scalanlp/breeze

breeze.viz : plot two objects in same color

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#701 opened on Mar 22, 2018

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 (2 comments) (0 reactions) (0 assignees)Scala (3,453 stars) (690 forks)batch import
good first issue

Description

Hello,

on several occasions already I needed to plot two objects (eg. dots and a line) in the same color. I would like to avoid specifying the color explicitly but rather use the builtin palette to be robust against possible future changes.

I've checked the plot/package.scala and the plot/PaintScale.scala implementation to find a way, but I do not see anything like this implemented. Do you have any idea?

My next try would have been to explicitly pass the palette PaintScale.Category10 to plot, but it only accepts colorcode: String. A conversion function, the inverse of PaintScale.convertToColor doesn't exist. Do you know a work-around?

Alternatively, would you be interested in a PR for either one of those:

  • a new argument to plot, namely color: java.awt.Color to use it like this: color=PaintScale.Category10(1) to get the same color as the second plot
  • an inverse conversion function (might be hard to maintain)
  • a new magic string to pass to colorcode, indicating to take the same color as plot number x, e.g. colorcode="plot1" to use the same color as the second plot.

Cheers!

Contributor guide

Tech stack
scala
Domain
data
Issue type
feature
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.
clear
Prerequisites
Scala basicsBreeze libraryJava AWT basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55
Research direction
Investigate the existing color handling in `plot/package.scala` and `PaintScale.scala`. Determine the feasibility of adding a new parameter to the `plot` function that accepts a `java.awt.Color` object derived from the palette (e.g., `PaintScale.Category10(1)`). Alternatively, implement an inverse conversion function from palette index to Color. Provide a pull request implementing the chosen approach, including tests to verify that two objects can share the same color from the built in palette.