pdfkit/lib/mixins/annotations.js

export default { 
  annotate(x, y, w, h, options) {
    options.Type = 'Annot';
    options.Rect = this._convertRect(x, y, w, h);
    options.Border = [0, 0, 0];
    if (options.Subtype !== 'Link') { if (options.C == null) { options.C = this._normalizeColor(options.color || [0, 0, 0]); } } // convert colors
    delete options.color;
    
    if (typeof options.Dest === 'string') {
      options.Dest = new String(options.Dest);
    }
    
    // Capitalize keys  
    for (let key in options) {
      const val = options[key];
      options[key[0].toUpperCase() + key.slice(1)] = val;
    }
      
    const ref = this.ref(options);
    this.page.annotations.push(ref);
    ref.end();
    return this;
  },
    
  note(x, y, w, h, contents, options) {
    if (options == null) { options = {}; }
    options.Subtype = 'Text';
    options.Contents = new String(contents);
    options.Name = 'Comment';
    if (options.color == null) { options.color = [243, 223, 92]; }
    return this.annotate(x, y, w, h, options);
  },
    
  link(x, y, w, h, url, options) {
    if (options == null) { options = {}; }
    options.Subtype = 'Link';

    if (typeof url === 'number') {
      // Link to a page in the document (the page must already exist)
      const pages = this._root.data.Pages.data;
      if ((url >= 0) && (url < pages.Kids.length)) {
        options.A = this.ref({
          S: 'GoTo',
          D: [pages.Kids[url], 'XYZ', null, null, null]});
        options.A.end();
      } else {
        throw new Error(`The document has no page ${url}`);
      }

    } else {
      // Link to an external url
      options.A = this.ref({
        S: 'URI',
        URI: new String(url)
      });
      options.A.end();
    }

    return this.annotate(x, y, w, h, options);
  },

  _markup(x, y, w, h, options) {
    if (options == null) { options = {}; }
    const [x1, y1, x2, y2] = this._convertRect(x, y, w, h);
    options.QuadPoints = [x1, y2, x2, y2, x1, y1, x2, y1];
    options.Contents = new String;
    return this.annotate(x, y, w, h, options);
  },
    
  highlight(x, y, w, h, options) {
    if (options == null) { options = {}; }
    options.Subtype = 'Highlight';
    if (options.color == null) { options.color = [241, 238, 148]; }
    return this._markup(x, y, w, h, options);
  },
    
  underline(x, y, w, h, options) {
    if (options == null) { options = {}; }
    options.Subtype = 'Underline';
    return this._markup(x, y, w, h, options);
  },
    
  strike(x, y, w, h, options) {
    if (options == null) { options = {}; }
    options.Subtype = 'StrikeOut';
    return this._markup(x, y, w, h, options);
  },
    
  lineAnnotation(x1, y1, x2, y2, options) {
    if (options == null) { options = {}; }
    options.Subtype = 'Line';
    options.Contents = new String;
    options.L = [x1, this.page.height - y1, x2, this.page.height - y2];
    return this.annotate(x1, y1, x2, y2, options);
  },
    
  rectAnnotation(x, y, w, h, options) {
    if (options == null) { options = {}; }
    options.Subtype = 'Square';
    options.Contents = new String;
    return this.annotate(x, y, w, h, options);
  },
    
  ellipseAnnotation(x, y, w, h, options) {
    if (options == null) { options = {}; }
    options.Subtype = 'Circle';
    options.Contents = new String;
    return this.annotate(x, y, w, h, options);
  },
    
  textAnnotation(x, y, w, h, text, options) {
    if (options == null) { options = {}; }
    options.Subtype = 'FreeText';
    options.Contents = new String(text);
    options.DA = new String;
    return this.annotate(x, y, w, h, options);
  },
    
  _convertRect(x1, y1, w, h) {
    // flip y1 and y2
    let y2 = y1;
    y1 += h;
    
    // make x2
    let x2 = x1 + w;
    
    // apply current transformation matrix to points
    const [m0, m1, m2, m3, m4, m5] = this._ctm;
    x1 = (m0 * x1) + (m2 * y1) + m4;
    y1 = (m1 * x1) + (m3 * y1) + m5;
    x2 = (m0 * x2) + (m2 * y2) + m4;
    y2 = (m1 * x2) + (m3 * y2) + m5;
    
    return [x1, y1, x2, y2];
  }
};