IM 6->7 Transparency changes??

[Eric B]

Hello,
I've updated my IM to the lastest 7.04 from an earlier 6.9.x (Q16-x64 Win10)
I use a IM script to resize my pictures, as following:

Code: Select all

convert $file -filter Lanczos -resize $resize -format JPEG -quality 85 -gravity SouthEast $signatureFile -compose atop -geometry +0+0 -channel A -evaluate Divide 2 -composite -gravity NorthWest headline.png -compose atop -geometry +0+0 -composite $s

where $file is my source file, $resize is the target resolution, $s is the target filename, $signatureFile and headline.png are generated pictures from the metadata. These 2 picts are transparent (using alpha channel) and thus attached with transparency to my target file.

This line used to work perfectly with IM 6.x, but with the recent 7.0.4, the signature and headline are not transparent anymore in the target.

Did some of these options changed in v7? Or it is a bug?

[snibgo]

Try "-alpha Activate" before "-channel A".

[Eric B]

thanks, but unfortunately did not help.

[Eric B]

and if I ommit the -channel A, the headline and signature DO get transparent. BUT the other channels are affected and the whole picture is much darker.

[Eric B]

for now, I uninstalled IM 7 and installed the latest 6.9.7 which works perfectly for that purpose.
Looking at the changelog ( http://www.imagemagick.org/script/changelog.php ), it seems that a few bugs related to alpha channel got recently fixed. Still not yet all?
@moderator: please feel free to move this topic to the bug section if confirmed!

[snibgo]

I've just noticed: you have no "+channel". You should have this when you no longer want to restrict the processing.

[Eric B]

What the kind of convert I am using, is there any benefit using IM7 instead of IM6 ? Can we expect better quality? better speed?