jimp-dev/jimp

Darken results in degraded image

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#706 opened on Feb 26, 2019

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Description

I have a test, on jsFiddle (uses the browser version of 0.5.6), https://jsfiddle.net/niccih/mdftLojv/24/, where I am trying to darken the image. As can be seen the result (second image) is not quite what I was hoping for in that the quality has degraded noticeably.

Any advice as to what I may be missing, or what alternative steps I may take will be greatly appreciated. Note that the 'brightness' example is just for my own reference and is not the result I am looking for. Other image manipulation packages seem fine when darkening the same image, but not being browser based, they are not a viable option (my requirements are dependant on being browser based), hence wanting to use Jimp.

Contributor guide

Research direction
Inspect the 'darken' method implementation in jimp and trace the code path to identify why quality degrades. Check if there is a color conversion or precision loss issue.
Tech stack
javascript
Domain
frontend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Git
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65