Convert images to text on iOS

Nutrient supports extracting textual information from a scanned PDF. To do so, follow the steps below:

First, convert the image into a PDF file as described in the image-to-PDF conversion guide.
Next, perform OCR on the PDF file so that the textual information is extracted out of the image. This process is described in detail in the converting a scan into a searchable PDF guide.
After performing OCR on the document, use PSPDFTextParser to retrieve the text, text blocks, words, or glyphs from a page. Here’s a detailed guide explaining how to do that.

This entire process is explained with the sample code below:

// Convert the image to a PDF file.
let image: UIImage = ...
let outputFileURL: URL = ... // Writable file URL.
let pageTemplate = PageTemplate(pageType: .emptyPage, identifier: nil)
let newPageConfiguration = PDFNewPageConfiguration(pageTemplate: pageTemplate) { builder in
    builder.item = ProcessorItem(image: image, jpegCompressionQuality: 0.7, builderBlock: nil)
    builder.pageSize = image.size
}

let configuration = Processor.Configuration()
configuration.addNewPage(at: 0, configuration: newPageConfiguration)

do {
    try Processor(configuration: configuration, securityOptions: nil).write(toFileURL: outputFileURL)
} catch {
    print("Could not create PDF file: \(error)")
}

// Perform OCR on the file.
let document = Document(url: outputFileURL)
guard let processorConfiguration = Processor.Configuration(document: document) else {
    return
}
// Mark the processor to perform OCR on all document pages and detect text in English.
processorConfiguration.performOCROnPages(at: IndexSet(0..<IndexSet.Element(document.pageCount)), options: ProcessorOCROptions(language: .english))

let processor = Processor(configuration: processorConfiguration, securityOptions: nil)
let ocrURL: URL = ... // Writable file URL.

DispatchQueue.global(qos: .userInitiated).async {
    do {
    	// This performs the actual OCR and generates the new document at the provided URL.
        try processor.write(toFileURL: ocrURL)
    } catch {
        // Handle error.
    }
    DispatchQueue.main.async {
        let ocrDocument = Document(url: ocrURL)

        // Retrieve text from the document.
        guard let textParser = ocrDocument.textParserForPage(at: 0) else {
            // Handle failure
        }
        print("Text of page 0: \(textParser.text)")

        for textBlock in textParser.textBlocks {
            print("TextBlock at \(textBlock.frame): \(textBlock.content)")
        }
    }
}