Original Swift / Objective-C / AppleScriptObjC codes from which ocr.sh (https://gist.github.com/doraTeX/da9a1a26dffbf3fe5d6ec12a9c79267c) is converted

ocr.m

#import <Quartz/Quartz.h>
#import <Vision/Vision.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSString *target = @"test.pdf";
        CGFloat dpi = 200;
        PDFDocument *doc = [[PDFDocument alloc] initWithURL:[NSURL fileURLWithPath:target]];
        NSUInteger pageCount = [doc pageCount];
        
        VNRecognizeTextRequest *request = [[VNRecognizeTextRequest alloc] initWithCompletionHandler:^(VNRequest * _Nonnull request, NSError * _Nullable error) {
            NSArray<VNRecognizedTextObservation*> *observations = [request results];
            for (VNRecognizedTextObservation* observation in observations) {
                NSString *string = [[[observation topCandidates:1] firstObject] string];
                puts(string.UTF8String);
            }
        }];
        
        request.recognitionLevel = VNRequestTextRecognitionLevelAccurate;
        request.usesLanguageCorrection = YES;
        request.recognitionLanguages = @[@"ja", @"en"];
        
        NSInteger revision;
        if (@available(macOS 13.0, *)) {
            revision = VNRecognizeTextRequestRevision3;
        } else if (@available(macOS 11.0, *)) {
            revision = VNRecognizeTextRequestRevision2;
        } else {
            revision = VNRecognizeTextRequestRevision1;
        }
        request.revision = revision;
        
        for (NSUInteger i=0; i<pageCount; i++) {
            CGFloat scaleFactor = dpi / (72.0 * [[NSScreen mainScreen] backingScaleFactor]);
            NSPDFImageRep *pdfImageRep = [NSPDFImageRep imageRepWithData:[[doc pageAtIndex:i] dataRepresentation]];
            NSSize originalSize = pdfImageRep.bounds.size;
            NSSize scaledSize = NSMakeSize(originalSize.width * scaleFactor, originalSize.height * scaleFactor);
            NSRect targetRect = NSMakeRect(0, 0, scaledSize.width, scaledSize.height);
            NSImage *image = [[NSImage alloc] initWithSize: targetRect.size];
            [image lockFocus];
            [[NSColor whiteColor] set];
            [NSBezierPath fillRect: targetRect];
            [pdfImageRep drawInRect: targetRect];
            [image unlockFocus];
            CGImageRef cgImage = [[NSBitmapImageRep imageRepWithData:[image TIFFRepresentation]] CGImage];
            [[[VNImageRequestHandler alloc] initWithCGImage:cgImage options:@{}] performRequests:@[request] error:nil];
        }
 
        return 0;
    }
}

ocr.scpt

use framework "Quartz"
use framework "Vision"

global CA, PDFDocument, NSURL, VNRecognizeTextRequest, VNImageRequestHandler, NSScreen, NSImage, NSPDFImageRep, NSColor, NSBezierPath, NSMutableArray
set CA to current application
set PDFDocument to CA's PDFDocument
set NSURL to CA's NSURL
set VNRecognizeTextRequest to CA's VNRecognizeTextRequest
set VNImageRequestHandler to CA's VNImageRequestHandler
set NSScreen to CA's NSScreen
set NSImage to CA's NSImage
set NSPDFImageRep to CA's NSPDFImageRep
set NSColor to CA's NSColor
set NSBezierPath to CA's NSBezierPath
set NSMutableArray to CA's NSMutableArray

global request, scaleFactor
set request to VNRecognizeTextRequest's alloc's init
request's setRecognitionLevel:(CA's VNRequestTextRecognitionLevelAccurate)
request's setUsesLanguageCorrection:true


on ocrPDF(filePath, dpi)
	set doc to PDFDocument's alloc's initWithURL:(NSURL's fileURLWithPath:filePath)
	set pageCount to doc's pageCount
	set resultTexts to NSMutableArray's new()
	set scaleFactor to (dpi / (72.0 * (NSScreen's mainScreen's backingScaleFactor)))
	
	repeat with i from 1 to pageCount
		set pdfImageRep to (NSPDFImageRep's imageRepWithData:((doc's pageAtIndex:(i - 1))'s dataRepresentation))
		set originalSize to pdfImageRep's |bounds|
		set originalWidth to CA's NSWidth(originalSize)
		set originalHeight to CA's NSHeight(originalSize)
		set scaledSize to CA's NSMakeSize(originalWidth * scaleFactor, originalHeight * scaleFactor)
		set targetRect to CA's NSMakeRect(0, 0, scaledSize's width, scaledSize's height)
		
		set image to (NSImage's alloc's initWithSize:(targetRect's item 2))
		image's lockFocus()
		NSColor's whiteColor's |set|()
		(NSBezierPath's fillRect:targetRect)
		(pdfImageRep's drawInRect:targetRect)
		image's unlockFocus()
		set tiff to image's TIFFRepresentation
		set ocrText to my ocrTIFF(tiff)
		(resultTexts's addObject:ocrText)
	end repeat
	return (resultTexts's componentsJoinedByString:linefeed) as text
end ocrPDF

on ocrImage(filePath)
	set scaleFactor to NSScreen's mainScreen's backingScaleFactor
	set bitmapImageRep to (CA's NSBitmapImageRep's imageRepWithData:((NSImage's alloc's initWithContentsOfFile:(filePath))'s TIFFRepresentation))
	set srcSize to CA's NSMakeSize((bitmapImageRep's pixelsWide as real) / scaleFactor, (bitmapImageRep's pixelsHigh as real) / scaleFactor)
	set srcImage to (NSImage's alloc's initWithSize:srcSize)
	srcImage's addRepresentation:bitmapImageRep
	set newImage to (NSImage's alloc's initWithSize:srcSize)
	
	set targetRect to CA's NSMakeRect(0, 0, srcSize's width, srcSize's height)
	newImage's lockFocus()
	NSColor's whiteColor's |set|()
	(NSBezierPath's fillRect:targetRect)
	(srcImage's drawInRect:targetRect)
	newImage's unlockFocus()
	set tiff to newImage's TIFFRepresentation
	return my ocrTIFF(tiff)
end ocrImage

on ocrTIFF(tiff)
	set resultTexts to NSMutableArray's new()
	set requestHandler to (VNImageRequestHandler's alloc's initWithData:tiff options:(missing value))
	(requestHandler's performRequests:[request] |error|:(missing value))
	set results to request's results()
	
	repeat with aResult in results
		(resultTexts's addObject:(((aResult's topCandidates:1)'s objectAtIndex:0)'s |string|()))
	end repeat
	
	return (resultTexts's componentsJoinedByString:linefeed) as text
end ocrTIFF

on ocr(filePath, lang, dpi)
	if lang is "ja" then
		request's setRecognitionLanguages:["ja", "en"]
	else
		request's setRecognitionLanguages:["en"]
	end if
	
	set pathExtension to ((CA's NSString's stringWithString:filePath)'s pathExtension as text)
	if pathExtension is "pdf" then
		my ocrPDF(filePath, dpi)
	else
		my ocrImage(filePath)
	end if
end ocr

set ocrResult to my ocr("test.pdf", "ja", 200)

ocr.swift

import CoreGraphics
import Quartz
import Vision

let target = "test.pdf"
let dpi: CGFloat = 200

let doc = PDFDocument(url: URL(filePath: target))!
let pageCount = doc.pageCount

let request = VNRecognizeTextRequest { (request, _) in
    let observations = request.results as? [VNRecognizedTextObservation] ?? []
    let obs = observations.map { $0.topCandidates(1).first?.string ?? ""}
    let result = obs.joined(separator: "\n")
    print(result)
}

request.recognitionLevel = VNRequestTextRecognitionLevel.accurate
request.usesLanguageCorrection = true
request.recognitionLanguages = ["ja", "en"]
let revision: Int
if #available(macOS 13.0, *) {
    revision = VNRecognizeTextRequestRevision3
} else if #available(macOS 11.0, *) {
    revision = VNRecognizeTextRequestRevision2
} else {
    revision = VNRecognizeTextRequestRevision1
}
request.revision = revision


for i in 0..<pageCount {
    let scaleFactor = dpi / (72.0*NSScreen.main!.backingScaleFactor)
    let pdfImageRep = NSPDFImageRep(data: doc.page(at: i)!.dataRepresentation!)!
    let originalSize = pdfImageRep.bounds.size
    let scaledSize = NSSize(width: originalSize.width * scaleFactor, height: originalSize.height * scaleFactor)
    let targetRect = NSRect(origin: NSPoint.zero, size: scaledSize)
    let image = NSImage(size: targetRect.size)
    image.lockFocus()
    NSColor.white.set()
    NSBezierPath.fill(targetRect)
    pdfImageRep.draw(in: targetRect)
    image.unlockFocus()
    let cgImage = NSBitmapImageRep(data: image.tiffRepresentation!)!.cgImage!

    try! VNImageRequestHandler(cgImage: cgImage, options: [:]).perform([request])
}