Please add language and custom words settings in JS

[ElicaInc]

Thank you for sharing this great module! if we can set automaticallyDetectsLanguage, recognitionLanguages, customWords, usesLanguageCorrection, and recognitionLevel in JS, it would be nice.

[spetrey]

big +1, language settings support would be incredible. for reference, here's the link to the Vision framework documentation on Language Settings: https://developer.apple.com/documentation/vision/recognizing_text_in_images#3601256

[ElicaInc]

Here is a sample code in TextRecognition.swift

@objc(recognize:withOptions:withResolver:withRejecter:)
    func recognize(imgPath: String, options: [String: Any], resolve: @escaping RCTPromiseResolveBlock, reject: @escaping RCTPromiseRejectBlock) {
        guard !imgPath.isEmpty else { reject("ERR", "You must include the image path", nil); return }

        let formattedImgPath = imgPath.stripPrefix("file://")
        var threshold: Float = 0.0

        var languages: [String] = ["en-US"]
        var autoDetetsLanguage: Bool = true
        var customWords: [String] = []
        var useLanguageCorrection: Bool = false
        var recognitionLevel: VNRequestTextRecognitionLevel = .accurate

        if let ignoreThreshold = options["visionIgnoreThreshold"] as? Float, !ignoreThreshold.isZero {
            threshold = ignoreThreshold
        }

        if let automaticallyDetectsLanguage = options["automaticallyDetectsLanguage"] as? Bool {
            autoDetetsLanguage = automaticallyDetectsLanguage
        }

        if let recognitionLanguages = options["recognitionLanguages"] as? [String] {
            languages = recognitionLanguages
        }

        if let words = options["customWords"] as? [String] {
            customWords = words
        }

        if let usesCorrection = options["usesLanguageCorrection"] as? Bool {
            useLanguageCorrection = usesCorrection
        }

        if let level = options["recognitionLevel"] as? String, level == "fast" {
            recognitionLevel = .fast
        }

        do {
            let imgData = try Data(contentsOf: URL(fileURLWithPath: formattedImgPath))
            let image = UIImage(data: imgData)

            guard let cgImage = image?.cgImage else { return }

            let requestHandler = VNImageRequestHandler(cgImage: cgImage)

            let ocrRequest = VNRecognizeTextRequest { (request: VNRequest, error: Error?) in
                self.recognizeTextHandler(request: request, threshold: threshold, error: error, resolve: resolve, reject: reject)
            }

              /* Revision 3, .accurate, iOS 16 and higher
               ["en-US", "fr-FR", "it-IT", "de-DE", "es-ES", "pt-BR", "zh-Hans", "zh-Hant", "yue-Hans", "yue-Hant", "ko-KR", "ja-JP", "ru-RU", "uk-UA"]
               */

              /* Revision 3, .fast, iOS 16 and higher
               ["en-US", "fr-FR", "it-IT", "de-DE", "es-ES", "pt-BR"]
               */

              /* Revision 2, .accurate, iOS 14 and higher
               ["en-US", "fr-FR", "it-IT", "de-DE", "es-ES", "pt-BR", "zh-Hans", "zh-Hant"]
               */

              /* Revision 2, .fast iOS, 14 and higher
               ["en-US", "fr-FR", "it-IT", "de-DE", "es-ES", "pt-BR"]
               */

            if autoDetetsLanguage {
                if #available(iOS 16.0, *) {
                    ocrRequest.automaticallyDetectsLanguage = true
                } else {
                    ocrRequest.recognitionLanguages = languages
                }
            } else {
                ocrRequest.recognitionLanguages = languages
            }

            ocrRequest.customWords = customWords
            ocrRequest.usesLanguageCorrection = useLanguageCorrection
            ocrRequest.recognitionLevel = recognitionLevel

            try requestHandler.perform([ocrRequest])
        } catch {
            print(error)
            reject("ERR", error.localizedDescription, nil)
        }
    }

Call 'recognitionLanguages' in JS

    const text = await TextRecognition.recognize(img, {
      automaticallyDetectsLanguage: false,
      recognitionLanguages: ["en-US"]
    });

Hope this works!

[spetrey]

@ElicaInc yeah this feels right. I'm thinking typing the supported langs for recognitionLanguages would be nice:

// react-native-text-recognition/src/index.tsx
import { NativeModules } from 'react-native';

type SupportedLanuages = "en-US" | "fr-FR" | "it-IT" | "de-DE" | "es-ES" | "pt-BR" | "zh-Hans" | "zh-Hant" | "yue-Hans" | "yue-Hant" | "ko-KR" | "ja-JP" | "ru-RU" | "uk-UA"

export type TextRecognitionOptions = {
  visionIgnoreThreshold?: number;
  automaticallyDetectsLanguage: boolean,
  recognitionLanguages: SupportedLanuages[],
};
...

As for the swift code — I will admit that while swift is not my forte, I will happily test any PRs! 😄

@JoeyEamigh do you have any thoughts here?