Alpha on already transparent images..

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dognose
Posts: 243
Joined: 2005-03-08T22:16:37-07:00

Alpha on already transparent images..

Post by dognose » 2018-03-08T09:35:25-07:00

I'm trying make an image with transparency more see though.
I'm using
convert image.png -alpha on -channel a -evaluate set 50% out.png

However, it removes the areas that were completely transparent and makes them 50%..
So, I'm losing the mask..

How can I keep the mask and bump up the rest of the alpha?

snibgo
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Re: Alpha on already transparent images..

Post by snibgo » 2018-03-08T10:13:54-07:00

Instead of setting the alpha, you should multiply it, eg by 0.5.
snibgo's IM pages: im.snibgo.com

dognose
Posts: 243
Joined: 2005-03-08T22:16:37-07:00

Re: Alpha on already transparent images..

Post by dognose » 2018-03-08T10:44:06-07:00

-evaluate multiply 0.5

works great, THANKS!

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