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[BUG]: The `quiver` trace ignores a discrete `marker.color` array and results in every arrow being black

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#8,026 0 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
72/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Active
Tech stack
javascript
Domain
data-visualization

Research direction

Reproduce the issue through the Plotly.newPlot calls in the browser devtools, starting with the quiver trace implementation. Compare handling of the discrete marker.color array with the numeric colorscale case, then verify that each arrow uses its corresponding color while single colors and colorscales continue to work.

Written by the indexing model from the issue text.

Description

bug P2 size: 3
Description

The quiver trace ignores a discrete marker.color array. Every arrow ends up black instead of taking its per-point color. A numeric array with a colorscale works, and a single color string works.

Screenshots/Video
No colorscale (the bug) With colorscale (for comparison)
Image Image
Steps to reproduce
  • Open plotly devtools
  • Run the following snippet in the browser devtools console 
     Plotly.newPlot(gd, [{
   type: 'quiver',
   x: [1, 2, 3], y: [1, 2, 3],
   u: [1, 1, 1], v: [0, 1, 0],
   marker: { color: ['rgb(23, 103, 194)', '#FF4136', '#2ECC40'], line: { width: 3 } }
 }]);
  • Note that all three arrows are rgb(0, 0, 0) (by inspection of using your eyes)
  • Run the following modified snippet: 
     Plotly.newPlot(gd, [{
   type: 'quiver',
   x: [1, 2, 3], y: [1, 2, 3],
   u: [1, 1, 1], v: [0, 1, 0],
   marker: { color: [0, 5, 10], line: { width: 3 } },
   colorscale: 'Viridis'
 }]);
  • Note that the arrows have the correct color
Notes
  • marker.color is documented as arrayOk, so the black arrows seem to be a rendering bug (rather than an unsupported input)
  • Per the schema, each arrow should be drawn as its own color from the array. If this behavior is intentional, we should update the description.
  • This was found while working on #8025
Dominant language
JavaScript
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Forks
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Avg merge
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Merged PRs (30d)
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