drawing is broken when using special characters for axis labels

[benmkw]

I used "€" so I assume only ascii is allowed or maybe it would have to be wrapped into im_str! or sth. on an api level. I've not looked into the internals but maybe this helps someone debugging :)

[4bb4]

I'll try to reproduce this on my end. Things do get wrapped in im_str!, for the axis labels this happens here: https://github.com/4bb4/implot-rs/blob/master/src/plot.rs#L245 - but maybe something else is going wrong. What are you seeing when you use €? Nothing? Or weird other letters?

[benmkw]

If I e.g. change the y_label in my wgpu pr in show_basic_plot to "€" it crashes.

    Plot::new("Simple line plot")
        // The size call could also be omitted, though the defaults don't consider window
        // width, which is why we're not doing so here.
        .size(content_width, 300.0)
        .y_label(&"€")
        .build(plot_ui, || {
            // If this is called outside a plot build callback, the program will panic.
            let x_positions = vec![0.1, 0.9];
            let y_positions = vec![0.1, 0.9];
            PlotLine::new("legend label").plot(&x_positions, &y_positions);
        });

Assertion failed: ((int)draw_list->_VtxCurrentIdx == draw_list->VtxBuffer.Size), function AddDrawListToDrawData, file third-party/imgui/imgui.cpp, line 4047.
fish: 'cargo run --release' terminated by signal SIGABRT (Abort)

interestingly it does not crash if used as x_label but just shows a "?"

I certainly had it not crash at the y axis and just produce artefacts for rendering though (hundreds of long white lines across the plotting area) as well.

[4bb4]

interestingly it does not crash if used as x_label but just shows a "?"

This sounds like a memory issue. I'll have to walk through it with a debugger to see what's going wrong - I thought I could just do im_str!("{}" my_string).as_ptr() and presto I have a char ptr, but apparently things are not that simple...

EDIT: Ooh, I think I know what the problem is - the result of im_str!() is a temporary here and may be deleted before it is used. I'll try out a fix (probably not before tomorrow though) and let you know how it goes.

EDIT 2: Now with the right account xD I wondered why I got a notification for my own comment

[4bb4]

I did some checks, here's what I found so far:

• The question mark is also displayed when you just add a "€" somewhere in a call to ui.text. That tells me that likely the font that is loaded just can't display that.
• The data appears to make it into the C++ implot code OK, where for the Y axis, it gets fed to a AddVerticalText function, which does some fancy stuff for dealing with UTF: https://github.com/epezent/implot/blob/master/implot.cpp#L255. It would be interesting to see if we see the glitches also in the C++ version - if we do, that means it's a bug in implot itself.

[aloucks]

Did you verify that "€" is represented in the glyph ranges that you used and is it in your texture atlas?

[4bb4]

@aloucks No, and I suspect that this may be the issue. I did check that the FindGlyph call in https://github.com/epezent/implot/blob/master/implot.cpp#L277 returned a non-null pointer when I was stepping through it with a debugger, if I remember correctly.

If this is the issue, I'd be interested in what to do / check in the code in order to make sure that a user specifying valid UTF does not lead to the program drawing glitches or even crashing though - if that's possible with reasonable effort.

[4bb4]

@benmkw Have you tried out another font in the meantime?

[benmkw]

No :/ I played with using your project as a template basically to port imnodes though until my laptop broke yesterday so I was/ am in the process of looking at more details/ trying some things out for this whole API thing. I‘ll have to see how much further I push this on windows or if I do a bit less for a bit.

[4bb4]

Alright, I need to try using other fonts for work at some point in the future anyway, I'll make sure to plop an € in there to see if it works and ping you with an update