React Native Requires Chilkat v11.7.0+

Why a PDF Text Replacement Is Refused: the Font Rule

See more PDF Text Replacement Examples

A PDF stores glyphs drawn with particular fonts, so new text can only be drawn when the original font can draw it. This example shows the two common refusals. A font embedded as a subset carries only the glyphs the document used: a value made of other characters is refused with the reason missingGlyph, and the report names the font and the characters it lacks. A font that is neither one of the standard 14 nor embedded (here Verdana) is refused with nonStandardUnembeddedFont, because Chilkat cannot know what a viewer will draw for it. A non-embedded Arial, Times New Roman or Courier New is treated as the standard font every viewer substitutes for it. React Native

import { JsonObject, Pdf } from '@chilkat/react-native'

function chilkatExample() {
  let success = false;

  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // The PDF used in this example is available at quote_subset_font.pdf
  // and letter_verdana.pdf

  // 1. An embedded subset font: only the glyphs the document uses are in the PDF.
  const pdf = new Pdf();
  try {
    pdf.loadFile('qa_data/pdf/quote_subset_font.pdf');
  } catch {
    console.log(pdf.lastErrorText);
    return;
  }

  const json = new JsonObject();
  const jsonOut = new JsonObject();

  // The regular face's subset carries the characters of the quotation's text, among them the digits of
  // "58341".  A new number made of those digits can be drawn...
  json.updateString('labels[0].label', 'Quote #:');
  json.updateString('labels[0].value', '58314');
  try {
    pdf.textReplace('check', json, jsonOut);
  } catch {
    console.log(pdf.lastErrorText);
    return;
  }

  console.log(`58314: ok = ${jsonOut.boolOf('ok')}`);

  // ...but "Q" and "-" are not in the subset (nothing in the quotation's regular text uses them).
  json.updateString('labels[0].value', 'Q-58341');
  try {
    pdf.textReplace('check', json, jsonOut);
  } catch {
    console.log(pdf.lastErrorText);
    return;
  }

  console.log(`Q-58341: ok = ${jsonOut.boolOf('ok')}`);
  if (!jsonOut.boolOf('ok')) {
    // The problem names the font and the characters it cannot draw.
    console.log(`    reason: ${jsonOut.stringOf('problems[0].reason')}`);
    console.log(`    font: ${jsonOut.stringOf('problems[0].font')}`);
    console.log(`    missing: ${jsonOut.stringOf('problems[0].chars')}`);
  }

  // "apply" with a problem returns false and changes nothing.
  success = true;
  try {
    pdf.textReplace('apply', json, jsonOut);
  } catch {
    success = false;
  }
  console.log(`apply returned ${success}, applied = ${jsonOut.boolOf('applied')}`);

  // 2. A font that is not embedded and not one of the standard 14.
  const pdf2 = new Pdf();
  try {
    pdf2.loadFile('qa_data/pdf/letter_verdana.pdf');
  } catch {
    console.log(pdf2.lastErrorText);
    return;
  }

  const json2 = new JsonObject();
  json2.updateString('labels[0].label', 'Account Number:');
  json2.updateString('labels[0].value', '0000099999');
  try {
    pdf2.textReplace('check', json2, jsonOut);
  } catch {
    console.log(pdf2.lastErrorText);
    return;
  }

  console.log(`Verdana, not embedded: ok = ${jsonOut.boolOf('ok')}, reason: ${jsonOut.stringOf('problems[0].reason')}, font: ${jsonOut.stringOf('problems[0].font')}`);

  // Sample output:

  // 58314: ok = true
  // Q-58341: ok = false
  //     reason: missingGlyph
  //     font: AAAAAA+DejaVuSans
  //     missing: Q-
  // apply returned false, applied = false
  // Verdana, not embedded: ok = false, reason: nonStandardUnembeddedFont, font: Verdana
}