Swift图像处理

Question

我是Swift的新手，我正在尝试创建一个类/结构Filter，它在构造函数中使用过滤器公式和强度。这个类有一个方法，可以在其参数中的图像上应用给定强度的给定公式，然后返回修改后的图像。

我们有一个名为RGBAImage.swift的类，它有将UIImage转换为RGBAImage的方法，反之亦然。

这是我创建的类：

import UIKit

let image = UIImage(named: "sample")!



class imageFilter{

    func increaseContrast(image: UIImage) -> UIImage{
        let rgbaImage = RGBAImage(image: image)!
        var totalRed = 0
        var totalGreen = 0
        var totalBlue = 0
        let pixelCount = rgbaImage.width * rgbaImage.height
        for y in 0..<rgbaImage.height {
            for x in 0..<rgbaImage.width {
                let index = y * rgbaImage.width + x
                let pixel = rgbaImage.pixels[index]
                totalRed += Int(pixel.red)
                totalGreen += Int(pixel.green)
                totalBlue += Int(pixel.blue)
            }
        }

        let avgRed = totalRed/pixelCount
        let avgGreen = totalGreen/pixelCount
        let avgBlue = totalBlue/pixelCount

        for y in 0..<rgbaImage.height {
            for x in 0..<rgbaImage.width {
                let index = y * rgbaImage.width + x
                var pixel = rgbaImage.pixels[index]
                let redDelta = Int(pixel.red) - avgRed
                let greenDelta = Int(pixel.green) - avgGreen
                let blueDelta = Int(pixel.blue) - avgBlue
                pixel.red = UInt8(max(min(255, avgRed + 2 * redDelta), 0))
                pixel.blue = UInt8(max(min(255, avgBlue + 2 * blueDelta), 0))
                pixel.green = UInt8(max(min(255, avgGreen + 2 * greenDelta), 0))
                rgbaImage.pixels[index] = pixel

                }
            }
        let finished = rgbaImage.toUIImage()!
        return (finished)
        }

}

let test = imageFilter.increaseContrast(image)

最后一行有一个错误，说

无法将类型为"UImage"的值转换为所需的参数类型"imageFilter"

这是RGBA类：

import UIKit
 public struct Pixel {
    public var value: UInt32
public var red: UInt8 {
    get {
        return UInt8(value & 0xFF)
    }
    set {
        value = UInt32(newValue) | (value & 0xFFFFFF00)
    }
}
public var green: UInt8 {
    get {
        return UInt8((value >> 8) & 0xFF)
    }
    set {
        value = (UInt32(newValue) << 8) | (value & 0xFFFF00FF)
    }
}
public var blue: UInt8 {
    get {
        return UInt8((value >> 16) & 0xFF)
    }
    set {
        value = (UInt32(newValue) << 16) | (value & 0xFF00FFFF)
    }
}
public var alpha: UInt8 {
    get {
        return UInt8((value >> 24) & 0xFF)
    }
    set {
        value = (UInt32(newValue) << 24) | (value & 0x00FFFFFF)
    }
    }
}


public struct RGBAImage {
 public var pixels: UnsafeMutableBufferPointer<Pixel>
public var width: Int
public var height: Int
public init?(image: UIImage) {
    guard let cgImage = image.CGImage else { return nil }
    // Redraw image for correct pixel format
    let colorSpace = CGColorSpaceCreateDeviceRGB()
    var bitmapInfo: UInt32 = CGBitmapInfo.ByteOrder32Big.rawValue
    bitmapInfo |= CGImageAlphaInfo.PremultipliedLast.rawValue & CGBitmapInfo.AlphaInfoMask.rawValue
    width = Int(image.size.width)
    height = Int(image.size.height)
    let bytesPerRow = width * 4
    let imageData = UnsafeMutablePointer<Pixel>.alloc(width * height)
    guard let imageContext = CGBitmapContextCreate(imageData, width, height, 8, bytesPerRow, colorSpace, bitmapInfo) else { return nil }
    CGContextDrawImage(imageContext, CGRect(origin: CGPointZero, size: image.size), cgImage)
    pixels = UnsafeMutableBufferPointer<Pixel>(start: imageData, count: width * height)
}
public func toUIImage() -> UIImage? {
    let colorSpace = CGColorSpaceCreateDeviceRGB()
    var bitmapInfo: UInt32 = CGBitmapInfo.ByteOrder32Big.rawValue
    bitmapInfo |= CGImageAlphaInfo.PremultipliedLast.rawValue & CGBitmapInfo.AlphaInfoMask.rawValue
    let bytesPerRow = width * 4
    let imageContext = CGBitmapContextCreateWithData(pixels.baseAddress, width, height, 8, bytesPerRow, colorSpace, bitmapInfo, nil, nil)
    guard let cgImage = CGBitmapContextCreateImage(imageContext) else {return nil}
    let image = UIImage(CGImage: cgImage)
    return image
}
}

Answer 1

我确信您的问题是在尝试调用类的成员方法时没有创建类的实例。

将最后一行替换为以下代码：

let test = imageFilter()
let processedImg = test.increaseContrast(image)