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Converting some icons creates black stripes on transparency

Posted: 2013-05-24T06:24:30-07:00
by Jacket
For a project of mine I'm fetching websites favicons and storing them to be displayed in a website. Sounds pretty trivial, but I have one strange issue. Almost all icons come in a .ico format, which is not very web friendly. Some icons also have different sizes in them. I'm using Imagemagick to convert them to PNG and extract only the 16x16 icon.

I'm using the following command line for this:

Code: Select all

convert source.ico -geometry 16x16 -alpha on -background none -flatten out.png
Unfortunately on some icons this creates some nasty horizontal black stripes in the transparent areas. Here is an example:

This is the original icon:

http://g.etfv.co/http://www.mysqlperformanceblog.com/

This is the result:

Image

Here it is again embedded here:

Image

What could be wrong here? My ImageMagick is version 6.5.4-7

Re: Converting some icons creates black stripes on transpare

Posted: 2013-05-24T06:48:06-07:00
by snibgo
You are using an ancient version of ImageMagic. With v6.8.5, your command gives me no black lines.

Re: Converting some icons creates black stripes on transpare

Posted: 2013-05-24T09:37:44-07:00
by Jacket
Thanks I will update. This is the version that comes with CentOS 6.4.