1、圖片的壓縮

封裝類方法

+ (UIImage*)imageWithImageSimple:(UIImage*)image scaledToSize:(CGSize)newSize
{
    // Create a graphics image context
    UIGraphicsBeginImageContext(newSize);
    
    // Tell the old image to draw in this new context, with the desired
    // new size
    [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
    
    // Get the new image from the context
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    
    // End the context
    UIGraphicsEndImageContext();
    
    // Return the new image.
    return newImage;
}

//屏幕截圖並壓縮
    UIImage *snapshot =  [UIImage imageWithCGImage:[AppDelegate screenShots].CGImage scale:1 orientation:UIImageOrientationLeft];
    _updataImg =[AppDelegate imageWithImageSimple:snapshot scaledToSize:CGSizeMake(snapshot.size.width/3, snapshot.size.height/3)];

2、保存View為內容Img

-(void)savetoLocal
{
    _moreVC.hidden =YES;
    UIImage * saveimg=[self saveImage];
     UIImageWriteToSavedPhotosAlbum(saveimg, self, @selector(imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:), nil);
    
}
-(UIImage*)saveImage{
    UIGraphicsBeginImageContext(CGSizeMake(self.view.bounds.size.width, self.view.bounds.size.height - 20));//保存self.view上的內容
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return viewImage;
}

- (void)imageSavedToPhotosAlbum:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
    NSString *message = @"呵呵";
    if (!error) {
        message = @"成功保存到相冊";
    }else
    {
        message = [error description];
    }
    NSLog(@"message is %@",message);
}