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alandefreitas / matplotplusplus

Matplot++: A C++ Graphics Library for Data Visualization 📊🗾
https://alandefreitas.github.io/matplotplusplus/
MIT License
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Class interface seems not to add axes #367

Open MrMoose opened 10 months ago

MrMoose commented 10 months ago

Bug category

Describe the bug

I was attempting to plot two scatter plots in one figure. I am trying to use the "class interface" which doesn't rely on global data in order to be more in-line with the rest of the code and potentially thread in the future.

According to how I understand some examples, this should work:

namespace plt = matplot;
plt::figure_handle figure = plt::figure();
plt::title("Points");
figure->size(1920, 1080);

plt::axes_handle axes_red = figure->add_axes();
plt::line_handle lh1 = axes_red->scatter(x, y, 10);
lh1->marker_face_color(plt::string_to_color("red"));

plt::axes_handle axes_blue = figure->add_axes();
plt::line_handle lh2 = axes_blue->scatter(h, y, 10);
lh2->marker_face(true);
lh2->marker_face_color(plt::string_to_color("blue"));

figure->save(...);

However, if I do it like this, the second axes (plot) will always replace the first and only one plot is drawn. If I insert this (which as I understand is meant to be for global data interface):

...
plt::axes_handle axes_red = figure->add_axes();
plt::line_handle lh1 = axes_red->scatter(x, y, 10);
lh1->marker_face_color(plt::string_to_color("red"));
plt::hold(true);
plt::axes_handle axes_blue = figure->add_axes();
plt::line_handle lh2 = axes_blue->scatter(h, y, 10);
...

It works. Am I misusing this? Because I was under the impression hold() is only needed for global data interface and add_axes() is pretty clear in it's meaning to add an axes, right?

Steps to Reproduce

Try above code sample.

Output

One scatter plot without hold(), two scatter plots with hold().

Platform

Environment Details:

Additional context

Latest gnuplot installed, matplot++ built from sources with JPEG dependency but without anything else.