I want to use pdftron and all things work perfect but when i copy text from pdf some characters convert to blank square and question mark, any idea?
here is my pdf.
I wrote this code:
WebViewer({
    path: '/assets/plugins/pdftron',
    initialDoc: '/practical.pdf',
    fullAPI: true,
    disableLogs: true
}, document.getElementById('pdf')).then((instance) => {
    // PDFNet is only available with full API enabled
    const { PDFNet, docViewer } = instance;
    let Feature = instance.Feature;
    instance.disableFeatures([Feature.NotesPanel]);
    docViewer.on('documentLoaded', () => {
        // call methods relating to the loaded document
    });
    instance.textPopup.add({
        type: 'actionButton',
        img: '/language.svg',
        onClick: () => {
            const quads = docViewer.getSelectedTextQuads(docViewer.getCurrentPage());
            const text = docViewer.getSelectedText();
            $("#out-pdf").html(text);
            console.log(quads);
        },
    });
});
