getting colors from the image

dinasset · **Posted:** Thu Dec 04, 2014 4:51 pm **(#1)**

GIMP Version: 2.8.14
Operating System: Windows
GIMP Experience: Beginner Level

List any relevant plug-ins or scripts:
none

List any ERROR messages you received:
none

Hi all gimp experts.
So far I was lucky in getting from the "magical circle" of gimp experts very useful info (and even full routines already written which I could insert into my scripts!)
Today my help request is this:
- is it possible in a script getting the colours of which the image is composed?
Well, not the complete list of an original photo, but for instance the list of the x colours of an image reduced by the cartoonizing filter (x=8, 16, or 32)
Going thru a random picking of pixels from the image until the x different colours have been picked does not seem to me a very clever solution...
Suggestions?
Thanks a lot

ofnuts · **Joined:** Oct 25, 2010 **Posts:** 4812

If the image is color-indexed you can get the colors from the colormap.

A script of mine that plays with the color map(NSFSM warning: python)

Wallace · **Posted:** Thu Dec 04, 2014 6:10 pm **(#3)**

You can also try this...

And also this...
Translate into Palette...

http://registry.gimp.org/node/28695

Graechan · **Posted:** Thu Dec 04, 2014 7:40 pm **(#4)**

while on the subject how would I get the average color

molly · **Joined:** Apr 07, 2010 **Posts:** 14182

My Santa Palette

Wallace · **Posted:** Thu Dec 04, 2014 8:08 pm **(#6)**

Graechan wrote:

while on the subject how would I get the average color

I'd like to know that too.

ofnuts · **Joined:** Oct 25, 2010 **Posts:** 4812

Wallace wrote:

Graechan wrote:

while on the subject how would I get the average color

I'd like to know that too.

Filter>Blur>Pixelize and give the size of the canvas (in other words, pixelize to one single big fat "pixel"). Then sample the color of that area.

ofnuts · **Joined:** Oct 25, 2010 **Posts:** 4812

Wallace wrote:

You can also try this...
[ Image ]
[ Image ]
[ Image ]
And also this...
Translate into Palette...
[ Image ]
http://registry.gimp.org/node/28695

Not a very good method. It scales the image to X*Y pixels, then samples each pixel. No check that the same color shows up twice in the palette...

Graechan · **Posted:** Thu Dec 04, 2014 9:20 pm **(#9)**

the Pixelize method is simple but effective I've been trying to get something using the procedure (gimp-histogram drawable channel start-range end-range)
Thank you ofnuts

Wallace · **Posted:** Thu Dec 04, 2014 9:47 pm **(#10)**

ofnuts wrote:

Wallace wrote:

Graechan wrote:

while on the subject how would I get the average color

I'd like to know that too.

Filter>Blur>Pixelize and give the size of the canvas (in other words, pixelize to one single big fat "pixel"). Then sample the color of that area.

That's crazy, but cool. :bigthup

Why would someone need or want to do this?

Graechan · **Posted:** Thu Dec 04, 2014 9:51 pm **(#11)**

Quote:

That's crazy, but cool. :bigthup

Why would someone need or want to do this?

Me of cause, I wanted the average color for a 'border color' in a script

saulgoode · **Posted:** Fri Dec 05, 2014 12:18 am **(#12)**

One could also use the color picker with a sufficiently large radius (half the length of the diagonal).

Code: Select all

(gimp-image-pick-color image 
                       layer 
                       (/ width 2) 
                       (/ height 2) 
                       TRUE 
                       TRUE
                       (/ (sqrt (+ (pow width 2) 
                                   (pow height 2) ))
                          2 ))

dinasset · **Posted:** Fri Dec 05, 2014 2:51 am **(#13)**

wow! a lot of discussions/contributions!
it seems to be an "attractive" topic!
I need some time to "process" internally (by understanding and experimenting) all the infos.
Thanks a lot!

Graechan · **Posted:** Fri Dec 05, 2014 2:53 am **(#14)**

Saulgoode I've not seen this scheme language parameter before 'pow'

saulgoode · **Posted:** Fri Dec 05, 2014 4:28 am **(#15)**

Graechan wrote:

Saulgoode I've not seen this scheme language parameter before 'pow'

I should have used 'expt' ('pow' is deprecated).

Odinbc · **Posted:** Fri Dec 05, 2014 12:36 pm **(#16)**

Graechan wrote:

while on the subject how would I get the average color

8.29. Border Average can be used with or without a selection.

Graechan · **Posted:** Fri Dec 05, 2014 7:58 pm **(#17)**

Thank you Saulgoode I found expt in my paperwork but I'm still confused, just the same I'll accept it works,
at least It shows I attempt to understand and learn from your snippets of code

ofnuts · **Joined:** Oct 25, 2010 **Posts:** 4812

Graechan wrote:

Thank you Saulgoode I found expt in my paperwork but I'm still confused, just the same I'll accept it works,
at least It shows I attempt to understand and learn from your snippets of code

You didn't recognize Pythagore's theorem (diagonal=square_root(height²*width²))?

dinasset · **Posted:** Sun Nov 29, 2015 4:23 pm **(#19)**

just today I tried to use the pdb.plug_in_borderaverage but I was unable to get the expected result (neither the FG was set automatically by the filter nor I could set it by myself using the returned colour).
On the opposite, Saulgoode's method works fine (getting the average image colour).
Does someone know whether the mentioned plug-in does still work?
Sometimes it could be better to get the average colour of the borders -as the plug-in promises- instead of the more or less full image

Odinbc · **Posted:** Sun Nov 29, 2015 6:06 pm **(#20)**

The Border Average Filter works fine. The Border Size and Number of Colors choices can give radically different results, especially Bucket Size.