I need to detect the predominant color or the ligthing of a picture. It is possible? And how?
It is possibile to extract that data from a CGIMAGE? Thanks
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Use digicolor meter application. – Anoop Vaidya May 17 '13 at 15:04
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Really cool advice, but I mean how can I do it "programmatically". Thanks – JosephITA May 20 '13 at 09:12
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I am not much into graphics stuff. So from my knowlwdge..you need to trace all the pixels and keep on storing the REQUIRED color if found, "how you will come to know this pixel is predominant" is your logic – Anoop Vaidya May 20 '13 at 09:18
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Resize the image to 1x1 pixel. Use the category UIImage+ColorAtPixel.h to extract the value of the pixel. You can transform the CGImage to a UIImage with imageWithCGImage:.
To extract the value of the pixel, the category creates a context (CGBitmapContextCreate) with a RGBA buffer of 4 char and draws the image there. Then it extracts the color from the 4 components (RGBA) of the image.
Jano
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There are many around. For example, scale to 1x1 using http://stackoverflow.com/a/2658801/412916 and then get the color at 0,0 with http://stackoverflow.com/a/1262893/412916 calling UIColor *color = [[[self class] getRGBAsFromImage:roses atX:0 andY:0 count:1] objectAtIndex:0]; – Jano May 20 '13 at 12:16