53 lines
1.7 KiB
Swift
53 lines
1.7 KiB
Swift
import AppKit
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enum ImageLoaderError: Error
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{
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case loadFailed(_ message: String)
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}
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struct NSImageLoader: LoaderProtocol
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{
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typealias T = Image
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func load(url: URL) -> T?
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{
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guard let image = try? NSImageLoader.loadImage(url: url) else { return nil }
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return image
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}
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func load(url: URL, content: inout ContentManager) -> T? { return load(url: url) }
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static func loadImage(url: URL) throws -> Image
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{
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try autoreleasepool
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{
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// Open as a Core Graphics image
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guard let nsImg = NSImage(contentsOf: url),
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let image = nsImg.cgImage(forProposedRect: nil, context: nil, hints: nil)
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else { throw ImageLoaderError.loadFailed("Failed to open image \"\(url.absoluteString)\"") }
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// Convert to 8-bit ARGB (SRGB) w/ premultiplied alpha
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let alphaInfo = image.alphaInfo == .none ? CGImageAlphaInfo.noneSkipLast : CGImageAlphaInfo.premultipliedLast
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guard let colourspace = CGColorSpace(name: CGColorSpace.sRGB),
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let context = CGContext(data: nil,
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width: image.width,
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height: image.height,
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bitsPerComponent: 8,
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bytesPerRow: image.width * 4,
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space: colourspace,
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bitmapInfo: alphaInfo.rawValue | CGBitmapInfo.byteOrder32Big.rawValue)
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else { throw ImageLoaderError.loadFailed("Coudn't create graphics context") }
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let flipVertical = CGAffineTransform(a: 1, b: 0, c: 0, d: -1, tx: 0, ty: CGFloat(image.height))
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context.concatenate(flipVertical)
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context.draw(image, in: CGRect(x: 0, y: 0, width: image.width, height: image.height))
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guard let data = context.data else { throw ImageLoaderError.loadFailed("what") }
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return Image(
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pixels: Data(bytes: data, count: 4 * image.width * image.height),
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width: image.width,
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height: image.height)
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}
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}
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}
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