Legacy ImageMagick Discussions Archive

Appreciate the checks - libpng 1.2.50 (!!) was the culprit.

Many thanks

Tested on these 2 setups:
ImageMagick 7.0.7-11 Q16 x64 Ubuntu
ImageMagick 7.0.8-7 Q16 x86_64 Win10

A fully transparent 6750x5732 png file created in Photoshop causes this error:
identify: Read Exception `test.png' @ error/png.c/MagickPNGErrorHandler/1711.

I used this command to reproduce ...

Interesting.

Yes I've got a mix of grayscale, rgb, alpha and no aplha.

Honestly I need to do better normalization of my image set before processing them.

getQuantumDepth() in PHP returns as Q16.

Also after testing about 100 images, there are only 20 around the 257 factor.

The factors themselves range from 127 to 3526, which leaves me scratching my head.

I'm going to sidestep the whole issue and just start fresh without Imagick.

Thanks

snibgo wrote: 2018-07-13T12:36:20-07:00 The relationship between some pairs is a factor of 257.

It would make more sense if it were 255.

I'll take a larger sample then and either go with 257 if it's the most common, or average everything.

Thanks

I'm converting a script from Imagick in PHP to command line IM 7.
One thing has held me up for a while now.

This method in PHP:
$im->getImageChannelMean(Imagick::CHANNEL_ALL);

Returns the following means for 5 arbitrary images I was testing with:
22282.14894013
30473.356623976
38031.623559618 ...