Re: Cairo/GTK and cube example

Hi !

On Tue, Sep 14, 2010 at 11:50, Johan Mazel <[email protected]> wrote:
> Hi
> I'm trying to use Cairo and GTK.
> As a first step, I tried to compile and understand the cube example given at
> this address: http://webcvs.cairographics.org/cairo-ocaml/test/.

btw the current code is in the git repository, not CVS:
http://cgit.freedesktop.org/cairo-ocaml/


> I use this line for the native compilation: ocamlopt -I +lablgtk2 -I +cairo
> lablgtk.cmxa cairo.cmxa cairo_lablgtk.cmxa cube.ml -o cube.
>
> The first problem is that the bytecode compilation do not work:
> ocamlc -I +lablgtk2 -I +cairo lablgtk.cma cairo.cma cairo_lablgtk.cma
> cube.ml -o cube
> File "cube.ml", line 1, characters 0-1:
> Error: Error on dynamically loaded library:
> /usr/lib/ocaml/stublibs/dllmlcairo.so:
> /usr/lib/ocaml/stublibs/dllmlcairo.so: undefined symbol: caml_ba_byte_size

This looks like some binary incompatibility between ocaml and your
cairo-ocaml binary.
caml_ba_byte_size is a symbol from the Bigarray library that got
renamed at some point.

Did you compile cairo-ocaml yourself ? If no, you have to ensure that
you're using it with the same OCaml version that compiled it.


> I however tried to run the native executable generated but I get the
> following error:
> (process:6496): GLib-GObject-WARNING **: invalid (NULL) pointer instance
> (process:6496): GLib-GObject-CRITICAL **: g_signal_connect_data: assertion
> `G_TYPE_CHECK_INSTANCE (instance)' failed
> (process:6496): Gdk-CRITICAL **: gdk_pango_context_get_for_screen: assertion
> `GDK_IS_SCREEN (screen)' failed
> (process:6496): Pango-CRITICAL **: pango_context_set_font_description:
> assertion `context != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_context_set_base_dir: assertion
> `context != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_context_set_language: assertion
> `context != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_layout_new: assertion `context !=
> NULL' failed
> (process:6496): Pango-CRITICAL **: pango_layout_set_text: assertion `layout
> != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_layout_get_pixel_extents: assertion
> `PANGO_IS_LAYOUT (layout)' failed
> (process:6496): Pango-CRITICAL **: pango_layout_set_text: assertion `layout
> != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_layout_get_pixel_extents: assertion
> `PANGO_IS_LAYOUT (layout)' failed
> (process:6496): GLib-GObject-CRITICAL **: g_object_unref: assertion
> `G_IS_OBJECT (object)' failed
> (process:6496): Gtk-WARNING **: Screen for GtkWindow not set; you must
> always set
> a screen for a GtkWindow before using the window
> (process:6496): Gdk-CRITICAL **: gdk_pango_context_get_for_screen: assertion
> `GDK_IS_SCREEN (screen)' failed
> (process:6496): Pango-CRITICAL **: pango_context_set_font_description:
> assertion `context != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_context_set_base_dir: assertion
> `context != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_context_set_language: assertion
> `context != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_layout_new: assertion `context !=
> NULL' failed
> (process:6496): GLib-GObject-CRITICAL **: g_object_unref: assertion
> `G_IS_OBJECT (object)' failed
> (process:6496): Gdk-CRITICAL **: gdk_pango_context_get_for_screen: assertion
> `GDK_IS_SCREEN (screen)' failed
> (process:6496): Pango-CRITICAL **: pango_context_set_font_description:
> assertion `context != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_context_set_base_dir: assertion
> `context != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_context_set_language: assertion
> `context != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_layout_new: assertion `context !=
> NULL' failed
> (process:6496): Pango-CRITICAL **: pango_layout_set_text: assertion `layout
> != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_layout_set_alignment: assertion
> `layout != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_layout_set_ellipsize: assertion
> `PANGO_IS_LAYOUT (layout)' failed
> (process:6496): Pango-CRITICAL **: pango_layout_set_single_paragraph_mode:
> assertion `PANGO_IS_LAYOUT (layout)' failed
> (process:6496): Pango-CRITICAL **: pango_layout_set_width: assertion `layout
> != NULL' failed
> (process:6496): Pango-CRITICAL **: pango_layout_get_extents: assertion
> `layout != NULL' failed
> (process:6496): Gdk-CRITICAL **: gdk_screen_get_default_colormap: assertion
> `GDK_IS_SCREEN (screen)' failed
> (process:6496): Gdk-CRITICAL **: gdk_colormap_get_visual: assertion
> `GDK_IS_COLORMAP (colormap)' failed
> (process:6496): Gdk-CRITICAL **: gdk_screen_get_default_colormap: assertion
> `GDK_IS_SCREEN (screen)' failed
> (process:6496): Gdk-CRITICAL **: gdk_screen_get_root_window: assertion
> `GDK_IS_SCREEN (screen)' failed
> (process:6496): Gdk-CRITICAL **: gdk_screen_get_root_window: assertion
> `GDK_IS_SCREEN (screen)' failed
> (process:6496): Gdk-CRITICAL **: gdk_window_new: assertion `GDK_IS_WINDOW
> (parent)' failed
> Erreur de segmentation

probably simply the gtk initialization missing. Add gtkInit.cmx before
cube.ml while linking.

-- 
  Olivier