如何在 iOS 中将 UIImage 转换为 J2K (JPEG2000)？

Question

我已经设法让 OpenJPEG 在我的 iOS 应用程序中编译，但我不知道从哪里开始尝试将 UIImage 转换为 J2K 文件或内存缓冲区中的 J2K。有什么建议吗？

Answer 1

显然 ImageIO 可以做到这一点。您需要将图像 io 框架添加到您的项目中，然后此代码对我有用：

#import <ImageIO/ImageIO.h> // or @import ImageIO if modules enabled
#import <MobileCoreServices/MobileCoreServices.h>

// ...    

// quality is 0-1 (0 = smallest file size, 1 = lossless quality)
+ (NSData*) convertToJPEG2000:(UIImage*)image withQuality:(float)quality
{
    NSMutableData* d = [NSMutableData data];
    CGImageDestinationRef destinationRef = CGImageDestinationCreateWithData((__bridge CFMutableDataRef)d, kUTTypeJPEG2000, 1, NULL);
    CGImageDestinationSetProperties(destinationRef, NULL);
    CGImageDestinationAddImage(destinationRef, image.CGImage, (__bridge CFDictionaryRef)@{ (NSString*)kCGImageDestinationLossyCompressionQuality: @(quality) });

    if (!CGImageDestinationFinalize(destinationRef))
    {
        d = nil;
    }
    CFRelease(destinationRef);

    return d;
}