Fill form - Checkbox

Hi,

First, fantastic work and effort is put in here - the docs, the code, the explanations, the comments! Very concise and user friendly. Thank you for that.

Environment is typescript in node, and pdf-lib v1.16.0.

If in my PDF I have checkboxes like this (this was forwarded by 3rd party person, not generated by me)

and with logs like this

const form = pdfDoc.getForm();
form.getFields().forEach((field) => {
  console.log('FIELD ---- ', `name: ${field.getName()}; type: ${field.constructor.name}`);
});

i have output:

FIELD ---- name: Status; type: PDFCheckBox

With command const status = form.getCheckBox('Status'); and status.check(); the only first checkbox gets checked. The problem for me here is that I don’t know how to manipulate with particular checkboxes (‘Single or Head of household’, ‘Married’, ‘Married, but withhold at higher single rate’).

I was wondering where the problem lies:

• in the PDF implementation?
• or am I missing something in my code?

Giving any kind of directions or hints would be very much appreciated. If I can provide more details from logs, please let me know. Cheers!

[StefanZivkovic]

OK, we managed to do it after diving into PDFCheckBox.ts file & setValue method and PDFAcroCheckBox.ts file &setValue method. PDFCheckBox.ts file:

check() {
    const onValue = this.acroField.getOnValue() ?? PDFName.of('Yes');
    this.markAsDirty();
    this.acroField.setValue(onValue);       <<<---- this line
}

PDFAcroCheckBox.ts file:

setValue(value: PDFName) {
    const onValue = this.getOnValue() ?? PDFName.of('Yes');
    if (value !== onValue && value !== PDFName.of('Off')) {
      throw new InvalidAcroFieldValueError();
    }

    this.dict.set(PDFName.of('V'), value);      <<<---- this line

    const widgets = this.getWidgets();
    for (let idx = 0, len = widgets.length; idx < len; idx++) {
      const widget = widgets[idx];
      const state = widget.getOnValue() === value ? value : PDFName.of('Off');
      widget.setAppearanceState(state);       <<<---- and this line
    }
}

Our code for demonstration:

const status = form.getCheckBox('Status');
let widgets = status.acroField.getWidgets();

status.acroField.dict.set(PDFName.of('V'), widgets[1].getOnValue());
widgets[1].setAppearanceState(widgets[1].getOnValue());

status.acroField.dict.set(PDFName.of('V'), widgets[0].getOnValue());
widgets[0].setAppearanceState(widgets[0].getOnValue());

status.acroField.dict.set(PDFName.of('V'), widgets[2].getOnValue());
widgets[2].setAppearanceState(widgets[2].getOnValue());

Now we can check all checkboxes if we want while with status.check() we can check only first one.

I have also tried w/ & w/o .markAsDirty() method but it made no visual difference. Any suggestions or corrections are most welcomed!

EDIT: another way of managing something is to edit PDF online with https://www.pdfescape.com/, delete existing checkboxes and insert your own checkbox form fields. In that way you should have desired behavior with .check().

[quickskape]

I took a similar approach when field.check() check didn’t work for me. Same scenario where multiple checkboxes for a given field and I want to be able to set one of them

const acroFieldWidgets = field.acroField.getWidgets()
if (!acroFieldWidgets) {
    return
}

const acroFieldFormValue = acroFieldWidgets.find(x => x.getOnValue() === PDFName.of(formFieldValue))
if (!acroFieldFormValue) {
    return
}

const acroFieldOnValue = acroFieldFormValue.getOnValue()
if (!acroFieldOnValue) {
    return
}

acroFieldFormValue.dict.set(acroFieldOnValue, PDFHexString.fromText(formFieldValue))
acroFieldFormValue.setAppearanceState(acroFieldOnValue)

It provided the ability to set an individual check box for a field however I am still facing issues with this, as once I call field.enableReadOnly() It changes the appearance of the checkbox from a cross to a tick.