jimp-dev/jimp

Darken results in degraded image

Open

#706 创建于 2019年2月26日

在 GitHub 查看
 (2 评论) (0 反应) (0 负责人)JavaScript (13,218 star) (785 fork)batch import
bughelp wanted

描述

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.

贡献者指南

技术栈
javascript
领域
performance
议题类型
bug
难度面向新贡献者的预计实现难度，1 表示很小改动，5 表示专家级工作。
3
预计时间有经验贡献者完成调查、实现、测试并准备 pull request 的粗略时间范围。
half day
活动状态议题当前的可参与程度：新鲜、活跃、陈旧、阻塞或等待维护者输入。
stale
清晰度议题是否清楚说明期望改动、验收标准和下一步。
clear
前置要求
basic JavaScriptfamiliarity with canvas/ImageData
新手友好度1-100 的估计分数，表示该议题对首次贡献者的友好程度。
35
研究方向
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.