Printing in GTK#
I just finished porting Tomboy’s print code to GTK so that we would be more portable and I thought other Mono apps looking to move from libgnomeprint or wanting to add printing support might find a code example helpful.
First, To start printing you do something like:
private void PrintButtonClicked (object sender, EventArgs args)
{
Gtk.PrintOperation op = new PrintOperation ();
op.BeginPrint += new BeginPrintHandler (OnBeginPrint);
op.DrawPage += new DrawPageHandler(OnDrawPage);
op.Run (Gtk.PrintOperationAction.PrintDialog, this.Window);
}
after the PrintOperation is set off you need to handle the BeginPrint event. The main things that need to be done are finding out how many lines will fit on a page and how many lines you have:
public void OnBeginPrint(object sender, Gtk.BeginPrintArgs args)
{
PrintOperation op = (PrintOperation)sender;
lines_per_page = (int)Math.Floor ((double)args.Context.Height / (double)font_size);
Gtk.TextIter start_iter, end_iter;
this.Buffer.GetBounds (out start_iter, out end_iter);
lines = this.Buffer.GetText (start_iter, end_iter, false).Split ('\n');
op.NPages = (int)Math.Ceiling ((double)lines.Length / (double)lines_per_page);
}
Finally, now that you have the printing setup, you need to actually render the data to be printed:
public void OnDrawPage(object sender, Gtk.DrawPageArgs args)
{
PrintOperation op = (PrintOperation)sender;
Cairo.Context cr = args.Context.CairoContext;
int line = args.PageNr * lines_per_page;
int num_lines = 0;
if (args.PageNr+1 != op.NPages)
num_lines = line + lines_per_page;
else
num_lines = lines.Length;
cr.MoveTo (0, 0);
for (int i = 0; i < lines_per_page && line < num_lines; i++)
{
Pango.Layout layout = args.Context.CreatePangoLayout ();
Pango.FontDescription desc = Pango.FontDescription.FromString (”sans ” + font_size);
desc.Size = (int)(font_size * Pango.Scale.PangoScale);
layout.FontDescription = desc;
layout.SetText (lines[line]);
Pango.CairoHelper.ShowLayout (cr, layout);
cr.RelMoveTo (0, font_size);
line++;
}
}
This does not take into account styles but will give you the basic idea of what needs to be done.
