mastodon-ios/Mastodon/Extension/UIIamge.swift

43 lines
1.5 KiB
Swift

//
// UIIamge.swift
// Mastodon
//
// Created by sxiaojian on 2021/1/28.
//
import UIKit
import CoreImage
import CoreImage.CIFilterBuiltins
extension UIImage {
static func placeholder(size: CGSize = CGSize(width: 1, height: 1), color: UIColor) -> UIImage {
let render = UIGraphicsImageRenderer(size: size)
return render.image { (context: UIGraphicsImageRendererContext) in
context.cgContext.setFillColor(color.cgColor)
context.fill(CGRect(origin: .zero, size: size))
}
}
}
// refs: https://www.hackingwithswift.com/example-code/media/how-to-read-the-average-color-of-a-uiimage-using-ciareaaverage
extension UIImage {
@available(iOS 14.0, *)
var dominantColor: UIColor? {
guard let inputImage = CIImage(image: self) else { return nil }
let filter = CIFilter.areaAverage()
filter.inputImage = inputImage
filter.extent = inputImage.extent
guard let outputImage = filter.outputImage else { return nil }
var bitmap = [UInt8](repeating: 0, count: 4)
let context = CIContext(options: [.workingColorSpace: kCFNull])
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: CGFloat(bitmap[3]) / 255)
}
}