Change Transparent Background to Color/Opacity

[markfinch]

I have some Social Media Icons that have a transparent background and I want to change the full transparency to semi-transparent colors. I have searched for hours but haven't found the magic bullet to do this.

How does one go about changing a transparent background to a translucent one? Thanks,

Mark

[fmw42]

try

convert image.png -background "rgba(r,g,b,a)" -flatten result.png

for color definitions, see http://www.imagemagick.org/script/color.php

(note alpha values in rgba format are always in the range 0 to 1)

[markfinch]

convert image.png -background "rgba(r,g,b,a)" -flatten result.png

didn't work on Ubuntu 13.04. For some reason both rgba and the -flatten shortcut did not work.

What did work is:

Code: Select all

convert image.png -background '#RRGGBBAA' -layers flatten result.png

I must have typed basically that command a dozen times yesterday with variations on the color with both rgba() and hex values not in ' and with/without -flatten shortcut to no avail. Any ideas why RGBA, hex not in ' and shortcuts don't work?

Thanks a lot.

M

[snibgo]

Users of Ubuntu often seem to be running very old versions of IM. What is your version?

[fmw42]

what was the exact value for rgba(....) that you used. It works fine for me on IM 6.8.6.9 Q16 Mac OSX.

[markfinch]

Ubuntu 13.04 with ImageMagick 6.7.7-10 (although I think it was just updated today and haven't tried using rgba yet. Just double checked the package log and it was updated today. Not certain what the previous version was.) Although it would seem even if they aren't on the latest something as basic as that command would work since it has been available for awhile. Guessing it is some option not enabled by the package maintainer.

the line was convert file -background "rbga(0,0,0,.8)" -layers flatten, newfile and also did single quote ' and a grey value of 55,55,55,.8 as well as used 0.8.

Decided to go ahead and do a quick check with the new version and it still generates an errors.
convert.im6: unrecognized option `-flatten,' @ error/convert.c/ConvertImageCommand/1582.
convert.im6: unrecognized color `rbga(0,0,0,0.8)' @ warning/color.c/QueryMagickColorCompliance/2684

If one of you can confirm this command works with a png with a transparent background and sets the background to a translucent black or grey I will file a bug in Launch Pad on this.

[snibgo]

Code: Select all

convert.im6: unrecognized option `-flatten,' @ error/convert.c/ConvertImageCommand/1582.

Don't use a comma.

[markfinch]

Don't use a comma.

Comma was in there from the bash script I was using and has to be there, but on single convert removing the comma does work for using flatten shortcut. Although the rgba error is still thrown. Next time I am running the script I will try putting a space between -flatten and comma.

[fmw42]

You cannot have a comma in IM syntax even with spaces in bash script. Why do you think you need that? What was your full command? Do you need it for some other calling API such as PHP?