JuliaPlots/Plots.jl

[BUG] Pyplot errorbar markers are not centered

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#2,823 opened on Jun 30, 2020

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PyPlotbuggood first issue

Description

#2542 # Backends

This bug occurs on ( insert x below )

Backend yes no untested
gr (default) x
pyplot x
plotly
plotlyjs
pgfplotsx
inspectdr

image

Notice how error caps are not exactly in the middle: image

I was thinking it related to matplotlib/matplotlib#7233

A hack could be to comment out this line https://github.com/JuliaPlots/Plots.jl/blob/709a8a96093b512693b8703d195b5a5da0636a13/src/backends/pyplot.jl#L128

However, maybe there is a more graceful way to handle this?

I'm not sure about the exact origin of this issue right now

Contributor guide

Tech stack
python
Domain
data
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
None
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
Investigate the pyplot backend in Plots.jl, specifically the marker centering logic in src/backends/pyplot.jl around line 128. The proposed hack is to comment out that line, but a more robust fix may involve adjusting the offset calculation. Check if the issue is related to matplotlib/matplotlib#7233. Implement a fix that ensures errorbar caps are centered on markers.