Can I pick a random color which are not in the image?

[FiveShipHUN]

So, I'm working on a 2D game. There's an image where you can see the areas. Every area has a unique color on the image. (It wasn't made by me.) I want to add few more areas, but I don't know how to pick a color wich are not in the image yet.

Here's the image: https://imgur.com/yZYQzzv

 

[Pixey]

Hello @FiveShipHUN and Welcome

 

This may be of help to you

 

[FiveShipHUN]

Can you help me how to use it and solve my problem?

[Pixey]

Perhaps the easiest way would be for you to use the color picker and click on an existing color on the map.

Then open your Color Wheel > click on More

And change one of RGB chanels - this way no two colors will be the same.

 

[FiveShipHUN]

That's unsafe (for me). There's a chance that I'll pick a color what already exists on the map. I need a precise color pick or something else what I can use in this situation.

[Ego Eram Reputo]

Your image has 3275 individual colors. However, I don't see any gray. This might give you a range of gray colors to choose from.

 

Small test: I uniformly recolored a single sea 'cell' with a random gray-ish color (#939598). Then used the Magic Wand tool with tolerance =10% to select the recolored cell. I got a single selection of 13684 pixels (find the number in the Status Bar). Next I held down Shift (=Global Flood Mode) & reselected the same cell. The number of selected pixels was the same. I concluded that there are no colors with 10% tolerance of #939598. That means that color is safe to use.

 

#2E5996 is another I found by the same method. How many new colors do you need?

[Reptillian]

I found a solution to this problem though it only works with G'MIC-QT plugin. Copy and paste this to code[local] or code[global] under Various section of G'MIC QT.

iw={w}
ih={h}
IR=249
IG=211
IB=150

to_rgb
$iw,$ih,1,3,[$IR,$IG,$IB]
+eq
k.
n. 0,255
f "i==[255,255,255]?[255,255,255]:[0,0,0]" k.
if {ia!=0} v + error "Color exists, pick another color!" fi
$iw,$ih,1,3,[$IR,$IG,$IB]
k.

Then, click update to verify color does not exist. Change IR,IG,IB value to the color you want.

 

By the way, this can be automated, but I'll figure that out.

Edited April 28, 2019 by Reptillian