OSStatus GenerateThumbnailForURL(void *thisInterface, QLThumbnailRequestRef thumbnail, CFURLRef url, CFStringRef contentTypeUTI, CFDictionaryRef options, CGSize maxSize)
{@autoreleasepool{// Get the UTI propertiesNSDictionary* uti_declarations = (__bridge_transfer NSDictionary*)UTTypeCopyDeclaration(contentTypeUTI);// Get the extensions corresponding to the image UTI, for some UTI there can be more than 1 extension (ex image.jpeg = jpeg, jpg...)// If it fails for whatever reason fallback to the filename extensionid extensions = uti_declarations[(__bridge NSString*)kUTTypeTagSpecificationKey][(__bridge NSString*)kUTTagClassFilenameExtension];NSString* extension = ([extensions isKindOfClass:[NSArray class]]) ? extensions[0] : extensions;if (nil == extension)extension = ([(__bridge NSURL*)url pathExtension] != nil) ? [(__bridge NSURL*)url pathExtension] : @"";extension = [extension lowercaseString];// Create the properties dicCFTypeRef keys[1] = {kQLThumbnailPropertyExtensionKey};CFTypeRef values[1] = {(__bridge CFStringRef)extension};CFDictionaryRef properties = CFDictionaryCreate(kCFAllocatorDefault, (const void**)keys, (const void**)values, 1, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);// Check by extension because it's highly unprobable that an UTI for these formats is declared// the simplest way to declare one is creating a dummy automator app and adding imported/exported UTI conforming to public.imageCGImageRef img_ref = NULL;CFStringRef filepath = CFURLCopyPath(url);if ([extension isEqualToString:@"insp"]){if (!QLThumbnailRequestIsCancelled(thumbnail)){// 1. decode the image img_ref = decode_insp_at_path(filepath, NULL);    if (filepath != NULL)CFRelease(filepath);// 2. render itif (img_ref != NULL){QLThumbnailRequestSetImage(thumbnail, img_ref, properties);CGImageRelease(img_ref);}elseQLThumbnailRequestSetImageAtURL(thumbnail, url, properties);}elseQLThumbnailRequestSetImageAtURL(thumbnail, url, properties);}else if ([extension isEqualToString:@"insv"]){if (!QLThumbnailRequestIsCancelled(thumbnail)){// 1. decode the imageimg_ref = decode_insv_at_path(filepath, NULL);if (filepath != NULL)CFRelease(filepath);// 2. render itif (img_ref != NULL){QLThumbnailRequestSetImage(thumbnail, img_ref, properties);CGImageRelease(img_ref);}elseQLThumbnailRequestSetImageAtURL(thumbnail, url, properties);}elseQLThumbnailRequestSetImageAtURL(thumbnail, url, properties);}elseQLThumbnailRequestSetImageAtURL(thumbnail, url, properties);if (properties != NULL)CFRelease(properties);} return noErr;
}

OSStatus GeneratePreviewForURL(void *thisInterface, QLPreviewRequestRef preview, CFURLRef url, CFStringRef contentTypeUTI, CFDictionaryRef options)
{@autoreleasepool{NSString* extension = [[(__bridge NSURL*)url pathExtension] lowercaseString];image_infos infos;memset(&infos, 0, sizeof(image_infos));CGImageRef img_ref = NULL;CFStringRef filepath = CFURLCopyPath(url);if ([extension isEqualToString:@"insp"]){// 1. decode the imageif (!QLPreviewRequestIsCancelled(preview)){img_ref = decode_insp_at_path(filepath, &infos);if (filepath != NULL)CFRelease(filepath);// 2. render itCFDictionaryRef properties = create_properties(url, infos.filesize, infos.width, infos.height, true);if (img_ref != NULL){// Have to draw the image ourselvesCGContextRef ctx = QLPreviewRequestCreateContext(preview, (CGSize){.width = OUT_WIDTH, .height = OUT_HEIGHT+LOGO_HEIGHT}, YES, properties);CGContextDrawImage(ctx, (CGRect){.origin = CGPointZero, .size.width = OUT_WIDTH, .size.height = OUT_HEIGHT+LOGO_HEIGHT}, img_ref);QLPreviewRequestFlushContext(preview, ctx);CGContextRelease(ctx);CGImageRelease(img_ref);}elseQLPreviewRequestSetURLRepresentation(preview, url, contentTypeUTI, properties);if (properties != NULL)CFRelease(properties);}}else if([extension isEqualToString:@"insv"]){// 1. decode the imageif (!QLPreviewRequestIsCancelled(preview)){img_ref = decode_insv_at_path(filepath, &infos);if (filepath != NULL)CFRelease(filepath);// 2. render itCFDictionaryRef properties = create_properties(url, infos.filesize, infos.width, infos.height, true);if (img_ref != NULL){// Have to draw the image ourselvesCGContextRef ctx = QLPreviewRequestCreateContext(preview, (CGSize){.width = OUT_WIDTH, .height = OUT_HEIGHT+LOGO_HEIGHT}, YES, properties);CGContextDrawImage(ctx, (CGRect){.origin = CGPointZero, .size.width = OUT_WIDTH, .size.height = OUT_HEIGHT+LOGO_HEIGHT}, img_ref);QLPreviewRequestFlushContext(preview, ctx);CGContextRelease(ctx);CGImageRelease(img_ref);}elseQLPreviewRequestSetURLRepresentation(preview, url, contentTypeUTI, properties);if (properties != NULL)CFRelease(properties);}}else{// Standard images (supported by the OS by default)size_t width = 0, height = 0, file_size = 0;properties_for_file(url, &width, &height, &file_size);// Request preview with updated titlebarCFDictionaryRef properties = create_properties(url, file_size, width, height, false);QLPreviewRequestSetURLRepresentation(preview, url, contentTypeUTI, properties);if (properties != NULL)CFRelease(properties);}}return kQLReturnNoError;
}