I'll make a PR later this week or so.

[whitequark]

Thank you! I suggest adding the font under res/fonts and then adding a separate item in the TTF font selector, say Bitstream Vera Sans (built-in). This would clearly establish that this font will never go missing.

[he-la]

Ended up getting around to implementing it tonight.