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iOS Swift UIImage subscript extension to get pixel color
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import UIKit | |
extension UIImage { | |
subscript (x: Int, y: Int) -> UIColor? { | |
guard x >= 0 && x < Int(size.width) && y >= 0 && y < Int(size.height), | |
let cgImage = cgImage, | |
let provider = cgImage.dataProvider, | |
let providerData = provider.data, | |
let data = CFDataGetBytePtr(providerData) else { | |
return nil | |
} | |
let numberOfComponents = 4 | |
let pixelData = ((Int(size.width) * y) + x) * numberOfComponents | |
let r = CGFloat(data[pixelData]) / 255.0 | |
let g = CGFloat(data[pixelData + 1]) / 255.0 | |
let b = CGFloat(data[pixelData + 2]) / 255.0 | |
let a = CGFloat(data[pixelData + 3]) / 255.0 | |
return UIColor(red: r, green: g, blue: b, alpha: a) | |
} | |
} |
This code won't work if image is stored in BGR format.
Why are you copying your data? You can get the byte pointer directly from the provider.
I haven’t looked at this code in awhile but looks like it needs a guard statement, I can update a lil later today
…Sent from my iPhone
On Jul 3, 2019, at 08:10, Leroy ***@***.***> wrote:
Ive got these errors. whats wrong?
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I want to extract RGB values for all pixels from a frame captured during ARSession. The CVPixelBufferFormat for that is of type kCVPixelFormatType_420YpCbCr8BiPlanarFullRange. Will this code work for this format type as well?
I am new to Swift, I am having a tough time trying to understand the format types and difference in manipulating them.
Doesn't work on black for some reason
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can this code show the color of the pixel of a image? For example, I have uiImage, and I would like to know the color of the pixel located in [100.100], how to operate?