interlaced pngs

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interlaced pngs

Post by albertleidinger »


Im uploading a transparent png to my webapp. Its creating a png-thumbnail through PerlMagick but the result is not interlaced.

1.) the uploaded png is interlaced
2.) I tried $resizedImg->set( interlace => $param) with $param = Line, Plain and Partition.

Any help is wellcome: Just trying to create interlaced png-thumbnails.

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Post by glennrp »

Use "plane" not "plain" for interlacing.


Post by albertleidinger »

Oh my god ...

thx - the simpler the error the harder to find.

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Re: interlaced pngs

Post by Vanns »

convert -strip -interlace JPEG -quality 80 origi.jpg output-file.jpg

origi image size : 40.6 kb
output-file image size : 11.3 kb

But if I convert one png file as

convert -strip -interlace PNG -quality 80 he.png output-file.png

he.png image size : 711 kb
output-file image size : 1 mb

convert -strip -interlace PNG he.png output-file.png

he.png image size : 711 kb
output-file image size : 972.3 kb

Why the file size has been increased in case of PNG after conversion to output-file.png?

Am I using correct parameters for png conversions?
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Re: interlaced pngs

Post by snibgo »

Interlacing will change the data used by the compression algorithm.
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