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iOS實(shí)現(xiàn)裁剪框和圖片剪裁功能

 更新時(shí)間：2016年03月22日 15:00:12   作者：jiangamh  
這篇文章主要為大家詳細(xì)介紹了iOS實(shí)現(xiàn)裁剪框和圖片剪裁功能，文中示例代碼介紹的非常詳細(xì)，具有一定的參考價(jià)值，感興趣的小伙伴們可以參考一下

圖片處理中經(jīng)常用的圖片剪裁，就是通過(guò)剪裁框確定圖片剪裁的區(qū)域，然后剪去該區(qū)域的圖片，今天實(shí)現(xiàn)了一下，其實(shí)圖片剪裁本身不難，主要剪裁框封裝發(fā)了點(diǎn)時(shí)間，主要功能可以拖動(dòng)四個(gè)角縮放，但不能超出父視圖，拖動(dòng)四個(gè)邊單方向縮放，不能超出父視圖，拖動(dòng)中間部分單單移動(dòng)，不改變大小，不能超出父視圖。下面列舉一些主要代碼。

四個(gè)角的處理代碼：

-(void)btnPanGesture:(UIPanGestureRecognizer*)panGesture
{
 UIView *vw = panGesture.view;
 CGRect oldFrame = self.frame;
 CGRect oldIntersectRect = CGRectIntersection(self.frame, self.superview.bounds);

 CGPoint transport = [panGesture translationInView:vw];
 if (vw.tag == 4) {
 self.width = self.preFrame.size.width + transport.x;
 self.height = self.preFrame.size.height + transport.y;
 }
 else if(vw.tag == 3)
 {
 self.x = self.preFrame.origin.x + transport.x;
 self.width = self.preFrame.size.width - transport.x;
 self.height = self.preFrame.size.height + transport.y;
 }
 else if(vw.tag == 2)
 {
 self.width = self.preFrame.size.width + transport.x;
 self.y = self.preFrame.origin.y + transport.y;
 self.height = self.preFrame.size.height - transport.y;
 }
 else if(vw.tag == 1)
 {
 self.x = self.preFrame.origin.x + transport.x;
 self.width = self.preFrame.size.width - transport.x;
 self.y = self.preFrame.origin.y + transport.y;
 self.height = self.preFrame.size.height - transport.y;
 }
 if (panGesture.state == UIGestureRecognizerStateEnded) {
 self.preFrame = self.frame;
 }
 if (self.width < MinWidth || self.height < MinHeight) {
 self.frame = oldFrame;
 }
 CGRect newFrame = self.frame;
 if (newFrame.size.width * newFrame.size.height > oldFrame.size.height * oldFrame.size.width) {

 CGRect newIntersectRect = CGRectIntersection(self.frame, self.superview.bounds);
 if (newFrame.size.width * newFrame.size.height > newIntersectRect.size.width * newIntersectRect.size.height) {
 self.frame = oldFrame;
 }
 }
 self.preCenter = self.center;
}

我是通過(guò)視圖于父視圖的frame的交集部分的面積判斷是否超出父視圖的。

四個(gè)邊的控制代碼：

-(void)viewPanGesture:(UIPanGestureRecognizer*)panGesture
{
 UIView *vw = panGesture.view;
 CGRect oldFrame = self.frame;
 CGRect oldIntersectRect = CGRectIntersection(self.frame, self.superview.bounds);

 CGPoint transport = [panGesture translationInView:vw];
 if (vw.tag == 1) {
 self.y = self.preFrame.origin.y + transport.y;
 self.height = self.preFrame.size.height - transport.y;
 }
 else if(vw.tag == 2)
 {
 self.x = self.preFrame.origin.x + transport.x;
 self.width = self.preFrame.size.width - transport.x;
 }
 else if(vw.tag == 3)
 {
 self.height = self.preFrame.size.height + transport.y;
 }
 else if(vw.tag == 4)
 {
 self.width = self.preFrame.size.width + transport.x;
 }
 if (panGesture.state == UIGestureRecognizerStateEnded) {
 self.preFrame = self.frame;
 }
 if (self.width < MinWidth || self.height < MinHeight) {
 self.frame = oldFrame;

 }
 self.preCenter = self.center;
 CGRect newFrame = self.frame;
 if (newFrame.size.width * newFrame.size.height > oldFrame.size.height * oldFrame.size.width) {

 CGRect newIntersectRect = CGRectIntersection(self.frame, self.superview.bounds);
 if (oldIntersectRect.size.width * oldIntersectRect.size.height >= newIntersectRect.size.width * newIntersectRect.size.height) {
 self.frame = oldFrame;
 self.preCenter = self.preCenter;
 }

 }

}

中間部分移動(dòng)的控制代碼：

-(void)contentViewPanGestureAction:(UIPanGestureRecognizer*)panGesture
{
 CGPoint transport = [panGesture translationInView:self];
 CGRect oldFrame = self.frame;
 CGRect oldIntersectRect = CGRectIntersection(self.frame, self.superview.bounds);
 CGFloat oldMj = oldIntersectRect.size.width * oldIntersectRect.size.height;

 self.center = CGPointMake(self.preCenter.x + transport.x, self.preCenter.y + transport.y);

 if (panGesture.state == UIGestureRecognizerStateEnded) {

 self.preCenter = self.center;
 }
 CGRect newIntersectRect = CGRectIntersection(self.frame, self.superview.bounds);
 CGFloat newMj = newIntersectRect.size.width * newIntersectRect.size.height;

 if (newMj < oldMj) {
 self.frame = oldFrame;
 self.preCenter = self.center;
 }
}

剪裁框?qū)崿F(xiàn)的核心代碼如上，個(gè)人覺(jué)得最不好處理的是對(duì)超出父視圖的控制，要保證不能超出父視圖，個(gè)人主要用到的是通過(guò)子視圖與父視圖的交集部分的面積的改變來(lái)獲知是否超出父視圖，如果超出父視圖，就會(huì)退到之前的frame，不知道是否還有其他好的方法，有的話可以一起交流一下。

圖片剪裁部分

代碼如下：

-(void)cropImg
{
 CGRect cropFrame = self.cropView.frame;
 CGFloat orgX = cropFrame.origin.x * (self.img.size.width / self.imgView.frame.size.width);
 CGFloat orgY = cropFrame.origin.y * (self.img.size.height / self.imgView.frame.size.height);
 CGFloat width = cropFrame.size.width * (self.img.size.width / self.imgView.frame.size.width);
 CGFloat height = cropFrame.size.height * (self.img.size.height / self.imgView.frame.size.height);
 CGRect cropRect = CGRectMake(orgX, orgY, width, height);
 CGImageRef imgRef = CGImageCreateWithImageInRect(self.img.CGImage, cropRect);

 CGFloat deviceScale = [UIScreen mainScreen].scale;
 UIGraphicsBeginImageContextWithOptions(cropFrame.size, 0, deviceScale);
 CGContextRef context = UIGraphicsGetCurrentContext();
 CGContextTranslateCTM(context, 0, cropFrame.size.height);
 CGContextScaleCTM(context, 1, -1);
 CGContextDrawImage(context, CGRectMake(0, 0, cropFrame.size.width, cropFrame.size.height), imgRef);
 UIImage *newImg = UIGraphicsGetImageFromCurrentImageContext();
 CGImageRelease(imgRef);
 UIGraphicsEndImageContext();

 ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
 [library toolWriteImageToSavedPhotosAlbum:newImg.CGImage metadata:nil completionBlock:^(NSURL *assetURL, NSError *error) {
 if(error)
 {
 JGLog(@"寫(xiě)入出錯(cuò)");
 }
 } groupName:@"相冊(cè)名稱(chēng)"];
}

這里要注意一點(diǎn)CGContextDrawImage這個(gè)函數(shù)的坐標(biāo)系和UIKIt的坐標(biāo)系上下顛倒，需對(duì)坐標(biāo)系處理如下：

CGContextTranslateCTM(context, 0, cropFrame.size.height);
CGContextScaleCTM(context, 1, -1);

看看效果：

剪裁之后的圖片：

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助。

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