在缩放,旋转和平移后保存已编辑的图像

Question

我已经创建了这个类的Swift版本:https://github.com/bennythemink/ZoomRotatePanImageView/blob/master/ZoomRotatePanImageView.m效果很好.现在我想将修改后的图像保存到文件中.问题是我想以全分辨率保存它,而且我想保存只对用户可见的区域.

让我举个简单的例子:

这就是它在我的应用程序中的外观.图像是iOS模拟器中的一些示例.大多数是在屏幕外.我只想看到可见的部分.

保存后没有裁剪它看起来像这样:

到目前为止,剪裁后效果非常好.

但现在让我们做一些改变:

保存后:

看起来它被错误的支点所改变.我该如何解决？

这是我保存的代码:

    UIGraphicsBeginImageContextWithOptions(image.size, false, 0)
    let context = UIGraphicsGetCurrentContext()
    let transform = imageView.transform
    let imageRect = CGRectMake(0, 0, image.size.width, image.size.height)

    CGContextSetFillColorWithColor(context, UIColor.blueColor().CGColor) //for debugging
    CGContextFillRect(context, imageRect)

    CGContextConcatCTM(context, transform)

    image.drawInRect(imageRect)
    let newImage = UIGraphicsGetImageFromCurrentImageContext()!
    UIGraphicsEndImageContext()

有一种更简单的方法来实现它:

UIGraphicsBeginImageContextWithOptions(imageContainer.bounds.size, false, 0)
self.imageContainer.drawViewHierarchyInRect(imageContainer.bounds, afterScreenUpdates: true)
let screenshot = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext() 

但是输出图像的视图大小不是实际图像,我希望它以全分辨率.

Answer 1

更新了代码以处理任何大小的图像：

     let boundsScale = imageView.bounds.size.width / imageView.bounds.size.height
    let imageScale = image!.size.width / image!.size.height

    let size = (image?.size)!

    var canvasSize = size

    if boundsScale > imageScale {
        canvasSize.width =  canvasSize.height * boundsScale
    }else{
        canvasSize.height =  canvasSize.width / boundsScale
    }

    let xScale = canvasSize.width / imageView.bounds.width
    let yScale = canvasSize.height / imageView.bounds.height

    let center = CGPointApplyAffineTransform(imageView.center, CGAffineTransformScale(CGAffineTransformIdentity, xScale, yScale))

    let xCenter = center.x
    let yCenter = center.y

    UIGraphicsBeginImageContextWithOptions(canvasSize, false, 0);
    let context = UIGraphicsGetCurrentContext()!

    //Apply transformation
    CGContextTranslateCTM(context, xCenter, yCenter)

    CGContextConcatCTM(context, imageView.transform)

    CGContextTranslateCTM(context, -xCenter, -yCenter)

    var drawingRect : CGRect = CGRectZero
    drawingRect.size = canvasSize

    //Transaltion
    drawingRect.origin.x = (xCenter - size.width*0.5)
    drawingRect.origin.y = (yCenter - size.height*0.5)

    //Aspectfit calculation
    if boundsScale > imageScale {
        drawingRect.size.width =  drawingRect.size.height * imageScale
    }else{
        drawingRect.size.height = drawingRect.size.width / imageScale
    }

    image!.drawInRect(drawingRect)

    let newImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

模拟器屏幕截图

保存的图片