plots.pl - start_mark and end_mark don't respect the color option

[dlglin]

When graphing a formula using plots.pl, start_mark and end_mark are plotted in black in jsgraph even if color is set. In hardcopy they match the color of the graph. Here's a MWE:

DOCUMENT();

loadMacros(
    "PGstandard.pl","PGML.pl",'plots.pl',"PGcourse.pl");

$plot=Plot();
$plot->add_function('.5x','x',-5,5,color=>'red',start_mark=>'arrow', end_mark=>'arrow');

BEGIN_PGML
[! !]{$plot}
END_PGML

ENDDOCUMENT();

[somiaj]

Works for me. Did you test this on the 2.21-rc or 2.20?

[dlglin]

This is what I'm seeing on two different servers on 2.21.

[somiaj]

Wonder what the difference is. I wonder if jsxgraph version or browser can affect that.

[dlglin]

Looks like it's a Safari thing. It displays correctly in Firefox and Chrome on my Mac, but Safari shows the picture above.

[somiaj]

I can't test Safari, but does the error only happen with arrows? Do other end marks like circles, etc work? Seems there is an bug in webkit (safari) svg rendering and inheriting the color correctly.

Reason I ask about other marks, is it looks like I could fix the arrow fairly easily, but want to make sure I don't have to worry about other marks as well.

[dlglin]

closed_circle, open_circle (and circle) all inherit the colour correctly. It appears to be just arrows that aren't working.

[somiaj]

@dlglin I can't test safari, but does #1484 fix the issue for you?

[somiaj]

This is a JSXGraph issue and a safari limitation.

If this jsfiddle isn't working in Safari, https://jsfiddle.net/tc9oud4g/, then not much we can do.

Just to reference the original JSXGraph issue: jsxgraph/jsxgraph#772

This could be a regression due to how they detect if safari is being used, or maybe their original fix only fixed some cases but not all. I would probably mention that the issue is still being seen in 1.13.0 with that jsfiddle example.