GtkSourceViewMM, gutter, and xpm pixmap error...

[Basile Starynkevitch <basile starynkevitch net>]

Hello List

(again, on the same program, different bug or misunderstanding)

I don't understand well how to use Gutter-s and marks inside. Sorry, I am giving a lot of details.
The questions are at the end of the email.



################# detailed context 
I'm using the following packages on GNU/Linux/Debian/AMD64/Sid
libgtksourceviewmm-3.0-dev      3.2.0-1
libgtkmm-3.0-dev                3.2.0-1

Look into http://mail.gnome.org/archives/gtkmm-list/2012-March/msg00048.html
to briefly understand my motivation and goals. (I'm working on GCC MELT, a plugin for GCC).

I'm writing a simple probe program in GTkSourceViewMM to display a C source
code file, with interesting locations where the MELT plugin could display
interesting informations related to some source code location. That probe
program has a GTK user interface and is interacting asynchronously with GCC
thru two textual pipes.


my GPLv3 source code inside the GCC MELT branch. See http://gcc-melt.org/
for more about MELT (MELT is a high-level domain specific language to extend GCC; it has
a lispy syntax and is translated to C; the melt.so plugin is a meta-plugin to GCC, etc..)

The source code is exactly in the file simplemelt-gtkmm-probe.cc of the contrib
directory of that branch. You can fetch it with

 svn co svn://gcc.gnu.org/svn/gcc/branches/melt-branch/contrib

I'm talking of the svn revision  185560 of it.

To reproduce my bug you'll need the two files simplemelt-gtkmm-probe.cc and paranoia.cc

Compile simplemelt-gtkmm-probe.cc as 

g++ -std=gnu++0x -Wall -O -g  \
  $(pkg-config --cflags --libs gtksourceviewmm-3.0  gtkmm-3.0  gtk+-3.0) \
  -o simplemelt-gtkmm-probe simplemelt-gtkmm-probe.cc

the file paranoia.cc is only needed as an input data.

Run the program under gdb, e.g.
  simplemelt-gtkmm-probe -D -t -C 0 -R 1 --g-fatal-warnings

Then type the following lines separated by two newlines each:

  showfile_pcd "paranoia.cc" 1


  marklocation_pcd 1 1 15 3



I am getting an error; (I'll try to explain what I am understanding of it below)

GdkPixbuf-CRITICAL **: gdk_pixbuf_scale_simple: assertion `dest_width > 0' failed

Program received signal SIGTRAP, Trace/breakpoint trap.
0x00007ffff42a59fa in g_logv () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
(gdb) bt
#0  0x00007ffff42a59fa in g_logv () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007ffff42a5bc2 in g_log () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007ffff4ef2ef4 in gdk_pixbuf_scale_simple () from /usr/lib/x86_64-linux-gnu/libgdk_pixbuf-2.0.so.0
#3  0x00007ffff793b18a in gtk_source_pixbuf_helper_render () from /usr/lib/libgtksourceview-3.0.so.0
#4  0x00007ffff793937c in ?? () from /usr/lib/libgtksourceview-3.0.so.0
#5  0x00007ffff7bbd054 in Gsv::GutterRenderer_Class::draw_vfunc_callback (self=0x64a280, cr=0x7ffff4a8cd60, 
    background_area=0x7fffffffd770, cell_area=0x7fffffffd780, start=0x7fffffffd5b0, end=0x7fffffffd600, 
    state=GTK_SOURCE_GUTTER_RENDERER_STATE_NORMAL) at gutterrenderer.cc:418
#6  0x00007ffff793564c in ?? () from /usr/lib/libgtksourceview-3.0.so.0
#7  0x00007ffff5cbaed3 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#8  0x00007ffff5df2a80 in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#9  0x00007ffff455c622 in g_closure_invoke () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#10 0x00007ffff456e3a3 in ?? () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#11 0x00007ffff4575f57 in g_signal_emit_valist () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#12 0x00007ffff4576aa2 in g_signal_emit () from /usr/lib/x86_64-linux-gnu/libgobject-2.0.so.0
#13 0x00007ffff5e0464a in ?? () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#14 0x00007ffff5e047f1 in gtk_widget_send_expose () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0
#15 0x00007ffff5cbaddc in gtk_main_do_event () from /usr/lib/x86_64-linux-gnu/libgtk-3.so.0




################################### what I understood or suspect

Graphically, I would like to have marks for a source code view, like Gnu
Emacs is displaying when you run the gdb debugger inside it with M-X gdb ;
the marks should appear at the left of a given source code line.

I want to display some marks at the left of a GtkSourceView and also some
tiny buttons inside the GtkSourceView text. I want one mark per line
containing these tiny buttons. As a general remark, I feel that the gutters
are lacking documentation and examples...


When the probe recieves the "marklocation_pcd 1 1 15 3" command, it should
create a mark and afd a tinty button inside a GtkTextSourceView & Buffer...

A mark has an XPM pixbuf for it. That XPM pixbuf is made once at application
initialization time with line 839

    _app_key_7x11_pixbuf
      = Gdk::Pixbuf::create_from_xpm_data (smelt_key_7x11_xpm);
    assert (_app_key_7x11_pixbuf && _app_key_7x11_pixbuf->gobj() != nullptr);


The gutter is obtained in my ShownFile internal class, near line 266 (a
member function of my ShownFile class)

    Glib::RefPtr<Gsv::Gutter> left_gutter() {
      return _sfilview.get_gutter(Gtk::TEXT_WINDOW_LEFT);
    }

when I am creating a mark, I am near line 1155

  Glib::RefPtr<Gsv::Gutter> gut = sfil->left_gutter();
  auto gutrenderer = new Gsv::GutterRendererPixbuf();
  gutrenderer->set_pixbuf(SmeltAppl::instance()->key_16x16_pixbuf());
  gut->insert(gutrenderer,lineno-1);

and when the gtksourceview is refreshed, I crash with as I am showing before
gdk_pixbuf_scale_simple: assertion `dest_width > 0' failed


################################ Questions

What do I do wrong? How to use gutter and add pixbuf inside? The
Gsv::GutterRendererPixbuf class is barely documented, and I would like an
example or some advice for it; do you have some?? Why does GtkSourceViewMM
has to scale an XPM pixbuf? How could I validate the pixbuf at its creation
time?


Regards.

PS: Sorry for such a long email, I wanted to give all the details that might
be relevant.

-- 
Basile STARYNKEVITCH         http://starynkevitch.net/Basile/
email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
8, rue de la Faiencerie, 92340 Bourg La Reine, France
*** opinions {are only mines, sont seulement les miennes} ***