GI.Gtk.Objects.PrintContext

A GtkPrintContext encapsulates context information that is required when drawing pages for printing, such as the cairo context and important parameters like page size and resolution. It also lets you easily create Layout and Context objects that match the font metrics of the cairo surface.

GtkPrintContext objects gets passed to the PrintOperation::begin-print, PrintOperation::end-print, PrintOperation::request-page-setup and PrintOperation::draw-page signals on the PrintOperation.

## Using GtkPrintContext in a PrintOperation::draw-page callback

C code

static void
draw_page (GtkPrintOperation *operation,
	   GtkPrintContext   *context,
	   int                page_nr)
{
  cairo_t *cr;
  PangoLayout *layout;
  PangoFontDescription *desc;

  cr = gtk_print_context_get_cairo_context (context);

  // Draw a red rectangle, as wide as the paper (inside the margins)
  cairo_set_source_rgb (cr, 1.0, 0, 0);
  cairo_rectangle (cr, 0, 0, gtk_print_context_get_width (context), 50);

  cairo_fill (cr);

  // Draw some lines
  cairo_move_to (cr, 20, 10);
  cairo_line_to (cr, 40, 20);
  cairo_arc (cr, 60, 60, 20, 0, M_PI);
  cairo_line_to (cr, 80, 20);

  cairo_set_source_rgb (cr, 0, 0, 0);
  cairo_set_line_width (cr, 5);
  cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
  cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND);

  cairo_stroke (cr);

  // Draw some text
  layout = gtk_print_context_create_pango_layout (context);
  pango_layout_set_text (layout, "Hello World! Printing is easy", -1);
  desc = pango_font_description_from_string ("sans 28");
  pango_layout_set_font_description (layout, desc);
  pango_font_description_free (desc);

  cairo_move_to (cr, 30, 20);
  pango_cairo_layout_path (cr, layout);

  // Font Outline
  cairo_set_source_rgb (cr, 0.93, 1.0, 0.47);
  cairo_set_line_width (cr, 0.5);
  cairo_stroke_preserve (cr);

  // Font Fill
  cairo_set_source_rgb (cr, 0, 0.0, 1.0);
  cairo_fill (cr);

  g_object_unref (layout);
}

Printing support was added in GTK+ 2.10.

Exported types

newtype PrintContext

Memory-managed wrapper type.

Constructors

PrintContext (ManagedPtr PrintContext)

Instances

GObject PrintContext

Defined in GI.Gtk.Objects.PrintContext

Methods

gobjectType :: PrintContext -> IO GType

IsObject PrintContext

Defined in GI.Gtk.Objects.PrintContext

IsPrintContext PrintContext

Defined in GI.Gtk.Objects.PrintContext

class GObject o => IsPrintContext o

Type class for types which can be safely cast to PrintContext, for instance with toPrintContext.

Instances

(GObject a, (UnknownAncestorError PrintContext a :: Constraint)) => IsPrintContext a

Defined in GI.Gtk.Objects.PrintContext

IsPrintContext PrintContext

Defined in GI.Gtk.Objects.PrintContext

toPrintContext :: (MonadIO m, IsPrintContext o) => o -> m PrintContext

Cast to PrintContext, for types for which this is known to be safe. For general casts, use castTo.

noPrintContext :: Maybe PrintContext

A convenience alias for Nothing :: Maybe PrintContext.

Methods

createPangoContext

printContextCreatePangoContext

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> m Context

Returns: a new Pango context for context

Creates a new Context that can be used with the PrintContext.

Since: 2.10

createPangoLayout

printContextCreatePangoLayout

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> m Layout

Returns: a new Pango layout for context

Creates a new Layout that is suitable for use with the PrintContext.

Since: 2.10

getCairoContext

printContextGetCairoContext

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> m Context

Returns: the cairo context of context

Obtains the cairo context that is associated with the PrintContext.

Since: 2.10

getDpiX

printContextGetDpiX

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> m Double

Returns: the horizontal resolution of context

Obtains the horizontal resolution of the PrintContext, in dots per inch.

Since: 2.10

getDpiY

printContextGetDpiY

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> m Double

Returns: the vertical resolution of context

Obtains the vertical resolution of the PrintContext, in dots per inch.

Since: 2.10

getHardMargins

printContextGetHardMargins

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> m (Bool, Double, Double, Double, Double)

Returns: True if the hard margins were retrieved

Obtains the hardware printer margins of the PrintContext, in units.

Since: 2.20

getHeight

printContextGetHeight

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> m Double

Returns: the height of context

Obtains the height of the PrintContext, in pixels.

Since: 2.10

getPageSetup

printContextGetPageSetup

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> m PageSetup

Returns: the page setup of context

Obtains the PageSetup that determines the page dimensions of the PrintContext.

Since: 2.10

getPangoFontmap

printContextGetPangoFontmap

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> m FontMap

Returns: the font map of context

Returns a FontMap that is suitable for use with the PrintContext.

Since: 2.10

getWidth

printContextGetWidth

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> m Double

Returns: the width of context

Obtains the width of the PrintContext, in pixels.

Since: 2.10

setCairoContext

printContextSetCairoContext

Arguments

:: (HasCallStack, MonadIO m, IsPrintContext a)

=> a

context: a PrintContext

-> Context

cr: the cairo context

-> Double

dpiX: the horizontal resolution to use with cr

-> Double

dpiY: the vertical resolution to use with cr

-> m ()

Sets a new cairo context on a print context.

This function is intended to be used when implementing an internal print preview, it is not needed for printing, since GTK+ itself creates a suitable cairo context in that case.

Since: 2.10