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Index › Programming Questions & Help › Syntax Questions › How to define a color range
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How to define a color range? (Read 457 times)
ganeshXL
How to define a color range?
Nov 9th, 2007, 2:44am  
I'm "scanning" an image (JPG) and extract color values in order to get a nice color palette for some experiments.

That all works like a charm, the values are stored in an array - but I'm wondering if there's a way to exclude a certain color range.

e.g. an image has nice shades of blue, but also a lot of white areas. How would I exclude the white hex colors from the array, so that I'm only left with the blue colors?
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zzz
Re: How to define a color range?
Reply #1 - Nov 9th, 2007, 5:39am  
negative of the image is black and yellow, does it help?
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antiplastik
Re: How to define a color range?
Reply #2 - Nov 9th, 2007, 7:17am  
Hi. Each color has red, green and blue components, varying from 0 to 255 (or 0.0 to 1.0). You can retrieve them using red(), green() and blue() methods.

Assuming that blue shades are around rgb(0, 0, 255), you could 'test' every color of your array to see if the amount of red, green and blue for this specified color results in a blue shade. This somehow boils down to creating a blue filter.
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