acroform.js

const FIELD_FLAGS = {
  readOnly: 1,
  required: 2,
  noExport: 4,
  multiline: 0x1000,
  password: 0x2000,
  toggleToOffButton: 0x4000,
  radioButton: 0x8000,
  pushButton: 0x10000,
  combo: 0x20000,
  edit: 0x40000,
  sort: 0x80000,
  multiSelect: 0x200000,
  noSpell: 0x400000
};
const FIELD_JUSTIFY = {
  left: 0,
  center: 1,
  right: 2
};
const VALUE_MAP = { value: 'V', defaultValue: 'DV' };
const FORMAT_SPECIAL = {
  zip: '0',
  zipPlus4: '1',
  zip4: '1',
  phone: '2',
  ssn: '3'
};
const FORMAT_DEFAULT = {
  number: {
    nDec: 0,
    sepComma: false,
    negStyle: 'MinusBlack',
    currency: '',
    currencyPrepend: true
  },
  percent: {
    nDec: 0,
    sepComma: false
  }
};

export default {
  /**
   * Must call if adding AcroForms to a document. Must also call font() before
   * this method to set the default font.
   */
  initForm() {
    if (!this._font) {
      throw new Error('Must set a font before calling initForm method');
    }
    this._acroform = {
      fonts: {},
      defaultFont: this._font.name
    };
    this._acroform.fonts[this._font.id] = this._font.ref();

    let data = {
      Fields: [],
      NeedAppearances: true,
      DA: new String(`/${this._font.id} 0 Tf 0 g`),
      DR: {
        Font: {}
      }
    };
    data.DR.Font[this._font.id] = this._font.ref();
    const AcroForm = this.ref(data);
    this._root.data.AcroForm = AcroForm;
    return this;
  },

  /**
   * Called automatically by document.js
   */
  endAcroForm() {
    if (this._root.data.AcroForm) {
      if (
        !Object.keys(this._acroform.fonts).length &&
        !this._acroform.defaultFont
      ) {
        throw new Error('No fonts specified for PDF form');
      }
      let fontDict = this._root.data.AcroForm.data.DR.Font;
      Object.keys(this._acroform.fonts).forEach(name => {
        fontDict[name] = this._acroform.fonts[name];
      });
      this._root.data.AcroForm.data.Fields.forEach(fieldRef => {
        this._endChild(fieldRef);
      });
      this._root.data.AcroForm.end();
    }
    return this;
  },

  _endChild(ref) {
    if (Array.isArray(ref.data.Kids)) {
      ref.data.Kids.forEach(childRef => {
        this._endChild(childRef);
      });
      ref.end();
    }
    return this;
  },

  /**
   * Creates and adds a form field to the document. Form fields are intermediate
   * nodes in a PDF form that are used to specify form name heirarchy and form
   * value defaults.
   * @param {string} name - field name (T attribute in field dictionary)
   * @param {object} options  - other attributes to include in field dictionary
   */
  formField(name, options = {}) {
    let fieldDict = this._fieldDict(name, null, options);
    let fieldRef = this.ref(fieldDict);
    this._addToParent(fieldRef);
    return fieldRef;
  },

  /**
   * Creates and adds a Form Annotation to the document. Form annotations are
   * called Widget annotations internally within a PDF file.
   * @param {string} name - form field name (T attribute of widget annotation
   * dictionary)
   * @param {number} x
   * @param {number} y
   * @param {number} w
   * @param {number} h
   * @param {object} options
   */
  formAnnotation(name, type, x, y, w, h, options = {}) {
    let fieldDict = this._fieldDict(name, type, options);
    fieldDict.Subtype = 'Widget';
    if (fieldDict.F === undefined) {
      fieldDict.F = 4; // print the annotation
    }

    // Add Field annot to page, and get it's ref
    this.annotate(x, y, w, h, fieldDict);
    let annotRef = this.page.annotations[this.page.annotations.length - 1];

    return this._addToParent(annotRef);
  },

  formText(name, x, y, w, h, options = {}) {
    return this.formAnnotation(name, 'text', x, y, w, h, options);
  },

  formPushButton(name, x, y, w, h, options = {}) {
    return this.formAnnotation(name, 'pushButton', x, y, w, h, options);
  },

  formCombo(name, x, y, w, h, options = {}) {
    return this.formAnnotation(name, 'combo', x, y, w, h, options);
  },

  formList(name, x, y, w, h, options = {}) {
    return this.formAnnotation(name, 'list', x, y, w, h, options);
  },

  formRadioButton(name, x, y, w, h, options = {}) {
    return this.formAnnotation(name, 'radioButton', x, y, w, h, options);
  },

  formCheckbox(name, x, y, w, h, options = {}) {
    return this.formAnnotation(name, 'checkbox', x, y, w, h, options);
  },

  _addToParent(fieldRef) {
    let parent = fieldRef.data.Parent;
    if (parent) {
      if (!parent.data.Kids) {
        parent.data.Kids = [];
      }
      parent.data.Kids.push(fieldRef);
    } else {
      this._root.data.AcroForm.data.Fields.push(fieldRef);
    }
    return this;
  },

  _fieldDict(name, type, options = {}) {
    if (!this._acroform) {
      throw new Error(
        'Call document.initForms() method before adding form elements to document'
      );
    }
    let opts = Object.assign({}, options);
    if (type !== null) {
      opts = this._resolveType(type, options);
    }
    opts = this._resolveFlags(opts);
    opts = this._resolveJustify(opts);
    opts = this._resolveFont(opts);
    opts = this._resolveStrings(opts);
    opts = this._resolveColors(opts);
    opts = this._resolveFormat(opts);
    opts.T = new String(name);
    if (opts.parent) {
      opts.Parent = opts.parent;
      delete opts.parent;
    }
    return opts;
  },

  _resolveType(type, opts) {
    if (type === 'text') {
      opts.FT = 'Tx';
    } else if (type === 'pushButton') {
      opts.FT = 'Btn';
      opts.pushButton = true;
    } else if (type === 'radioButton') {
      opts.FT = 'Btn';
      opts.radioButton = true;
    } else if (type === 'checkbox') {
      opts.FT = 'Btn';
    } else if (type === 'combo') {
      opts.FT = 'Ch';
      opts.combo = true;
    } else if (type === 'list') {
      opts.FT = 'Ch';
    } else {
      throw new Error(`Invalid form annotation type '${type}'`);
    }
    return opts;
  },

  _resolveFormat(opts) {
    const f = opts.format;
    if (f && f.type) {
      let fnKeystroke;
      let fnFormat;
      let params = '';
      if (FORMAT_SPECIAL[f.type] !== undefined) {
        fnKeystroke = `AFSpecial_Keystroke`;
        fnFormat = `AFSpecial_Format`;
        params = FORMAT_SPECIAL[f.type];
      } else {
        let format = f.type.charAt(0).toUpperCase() + f.type.slice(1);
        fnKeystroke = `AF${format}_Keystroke`;
        fnFormat = `AF${format}_Format`;

        if (f.type === 'date') {
          fnKeystroke += 'Ex';
          params = String(f.param);
        } else if (f.type === 'time') {
          params = String(f.param);
        } else if (f.type === 'number') {
          let p = Object.assign({}, FORMAT_DEFAULT.number, f);
          params = String(
            [
              String(p.nDec),
              p.sepComma ? '0' : '1',
              '"' + p.negStyle + '"',
              'null',
              '"' + p.currency + '"',
              String(p.currencyPrepend)
            ].join(',')
          );
        } else if (f.type === 'percent') {
          let p = Object.assign({}, FORMAT_DEFAULT.percent, f);
          params = String([String(p.nDec), p.sepComma ? '0' : '1'].join(','));
        }
      }
      opts.AA = opts.AA ? opts.AA : {};
      opts.AA.K = {
        S: 'JavaScript',
        JS: new String(`${fnKeystroke}(${params});`)
      };
      opts.AA.F = {
        S: 'JavaScript',
        JS: new String(`${fnFormat}(${params});`)
      };
    }
    delete opts.format;
    return opts;
  },

  _resolveColors(opts) {
    let color = this._normalizeColor(opts.backgroundColor);
    if (color) {
      if (!opts.MK) {
        opts.MK = {};
      }
      opts.MK.BG = color;
    }
    color = this._normalizeColor(opts.borderColor);
    if (color) {
      if (!opts.MK) {
        opts.MK = {};
      }
      opts.MK.BC = color;
    }
    delete opts.backgroundColor;
    delete opts.borderColor;
    return opts;
  },

  _resolveFlags(options) {
    let result = 0;
    Object.keys(options).forEach(key => {
      if (FIELD_FLAGS[key]) {
        result |= FIELD_FLAGS[key];
        delete options[key];
      }
    });
    if (result !== 0) {
      options.Ff = options.Ff ? options.Ff : 0;
      options.Ff |= result;
    }
    return options;
  },

  _resolveJustify(options) {
    let result = 0;
    if (options.align !== undefined) {
      if (typeof FIELD_JUSTIFY[options.align] === 'number') {
        result = FIELD_JUSTIFY[options.align];
      }
      delete options.align;
    }
    if (result !== 0) {
      options.Q = result; // default
    }
    return options;
  },

  _resolveFont(options) {
    // add current font to document-level AcroForm dict if necessary
    if (this._acroform.fonts[this._font.id] === null) {
      this._acroform.fonts[this._font.id] = this._font.ref();
    }

    // add current font to field's resource dict (RD) if not the default acroform font
    if (this._acroform.defaultFont !== this._font.name) {
      options.DR = { Font: {} };
      options.DR.Font[this._font.id] = this._font.ref();
      options.DA = new String(`/${this._font.id} 0 Tf 0 g`);
    }
    return options;
  },

  _resolveStrings(options) {
    let select = [];
    function appendChoices(a) {
      if (Array.isArray(a)) {
        for (let idx = 0; idx < a.length; idx++) {
          if (typeof a[idx] === 'string') {
            select.push(new String(a[idx]));
          } else {
            select.push(a[idx]);
          }
        }
      }
    }
    appendChoices(options.Opt);
    if (options.select) {
      appendChoices(options.select);
      delete options.select;
    }
    if (select.length) {
      options.Opt = select;
    }

    Object.keys(VALUE_MAP).forEach(key => {
      if (options[key] !== undefined) {
        options[VALUE_MAP[key]] = options[key];
        delete options[key];
      }
    });
    ['V', 'DV'].forEach(key => {
      if (typeof options[key] === 'string') {
        options[key] = new String(options[key]);
      }
    });

    if (options.MK && options.MK.CA) {
      options.MK.CA = new String(options.MK.CA);
    }
    if (options.label) {
      options.MK = options.MK ? options.MK : {};
      options.MK.CA = new String(options.label);
      delete options.label;
    }
    return options;
  }
};