这是iOS创建的解决方案UIImage。有关macOS和的解决方案NSImage，请参见此答案。
唯一的问题是结构中的数据类型PixelData需要为UInt8。我在Playground中使用以下内容创建了测试图像：
public struct PixelData {
var a: UInt8
var r: UInt8
var g: UInt8
var b: UInt8
}
var pixels = [PixelData]()
let red = PixelData(a: 255, r: 255, g: 0, b: 0)
let green = PixelData(a: 255, r: 0, g: 255, b: 0)
let blue = PixelData(a: 255, r: 0, g: 0, b: 255)
for _ in 1...300 {
pixels.append(red)
}
for _ in 1...300 {
pixels.append(green)
}
for _ in 1...300 {
pixels.append(blue)
}
let image = imageFromARGB32Bitmap(pixels: pixels, width: 30, height: 30)
我更新imageFromARGB32Bitmap为使用Swift4。该函数现在返回a，UIImage?并在出现任何问题时guard用于返回nil。
func imageFromARGB32Bitmap(pixels: [PixelData], width: Int, height: Int) -> UIImage? {
guard width > 0 && height > 0 else { return nil }
guard pixels.count == width * height else { return nil }
let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.premultipliedFirst.rawValue)
let bitsPerComponent = 8
let bitsPerPixel = 32
var data = pixels // Copy to mutable []
guard let providerRef = CGDataProvider(data: NSData(bytes: &data,
length: data.count * MemoryLayout<PixelData>.size)
)
else { return nil }
guard let cgim = CGImage(
width: width,
height: height,
bitsPerComponent: bitsPerComponent,
bitsPerPixel: bitsPerPixel,
bytesPerRow: width * MemoryLayout<PixelData>.size,
space: rgbColorSpace,
bitmapInfo: bitmapInfo,
provider: providerRef,
decode: nil,
shouldInterpolate: true,
intent: .defaultIntent
)
else { return nil }
return UIImage(cgImage: cgim)
}
此函数可以用作的convenience初始化程序UIImage。这是实现：
extension UIImage {
convenience init?(pixels: [PixelData], width: Int, height: Int) {
guard width > 0 && height > 0, pixels.count == width * height else { return nil }
var data = pixels
guard let providerRef = CGDataProvider(data: Data(bytes: &data, count: data.count * MemoryLayout<PixelData>.size) as CFData)
else { return nil }
guard let cgim = CGImage(
width: width,
height: height,
bitsPerComponent: 8,
bitsPerPixel: 32,
bytesPerRow: width * MemoryLayout<PixelData>.size,
space: CGColorSpaceCreateDeviceRGB(),
bitmapInfo: CGBitmapInfo(rawValue: CGImageAlphaInfo.premultipliedFirst.rawValue),
provider: providerRef,
decode: nil,
shouldInterpolate: true,
intent: .defaultIntent)
else { return nil }
self.init(cgImage: cgim)
}
}
// Generate a 500x500 image of randomly colored pixels
let height = 500
let width = 500
var pixels: [PixelData] = .init(repeating: .init(a: 0, r: 0, g: 0, b: 0), count: width * height)
for index in pixels.indices {
pixels[index].a = 255
pixels[index].r = .random(in: 0...255)
pixels[index].g = .random(in: 0...255)
pixels[index].b = .random(in: 0...255)
}
let image = UIImage(pixels: pixels, width: width, height: height)
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