jimp-dev/jimp

Slightly faster version of resize2.js available

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#758 opened on Jul 6, 2019

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enhancementhelp wantedsolution in issue

Description

Rescaling with bilinear, bicubic, bezier and hermite interpolation is a bit slow. I'm using a copy of resize2.js in my own icon generator and refactored it. I inlined all functions which sometimes got called for every single pixel. This speeds up rescaling a bit. Feel free to use this version resize3.js which is otherwise identical to the original resize2.js (apart from the removal of the options parameter which was never used).

There is also resize4.js with an alternative bicubic implementation that is much faster. The limitation of this version is that source and target image must have the same width/height ratio.

Contributor guide

Tech stack
javascriptnodejs
Domain
performancebackend
Issue type
performance
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.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
JavaScriptbasic understanding of image resizing
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70
Research direction
Review the linked resize3.js and resize4.js files from the contributor's repository. The main task is to replace the existing resize2.js in the jimp library with resize3.js, which is functionally identical but faster due to inlined functions. Optionally, consider resize4.js, which offers even faster bicubic interpolation but requires source and target images to have the same width/height ratio. After integration, run the existing test suite to ensure no regressions.
Slightly faster version of resize2.js available · jimp-dev/jimp#758 | Good First Issue