我忘了计算比率。现在它工作得很好。
static func redimensionaNSImage(imagem: NSImage, tamanho: NSSize) -> NSImage {
var ratio:Float = 0.0
let imageWidth = Float(imagem.size.width)
let imageHeight = Float(imagem.size.height)
let maxWidth = Float(tamanho.width)
let maxHeight = Float(tamanho.height)
// Get ratio (landscape or portrait)
if (imageWidth > imageHeight) {
// Landscape
ratio = maxWidth / imageWidth;
}
else {
// Portrait
ratio = maxHeight / imageHeight;
}
// Calculate new size based on the ratio
let newWidth = imageWidth * ratio
let newHeight = imageHeight * ratio
// Create a new NSSize object with the newly calculated size
let newSize:NSSize = NSSize(width: Int(newWidth), height: Int(newHeight))
// Cast the NSImage to a CGImage
var imageRect:CGRect = CGRect(x: 0, y: 0, width: imagem.size.width, height: imagem.size.height)
let imageRef = imagem.cgImage(forProposedRect: &imageRect, context: nil, hints: nil)
// Create NSImage from the CGImage using the new size
let imageWithNewSize = NSImage(cgImage: imageRef!, size: newSize)
// Return the new image
return imageWithNewSize
}