Struct gtk4::PrintContext

source ·
#[repr(transparent)]
pub struct PrintContext { /* private fields */ }
Expand description

A PrintContext 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 pango::Layout and pango::Context objects that match the font metrics of the cairo surface.

PrintContext objects get passed to the signal::PrintOperation::begin-print, signal::PrintOperation::end-print, signal::PrintOperation::request-page-setup and signal::PrintOperation::draw-page signals on the PrintOperation object.

Using GtkPrintContext in a ::draw-page callback

⚠️ The following code is in c ⚠️

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);
}

Implements

glib::ObjectExt

Implementations§

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

Returns

a new Pango context for @self

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

Returns

a new Pango layout for @self

Obtains the cairo context that is associated with the PrintContext.

Returns

the cairo context of @self

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

Returns

the horizontal resolution of @self

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

Returns

the vertical resolution of @self

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

Returns

true if the hard margins were retrieved

top

top hardware printer margin

bottom

bottom hardware printer margin

left

left hardware printer margin

right hardware printer margin

Obtains the height of the PrintContext, in pixels.

Returns

the height of @self

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

Returns

the page setup of @self

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

Returns

the font map of @self

Obtains the width of the PrintContext, in pixels.

Returns

the width of @self

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.

cr

the cairo context

dpi_x

the horizontal resolution to use with @cr

dpi_y

the vertical resolution to use with @cr

Trait Implementations§

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