iOS-图片压缩到指定大小范围内KB、MB

╰+哭是因爲堅強的太久メ 2023-10-16 23:54 37阅读 0赞

- (void)viewDidLoad {
    
        [superviewDidLoad];
        // Do any additional setup after loading the view, typically from a nib.
        UIImageView *imgView = [[UIImageViewalloc]initWithFrame:CGRectMake(10,30, 300,415)];
        imgView.backgroundColor = [UIColoryellowColor];
        imgView.image = [UIImageimageNamed:@"1.jpg"];
        [self.viewaddSubview:imgView];
        //图像压缩
        UIImage *image = [selfscaleFromImage:imgView.image];
        //保存图像
        NSString *strFileName = [selfsaveImage:image];
        imgView.image = image;
        NSLog(@"图片保存路径:%@",strFileName);
    }
    
    //==========================
    // 图像压缩
    //==========================
    - (UIImage *)scaleFromImage:(UIImage *)image
    {
        if (!image)
        {
            returnnil;
        }
        NSData *data =UIImagePNGRepresentation(image);
        CGFloat dataSize = data.length/1024;
        CGFloat width  = image.size.width;
        CGFloat height = image.size.height;
        CGSize size;
    
        if (dataSize<=50)//小于50k
        {
            return image;
        }
        elseif (dataSize<=100)//小于100k
        {
            size = CGSizeMake(width/1.f, height/1.f);
        }
        elseif (dataSize<=200)//小于200k
        {
            size = CGSizeMake(width/2.f, height/2.f);
        }
        elseif (dataSize<=500)//小于500k
        {
            size = CGSizeMake(width/2.f, height/2.f);
        }
        elseif (dataSize<=1000)//小于1M
        {
            size = CGSizeMake(width/2.f, height/2.f);
        }
        elseif (dataSize<=2000)//小于2M
        {
            size = CGSizeMake(width/2.f, height/2.f);
        }
        else//大于2M
        {
            size = CGSizeMake(width/2.f, height/2.f);
        }
        NSLog(@"%f,%f",size.width,size.height);
        UIGraphicsBeginImageContext(size);
        [image drawInRect:CGRectMake(0,0, size.width, size.height)];
        UIImage *newImage =UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        if (!newImage)
        {
            return image;
        }
        return newImage;
    }
    
    //===============
    // 保存图像
    //===============
    - (NSString *)saveImage:(UIImage*)image
    {
        NSData *data;
        if (UIImagePNGRepresentation(image) ==nil)
        {
            data = UIImageJPEGRepresentation(image, 1.0);
        }
        else
        {
            data = UIImagePNGRepresentation(image);
        }
        
        //图片保存的路径
        //这里将图片放在沙盒的documents文件夹中
        NSString * DocumentsPath = [NSHomeDirectory()stringByAppendingPathComponent:@"Documents"];
        //文件管理器
        NSFileManager *fileManager = [NSFileManagerdefaultManager];
        //把刚刚图片转换的data对象拷贝至沙盒中并保存为image.png
        [fileManager createDirectoryAtPath:DocumentsPath withIntermediateDirectories:YESattributes:nilerror:nil];
        [fileManager createFileAtPath:[DocumentsPath stringByAppendingString:@"/image.png"]contents:data attributes:nil];
    
        //得到选择后沙盒中图片的完整路径
        NSString *filePath = [[NSStringalloc]initWithFormat:@"%@%@",DocumentsPath, @"/image.png"];
        return filePath;
    }