在Swift，Cocoa，Mac OSX中旋转NSImage

Question

有没有一种简单的方法可以在Mac OSX应用程序中旋转NSImage？或者只是使用Swift将方向从纵向设置为横向？

我正在玩CATransform3DMakeAffineTransform，但我无法让它工作。

CATransform3DMakeAffineTransform(CGAffineTransformMakeRotation(CGFloat(M_PI) * 90/180))

这是我第一次使用转换。所以请耐心等待我:)也许我正在采取错误的方法......

有人能帮帮我吗？

谢谢！

Answer 1

public extension NSImage {
public func imageRotatedByDegreess(degrees:CGFloat) -> NSImage {

    var imageBounds = NSZeroRect ; imageBounds.size = self.size
    let pathBounds = NSBezierPath(rect: imageBounds)
    var transform = NSAffineTransform()
    transform.rotateByDegrees(degrees)
    pathBounds.transformUsingAffineTransform(transform)
    let rotatedBounds:NSRect = NSMakeRect(NSZeroPoint.x, NSZeroPoint.y , self.size.width, self.size.height )
    let rotatedImage = NSImage(size: rotatedBounds.size)

    //Center the image within the rotated bounds
    imageBounds.origin.x = NSMidX(rotatedBounds) - (NSWidth(imageBounds) / 2)
    imageBounds.origin.y  = NSMidY(rotatedBounds) - (NSHeight(imageBounds) / 2)

    // Start a new transform
    transform = NSAffineTransform()
    // Move coordinate system to the center (since we want to rotate around the center)
    transform.translateXBy(+(NSWidth(rotatedBounds) / 2 ), yBy: +(NSHeight(rotatedBounds) / 2))
    transform.rotateByDegrees(degrees)
    // Move the coordinate system bak to normal 
    transform.translateXBy(-(NSWidth(rotatedBounds) / 2 ), yBy: -(NSHeight(rotatedBounds) / 2))
    // Draw the original image, rotated, into the new image
    rotatedImage.lockFocus()
    transform.concat()
    self.drawInRect(imageBounds, fromRect: NSZeroRect, operation: NSCompositingOperation.CompositeCopy, fraction: 1.0)
    rotatedImage.unlockFocus()

    return rotatedImage
}


var image = NSImage(named:"test.png")!.imageRotatedByDegreess(CGFloat(90))  //use only this values 90, 180, or 270
}

针对Swift 3进行了更新：

public extension NSImage {
public func imageRotatedByDegreess(degrees:CGFloat) -> NSImage {

    var imageBounds = NSZeroRect ; imageBounds.size = self.size
    let pathBounds = NSBezierPath(rect: imageBounds)
    var transform = NSAffineTransform()
    transform.rotate(byDegrees: degrees)
    pathBounds.transform(using: transform as AffineTransform)
    let rotatedBounds:NSRect = NSMakeRect(NSZeroPoint.x, NSZeroPoint.y , self.size.width, self.size.height )
    let rotatedImage = NSImage(size: rotatedBounds.size)

    //Center the image within the rotated bounds
    imageBounds.origin.x = NSMidX(rotatedBounds) - (NSWidth(imageBounds) / 2)
    imageBounds.origin.y  = NSMidY(rotatedBounds) - (NSHeight(imageBounds) / 2)

    // Start a new transform
    transform = NSAffineTransform()
    // Move coordinate system to the center (since we want to rotate around the center)
    transform.translateX(by: +(NSWidth(rotatedBounds) / 2 ), yBy: +(NSHeight(rotatedBounds) / 2))
    transform.rotate(byDegrees: degrees)
    // Move the coordinate system bak to normal
    transform.translateX(by: -(NSWidth(rotatedBounds) / 2 ), yBy: -(NSHeight(rotatedBounds) / 2))
    // Draw the original image, rotated, into the new image
    rotatedImage.lockFocus()
    transform.concat()
    self.draw(in: imageBounds, from: NSZeroRect, operation: NSCompositingOperation.copy, fraction: 1.0)
    rotatedImage.unlockFocus()

    return rotatedImage
    }
}

class SomeClass: NSViewController {
       var image = NSImage(named:"test.png")!.imageRotatedByDegreess(degrees: CGFloat(90))  //use only this values 90, 180, or 270
}

Answer 2

感谢这个解决方案，但它对我来说并不完美。您可能已经注意到pathBounds没有在任何地方使用。在我看来，必须像这样使用：

let rotatedBounds:NSRect = NSMakeRect(NSZeroPoint.x, NSZeroPoint.y , pathBounds.bounds.size.width, pathBounds.bounds.size.height )

否则图像将旋转但裁剪为方形边界。

Answer 3

让IKImageView做繁重的工作：

import Quartz

extension NSImage {
    func imageRotated(by degrees: CGFloat) -> NSImage {
        let imageRotator = IKImageView()
        var imageRect = CGRect(x: 0, y: 0, width: self.size.width, height: self.size.height)
        let cgImage = self.cgImage(forProposedRect: &imageRect, context: nil, hints: nil)
        imageRotator.setImage(cgImage, imageProperties: [:])
        imageRotator.rotationAngle = CGFloat(-(degrees / 180) * CGFloat(M_PI))
        let rotatedCGImage = imageRotator.image().takeUnretainedValue()
        return NSImage(cgImage: rotatedCGImage, size: NSSize.zero)
    }
}

Answer 4

这是一个简单的Swift（4+）解决方案，用于绘制围绕中心旋转的图像：

extension NSImage {
    /// Rotates the image by the specified degrees around the center.
    /// Note that if the angle is not a multiple of 90°, parts of the rotated image may be drawn outside the image bounds.
    func rotated(by angle: CGFloat) -> NSImage {
        let img = NSImage(size: self.size, flipped: false, drawingHandler: { (rect) -> Bool in
            let (width, height) = (rect.size.width, rect.size.height)
            let transform = NSAffineTransform()
            transform.translateX(by: width / 2, yBy: height / 2)
            transform.rotate(byDegrees: angle)
            transform.translateX(by: -width / 2, yBy: -height / 2)
            transform.concat()
            self.draw(in: rect)
            return true
        })
        img.isTemplate = self.isTemplate // preserve the underlying image's template setting
        return img
    }
}