iOS CGImageRef

来源：互联网发布：sar源码编辑：程序博客网时间：2024/04/28 13:38

图片截取

    UIImageView * imgView =[[UIImageView alloc]initWithFrame:CGRectMake(0, 100, 420, 375)];    [self.view addSubview:imgView];    UIImage * img =[UIImage imageNamed:@"zc.jpg"];    CGImageRef imgRef =[img CGImage];   //截取位置    imgRef =CGImageCreateWithImageInRect(imgRef, CGRectMake(0, 0, 420, 400));    img =[UIImage imageWithCGImage:imgRef];    imgView.image =img;

注：imgView.contentMode =UIViewContentModeScaleAspectFill; //保持图片原有比例拉伸，默认是哪里短哪里拉伸。

调整图片尺寸

    UIGraphicsBeginImageContextWithOptions(CGSizeMake(200, 200), NO, 0.0f);    [img drawInRect:CGRectMake(0, 0, 200, 200)];    UIImage * newImage =UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();

注：创建一个200*200的画布，将图片画在指定范围。

Core Image过滤器

    imgView =[[UIImageView alloc]initWithFrame:CGRectMake(20, 80, 150, 150)];    imgView.image =[UIImage imageNamed:@"zc.jpg"];    [self.view addSubview:imgView];    UISlider * slider =[[UISlider alloc]initWithFrame:CGRectMake(20, 250, 200, 20)];    slider.maximumValue =1.0f;    slider.minimumValue =-1.0f;    slider.value=0.0f;    [slider addTarget:self action:@selector(changeValue:) forControlEvents:UIControlEventValueChanged];    [self.view addSubview:slider];    _context =[CIContext contextWithOptions:nil];    _filter =[CIFilter filterWithName:@"CIColorControls"];    //设置输入源    [_filter setValue:[CIImage imageWithCGImage:[UIImage imageNamed:@"zc.jpg"].CGImage] forKey:@"inputImage"];}-(void)changeValue:(UISlider *)slider{    //设置滤镜参数    [_filter setValue:[NSNumber numberWithFloat:slider.value] forKey:@"inputSaturation"];    //取得输出图像    CIImage *outputImage =[_filter outputImage];    //转格式    CGImageRef temp =[_context createCGImage:outputImage fromRect:[outputImage extent]];    UIImage * newImage =[UIImage imageWithCGImage:temp];    imgView.image =newImage;}

注：@import CoreImage; 加CoreImage.framework

0 0