Just need a little help with the stack I think

[jonfhancock]

OK, I have two images to work with in the beginning, and I have three successful commands to get me to the finished result. I am trying to combine the commands down to one and avoid temporary images.

The starting images are:
android.png


and concentric.png


The first command uses the android as an alpha channel mask so I end up with an android cutout of concentric.png including the drop shadow

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convert concentric.png android.png -alpha Set -compose Dst_In -composite android-con.png

The result is android-con.png


But it is a little too transparent, so the next command just doubles it up

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convert android-con.png \( +clone \) -composite android-dub.png

Which yields android-dub.png


But, I want to bring in a white glow in place of the blue drop shadow to help define the lines a little better, so I run:

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convert android.png -negate android-con.png -composite android-final.png

Which yields the final result android-final.png



Now for combining them:

I started with bringing it down to two commands:

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convert concentric.png android.png -alpha Set -compose Dst_In -composite android-con.png

convert android.png -negate \( android-con.png \( +clone \) -composite \) -composite android-final.png

Which works great. But, when I try to replace "android-con.png" with the first command, the image comes out wrong.

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convert android.png -negate \( \( concentric.png android.png -alpha Set -compose Dst_In -composite \) \( +clone \) -composite \) -composite android-fail.png

Yields android-fail.png


I'm sure I'm misunderstanding either the way parentheses work, or the way +clone works. Any advice?

Thanks,

Jon F Hancock

[fmw42]

try adding -respect-parenthesis at the beginning after convert in case -negate is creaping into the parenthese. Just a guess.

and/or

replace

android.png -negate

with

\( android.png -negate \)

[jonfhancock]

That actually gets me pretty close. This command:

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convert -respect-parenthesis android.png -negate \( \( concentric.png android.png -alpha Set -compose Dst_In -composite \) \( +clone \) -composite \) -composite android-fail.png

Yields:
android-fail2.png


Which is just a little darker than android-final.png



It sort of looks like the order is wonky, or the way it is composited is not quite right. I've tried reordering things, taking out parenthesis, and adding parenthesis, but can't seem to get any better result. Hmm

[anthony]

try adding -respect-parenthesis at the beginning after convert in case -negate is creaping into the parenthese. Just a guess.

-negate is an operator, it is applied, not remembered.

[anthony]

The very dirst command shoudl have done teh job...

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convert concentric.png android.png -alpha Set -compose Dst_In -composite android-con.png

The problem is that you are removing most of the darker parts of the concentric image, as they fall outside the android shape, and as such the whole image looks so much lighter than it really is.

I would suggest take the result of the above and just 'darken' it a little more using -level, sigmoidal-conrast, or -module.
That later can adjust both luminance and saturation to get the result you want.

Question are you sure your androis shape isn't semi-transparent! That would also be the cause of your problems!!
In which case do a level adjustment of just the alpha channel and fix its transparency!

[jonfhancock]

Thanks, anthony!

The android is semi-transparent. I've been reading through the imagemagick documentation, but I can't seem to grok how to adjust only the alpha channel. Do you have an example handy?

Thanks,

Jon

[Drarakel]

If you still wonder why the combining of your original commands wasn't completely successful: As you first use a special compositing method, you have to change it back to the default ("-compose src-over") right before the second composite. Personally, I would also avoid nested parentheses as long as possible (though that was not the reason for the differing results).

So, an equivalent for your two commands..

I started with bringing it down to two commands:

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convert concentric.png android.png -alpha Set -compose Dst_In -composite android-con.png

convert android.png -negate \( android-con.png \( +clone \) -composite \) -composite android-final.png

..would be that:

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convert concentric.png android.png -alpha Set -compose Dst_In -composite -compose src-over +clone -composite ( android.png -negate ) +swap -composite android-final2.png