Struct PrintOperation

pub struct PrintOperation { /* private fields */ }

PrintOperation is the high-level, portable printing API.

It looks a bit different than other GTK dialogs such as the FileChooser, since some platforms don’t expose enough infrastructure to implement a good print dialog. On such platforms, PrintOperation uses the native print dialog. On platforms which do not provide a native print dialog, GTK uses its own, see PrintUnixDialog.

The typical way to use the high-level printing API is to create a PrintOperation object with new() when the user selects to print. Then you set some properties on it, e.g. the page size, any PrintSettings from previous print operations, the number of pages, the current page, etc.

Then you start the print operation by calling PrintOperationExt::run(). It will then show a dialog, let the user select a printer and options. When the user finished the dialog, various signals will be emitted on the PrintOperation, the main one being draw-page, which you are supposed to handle and render the page on the provided PrintContext using Cairo.

The high-level printing API

⚠️ The following code is in c ⚠️

static GtkPrintSettings *settings = NULL;

static void
do_print (void)
{
  GtkPrintOperation *print;
  GtkPrintOperationResult res;

  print = gtk_print_operation_new ();

  if (settings != NULL)
    gtk_print_operation_set_print_settings (print, settings);

  g_signal_connect (print, "begin_print", G_CALLBACK (begin_print), NULL);
  g_signal_connect (print, "draw_page", G_CALLBACK (draw_page), NULL);

  res = gtk_print_operation_run (print, GTK_PRINT_OPERATION_ACTION_PRINT_DIALOG,
                                 GTK_WINDOW (main_window), NULL);

  if (res == GTK_PRINT_OPERATION_RESULT_APPLY)
    {
      if (settings != NULL)
        g_object_unref (settings);
      settings = g_object_ref (gtk_print_operation_get_print_settings (print));
    }

  g_object_unref (print);
}

By default PrintOperation uses an external application to do print preview. To implement a custom print preview, an application must connect to the preview signal. The functions PrintOperationPreviewExt::render_page(), PrintOperationPreviewExt::end_preview() and PrintOperationPreviewExt::is_selected() are useful when implementing a print preview.

Properties

allow-async

Determines whether the print operation may run asynchronously or not.

Some systems don’t support asynchronous printing, but those that do will return PrintOperationResult::InProgress as the status, and emit the done signal when the operation is actually done.

The Windows port does not support asynchronous operation at all (this is unlikely to change). On other platforms, all actions except for PrintOperationAction::Export support asynchronous operation.

Readable | Writeable

current-page

The current page in the document.

If this is set before PrintOperationExt::run(), the user will be able to select to print only the current page.

Note that this only makes sense for pre-paginated documents.

Readable | Writeable

custom-tab-label

Used as the label of the tab containing custom widgets.

Note that this property may be ignored on some platforms.

If this is None, GTK uses a default label.

Readable | Writeable

default-page-setup

The PageSetup used by default.

This page setup will be used by PrintOperationExt::run(), but it can be overridden on a per-page basis by connecting to the request-page-setup signal.

Readable | Writeable

embed-page-setup

If true, page size combo box and orientation combo box are embedded into page setup page.

Readable | Writeable

export-filename

The name of a file to generate instead of showing the print dialog.

Currently, PDF is the only supported format.

The intended use of this property is for implementing “Export to PDF” actions.

“Print to PDF” support is independent of this and is done by letting the user pick the “Print to PDF” item from the list of printers in the print dialog.

Readable | Writeable

has-selection

Determines whether there is a selection in your application.

This can allow your application to print the selection. This is typically used to make a “Selection” button sensitive.

Readable | Writeable

job-name

A string used to identify the job (e.g. in monitoring applications like eggcups).

If you don’t set a job name, GTK picks a default one by numbering successive print jobs.

Readable | Writeable

n-pages

The number of pages in the document.

This must be set to a positive number before the rendering starts. It may be set in a begin-print signal handler.

Note that the page numbers passed to the request-page-setup and draw-page signals are 0-based, i.e. if the user chooses to print all pages, the last ::draw-page signal will be for page @n_pages - 1.

Readable | Writeable

n-pages-to-print

The number of pages that will be printed.

Note that this value is set during print preparation phase (PrintStatus::Preparing), so this value should never be get before the data generation phase (PrintStatus::GeneratingData). You can connect to the status-changed signal and call PrintOperationExt::n_pages_to_print() when print status is PrintStatus::GeneratingData.

This is typically used to track the progress of print operation.

Readable

print-settings

The PrintSettings used for initializing the dialog.

Setting this property is typically used to re-establish print settings from a previous print operation, see PrintOperationExt::run().

Readable | Writeable

show-progress

Determines whether to show a progress dialog during the print operation.

Readable | Writeable

status

The status of the print operation.

Readable

status-string

A string representation of the status of the print operation.

The string is translated and suitable for displaying the print status e.g. in a Statusbar.

See the status property for a status value that is suitable for programmatic use.

Readable

support-selection

If true, the print operation will support print of selection.

This allows the print dialog to show a “Selection” button.

Readable | Writeable

track-print-status

If true, the print operation will try to continue report on the status of the print job in the printer queues and printer.

This can allow your application to show things like “out of paper” issues, and when the print job actually reaches the printer. However, this is often implemented using polling, and should not be enabled unless needed.

Readable | Writeable

unit

The transformation for the cairo context obtained from PrintContext is set up in such a way that distances are measured in units of @unit.

Readable | Writeable

use-full-page

If true, the transformation for the cairo context obtained from PrintContext puts the origin at the top left corner of the page.

This may not be the top left corner of the sheet, depending on page orientation and the number of pages per sheet. Otherwise, the origin is at the top left corner of the imageable area (i.e. inside the margins).

Readable | Writeable

Signals

begin-print

Emitted after the user has finished changing print settings in the dialog, before the actual rendering starts.

A typical use for ::begin-print is to use the parameters from the PrintContext and paginate the document accordingly, and then set the number of pages with PrintOperationExt::set_n_pages().

create-custom-widget

Emitted when displaying the print dialog.

If you return a widget in a handler for this signal it will be added to a custom tab in the print dialog. You typically return a container widget with multiple widgets in it.

The print dialog owns the returned widget, and its lifetime is not controlled by the application. However, the widget is guaranteed to stay around until the custom-widget-apply signal is emitted on the operation. Then you can read out any information you need from the widgets.

custom-widget-apply

Emitted right before ::begin-print if you added a custom widget in the ::create-custom-widget handler.

When you get this signal you should read the information from the custom widgets, as the widgets are not guaranteed to be around at a later time.

done

Emitted when the print operation run has finished doing everything required for printing.

@result gives you information about what happened during the run. If @result is PrintOperationResult::Error then you can call Gtk::PrintOperation::get_error() for more information.

If you enabled print status tracking then PrintOperationExt::is_finished() may still return false after the ::done signal was emitted.

draw-page

Emitted for every page that is printed.

The signal handler must render the @page_nr’s page onto the cairo context obtained from @context using PrintContext::cairo_context().

⚠️ The following code is in c ⚠️

static void
draw_page (GtkPrintOperation *operation,
           GtkPrintContext   *context,
           int                page_nr,
           gpointer           user_data)
{
  cairo_t *cr;
  PangoLayout *layout;
  double width, text_height;
  int layout_height;
  PangoFontDescription *desc;

  cr = gtk_print_context_get_cairo_context (context);
  width = gtk_print_context_get_width (context);

  cairo_rectangle (cr, 0, 0, width, HEADER_HEIGHT);

  cairo_set_source_rgb (cr, 0.8, 0.8, 0.8);
  cairo_fill (cr);

  layout = gtk_print_context_create_pango_layout (context);

  desc = pango_font_description_from_string ("sans 14");
  pango_layout_set_font_description (layout, desc);
  pango_font_description_free (desc);

  pango_layout_set_text (layout, "some text", -1);
  pango_layout_set_width (layout, width * PANGO_SCALE);
  pango_layout_set_alignment (layout, PANGO_ALIGN_CENTER);

  pango_layout_get_size (layout, NULL, &layout_height);
  text_height = (double)layout_height / PANGO_SCALE;

  cairo_move_to (cr, width / 2,  (HEADER_HEIGHT - text_height) / 2);
  pango_cairo_show_layout (cr, layout);

  g_object_unref (layout);
}

Use PrintOperationExt::set_use_full_page() and PrintOperationExt::set_unit() before starting the print operation to set up the transformation of the cairo context according to your needs.

end-print

Emitted after all pages have been rendered.

A handler for this signal can clean up any resources that have been allocated in the begin-print handler.

paginate

Emitted after the ::begin-print signal, but before the actual rendering starts.

It keeps getting emitted until a connected signal handler returns true.

The ::paginate signal is intended to be used for paginating a document in small chunks, to avoid blocking the user interface for a long time. The signal handler should update the number of pages using PrintOperationExt::set_n_pages(), and return true if the document has been completely paginated.

If you don’t need to do pagination in chunks, you can simply do it all in the ::begin-print handler, and set the number of pages from there.

preview

Gets emitted when a preview is requested from the native dialog.

The default handler for this signal uses an external viewer application to preview.

To implement a custom print preview, an application must return true from its handler for this signal. In order to use the provided @context for the preview implementation, it must be given a suitable cairo context with PrintContext::set_cairo_context().

The custom preview implementation can use PrintOperationPreviewExt::is_selected() and PrintOperationPreviewExt::render_page() to find pages which are selected for print and render them. The preview must be finished by calling PrintOperationPreviewExt::end_preview() (typically in response to the user clicking a close button).

request-page-setup

Emitted once for every page that is printed.

This gives the application a chance to modify the page setup. Any changes done to @setup will be in force only for printing this page.

status-changed

Emitted at between the various phases of the print operation.

See PrintStatus for the phases that are being discriminated. Use PrintOperationExt::status() to find out the current status.

update-custom-widget

Emitted after change of selected printer.

The actual page setup and print settings are passed to the custom widget, which can actualize itself according to this change.

PrintOperationPreview

got-page-size

Emitted once for each page that gets rendered to the preview.

A handler for this signal should update the @context according to @page_setup and set up a suitable cairo context, using PrintContext::set_cairo_context().

ready

The ::ready signal gets emitted once per preview operation, before the first page is rendered.

A handler for this signal can be used for setup tasks.

Implements

PrintOperationExt, [trait@glib::ObjectExt], PrintOperationPreviewExt

GLib type: GObject with reference counted clone semantics.

Implementations

impl PrintOperation

pub const NONE: Option<&'static PrintOperation> = None

pub fn new() -> PrintOperation

Creates a new PrintOperation.

Returns

a new PrintOperation

pub fn builder() -> PrintOperationBuilder

Creates a new builder-pattern struct instance to construct PrintOperation objects.

This method returns an instance of PrintOperationBuilder which can be used to create PrintOperation objects.

impl PrintOperation

pub fn error(&self) -> Option<Error>

Trait Implementations

impl Clone for PrintOperation

fn clone(&self) -> Self

Makes a clone of this shared reference.

This increments the strong reference count of the object. Dropping the object will decrement it again.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PrintOperation

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for PrintOperation

fn default() -> Self

Returns the “default value” for a type.

impl HasParamSpec for PrintOperation

type ParamSpec = ParamSpecObject

type SetValue = PrintOperation

Preferred value to be used as setter for the associated ParamSpec.

type BuilderFn = fn(_: &str) -> ParamSpecObjectBuilder<'_, PrintOperation>

fn param_spec_builder() -> Self::BuilderFn

impl Hash for PrintOperation

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Hashes the memory address of this object.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T: PrintOperationImpl> IsSubclassable<T> for PrintOperation

fn class_init(class: &mut Class<Self>)

Override the virtual methods of this class for the given subclass and do other class initialization.

fn instance_init(instance: &mut InitializingObject<T>)

Instance specific initialization.

impl Ord for PrintOperation

fn cmp(&self, other: &Self) -> Ordering

Comparison for two GObjects.

Compares the memory addresses of the provided objects.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl ParentClassIs for PrintOperation

type Parent = Object

impl<OT: ObjectType> PartialEq<OT> for PrintOperation

fn eq(&self, other: &OT) -> bool

Equality for two GObjects.

Two GObjects are equal if their memory addresses are equal.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<OT: ObjectType> PartialOrd<OT> for PrintOperation

fn partial_cmp(&self, other: &OT) -> Option<Ordering>

Partial comparison for two GObjects.

Compares the memory addresses of the provided objects.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for PrintOperation

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for PrintOperation

impl IsA<PrintOperationPreview> for PrintOperation