Legacy ImageMagick Discussions Archive

Hi, I'm pretty new to imagemagick but i would like to have this:



In Gimp, i import the two images as layers and then i apply screen method to the first one.
I have to do this often now.

Is it possible to manage this process in ImageMagick?
thanks in advance

Post a URL to your blue and red images. We need to download them to verify our solution works properly before we post it.

Here some example images:

Layer 1 http://img171.imageshack.us/img171/9655/tntb.jpg
Layer 2 http://img412.imageshack.us/img412/6971/tntrg.jpg

Overlay result with screen http://img25.imageshack.us/img25/9655/tntb.jpg

In some cases the layers could be 3 so the screen mode shoul be applied both to the 2 upper layers.

Screen is applied between images not too images.

Also you can swap images being 'screen'ed without change. Of as screen does not do anything with black you can use flatten...

Question are the images just differenet channels. If so you can channel copy them together too!

Hi Antony,

I can't understand very well what you are explaining me but both codes seem to take the desided effect!
So, thanks!!
(In the 2nd I have "convert: unable to access configure file `colors.xml' @ configure.c/GetConfigureOptions/589.
logout" but it can be configuration of IM installed with MacTex. The result is fine anyway.)

I'm writing the first one as bash scripts:
Complete layers Usually the three images end with _A _I3 and _N21 which are the filters through the same sample is viewed.
In addition, i need to add a thick white bar at the bottom-right as a lenght indicator and hide the original thinner scale-bar.
I add a bar.png file as a white line in black background to fully cover the original bar.
2 layers with bar: the black region doesn't seem to cover anyway..
What's wrong?

Not quite sure what you mean from the last example. Do you have images?

However note that -composite only composes two images with a optional third masking image.
It does not work for more than two images at a time.

The -flatten however does work to merge multiple images. The only problem is that it requires an initial color canvas which it creates using the -background color.

I will look at expanding -evaluate-sequence to allow -flatten type compose operations but without needing an initial canvas (assumes all images are the same size).

The color.xml bug is a configuration option. IM did nto find that file which it uses to figure out what a color name like "black" actually means in terms of RGB values. You can down load from from sources and install into an appropriate directory. On my system (linux) that is in...
/usr/share/ImageMagick-6.6.2/config/colors.xml

You can also install it in a personal ~/.magick sub-directory too.

Ok let's make a sum:
Layers could be up to 3 and have the same dimensions. There's always a file_A which has to be overlayed with file_I3.jpg or file_N21.jpg or both them.
Layers:
File_A.jpg http://img171.imageshack.us/img171/9655/tntb.jpg
FILE_I3.jpg http://img193.imageshack.us/img193/6885/tnti3.jpg
File_N21.jpg http://img412.imageshack.us/img412/6971/tntrg.jpg
I created 3 scripts corresponding to the 3 possible combination 1+2 1+3 1+2+3.
Full example in my previous message: result http://img203.imageshack.us/img203/8995/merge.jpg

Now i want to hide the thin scalebar in right-bottom corner and overwrite with o thicker straight line like this one http://img25.imageshack.us/img25/5205/barraxo.png
My latest code doesn't work because the black area of bar.png didn't cover the previous scalebar see here http://img138.imageshack.us/img138/8686/85987719.jpg
I tried to modify it like this and works (maybe there was a simpler way): That's the result i wanted http://img541.imageshack.us/img541/2258/mergel.jpg .

The images aprear to be purely separate Red/Green/Blur composites. that could be merged together. Though there seems to be some extra elements in other channels.

Hmmm rather than 'screen' 'Plus may work better...
convert tntb.jpg tnti3.jpg tntrg.jpg -background black -compose Plus -flatten result.jpg

As for the 'scale' at the bottom. why not just draw over it with a black rectangle!

I feel really silly asking this, but every time I try to implement an example it ends up not working...

From the PC command line, every time I try to string multiple commands together the "\" in all examples creates an error. I thought maybe it was a hard return, but I need all my logic to fire off at once. I'm trying to overlay a couple images, but would like to resize 1 image, so I need a way to break up my script. HELP! I know this is basic stuff, but I couldn't find a dummies guide to what this "\" meant.

Backslash "\" in Unix means (a) the shell should treat the next character literally without interpreting it, or (b) when it is the final character on the line, the command continues on the next line.

The Windows equivalent is caret "^".

See also http://www.imagemagick.org/Usage/windows/