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import Accelerate
extension UIImage {
var averageColor: UIColor? {
guard let inputImage = CIImage(image: self) else { return nil }
let extentVector = CIVector(x: inputImage.extent.origin.x, y: inputImage.extent.origin.y, z: inputImage.extent.size.width, w: inputImage.extent.size.height)
guard let filter = CIFilter(name: "CIAreaAverage", parameters: [kCIInputImageKey: inputImage, kCIInputExtentKey: extentVector]) else { return nil }
guard let outputImage = filter.outputImage else { return nil }
var bitmap = [UInt8](repeating: 0, count: 4)
let context = CIContext(options: [.workingColorSpace: kCFNull as Any])
context.render(outputImage, toBitmap: &bitmap, rowBytes: 4, bounds: CGRect(x: 0, y: 0, width: 1, height: 1), format: .RGBA8, colorSpace: nil)
return UIColor(red: CGFloat(bitmap[0]) / 255, green: CGFloat(bitmap[1]) / 255, blue: CGFloat(bitmap[2]) / 255, alpha: 1)
}
var averageColorS: UIColor? {
guard let inputCGImage = cgImage else {
print("unable to get cgImage")
return nil
}
let colorSpace = CGColorSpaceCreateDeviceRGB()
let width = inputCGImage.width
let height = inputCGImage.height
let bytesPerPixel = 4
let bitsPerComponent = 8
let bytesPerRow = bytesPerPixel * width
let bitmapInfo = CGImageAlphaInfo.premultipliedLast.rawValue | CGBitmapInfo.byteOrder32Big.rawValue
guard let context = CGContext(data: nil, width: width, height: height, bitsPerComponent: bitsPerComponent, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo) else {
print("unable to create context")
return nil
}
context.draw(inputCGImage, in: CGRect(x: 0, y: 0, width: width, height: height))
guard let buffer = context.data else {
print("unable to get context data")
return nil
}
let pixelBuffer = buffer.bindMemory(to: UInt8.self, capacity: width * height)
let pixelCount = width * height
let channelsPerPixel: Int = 4
let m: Int32 = Int32(channelsPerPixel)
let n: Int32 = Int32(pixelCount)
let lda = m
var a = [Float](repeating: 0, count: pixelCount * channelsPerPixel)
vDSP_vfltu8(pixelBuffer, vDSP_Stride(1), &a, vDSP_Stride(1), vDSP_Length(pixelCount * channelsPerPixel))
var x = [Float](repeating: 1 / Float(pixelCount) / 255, count: pixelCount)
var y = [Float](repeating: 0, count: channelsPerPixel)
cblas_sgemv(CblasColMajor, CblasNoTrans, m, n, 1, &a, lda, &x, 1, 1, &y, 1)
return UIColor(red: CGFloat(y[0]), green: CGFloat(y[1]), blue: CGFloat(y[2]), alpha: 1)
}
var averageColorD: UIColor? {
guard let inputCGImage = cgImage else {
print("unable to get cgImage")
return nil
}
let colorSpace = CGColorSpaceCreateDeviceRGB()
let width = inputCGImage.width
let height = inputCGImage.height
let bytesPerPixel = 4
let bitsPerComponent = 8
let bytesPerRow = bytesPerPixel * width
let bitmapInfo = CGImageAlphaInfo.premultipliedLast.rawValue | CGBitmapInfo.byteOrder32Big.rawValue
guard let context = CGContext(data: nil, width: width, height: height, bitsPerComponent: bitsPerComponent, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo) else {
print("unable to create context")
return nil
}
context.draw(inputCGImage, in: CGRect(x: 0, y: 0, width: width, height: height))
guard let buffer = context.data else {
print("unable to get context data")
return nil
}
let pixelBuffer = buffer.bindMemory(to: UInt8.self, capacity: width * height)
let pixelCount = width * height
let channelsPerPixel: Int = 4
let m: Int32 = Int32(channelsPerPixel)
let n: Int32 = Int32(pixelCount)
let lda = m
var a = [Double](repeating: 0, count: pixelCount * channelsPerPixel)
vDSP_vfltu8D(pixelBuffer, vDSP_Stride(1), &a, vDSP_Stride(1), vDSP_Length(pixelCount * channelsPerPixel))
var x = [Double](repeating: 1 / Double(pixelCount) / 255, count: pixelCount)
var y = [Double](repeating: 0, count: channelsPerPixel)
cblas_dgemv(CblasColMajor, CblasNoTrans, m, n, 1, &a, lda, &x, 1, 1, &y, 1)
return UIColor(red: CGFloat(y[0]), green: CGFloat(y[1]), blue: CGFloat(y[2]), alpha: 1)
}
}
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