PDFDropdown · PDF-LIB

Represents a dropdown field of a PDFForm.

PDFDropdown fields are interactive text boxes that display a single element (the currently selected value). The purpose of a dropdown is to enable users to select a single option from a set of possible options. Users can click on a dropdown to view the full list of options it provides. Clicking on an option in the list will cause it to be selected and displayed in the dropdown's text box. Some dropdowns allow users to enter text directly into the box from their keyboard, rather than only being allowed to choose an option from the list (see PDFDropdown.isEditable).

Hierarchy

PDFField

↳ PDFDropdown

Index

Properties

Methods

Properties

acroField

• acroField: PDFAcroComboBox

Overrides PDFField.acroField

Defined in api/form/PDFDropdown.ts:55

The low-level PDFAcroComboBox wrapped by this dropdown.

doc

• doc: PDFDocument

Inherited from PDFField.doc

Defined in api/form/PDFField.ts:92

The document to which this field belongs.

ref

• ref: PDFRef

Inherited from PDFField.ref

Defined in api/form/PDFField.ts:89

The unique reference assigned to this field within the document.

Methods

addOptions

▸ addOptions(options: string | string[]): void

Defined in api/form/PDFDropdown.ts:157

Add to the list of options that are available for this dropdown. Users will be able to select these values in a PDF reader. In addition to the values passed as options, any preexisting options for this dropdown will still be available for users to select. For example:

const dropdown = form.getDropdown('rockets.dropdown')
dropdown.addOptions(['Saturn IV', 'Falcon Heavy'])

Parameters:

Name	Type	Description
`options`	string \| string[]	New options that should be available in this dropdown.

Returns: void

addToPage

▸ addToPage(page: PDFPage, options?: FieldAppearanceOptions): void

Defined in api/form/PDFDropdown.ts:529

Show this dropdown on the specified page. For example:

const ubuntuFont = await pdfDoc.embedFont(ubuntuFontBytes)
const page = pdfDoc.addPage()

const form = pdfDoc.getForm()
const dropdown = form.createDropdown('best.gundam')
dropdown.setOptions(['Exia', 'Dynames'])
dropdown.select('Exia')

dropdown.addToPage(page, {
  x: 50,
  y: 75,
  width: 200,
  height: 100,
  textColor: rgb(1, 0, 0),
  backgroundColor: rgb(0, 1, 0),
  borderColor: rgb(0, 0, 1),
  borderWidth: 2,
  rotate: degrees(90),
  font: ubuntuFont,
})

This will create a new widget for this dropdown field.

Parameters:

Name	Type	Description
`page`	PDFPage	The page to which this dropdown widget should be added.
`options?`	FieldAppearanceOptions	The options to be used when adding this dropdown widget.

Returns: void

clear

▸ clear(): void

Defined in api/form/PDFDropdown.ts:261

Clear all selected values for this dropdown. This operation is equivalent to selecting an empty list. This method will update the underlying state of the dropdown to indicate that no values have been selected. For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.clear()

This method will mark this text field as dirty. See PDFDropdown.select for more details about what this means.

Returns: void

defaultUpdateAppearances

▸ defaultUpdateAppearances(font: PDFFont): void

Overrides void

Defined in api/form/PDFDropdown.ts:600

Update the appearance streams for each of this dropdown's widgets using the default appearance provider for dropdowns. For example:

const helvetica = await pdfDoc.embedFont(StandardFonts.Helvetica)
const dropdown = form.getDropdown('some.dropdown.field')
dropdown.defaultUpdateAppearances(helvetica)

Parameters:

Name	Type	Description
`font`	PDFFont	The font to be used for creating the appearance streams.

Returns: void

disableEditing

▸ disableEditing(): void

Defined in api/form/PDFDropdown.ts:334

Do not allow users to edit the selected value of this dropdown in PDF readers with their keyboard. This will constrain the selected value of this dropdown to the list of available options. Users will only be able to select an option from that list. For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.disableEditing()

Returns: void

disableExporting

▸ disableExporting(): void

Inherited from PDFField.disableExporting

Defined in api/form/PDFField.ts:247

Indicate that this field's value should not be exported when the form is submitted in a PDF reader. For example:

const field = form.getField('some.field')
field.disableExporting()

Returns: void

disableMultiselect

▸ disableMultiselect(): void

Defined in api/form/PDFDropdown.ts:413

Do not allow users to select more than one option from this dropdown's option list. For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.disableMultiselect()

Returns: void

disableReadOnly

▸ disableReadOnly(): void

Inherited from PDFField.disableReadOnly

Defined in api/form/PDFField.ts:170

Allow users to interact with this field and change its value in PDF readers via mouse and keyboard input. For example:

const field = form.getField('some.field')
field.disableReadOnly()

Returns: void

disableRequired

▸ disableRequired(): void

Inherited from PDFField.disableRequired

Defined in api/form/PDFField.ts:208

Do not require this field to have a value when the form is submitted. For example:

const field = form.getField('some.field')
field.disableRequired()

Returns: void

disableSelectOnClick

▸ disableSelectOnClick(): void

Defined in api/form/PDFDropdown.ts:497

Wait to store the option selected by a user until they leave this dropdown field (by clicking outside of it - on another field, for example). For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.disableSelectOnClick()

Returns: void

disableSorting

▸ disableSorting(): void

Defined in api/form/PDFDropdown.ts:375

Do not always display the option list of this dropdown in alphabetical order. Instead, display the options in whichever order they were added to the list. For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.disableSorting()

Returns: void

disableSpellChecking

▸ disableSpellChecking(): void

Defined in api/form/PDFDropdown.ts:453

Do not allow PDF readers to spell check the selected option of this dropdown. For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.disableSpellChecking()

Returns: void

enableEditing

▸ enableEditing(): void

Defined in api/form/PDFDropdown.ts:319

Allow users to edit the selected value of this dropdown in PDF readers with their keyboard. This means that the selected value of this dropdown will not be constrained by the list of available options. However, if this dropdown has any available options, users will still be allowed to select from that list. For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.enableEditing()

Returns: void

enableExporting

▸ enableExporting(): void

Inherited from PDFField.enableExporting

Defined in api/form/PDFField.ts:235

Indicate that this field's value should be exported when the form is submitted in a PDF reader. For example:

const field = form.getField('some.field')
field.enableExporting()

Returns: void

enableMultiselect

▸ enableMultiselect(): void

Defined in api/form/PDFDropdown.ts:401

Allow users to select more than one option from this dropdown's option list. For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.enableMultiselect()

Returns: void

enableReadOnly

▸ enableReadOnly(): void

Inherited from PDFField.enableReadOnly

Defined in api/form/PDFField.ts:158

Prevent PDF readers from allowing users to interact with this field or change its value. The field will not respond to mouse or keyboard input. For example:

const field = form.getField('some.field')
field.enableReadOnly()

Useful for fields whose values are computed, imported from a database, or prefilled by software before being displayed to the user.

Returns: void

enableRequired

▸ enableRequired(): void

Inherited from PDFField.enableRequired

Defined in api/form/PDFField.ts:196

Require this field to have a value when the form is submitted. For example:

const field = form.getField('some.field')
field.enableRequired()

Returns: void

enableSelectOnClick

▸ enableSelectOnClick(): void

Defined in api/form/PDFDropdown.ts:484

Store the option selected by a user immediately after the user clicks the option. Do not wait for the user to leave this dropdown field (by clicking outside of it - on another field, for example). For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.enableSelectOnClick()

Returns: void

enableSorting

▸ enableSorting(): void

Defined in api/form/PDFDropdown.ts:362

Always display the option list of this dropdown in alphabetical order, irrespective of the order in which the options were added to this dropdown. For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.enableSorting()

Returns: void

enableSpellChecking

▸ enableSpellChecking(): void

Defined in api/form/PDFDropdown.ts:441

Allow PDF readers to spell check the selected option of this dropdown. For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.enableSpellChecking()

Returns: void

getName

▸ getName(): string

Inherited from PDFField.getName

Defined in api/form/PDFField.ts:128

Get the fully qualified name of this field. For example:

const fields = form.getFields()
fields.forEach(field => {
  const name = field.getName()
  console.log('Field name:', name)
})

Note that PDF fields are structured as a tree. Each field is the descendent of a series of ancestor nodes all the way up to the form node, which is always the root of the tree. Each node in the tree (except for the form node) has a partial name. Partial names can be composed of any unicode characters except a period (.). The fully qualified name of a field is composed of the partial names of all its ancestors joined with periods. This means that splitting the fully qualified name on periods and taking the last element of the resulting array will give you the partial name of a specific field.

Returns: string

The fully qualified name of this field.

getOptions

▸ getOptions(): string[]

Defined in api/form/PDFDropdown.ts:82

Get the list of available options for this dropdown. These options will be displayed to users who click on this dropdown in a PDF reader. For example:

const dropdown = form.getDropdown('some.dropdown.field')
const options = dropdown.getOptions()
console.log('Dropdown options:', options)

Returns: string[]

The options for this dropdown.

getSelected

▸ getSelected(): string[]

Defined in api/form/PDFDropdown.ts:111

Get the selected options for this dropdown. These are the values that were selected by a human user via a PDF reader, or programatically via software. For example:

const dropdown = form.getDropdown('some.dropdown.field')
const selections = dropdown.getSelected()
console.log('Dropdown selections:', selections)

NOTE: Note that PDF readers only display one selected option when rendering dropdowns. However, the PDF specification does allow for multiple values to be selected in a dropdown. As such, the pdf-lib API supports this. However, in most cases the array returned by this method will contain only a single element (or no elements).

Returns: string[]

The selected options in this dropdown.

isEditable

▸ isEditable(): boolean

Defined in api/form/PDFDropdown.ts:303

Returns true if users are allowed to edit the selected value of this dropdown directly and are not constrained by the list of available options. See PDFDropdown.enableEditing and PDFDropdown.disableEditing. For example:

const dropdown = form.getDropdown('some.dropdown.field')
if (dropdown.isEditable()) console.log('Editing is enabled')

Returns: boolean

Whether or not this dropdown is editable.

isExported

▸ isExported(): boolean

Inherited from PDFField.isExported

Defined in api/form/PDFField.ts:223

Returns true if this field's value should be exported when the form is submitted. See PDFField.enableExporting and PDFField.disableExporting. For example:

const field = form.getField('some.field')
if (field.isExported()) console.log('Exporting is enabled')

Returns: boolean

Whether or not this field's value should be exported.

isMultiselect

▸ isMultiselect(): boolean

Defined in api/form/PDFDropdown.ts:389

Returns true if multiple options can be selected from this dropdown's option list. See PDFDropdown.enableMultiselect and PDFDropdown.disableMultiselect. For example:

const dropdown = form.getDropdown('some.dropdown.field')
if (dropdown.isMultiselect()) console.log('Multiselect is enabled')

Returns: boolean

Whether or not multiple options can be selected.

isReadOnly

▸ isReadOnly(): boolean

Inherited from PDFField.isReadOnly

Defined in api/form/PDFField.ts:143

Returns true if this field is read only. This means that PDF readers will not allow users to interact with the field or change its value. See PDFField.enableReadOnly and PDFField.disableReadOnly. For example:

const field = form.getField('some.field')
if (field.isReadOnly()) console.log('Read only is enabled')

Returns: boolean

Whether or not this is a read only field.

isRequired

▸ isRequired(): boolean

Inherited from PDFField.isRequired

Defined in api/form/PDFField.ts:184

Returns true if this field must have a value when the form is submitted. See PDFField.enableRequired and PDFField.disableRequired. For example:

const field = form.getField('some.field')
if (field.isRequired()) console.log('Field is required')

Returns: boolean

Whether or not this field is required.

isSelectOnClick

▸ isSelectOnClick(): boolean

Defined in api/form/PDFDropdown.ts:471

Returns true if the option selected by a user is stored, or "committed", when the user clicks the option. The alternative is that the user's selection is stored when the user leaves this dropdown field (by clicking outside of it - on another field, for example). See PDFDropdown.enableSelectOnClick and PDFDropdown.disableSelectOnClick. For example:

const dropdown = form.getDropdown('some.dropdown.field')
if (dropdown.isSelectOnClick()) console.log('Select on click is enabled')

Returns: boolean

Whether or not options are selected immediately after they are clicked.

isSorted

▸ isSorted(): boolean

Defined in api/form/PDFDropdown.ts:349

Returns true if the option list of this dropdown is always displayed in alphabetical order, irrespective of the order in which the options were added to the dropdown. See PDFDropdown.enableSorting and PDFDropdown.disableSorting. For example:

const dropdown = form.getDropdown('some.dropdown.field')
if (dropdown.isSorted()) console.log('Sorting is enabled')

Returns: boolean

Whether or not this dropdown's options are sorted.

isSpellChecked

▸ isSpellChecked(): boolean

Defined in api/form/PDFDropdown.ts:429

Returns true if the selected option should be spell checked by PDF readers. Spell checking will only be performed if this dropdown allows editing (see PDFDropdown.isEditable). See PDFDropdown.enableSpellChecking and PDFDropdown.disableSpellChecking. For example:

const dropdown = form.getDropdown('some.dropdown.field')
if (dropdown.isSpellChecked()) console.log('Spell checking is enabled')

Returns: boolean

Whether or not this dropdown can be spell checked.

needsAppearancesUpdate

▸ needsAppearancesUpdate(): boolean

Overrides void

Defined in api/form/PDFDropdown.ts:576

Returns true if this dropdown has been marked as dirty, or if any of this dropdown's widgets do not have an appearance stream. For example:

const dropdown = form.getDropdown('some.dropdown.field')
if (dropdown.needsAppearancesUpdate()) console.log('Needs update')

Returns: boolean

Whether or not this dropdown needs an appearance update.

select

▸ select(options: string | string[], merge: boolean): void

Defined in api/form/PDFDropdown.ts:218

Select one or more values for this dropdown. This operation is analogous to a human user opening the dropdown in a PDF reader and clicking on a value to select it. This method will update the underlying state of the dropdown to indicate which values have been selected. PDF libraries and readers will be able to extract these values from the saved document and determine which values were selected.

For example:

const dropdown = form.getDropdown('best.superhero.dropdown')
dropdown.select('One Punch Man')

This method will mark this dropdown as dirty, causing its appearance streams to be updated when either PDFDocument.save or PDFForm.updateFieldAppearances is called. The updated streams will display the selected option inside the widgets of this dropdown.

IMPORTANT: The default font used to update appearance streams is StandardFonts.Helvetica. Note that this is a WinAnsi font. This means that encoding errors will be thrown if the selected option for this field contains characters outside the WinAnsi character set (the latin alphabet).

Embedding a custom font and passing it to PDFForm.updateFieldAppearances or PDFDropdown.updateAppearances allows you to generate appearance streams with characters outside the latin alphabet (assuming the custom font supports them).

Selecting an option that does not exist in this dropdown's option list (see PDFDropdown.getOptions) will enable editing on this dropdown (see PDFDropdown.enableEditing).

NOTE: PDF readers only display one selected option when rendering dropdowns. However, the PDF specification does allow for multiple values to be selected in a dropdown. As such, the pdf-lib API supports this. However, it is not recommended to select more than one value with this method, as only one will be visible. PDFOptionList fields are better suited for displaying multiple selected values.

Parameters:

Name	Type	Default	Description
`options`	string \| string[]	-	The options to be selected.
`merge`	boolean	false	Whether or not existing selections should be preserved.

Returns: void

setFontSize

▸ setFontSize(fontSize: number): void

Defined in api/form/PDFDropdown.ts:286

Set the font size for this field. Larger font sizes will result in larger text being displayed when PDF readers render this dropdown. Font sizes may be integer or floating point numbers. Supplying a negative font size will cause this method to throw an error.

For example:

const dropdown = form.getDropdown('some.dropdown.field')
dropdown.setFontSize(4)
dropdown.setFontSize(15.7)

This method depends upon the existence of a default appearance (/DA) string. If this field does not have a default appearance string, or that string does not contain a font size (via the Tf operator), then this method will throw an error.

Parameters:

Name	Type	Description
`fontSize`	number	The font size to be used when rendering text in this field.

Returns: void

setOptions

▸ setOptions(options: string[]): void

Defined in api/form/PDFDropdown.ts:135

Set the list of options that are available for this dropdown. These are the values that will be available for users to select when they view this dropdown in a PDF reader. Note that preexisting options for this dropdown will be removed. Only the values passed as options will be available to select. For example:

const dropdown = form.getDropdown('planets.dropdown')
dropdown.setOptions(['Earth', 'Mars', 'Pluto', 'Venus'])

Parameters:

Name	Type	Description
`options`	string[]	The options that should be available in this dropdown.

Returns: void

updateAppearances

▸ updateAppearances(font: PDFFont, provider?: AppearanceProviderFor‹PDFDropdown›): void

Defined in api/form/PDFDropdown.ts:621

Update the appearance streams for each of this dropdown's widgets using the given appearance provider. If no provider is passed, the default appearance provider for dropdowns will be used. For example:

const helvetica = await pdfDoc.embedFont(StandardFonts.Helvetica)
const dropdown = form.getDropdown('some.dropdown.field')
dropdown.updateAppearances(helvetica, (field, widget, font) => {
  ...
  return drawTextField(...)
})

Parameters:

Name	Type	Description
`font`	PDFFont	The font to be used for creating the appearance streams.
`provider?`	AppearanceProviderFor‹PDFDropdown›	Optionally, the appearance provider to be used for generating the contents of the appearance streams.

Returns: void

`Static` of

▸ of(acroComboBox: PDFAcroComboBox, ref: PDFRef, doc: PDFDocument): PDFDropdown‹›

Defined in api/form/PDFDropdown.ts:51

NOTE: You probably don't want to call this method directly. Instead, consider using the PDFForm.getDropdown method, which will create an instance of PDFDropdown for you.

Create an instance of PDFDropdown from an existing acroComboBox and ref

Parameters:

Name	Type	Description
`acroComboBox`	PDFAcroComboBox	The underlying `PDFAcroComboBox` for this dropdown.
`ref`	PDFRef	The unique reference for this dropdown.
`doc`	PDFDocument	The document to which this dropdown will belong.

Returns: PDFDropdown‹›

Hierarchy

Index

Properties

Methods

Properties

acroField

doc

ref

Methods

addOptions

addToPage

clear

defaultUpdateAppearances

disableEditing

disableExporting

disableMultiselect

disableReadOnly

disableRequired

disableSelectOnClick

disableSorting

disableSpellChecking

enableEditing

enableExporting

enableMultiselect

enableReadOnly

enableRequired

enableSelectOnClick

enableSorting

enableSpellChecking

getName

getOptions

getSelected

isEditable

isExported

isMultiselect

isReadOnly

isRequired

isSelectOnClick

isSorted

isSpellChecked

needsAppearancesUpdate

select

setFontSize

setOptions

updateAppearances

Static of

`Static` of