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借鑑的UIImage的問題在UIScrollView中
這是要聽起來很瘋狂。我正在製作繪圖應用程序，我希望用戶能夠繪製比屏幕更大或更小的圖像。因此，當用戶從他的照片庫中選擇一個圖像時，它將被放入一個滾動視圖的圖像視圖中。用戶繪製與所選圖像尺寸相同的圖像視圖，並在另一個滾動視圖上繪製另一個圖像視圖。兩個滾動視圖的滾動是同步的，因此當您繪製時，滾動繪圖似乎在圖像上方（在正確的位置）。然而，由於某些原因，當用戶選擇一個長圖像（比如說400 x 2000）時，繪圖工作在圖像的頂部，但是當您向下滾動繪製時，繪製的線條會到達頂部。我無法弄清楚發生了什麼問題......我的代碼在下面。
關於代碼
cameraStill是包含圖像
drawable圖像視圖圖像
myScroll的高度被用於圖像
mainImageView滾動視圖， tempImageView,undo1,undo2,undo3是繪圖層
drawScroll爲繪圖層
圖像選擇
func imagePickerController(picker: UIImagePickerController, didFinishPickingImage image: UIImage!, editingInfo: [NSObject : AnyObject]!) {
self.dismissViewControllerAnimated(true, completion: {() -> Void in
})
if (image != nil) {
self.cameraStill.contentMode = UIViewContentMode.ScaleAspectFit
cameraStill.frame = CGRectMake(0, 0, screenWidth, screenWidth*(image.size.height/image.size.width))
// change uiimageivews size
mainImageView.frame = CGRectMake(0, 0, screenWidth, screenWidth*(image.size.height/image.size.width))
tempImageView.frame = CGRectMake(0, 0, screenWidth, screenWidth*(image.size.height/image.size.width))
undo1.frame = CGRectMake(0, 0, screenWidth, screenWidth*(image.size.height/image.size.width))
undo2.frame = CGRectMake(0, 0, screenWidth, screenWidth*(image.size.height/image.size.width))
undo3.frame = CGRectMake(0, 0, screenWidth, screenWidth*(image.size.height/image.size.width))
drawable = screenWidth*(image.size.height/image.size.width)
myScroll.contentSize = CGSize(width: screenWidth,height: screenWidth*(image.size.height/image.size.width))
drawScroll.contentSize = CGSize(width: screenWidth,height: screenWidth*(image.size.height/image.size.width))
if (screenWidth*(image.size.height/image.size.width) > (screenHeight-130)) {
myScroll.scrollEnabled = true
drawScroll.scrollEnabled = true
}
else {
myScroll.scrollEnabled = false
drawScroll.scrollEnabled = false
cameraStill.center = CGPoint(x: screenWidth/2, y: (screenHeight-130)/2)
mainImageView.center = CGPoint(x: screenWidth/2, y: (screenHeight-130)/2)
tempImageView.center = CGPoint(x: screenWidth/2, y: (screenHeight-130)/2)
undo1.center = CGPoint(x: screenWidth/2, y: (screenHeight-130)/2)
undo2.center = CGPoint(x: screenWidth/2, y: (screenHeight-130)/2)
undo3.center = CGPoint(x: screenWidth/2, y: (screenHeight-130)/2)
}
self.camera!.stopCamera()
}
//drawView.alpha = 1.0
}
滾動視圖繪圖
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
println("began")
if (drawingEnabled == true) {
c1 = 3
closeAllExtras()
swiped = false
if let touch = touches.first as? UITouch {
lastPoint = touch.locationInView(self.view)
}
}
}
func drawLineFrom(fromPoint: CGPoint, toPoint: CGPoint) {
//if (fromPoint.y > 50 && fromPoint.y < screenHeight-80 && toPoint.y > 50 && toPoint.y < screenHeight-80) {
// 1
UIGraphicsBeginImageContext(CGSize(width: view.frame.size.width,height: drawable))
let context = UIGraphicsGetCurrentContext()
tempImageView.image?.drawInRect(CGRect(x: 0, y: 0, width: view.frame.size.width, height: drawable))
// 2
CGContextMoveToPoint(context, fromPoint.x, fromPoint.y)
CGContextAddLineToPoint(context, toPoint.x, toPoint.y)
// 3
CGContextSetLineCap(context, kCGLineCapRound)
CGContextSetLineWidth(context, brushWidth)
CGContextSetRGBStrokeColor(context, red, green, blue, 1.0)
CGContextSetBlendMode(context, kCGBlendModeNormal)
// 4
CGContextStrokePath(context)
// 5
tempImageView.image = UIGraphicsGetImageFromCurrentImageContext()
tempImageView.alpha = opacity
UIGraphicsEndImageContext()
//}
}
override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
// 6
if (drawingEnabled == true) {
swiped = true
if let touch = touches.first as? UITouch {
let currentPoint = touch.locationInView(view)
drawLineFrom(lastPoint, toPoint: currentPoint)
// 7
lastPoint = currentPoint
}
}
}
func mergeViewContext(v1 : UIImageView, v2: UIImageView) {
UIGraphicsBeginImageContext(v1.frame.size)
v1.image?.drawInRect(CGRect(x: 0, y: 0, width: view.frame.size.width, height: drawable), blendMode: kCGBlendModeNormal, alpha: 1.0)
v2.image?.drawInRect(CGRect(x: 0, y: 0, width: view.frame.size.width, height: drawable), blendMode: kCGBlendModeNormal, alpha: 1.0)
v1.image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
v2.image = nil
}
override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {
if (drawingEnabled == true) {
if !swiped {
// draw a single point
drawLineFrom(lastPoint, toPoint: lastPoint)
}
mergeViewContext(mainImageView, v2: undo1)
undo1.image = undo2.image
undo2.image = nil
undo2.image = undo3.image
undo3.image = nil
UIGraphicsBeginImageContext(undo3.frame.size)
undo3.image?.drawInRect(CGRect(x: 0, y: 0, width: view.frame.size.width, height: drawable), blendMode: kCGBlendModeNormal, alpha: 1.0)
tempImageView.image?.drawInRect(CGRect(x: 0, y: 0, width: view.frame.size.width, height: drawable), blendMode: kCGBlendModeNormal, alpha: opacity)
undo3.image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
tempImageView.image = nil
}
Synching兩個渦旋視圖
func scrollViewDidScroll(scrollView: UIScrollView) {
if (scrollView == drawScroll) {
var offset = scrollView.contentOffset
myScroll.setContentOffset(offset, animated: false)
}
}