ngscopeclient preferences.yml font path shall use relative path by default

[bvernoux]

Today ngscopeclient preferences.yml use full path for all font for everything (label_font ...) even when created by default using fonts from ./fonts/xxx (usually DejaVuSans.ttf or DejaVuSansMono.ttf, potentially later DejaVuSans-Bold.ttf)
So it will be better to use relative path by default at least as when you launch ngscopeclient from an other path the old one which is a full path is not found and it prevent to ngscopeclient start with an error
How to fix it:

• Just use relative path "./font/"
  • The code to be modified is in src/ngscopeclient/PreferenceSchema.cpp to use relative path for font by default
  • It can be fixed directly in https://github.com/glscopeclient/scopehal/blob/master/scopehal/scopehal.cpp#L772 by checking if relative path is found before to check dir + relative path ...
    • See Update scopehal.cpp FindDataFile to use relative path when possible scopehal#779

[azonenberg]

Relative paths doesn't sound like a great idea, since we need to allow for things like running a dev build in your working copy followed by installing system wide, and not have them stepping on each other accessing stuff in /usr/share/fonts or similar.

The better solution is for the font loading code to detect failure to load a font file and fall back to a default font if the supplied filename is nonexistent or malformed. This will recover without crashing in the rare case of a font you have selected becoming unavailable, while also ensuring determinism in other cases.

[bvernoux]

I do not really see what is your point towards running a dev build in your working copy so please check the ngscopeclient/scopehal#779 that clearly solve any issue with relative or full path (if relative path is not available it do like before scanning all dir for full path ...)

[bvernoux]

Fixed in commit f236404