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.

This includes the cairo context and important parameters like page size and resolution. It also lets you easily create [classPango.Layout] and [classPango.Context] objects that match the font metrics of the cairo surface.

GtkPrintContext objects get passed to the [signalGtk.PrintOperation::begin-print], [signalGtk.PrintOperation::end-print], [signalGtk.PrintOperation::request-page-setup] and [signalGtk.PrintOperation::draw-page] signals on the [classGtk.PrintOperation] object.

Using GtkPrintContext in a ::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);
}

Instance Method Summary collapse

Instance Method Details

#cairo_context ⇒ cairo::Context

Obtains the cairo context that is associated with the GtkPrintContext.

Returns:

  • (cairo::Context) —

    the cairo context of context

#create_pango_context ⇒ Pango::Context

Creates a new PangoContext that can be used with the GtkPrintContext.

Returns:

  • (Pango::Context) —

    a new Pango context for context

#create_pango_layout ⇒ Pango::Layout

Creates a new PangoLayout that is suitable for use with the GtkPrintContext.

Returns:

  • (Pango::Layout) —

    a new Pango layout for context

#dpi_x ⇒ Float

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

Returns:

  • (Float) —

    the horizontal resolution of context

#dpi_y ⇒ Float

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

Returns:

  • (Float) —

    the vertical resolution of context

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

Obtains the hardware printer margins of the GtkPrintContext, 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:

  • (Boolean) —

    true if the hard margins were retrieved

#height ⇒ Float

Obtains the height of the GtkPrintContext, in pixels.

Returns:

  • (Float) —

    the height of context

#page_setup ⇒ Gtk::PageSetup

Obtains the GtkPageSetup that determines the page dimensions of the GtkPrintContext.

Returns:

#pango_fontmap ⇒ Pango::FontMap

Returns a PangoFontMap that is suitable for use with the GtkPrintContext.

Returns:

  • (Pango::FontMap) —

    the font map of context

#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)

#width ⇒ Float

Obtains the width of the GtkPrintContext, in pixels.

Returns:

  • (Float) —

    the width of context