finding the mousecolor in IOS

[Colin Holgate]

One exercise in that book I wrote is about using an image as a color picker. It uses the same technique as Scott mentioned, only I then set the color of another graphic to show that it has picked up the right color.

One thing to double check, the x and y values you're using, are those from the top left of the image? With mousecolor you use the card position, but with this imagedata technique you would subtract the left and top of the image in question, unless the image is the whole card.