ImageMagick-如何将白色水平展平为纯白色? [英] ImageMagick - How do I flatten white levels to pure white?

问题描述

我有一个白色背景的png图像，我想将其变为透明.使用以下命令，这非常简单:

I have a png image with a white background which I'd like to turn transparent. This is fairly simple with this command:

$ convert image.png -transparent white image-trans.png

但是，如果白色背景不是完全白色(即#FFFFFF，rgb(255,255,255)等)，则效果不佳.

However, if the white background is not completely white (i.e, #FFFFFF, rgb(255,255,255), etc), then this doesn't work well.

有没有一种方法可以将所有颜色降低到一定阈值以下以完成白色?谢谢.

Is there a way to set reduce everything below a certain threshold to complete white? Thanks.

推荐答案

您要查找的命令行选项是

The commandline option you are looking for is

-white-threshold value{%}

所以

convert image.png \
  -white-threshold 90% \
  -transparent white \
   image-trans.png

注意:各个参数的顺序很重要！ (您要先将所有浅灰色像素转换为白色，然后再将所有白色像素转换为透明.)

Note: Order of the respective parameters is significant! (You want first to convert all the light-gray pixels to white, then all white pixels to transparent.)

与我一起使用'ImageMagick版本6.7.8-0 2012-07-12 Q16' ...

Works for me with 'ImageMagick version 6.7.8-0 2012-07-12 Q16'...

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