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I'm creating a demo of 20 balls bouncing each other, with a background filled with a solid color. Color for each ball is chosen randomly with randint(0, 255) for each R, G, B tuple component.

Problem is some balls end up with a color that is very similar to background, making them hard to see. I would like to avoid that, either by rolling another color if the chosen one is too similar (within a given threshold), or by moving it away from the background color.

How to calculate a similarity index to use as a threshold? Or how to transform a color to make it, say, less blue-ish?

Obvious disclaimer: I know nothing about color theory, so I don't know if the above concepts even exists!

I'm coding in python, but I'm looking for concepts and strategies, so pseudo-code is fine (or just the theory).

EDIT:

To clarify a few points:

• Each ball have its own random color. I'd like them to remain as random as possible, and to explore as much as possible of the color space (be it RGB or HSV, pygame accepts both formats for defining color)

• I'd just like to avoid each color of being "too close" to background. Problem is not just about hue: I'm perfectly OK with a light-blue ball against a dark-blue background (or a "full-blue" against a "white-ish" blue, etc)

• For now, I don't care if a ball ends up with a color similar (or even identical) to another ball. Avoiding that is a bonus, but it's a minor issue.

• Background color is a constant, single RGB color. For now I'm using "basic" blue (0, 0, 255), but I'm not settled with that. So consider the background to be of an arbitrary color (with arbitrary hue, brightness, saturation, etc).

I'm creating a demo of 20 balls bouncing each other, with a background filled with a solid color. Color for each ball is chosen randomly with randint(0, 255) for each R, G, B tuple component.

Problem is some balls end up with a color that is very similar to background, making them hard to see. I would like to avoid that, either by rolling another color if the chosen one is too similar (within a given threshold), or by moving it away from the background color.

How to calculate a similarity index to use as a threshold? Or how to transform a color to make it, say, less blue-ish?

Obvious disclaimer: I know nothing about color theory, so I don't know if the above concepts even exists!

I'm coding in python, but I'm looking for concepts and strategies, so pseudo-code is fine (or just the theory).

EDIT:

To clarify a few points:

• Each ball have its own random color. I'd like them to remain as random as possible, and to explore as much as possible of the color space (be it RGB or HSV, pygame accepts both formats for defining color)

• I'd just like to avoid each color of being "too close" to background. Problem is not just about hue: I'm perfectly OK with a light-blue ball against a dark-blue background (or a "full-blue" against a "white-ish" blue, etc)

• For now, I don't care if a ball ends up with a color similar (or even identical) to another ball. Avoiding that is a bonus, but it's a minor issue.

• Background color is a constant, single RGB color. For now I'm using "basic" blue (0, 0, 255), but I'm not settled with that. So consider the background to be of an arbitrary color (with arbitrary hue, brightness, saturation, etc).

EDIT2:

TL,DR version: Just give a way to create X random colors so that none "fades in too much" against a background of arbitrary (but single and constant) color

I'm creating a demo of 20 balls bouncing each other, with a background filled with a solid color. Color for each ball is chosen randomly with randint(0, 255) for each R, G, B tuple component.

Problem is some balls end up with a color that is very similar to background, making them hard to see. I would like to avoid that, either by rolling another color if the chosen one is too similar (within a given threshold), or by moving it away from the background color.

How to calculate a similarity index to use as a threshold? Or how to transform a color to make it, say, less blue-ish?

Obvious disclaimer: I know nothing about color theory, so I don't know if the above concepts even exists!

I'm coding in python, but I'm looking for concepts and strategies, so pseudo-code is fine (or just the theory).

I'm creating a demo of 20 balls bouncing each other, with a background filled with a solid color. Color for each ball is chosen randomly with randint(0, 255) for each R, G, B tuple component.

Problem is some balls end up with a color that is very similar to background, making them hard to see. I would like to avoid that, either by rolling another color if the chosen one is too similar (within a given threshold), or by moving it away from the background color.

How to calculate a similarity index to use as a threshold? Or how to transform a color to make it, say, less blue-ish?

Obvious disclaimer: I know nothing about color theory, so I don't know if the above concepts even exists!

I'm coding in python, but I'm looking for concepts and strategies, so pseudo-code is fine (or just the theory).

EDIT:

To clarify a few points:

• Each ball have its own random color. I'd like them to remain as random as possible, and to explore as much as possible of the color space (be it RGB or HSV, pygame accepts both formats for defining color)

• I'd just like to avoid each color of being "too close" to background. Problem is not just about hue: I'm perfectly OK with a light-blue ball against a dark-blue background (or a "full-blue" against a "white-ish" blue, etc)

• For now, I don't care if a ball ends up with a color similar (or even identical) to another ball. Avoiding that is a bonus, but it's a minor issue.

• Background color is a constant, single RGB color. For now I'm using "basic" blue (0, 0, 255), but I'm not settled with that. So consider the background to be of an arbitrary color (with arbitrary hue, brightness, saturation, etc).