migrate gtk3 porting docs from wiki

src/gtk3-porting-examples/Finance.md

@@ -0,0 +1,39 @@
+Ticket of this port is [here](http://bugs.sugarlabs.org/ticket/3740), with some
+useful information that I'm using on the porting and to keep tracking
+this port.
+
+
+Gtk.EventBox
+============
+
+EventBox has not `get_colormap` method anymore and this method is used
+to set the background color. Now, instead of this one I'm using
+`Gdk.Color.parse` to parse the color string:
+
+`ebox = gtk.EventBox()`\
+`ebox.modify_bg(gtk.STATE_NORMAL, ebox.get_colormap().alloc_color('#000000'))`
+
+replaced by:
+
+`ebox = Gtk.EventBox()`\
+`parse, color = Gdk.Color.parse('#000000')`\
+`self.helpbox.modify_bg(Gtk.StateType.NORMAL, color)`
+
+Gtk.TreeViewColumn
+==================
+
+The callback function used by `Gtk.TreeViewColumn.set_cell_data_func`
+receives a new argument called: *data*
+
+`col = Gtk.TreeViewColumn(_('Description'), renderer)`\
+`col.set_cell_data_func(renderer, self.description_render_cb) `
+
+added a new argument to the function definition:
+
+`def description_render_cb(self, column, cell_renderer, model, iter, data):`
+
+Useful links
+============
+
+-   <http://developer.gnome.org/gtk3/3.5/GtkTreeViewColumn.html#GtkTreeCellDataFunc>
+-   <http://developer.gnome.org/gdk3/stable/gdk3-Colors.html#GdkColor>

src/gtk3-porting-examples/Implode.md

@@ -0,0 +1,136 @@
+Ticket of this port is [here](http://bugs.sugarlabs.org/ticket/3715), with some
+useful information that I'm using on the porting and to keep tracking
+this port.
+
+
+Porting Gtk.DrawingArea
+=======================
+
+There are some things related with `gtk.DrawingArea` that we have to
+change when we are porting an activity to GTK+ 3. The names of the signals
+change and the way that they work as well.
+
+Get allocation size
+-------------------
+
+*self.allocation* property is no longer available and we should use
+`self.get_allocation_width` to get the allocation size:
+
+`self.allocation.width`\
+`self.allocation.height`
+
+should be replaced by:
+
+`self.get_allocated_width()`\
+`self.get_allocated_height()`
+
+Signals
+-------
+
+### expose-event
+
+This signal was override by **draw** and it have to be connected with
+the method that was connected with the *expose-event* before. The method
+itself does not change but the arguments that it receives do. This is
+the new definition of the function in my case:
+
+`def _draw_event_cb(self, widget, cr):`
+
+### size-allocate
+
+This signal was used to resize the gtk.DrawingArea every time the window
+grows and at the startup of the activity. This is useful to re-draw the
+widget for different resolutions (desktops and XOs for example).
+
+I used the same function connected to this signal but I change the
+signal connected by **configure-event**. Here is the definition of the
+callback:
+
+`def _configure_event_cb(self, widget, event):`
+
+Focus
+-----
+
+Implode defines a new widget called *GridWidget* and it should be
+focusable because we want to move a cursor with the key arrows on it.
+So, this widget was using:
+
+`self.set_flags(Gtk.CAN_FOCUS)`
+
+but that method (*set\_flags*) is no longer available and we have to
+replace it by:
+
+`self.set_can_focus(True)`
+
+Another thing related with the focus is to know who has the actual
+focus. In gtk2 it was done by
+
+`.focus_child`
+
+and in GTK+ 3 it should be replaced by:
+
+`.get_focus_child()`
+
+Handling .svg with rsvg
+=======================
+
+**rsvg** is a library to manage *.svg* files. The only thing that I
+found that should be updated is the import and the loading of a rsvg
+from data.
+
+Replace the usual import:
+
+`import rsgv`
+
+by the GTK+ 3 one:
+
+`from gi.repository import Rsvg`
+
+This way to load a rsvg from data should be replaced:
+
+`rsvg.Handle(data=data)`
+
+by this new way
+
+`Rsvg.Handle.new_from_data(data)`
+
+Invalidate rectangle
+====================
+
+`Gdk.Window.invalidate_rect` takes a *Gdk.Rectangle* instead a tuple in
+GTK+ 3.
+
+`rect = Gdk.Rectangle()`\
+`rect.x, rect.y, rect.width, rect.height = (0, 0, width, height)`
+
+`self.get_window().invalidate_rect(rect, True)`
+
+Notes
+=====
+
+-   I had to add a third argument (None) to Gtk.Notebook.append\_page
+    but I don't know why
+-   Use **json** instead of *simplejson* or so
+-   Replace `gtk.VISIBLE` by **Gtk.AccelFlags.VISIBLE**
+
+Missing things (not ported yet)
+===============================
+
+-   *sugarless.py* is not working. The board is not shown. Do we update
+    this to keep it working? I mean, do we need to maintain this code?
+-   \[<span style="color: green;">DONE</span>\] ~~help dialogue is not
+    working. It shows the example board but it's one pixel size when it
+    opens~~
+-   When the help dialogue is shown and you hover the animation with the
+    mouse something strange happens and it starts to flap.
+    [Screenshot](http://bugs.sugarlabs.org/attachment/ticket/3715/53.png)
+
+Useful Links
+============
+
+-   <http://developer.gnome.org/gtk3/3.5/GtkWidget.html#GtkWidget-draw>
+-   <http://developer.gnome.org/gtk3/3.5/GtkWidget.html#GtkWidget-configure-event>
+-   <http://developer.gnome.org/rsvg/stable/>
+-   <http://developer.gnome.org/gdk3/stable/gdk3-Windows.html#gdk-window-invalidate-rect>
+-   <http://developer.gnome.org/gtk3/3.5/GtkWidget.html#gtk-widget-get-allocated-width>
+-   <http://developer.gnome.org/gtk3/3.5/GtkNotebook.html#gtk-notebook-append-page>