Color blindness - inability or decreased ability to see color or perceive color differences. So, this is nothing to be envied if someone hase it, but this is nice problem to implement in Delphi.

Unfortunately I not found information how to simulate it. Maybe you have some tips for me? Maybe some codes already exists?

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Code:

http://en.wikipedia.org/wiki/Color_blindness

This site might help a bit: http://vischeck.com/

Since this is subject to individual perception, and color blindness exists in varying degrees and "flavors", I would assume, that there can not be any "general" simulation algorithm. I would even go so far to say, that it would be impossible to simulate, because a color blind person would not be able to say, if he sees red as green or green as red (for example), since this person has no concept of red or green, and thus cannot put a "compatible" name to the perceieved sensation when presented with these colors.
If anything, you could attempt to give a conceptual impression of how a color blind person "feels" a picture when looking at it, by hue-shifting the respective colors closer to each other. But even then there is the variability in colors and strength of the blindness that needs to be addressed, and the resulting image merely would depict to a normal sighted person how good or bad a person with this particular form of simulated color blindness would be able to make out contrasts. But not at all how he would actually "see" it.

Thus, this problem becomes mildly complex, and rather useless atop of that, because it may never do more than serve illustrative purposes. Would that be worth your hassle?

The simulation of an given type of colour-blindness seems to possible by doing some simple matrix multiplication for each pixel.
I have found these Matrices on the internet, which are probably more accurate than anything you need for a fun application.

These Images show, what I meant with hue-shift. But do color blind people actually see red and green as yellow? Such that they also are incapable of discriminating between red an yellow (and green and yellow)?

The test whether a simulation works is done by letting color blind people compare the normal image with the processed one.

The question what they actually see seems to be more philosophic.
No one can tell if you and me see the same picture in our mind, but for daily life this thesis seems to work fine.

Zitat von Medium:

These Images show, what I meant with hue-shift. But do color blind people actually see red and green as yellow? Such that they also are incapable of discriminating between red an yellow (and green and yellow)?

This is a common misconception by people who see images processed by color blindness simulators, so I’m going to answer: I have a slight red/green “blindness”, and I do not see red or green as yellow. Most of the time when I get a color “wrong”, I just see it as a grayish red when it’s supposed to be green, or as a grayish green when it’s supposed to be red. Often it even switches forth and back (sort of like when you see an optical illusion, and you can’t decide whether the object you’re seeing is concave or convex. I hope that gives you an idea.). So, while (at least to me) it mostly happens with colors of low saturation (which means that they appear shifted towards gray/brown), it really doesn’t look like yellow, or brown, or gray or anything, it’s just “ambiguous” with a slight tendency to either red or green and a brownish/grayish tinge (again, because the affected colors have a low saturation). Interestingly, my knowledge about the object also affects how I see it – like, if the color of an object is ambiguous to me, and some one tells me that it’s green, I will actually start to see it as green and think “how could I not see that before?”. It’s quite funny.

As you can imagine, I have found no simulation that accurately represents what I see, and I think it’s impossible to simulate. However, there is of course a problem in judging this – since I see colors differently, I probably see the simulation differently as well, therefore it might be possible that people with “normal” perception perceive the colors in the simulation as I would perceive them without the filter – though I doubt it (this essentially leads to the problem mentioned in BUG’s post). Anyway, I think that these simulations are only supposed to give you an idea of how big the contrast between two colors is, not exactly recreate what a color blind person sees.

But as has been said before, please keep in mind that there are varying degrees of color blindness. Some people can’t distinguish red and green at all, others are only unable to distinguish specific combinations of hues, brightnesses and saturations, and the ranges are different for every person. There are also some people who can’t distinguish blue and yellow or can’t see any colors at all, although that’s very rare.

Thank you guys, I don't expected so much informations. Now I'm start reserching.

@Medium, I disagree with you, this is not something from cosmos, this has scientific basis, but as you remarked is not possible to receive exactly color that color-blindness peaple see, but is possible simulate it as I discovered

Added: Please check this tool:

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Code:

http://colorschemedesigner.com/

Added :

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Code:

http://colorschemedesigner.com/previous/colorscheme1/colorblind.js