Bug 5471 - FontDescription needs disposing
Summary: FontDescription needs disposing
Status: NEW
Alias: None
Product: Class Libraries
Classification: Mono
Component: Mono.Cairo ()
Version: unspecified
Hardware: PC Windows
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2012-06-02 13:24 UTC by pinggi
Modified: 2012-06-02 13:24 UTC (History)
1 user (show)

Is this bug a regression?: ---
Last known good build:

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Description pinggi 2012-06-02 13:24:37 UTC
I render text into DrawingArea with double buffering on using Cairo + Pango, like this:

using (Pango.Layout layout = PangoCairoHelper.CreateLayout(c)) {
	layout.FontDescription = Pango.FontDescription.FromString("Sans 9");
	PangoCairoHelper.LayoutPath(c, layout, true);

If I increase the window size, the background becomes black and the following text appears in the application log:

Cairo.Context: called from finalization thread, programmer is missing a call to Dispose
GLib:ERROR:gmain.c:2443:g_main_dispatch: assertion failed: (current->dispatching_sources == &current_source_link)

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

If I write it like this...

			using (Pango.Layout layout = PangoCairoHelper.CreateLayout(c)) {
				using (var fontDesc = Pango.FontDescription.FromString("Sans 9"))
					layout.FontDescription = fontDesc;
				layout.Alignment = Pango.Alignment.Left;
				PangoCairoHelper.LayoutPath(c, layout, true);

...window resizing works ok.

Why do I need to dispose newly created object? Isn't that the bad design of Pango wrapper? I think it is.