轉:http://blog.csdn.net/ch_soft/article/details/7338012
UIGraphicsBeginImageContext (CGSize)截圖 ,是從屏幕原點開始截取size大小的圖片
如何截取任意起點開始 size 大小的圖片,辦法就是用CGContextTranslateCTM轉換原點座標//導入頭文件//創建一個基於位圖的圖形上下文並指定大小爲CGSizeMake(200,400)
UIGraphicsBeginImageContext(CGSize)截圖,是從屏幕原點開始截取size大小的圖片
如何截取任意起點開始 size大小的圖片,辦法就是用CGContextTranslateCTM轉換原點座標//導入頭文件 //創建一個基於位圖的圖形上下文並指定大小爲CGSizeMake(200,400)
Java代碼
UIGraphicsBeginImageContext(CGSizeMake(200,400));
//renderInContext呈現接受者及其子範圍到指定的上下文
[self.view.layerrenderInContext:UIGraphicsGetCurrentContext()];
//返回一個基於當前圖形上下文的圖片
UIImage *aImage =UIGraphicsGetImageFromCurrentImageContext();
//移除棧頂的基於當前位圖的圖形上下文
UIGraphicsEndImageContext();
//以png格式返回指定圖片的數據
imageData =UIImagePNGRepresentation(aImage);
Java代碼
#import<QuartzCore/QuartzCore.h>
//將整個self.view大小的圖層形式創建一張圖片image UIGraphicsBeginImageContext(self.view.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage*image=UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//然後將該圖片保存到圖片圖
UIImageWriteToSavedPhotosAlbum(image,self,nil,nil);
-(IBAction)cutBtnClick:(id)sender;
{
CGRect frame=imageView.frame;
imageView.frame=CGRectMake(-420, 300, frame.size.width, frame.size.height);
// 第一種方法 從原點開始截取
// UIGraphicsBeginImageContext(CGSizeMake(320,100));
// [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
// UIImage*image=UIGraphicsGetImageFromCurrentImageContext();
// UIGraphicsEndImageContext();
//
// 第二種方法 按制定區域截取
UIGraphicsBeginImageContext(CGSizeMake(320, 200));
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage*parentImage=UIGraphicsGetImageFromCurrentImageContext();
CGImageRef imageRef = parentImage.CGImage;
CGRect myImageRect=CGRectMake(0, 100, 320, 100);
CGImageRef subImageRef = CGImageCreateWithImageInRect(imageRef, myImageRect);
CGSize size=CGSizeMake(320, 100);
UIGraphicsBeginImageContext(size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextDrawImage(context, myImageRect, subImageRef);
UIImage* image = [UIImage imageWithCGImage:subImageRef];
UIGraphicsEndImageContext();
CGImageRelease(imageRef);
UIGraphicsEndImageContext();
imageView.image=image;
[UIView beginAnimations:@"ToggleViews" context:nil];
[UIView setAnimationDuration:0.5];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
imageView.frame=CGRectMake(0, 300, frame.size.width, frame.size.height);
[UIView commitAnimations];
}