jimp-dev/jimp

luma709 greyscale

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#755 opened on Jun 26, 2019

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 (0 comments) (0 reactions) (0 assignees)JavaScript (13,218 stars) (785 forks)batch import
enhancementhelp wantedplugin-candidate

Description

Is your feature request related to a problem? Please describe. For a project I'm working on, I need to get the greyscale algorithm to use the LUMA709 colour intensities.

Describe the solution you'd like

Essentially this should do it:

parseInt(
          0.299 * this.bitmap.data[idx] +
          0.587 * this.bitmap.data[idx + 1] +
          0.114 * this.bitmap.data[idx + 2],
        10
      )

Describe alternatives you've considered

I started to make the change, but realised that adding a new arg for the algorithm type will be a breaking change (function greyscale(algorithm, cb) {). Firstly, I was wondering if this feature is something you'd consider adding? And if so, is there is a preference for how it's implemented (i.e. a brand new colour method function greyscale709(cb) or something), or if adding an extra arg is the way forward.

Additional context

Awesome library btw! <3

Contributor guide

Tech stack
javascriptnodejs
Domain
backend
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.
mostly clear
Prerequisites
JavaScriptNode.jsjimp library basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50
Research direction
Review the existing greyscale function in the jimp source code to understand its current signature and implementation. Consider the proposed API changes (e.g., adding an optional algorithm parameter or creating a new method). Engage with maintainers in the issue to decide on the preferred approach before coding.