Class: Gtk::PrintContext

Inherits:
Object
  • Object
show all
Defined in:
(unknown)

Overview

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 Pango::Layout and #PangoContext objects that match the font metrics of the cairo surface.

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

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

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.

Instance Method Summary collapse

Instance Method Details

#cairo_contextcairo::Context

Obtains the cairo context that is associated with the Gtk::PrintContext.

Returns:

  • (cairo::Context)

    the cairo context of context

#create_pango_contextPango::Context

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

Returns:

#create_pango_layoutPango::Layout

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

Returns:

#dpi_xFloat

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

Returns:

  • (Float)

    the horizontal resolution of context

#dpi_yFloat

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

Returns:

  • (Float)

    the vertical resolution of context

#get_hard_margins(top, bottom, left, right) ⇒ TrueClass

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

Parameters:

  • top (Float)

    top hardware printer margin

  • bottom (Float)

    bottom hardware printer margin

  • left (Float)

    left hardware printer margin

  • right (Float)

    right hardware printer margin

Returns:

  • (TrueClass)

    true if the hard margins were retrieved

#heightFloat

Obtains the height of the Gtk::PrintContext, in pixels.

Returns:

  • (Float)

    the height of context

#page_setupGtk::PageSetup

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

Returns:

#pango_fontmapPango::FontMap

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

Returns:

#set_cairo_context(cr, dpi_x, dpi_y) ⇒ nil

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.

Parameters:

  • cr (cairo::Context)

    the cairo context

  • dpi_x (Float)

    the horizontal resolution to use with cr

  • dpi_y (Float)

    the vertical resolution to use with cr

Returns:

  • (nil)

#widthFloat

Obtains the width of the Gtk::PrintContext, in pixels.

Returns:

  • (Float)

    the width of context