Make font loading more robust about plotters

[38]

Hi, thanks for feedback. That's an good idea and I am happy to add that.

Also could you please provide a stack backtrace to the panic. Since Plotters should returning error code instead of panicking inside the library. So if you can give me the backtrace it will be very helpful.

Thanks again!

[jkaessens]

Hi,
now that you put a finger on it, I realize that it's not actually panicking, it's just my lax error handling that made think it was panicking. Sorry for that!

However, the issue is still there. It's ChartContext::draw() returning with the error

Error: BackendError(FontError(FontLoadError(UnrecognizedFormat)))

For reference, it's Nimbus Sans Regular that irritates plotters.

[jkaessens]

I could narrow it down to the file src/chart/mesh.rs:157 where a default font "Arial" is loaded. If I replace the font face with something that I do have on my system, i.e. "DejaVu Sans", it works as expected. Specifying a different font for the label does not.

Maybe Nimbus Sans is causing trouble because it's a standard replacement font for Arial, thus leading to the above error?

[38]

Thanks for digging into it. I guess you are right, and it doesn't support OTF font loading.
The spot you are looking at is for drawing the axis label.

I am going to fix this once I have time. (Currently traveling and no time for coding)
What I am planning to do is allowing customize the default font. (Let me know if this won't help)

Plus I am currently planning to look into the entire font manipulate code since I have realized one of the library I used is leaking memory. I am going to make all those change and cleanup the font manipulating part completely once I have time.

Thanks a lot!

[38]

Seems we are now quite robust on font loading after we switch to font-kit, even though the proposed global defaults isn't ready yet. Closing this issue, and tracking the global defaults under issue #73