Plots Improvements - A continutation of #966

[somiaj]

This is the new branch of improvements to the new Plots library after my accidental merge of #966.

[somiaj]

Working on the colors, I think the issue @drgrice1 pointed out was due to contrast, and I do agree that the green doesn't look as good. I took the colors from the W3school color wheel and wanted something that wasn't as stark as just #00ff00. https://www.w3schools.com/colors/colors_wheels.asp

I liked the looks of the RYB color wheel, so I went with that, but I didn't pay close enough attention and noticed that the wheel they draw and the color codes they give do not match, and agree that green is the worst looking. Maybe I'll just grab the colors from the wheel directly. Here is a test problem.

DOCUMENT();
loadMacros('PGstandard.pl', 'PGML.pl', 'plots.pl',);

$plot = Plot(xvisible => 0, yvisible => 0);
$plot->add_dataset(
    [ -4, 1 ], [ -2, 1 ], [ -2, 3 ], [ -4, 3 ], [ -4, 1 ],
    width      => 5,
    color      => 'red',
    fill       => 'self',
    fill_color => 'red',
);
$plot->add_dataset(
    [ -1, 1 ], [ 1, 1 ], [ 1, 3 ], [ -1, 3 ], [ -1, 1 ],
    width      => 5,
    color      => 'yellow',
    fill       => 'self',
    fill_color => 'yellow',
);
$plot->add_dataset(
    [ 2, 1 ], [ 4, 1 ], [ 4, 3 ], [ 2, 3 ], [ 2, 1 ],
    width      => 5,
    color      => 'blue',
    fill       => 'self',
    fill_color => 'blue',
);
$plot->add_dataset(
    [ -4, -1 ], [ -2, -1 ], [ -2, -3 ], [ -4, -3 ], [ -4, -1 ],
    width      => 5,
    color      => 'orange',
    fill       => 'self',
    fill_color => 'orange',
);
$plot->add_dataset(
    [ -1, -1 ], [ 1, -1 ], [ 1, -3 ], [ -1, -3 ], [ -1, -1 ],
    width      => 5,
    color      => 'green',
    fill       => 'self',
    fill_color => 'green',
);
$plot->add_dataset(
    [ 2, -1 ], [ 4, -1 ], [ 4, -3 ], [ 2, -3 ], [ 2, -1 ],
    width      => 5,
    color      => 'purple',
    fill       => 'self',
    fill_color => 'purple',
);

for ('Tikz', 'JSXGraph') {
    $plot->image_type($_);
    $image{$_} = image($plot);
}

BEGIN_PGML
**Tikz Image:**

[$image{Tikz}]*

**JSXGraph Image:**

[$image{JSXGraph}]*

END_PGML
ENDDOCUMENT();

The green by itself without contrasting with blue doesn't look as bad, but I'll update to the colors shown in the wheel vs the color codes given (unless someone knows some decent color codes for a base pallet, I just thought the RGB codes were a bit much which was why I wanted to change them).

And here is what the colors look like if I grab the color codes from the color wheel W3 has vs use the codes they provide.

To me I like the red/blue/purple from the first, and the yellow/green/orange from the second image.

[somiaj]

I think I tracked down my initial dislike, seems svg defines #00ff00 as lime green, and that didn't look green to me, just updating green to be #008000 made a lot of difference to me. So here is the primary and secondary colors as defined by svg.

[somiaj]

Here are the colors I went with, let me know if you would prefer any changes.

[somiaj]

I have updated the examples for those who want to testing things, I have removed GD from all my test examples, as it has falling behind, and the focus now is JSXGraph for HTML and Tikz for hardcopy.

Plots_examples.tar.gz

[drgrice1]

Those colors look better.

[somiaj]

Here is a problem to see/test the line style changes.

DOCUMENT();
loadMacros('PGstandard.pl', 'PGML.pl', 'plots.pl',);

$plot = Plot(xvisible => 0, yvisible => 0);

@linestyles = (
    'solid',        'dashed',
    'short dashes', 'long dashes',
    'dotted',       'long medium dashes',
    'bad line style',
);
for my $i (0 .. 6) {
    $plot->add_dataset(
        [ -4, $i - 3 ], [ 4, $i - 3 ],
        linestyle  => $linestyles[$i],
        start_mark => 'arrow',
        end_mark   => 'arrow',
    );
}

for ('Tikz', 'JSXGraph') {
    $plot->image_type($_);
    $image{$_} = image($plot);
}

BEGIN_PGML
**Tikz Image:**

[$image{Tikz}]*

**JSXGraph Image:**

[$image{JSXGraph}]*
END_PGML
ENDDOCUMENT();

[somiaj]

Updated examples:

Plots_examples.tar.gz