網上現在有很多的圖片剪下和從圖片庫中取出圖片並擷取的demo，但是大部分都是固定的大小，而且我們系統本來就帶可編輯的圖片裁剪功能。不過那個是正方形的，並不適用於我們多變的需求。
1.做裁剪圖片需要先放一個父view，然後再在上面放原始圖片imageview最後還需要一個裁剪圖片的區域，為了防止用view會遮蓋螢幕，到時候想滑動圖片，縮放圖片的時候就會遇到麻煩，所以需要用layer，就是之前部落格提到的用calayer繪圖，將編輯框畫出來。這樣既有了裁剪範圍又不會遮擋介面手勢。
2.父view和手勢程式碼如下

 //宣告需要切圖的可滑動的背景
    self.originImageBoardView
 
 = [[UIView alloc] initWithFrame:CGRectMake(0, 64, SCREEN_WIDTH, SCREEN_HEIGHT-64)];
    self.originImageBoardView.clipsToBounds = YES;
    [self.view addSubview:self.originImageBoardView];
     //縮放圖片
    UIPinchGestureRecognizer *pinchOriginGestureRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self
 
 action:@selector(pinchGestureAction:)];
    //移動圖片
    UIPanGestureRecognizer *panOriginGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGestureAction:)];
    panOriginGestureRecognizer.maximumNumberOfTouches = 1;

    [self.originImageBoardView addGestureRecognizer:pinchOriginGestureRecognizer];
    [self
 
.originImageBoardView addGestureRecognizer:panOriginGestureRecognizer];

大圖片的view

//宣告原圖
    self.originImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT-64)];
    self.originImageView.image = self.originImage;
    //UIViewContentModeScaleAspectFit(將圖片全部顯示出來等比例縮放到螢幕能放下圖片為止，例如螢幕未鋪滿有，由於圖片比例不同所以顯示全部圖片內容後必定有部分不會被圖片顯示出來)UIViewContentModeScaleAspectFill(將圖片最小的部分顯示出來，例如圖片高度和寬度比例不同則全屏顯示，可能高度或者寬度超出螢幕)
    self.originImageView.contentMode = UIViewContentModeScaleAspectFit;
    [self.originImageBoardView addSubview:self.originImageView];

編輯框的程式碼

-(void)cutImageWithPath
{
    UIBezierPath *path = [UIBezierPath bezierPath];
    [path moveToPoint:CGPointMake(0, (SCREEN_HEIGHT+64-SCREEN_WIDTH/1.8)/2)];
    [path addLineToPoint:CGPointMake(SCREEN_WIDTH, (SCREEN_HEIGHT+64-SCREEN_WIDTH/1.8)/2)];
    [path addLineToPoint:CGPointMake(SCREEN_WIDTH, (SCREEN_HEIGHT+64+SCREEN_WIDTH/1.8)/2)];
    [path addLineToPoint:CGPointMake(0, (SCREEN_HEIGHT+64+SCREEN_WIDTH/1.8)/2)];
    [path closePath];
    CAShapeLayer *myLayer = [CAShapeLayer layer];
    myLayer.fillColor = [UIColor clearColor].CGColor;
    myLayer.strokeColor = [UIColor whiteColor].CGColor;
    myLayer.path = path.CGPath;
    myLayer.lineWidth=1;
    [self.view.layer addSublayer:myLayer];
}

兩個手勢的實現方法

- (void)pinchGestureAction:(UIPinchGestureRecognizer *)gestureRecognizer {

    UIView *gestureView = gestureRecognizer.view;
        gestureView = self.originImageView;
    CGAffineTransform affineTransform = CGAffineTransformScale(gestureView.transform,gestureRecognizer.scale, gestureRecognizer.scale);
    gestureView.transform = affineTransform;
    gestureRecognizer.scale = 1;
}

- (void)panGestureAction:(UIPanGestureRecognizer *)gestureRecognizer {
    UIView *gestureView = gestureRecognizer.view,
    *gestureViewSuperView = gestureView.superview;
    BOOL needPaddingDistance = NO;
    gestureView = self.originImageView;
    needPaddingDistance = NO;

    CGPoint touchPoint = [gestureRecognizer locationInView:gestureView.superview];

    if(gestureRecognizer.state == UIGestureRecognizerStateChanged) {
        CGPoint centerPoint = CGPointMake(gestureView.center.x + touchPoint.x - PreviousTapPoint.x, gestureView.center.y + touchPoint.y - PreviousTapPoint.y);
        if(needPaddingDistance) {
            CGFloat w = CGRectGetWidth(gestureView.frame),
            h = CGRectGetHeight(gestureView.frame);
            CGRect tempFrame = CGRectMake(centerPoint.x - w / 2, centerPoint.y - h / 2, w, h);
            if(!CGRectContainsRect(gestureViewSuperView.frame, tempFrame)) {
                return;
            }
        }
        gestureView.center = centerPoint;
    }
    PreviousTapPoint = touchPoint;
    [gestureRecognizer setTranslation:CGPointZero inView:gestureView.superview];
}

3.最後要上實現切圖的程式碼

UIGraphicsBeginImageContext(self.originImageBoardView.bounds.size); //currentView 當前的view
    [self.originImageBoardView.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *originFullImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    CGImageRef imageRef = originFullImage.CGImage;
    CGImageRef imagePartRef = CGImageCreateWithImageInRect(imageRef, self.cropView.frame);
    UIImage *cropImage = [UIImage imageWithCGImage:imagePartRef];
    CGImageRelease(imagePartRef);