Question

The following code translates a jpg into a string of chars.

 CGImageRef imageRef = example.CGImage;
    NSData *data     = (NSData *) CGDataProviderCopyData(CGImageGetDataProvider(imageRef));
    char *pixels     = (char *)[data bytes];

a small piece of the output is:

"GJYˇKO[ˇFJSˇILQˇKNSˇKKSˇOOYˇMMYˇNNVˇOOWˇOOWˇNNVˇLLTˇKKSˇMMUˇOOWˇJMT"

I guess the 3 Symbols together consist of the infomation of one pixel, right?
And if this is true, how can i interpret this Symbols (colors e.g.)?

Answer 1

This will all depend on the color space of your image. If there is an alpha channel 4 chars will be one pixel and without it will be 3 chars. If it is RGBA then G is your R, J is your G , Y is your B and ˇ is your A. And if it is ARGB it G is your A etc.. Also when you convert your pixels to a char * remember to keep track of the length because any RGBA value of 0 will cause a null termination.