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pdf-lib › PDFDropdown 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 ). Hierarchy Index Properties Methods Properties acroField• acroField: PDFAcroComboBox Overrides PDFField. Defined in The low-level PDFAcroComboBox wrapped by this dropdown. doc• doc: PDFDocument Inherited from PDFField. Defined in The document to which this field belongs. ref• ref: PDFRef Inherited from PDFField. Defined in The unique reference assigned to this field within the document. Methods addOptions▸ addOptions(options: string | string[]): void Defined in 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: NameTypeDescriptionoptions string | string[] New options that should be available in this dropdown. Returns: void addToPage▸ addToPage(page: PDFPage, options?: FieldAppearanceOptions): void Defined in 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: NameTypeDescriptionpage 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 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 for more details about what this means. Returns: void defaultUpdateAppearances▸ defaultUpdateAppearances(font: PDFFont): void Overrides void Defined in 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: NameTypeDescriptionfont PDFFont The font to be used for creating the appearance streams. Returns: void disableEditing▸ disableEditing(): void Defined in 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. Defined in 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 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. Defined in 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. Defined in 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 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 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 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 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. Defined in 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 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. Defined in 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. Defined in 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 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 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 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. Defined in 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 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 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 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 and . 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. Defined in Returns true if this field's value should be exported when the form is submitted. See and . 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 Returns true if multiple options can be selected from this dropdown's option list. See and . 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. Defined in 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 and . 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. Defined in Returns true if this field must have a value when the form is submitted. See and . 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 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 and . 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 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 and . 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 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 ). See and . 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 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 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 or 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 . 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 or 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 ) will enable editing on this dropdown (see ). 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: NameTypeDefaultDescriptionoptions 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 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: NameTypeDescriptionfontSize number The font size to be used when rendering text in this field. Returns: void setOptions▸ setOptions(options: string[]): void Defined in 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: NameTypeDescriptionoptions string[] The options that should be available in this dropdown. Returns: void updateAppearances▸ updateAppearances(font: PDFFont, provider?: ‹PDFDropdown›): void Defined in 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: NameTypeDescriptionfont PDFFont The font to be used for creating the appearance streams. provider? ‹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 NOTE: You probably don't want to call this method directly. Instead, consider using the method, which will create an instance of PDFDropdown for you. Create an instance of PDFDropdown from an existing acroComboBox and ref Parameters: NameTypeDescriptionacroComboBox 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‹› ← PDFDocumentPDFEmbeddedPage → (责任编辑：) |