jimp-dev/jimp

Darken results in degraded image

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#706 opened on 2019年2月26日

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 (2 comments) (0 reactions) (0 assignees)JavaScript (13,218 stars) (785 forks)batch import
bughelp wanted

説明

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.

コントリビューターガイド

技術スタック
javascript
領域
performance
Issue 種別
bug
難度新しい貢献者にとっての実装難度です。1 は非常に小さな変更、5 は専門的な作業です。
3
推定時間経験ある貢献者が調査、実装、テスト、pull request 準備にかけるおおよその時間範囲です。
half day
活動状況Issue が今どれだけ取り組みやすいかを示します。新しい、活発、古い、ブロック中、またはメンテナー入力待ちなどです。
stale
明確さ期待される変更、受け入れ条件、次の手順がどれだけ明確かを示します。
clear
前提条件
basic JavaScriptfamiliarity with canvas/ImageData
初心者向け度初回貢献者にどれだけ取り組みやすいかを 1-100 で推定したスコアです。
35
調査方針
The issue reports that the darken filter produces a degraded image. Reproduction is available at the provided jsFiddle link. Investigate the darken algorithm in the Jimp source code, likely in the color manipulation module (e.g., src/effects/darken.js or similar). Compare the implementation with other image processing libraries to identify why quality degrades when darkening. Check if there is an issue with integer rounding or color space handling. The maintainer may need to confirm expected behavior.