Add default plotting description for Collections

[Alexboiboi]

This adds a default description to the the Collection objects. This PR also makes the draw function get_trace public and therefore easily overridable when subclassing any magpylib core class. Some larger code base has been refactored, mainly in the traces_generic.py module.

import magpylib as magpy

sens = [magpy.Sensor(position=(0,0,2*i)) for i in range(5)]
src = [magpy.magnet.Cuboid(magnetization=(0,0,1), dimension=(1,1,1), position=(0,i/5,0)) for i in range(5)]
c1 = magpy.Collection(sens[0], style_label='Sensor Collection', style_color="red")
c2 = magpy.Collection(*src[:3], style_label='Source Collection', style_description="custom description")
c3 = magpy.Collection(*sens[1:], *src[3:])

magpy.show({"objects": c1, "col":1}, {"objects": c2, "col":2}, {"objects": c3, "col":3}, backend="matplotlib", figsize=(20,10))

[codecov-commenter]

Codecov Report

Merging #634 (c4fe7be) into main (03116b5) will decrease coverage by 0.17%.
The diff coverage is 97.44%.

❗ Your organization is not using the GitHub App Integration. As a result you may experience degraded service beginning May 15th. Please install the Github App Integration for your organization. Read more.

@@            Coverage Diff             @@
##             main     #634      +/-   ##
==========================================
- Coverage   99.22%   99.06%   -0.17%     
==========================================
  Files          54       55       +1     
  Lines        6883     6928      +45     
==========================================
+ Hits         6830     6863      +33     
- Misses         53       65      +12     

Files Changed	Coverage Δ
magpylib/_src/style.py	99.86% <66.66%> (-0.14%)	⬇️
magpylib/_src/display/traces_core.py	96.71% <96.71%> (ø)
magpylib/_src/display/traces_generic.py	100.00% <100.00%> (ø)
magpylib/_src/display/traces_utility.py	99.74% <100.00%> (+0.01%)	⬆️
magpylib/_src/obj_classes/class_BaseDisplayRepr.py	100.00% <100.00%> (ø)
magpylib/_src/obj_classes/class_Collection.py	100.00% <100.00%> (ø)
magpylib/_src/obj_classes/class_Sensor.py	100.00% <100.00%> (ø)
magpylib/_src/obj_classes/class_current_Line.py	100.00% <100.00%> (ø)
magpylib/_src/obj_classes/class_current_Loop.py	100.00% <100.00%> (ø)
magpylib/_src/obj_classes/class_magnet_Cuboid.py	100.00% <100.00%> (ø)
... and 7 more

[github-advanced-security]

CodeQL found more than 10 potential problems in the proposed changes. Check the Files changed tab for more details.

[OrtnerMichael]

@Alexboiboi

1. This works only in plotly, not in the other two backends.

2. Also: when did we descide that we can show objects without dimension ? I like the idea - but I don't rememeber that we discussed this. Is this new in this PR ?

[Alexboiboi]

1. This works only in plotly, not in the other two backends.

Will fix it. If we agree on below

2. Also: when did we decide that we can show objects without dimension ? I like the idea - but I don't remember that we discussed this. Is this new in this PR ?

Yes it is new. It came up because of a bug (see below). Then I implemented it

import magpylib as magpy

src = magpy.magnet.Cuboid()
magpy.show(magpy.Collection(src))

raises MagpylibMissingInput: Parameter dimension of Cuboid(id=140665705787888) must be set.

but

import magpylib as magpy

src = magpy.magnet.Cuboid()
magpy.show(magpy.Collection(src))

bypasses the check_function validation process.
Should we permit it in all cases and display a dimensionless scatter point like in the figure above?

[Alexboiboi]

@OrtnerMichael

I fixed the check_dimension bypass bug. I'll leave the feature of displaying unset dimension hidden in this PR and I opened an issue (#638) to discuss it.

Ready for review now i think

[OrtnerMichael]

seems to work