CODEWITHSUNDEEP
iosswiftpixelrgbaiphone-6
N.shaf
N.shaf

Reputation: 1

Colour of pixel is wrong only for iPhone 6 simulator

I need to read a colour of a pixel located at a point in an image and the code I have works in simulator for all iPhones (including iPhone 6 Plus) except iPhone 6.

I do not know why, but my guess is the index of the pixel is not correct since it detects a colour in a wrong location. I appreciate any help. This is the code that I have.

UIGraphicsBeginImageContext(upperCaseView.frame.size)
upperCaseView.layer.renderInContext(UIGraphicsGetCurrentContext()!)
snapshotImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

let pixelData = CGDataProviderCopyData(CGImageGetDataProvider(snapshotImage.CGImage))
let data: UnsafePointer<UInt8> = CFDataGetBytePtr(pixelData)

let pixelInfo: Int = ((Int(snapshotImage.size.width) * Int(point.y)) + Int(point.x)) * 4

print(data[pixelInfo])
print(data[pixelInfo+1])
print(data[pixelInfo+2])

Upvotes: 0

Views: 89

Answers (1)

N.shaf
N.shaf

Reputation: 1

Thank you so much Scott Thompson.

I used CGImageGetBytesPerRow instead of the image width and now it works. The correct code is below:

    UIGraphicsBeginImageContext(upperCaseView.frame.size)
    upperCaseView.layer.renderInContext(UIGraphicsGetCurrentContext()!)
    snapshotImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    let pixelData = CGDataProviderCopyData(CGImageGetDataProvider(snapshotImage.CGImage))
    let data: UnsafePointer<UInt8> = CFDataGetBytePtr(pixelData)

    let bytesPerPixel = (CGImageGetBitsPerPixel(snapshotImage.CGImage) / 8)
    let bytesPerRow = CGImageGetBytesPerRow(snapshotImage.CGImage)
    let pixelInfo: Int = (bytesPerRow * Int(point.y)) + (Int(point.x) * bytesPerPixel)

    print(data[pixelInfo])
    print(data[pixelInfo+1])
    print(data[pixelInfo+2])

Upvotes: 0

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