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我有以下在该应用功能：裁剪具有相同的CGRect相同的UIImage给出不同的结果
- 用户采取（或选择）的图像（以下
originalImage）。 originalImage被发送到一些外部API，它返回我需要添加到originalImage的点的坐标数组。- 由于点总是位于一个区域（面部），因此我想在靠近面部边框处裁剪
originalImage并仅向用户显示裁剪的结果。 - 裁剪结果显示后，我逐个添加点。
这里是一个没有工作的代码（除发送图像，让我们说这已经发生）
class ScanResultViewController{
@IBOutlet weak var scanPreviewImageView: UIImageView!
let originalImage = ORIGINAL_IMAGE //meaning we already have it
let scanDots = [["x":123, "y":123], ["x":234, "y":234]]//total 68 coordinates
var cropRect:CGRect!
override func viewDidLoad() {
super.viewDidLoad()
self.setScanImage()
}
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
self.animateScan(0)
}
func setScanImage(){
self.cropRect = self.getCropRect(self.scanDots, sourceImage:self.originalImage)
let croppedImage = self.originalImage.imageAtRect(self.cropRect)
self.scanPreviewImageView.image = croppedImage
self.scanPreviewImageView.contentMode = .ScaleAspectFill
}
func animateScan(index:Int){
let i = index
self.originalImage = self.addOnePointToImage(self.originalImage, pointImage: GREEN_DOT!, point: self.scanDots[i])
let croppedImage = self.originalImage.imageAtRect(self.cropRect)
self.scanPreviewImageView.image = croppedImage
self.scanPreviewImageView.contentMode = .ScaleAspectFill
if i < self.scanDots.count-1{
let delay = dispatch_time(DISPATCH_TIME_NOW, Int64(0.1 * Double(NSEC_PER_SEC)))
dispatch_after(delay, dispatch_get_main_queue()) {
self.animateScan(i+1)
}
}
}
func addOnePointToImage(sourceImage:UIImage, pointImage:UIImage, point: Dictionary<String,CGFloat>)->UIImage{
let rect = CGRect(x: 0, y: 0, width: sourceImage.size.width, height: sourceImage.size.height)
UIGraphicsBeginImageContextWithOptions(sourceImage.size, true, 0)
let context = UIGraphicsGetCurrentContext()
CGContextSetFillColorWithColor(context, UIColor.whiteColor().CGColor)
CGContextFillRect(context, rect)
sourceImage.drawInRect(rect, blendMode: .Normal, alpha: 1)
let pointWidth = sourceImage.size.width/66.7
pointImage.drawInRect(CGRectMake(point["x"]!-pointWidth/2, point["y"]!-pointWidth/2, pointWidth, pointWidth), blendMode: .Normal, alpha: 1)
let result = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return result
}
func getCropRect(points: Array<Dictionary<String,CGFloat>>, sourceImage:UIImage)->CGRect{
var topLeft:CGPoint = CGPoint(x: points[0]["x"]!, y: points[0]["y"]!)
var topRight:CGPoint = CGPoint(x: points[0]["x"]!, y: points[0]["y"]!)
var bottomLeft:CGPoint = CGPoint(x: points[0]["x"]!, y: points[0]["y"]!)
var bottomRight:CGPoint = CGPoint(x: points[0]["x"]!, y: points[0]["y"]!)
for p in points{
if p["x"]<topLeft.x {topLeft.x = p["x"]!}
if p["y"]<topLeft.y {topLeft.y = p["y"]!}
if p["x"]>topRight.x {topRight.x = p["x"]!}
if p["y"]<topRight.y {topRight.y = p["y"]!}
if p["x"]<bottomLeft.x {bottomLeft.x = p["x"]!}
if p["y"]>bottomLeft.y {bottomLeft.y = p["y"]!}
if p["x"]>bottomRight.x {bottomRight.x = p["x"]!}
if p["y"]>bottomRight.y {bottomRight.y = p["y"]!}
}
let rect = CGRect(x: topLeft.x, y: topLeft.y, width: (topRight.x-topLeft.x), height: (bottomLeft.y-topLeft.y))
return rect
}
}
extension UIImage{
public func imageAtRect(rect: CGRect) -> UIImage {
let imageRef: CGImageRef = CGImageCreateWithImageInRect(self.CGImage, rect)!
let subImage: UIImage = UIImage(CGImage: imageRef)
return subImage
}
}
的问题是在setScanImage所需区域精确裁剪并显示，但是当animateScan方法被调用时，同一图像的不同区域被裁剪（并显示），虽然cropRect是相同的，并且originalImage的大小完全相同。
任何想法，家伙？
顺便说一句，如果我显示originalImage没有裁剪它一切顺利。