[gtkmm] Adding more C++ power to Gtkmm

["r ve" <kaas_10 hotmail com>]

Some time ago, I've been complaining that Gtkmm does things too much C-like.

Because things won't change when keeping my mouth shut, here's a few 
suggestions that I would really like to see added in Gtkmm.



One example of something 'C-like' in Gtkmm is that some methods contain far 
too many arguments.

Here's a method with 16 (!!) arguments:

- Gdk::Pixbuf::composite_color(const Glib::RefPtr<Gdk::Pixbuf>& dest, int 
dest_x, int dest_y, int dest_width, int dest_height, double offset_x, double 
offset_y, double scale_x, double scale_y, InterpType interp_type, int 
overall_alpha, int check_x, int check_y, int check_size, guint32 color1, 
guint32 color2)

These arguments could be reduced to 13 arguments by rewriting it to this:

- Gdk::Pixbuf::composite_color(const Glib::RefPtr<Gdk::Pixbuf& dest, 
Gdk::Rectangle& dest_rect, double offset_x, double offset_y, double scale_x, 
double scale_y, InterpType interp_type, int overall_alpha, int check_x, int 
check_y, int check_size, guint32 color1, guint32 color2)

It could be reduced to 10 arguments by modifying the Gdk::Point class to 
become a template (would be useful for a few other classes as well):

- Gdk::Pixbuf::composite_color(const Glib::RefPtr<Gdk::Pixbuf& dest, 
Gdk::Rectangle& dest_rect, Gdk::Point<double>& offset, Gdk::Point<double>& 
scale, InterpType interp_type, int overall_alpha, Gdk::Point<int>& 
check_offset, int check_size, guint32 color1, guint32 color2)

Well, I think you get the point :)
10 arguments is still quite a lot imho, but it's much better than 16 (!) 
arguments.



Other things that could be done to improve Gtkmm is to add more overloaded 
operators.

The Gdk::Point class, for example, does only overload the == and != 
operators, but this class could be much more useful if it had operators for 
adding, subtracting and multiplying Gdk::Points.
On top of that, the Gdk::Point class doesn't have a Point(const Point& rhs) 
constructor, which can also prove to be useful at some times.

The Gdk::Rectangle class doesn't overload _any_ operator, that's bad because 
it's a pain to write something like this:

if ((rect1->get_x() != rect2->get_x()) && (rect1->get_y() != rect2->get_y()) 
&& (rect1->get_width() != rect2->get_width() && (rect1->get_height() != 
rect2->get_height()) bleh;

Instead of:

if (rect1 != rect2) bleh;

Which is not only much easier on the eyes, but faster to type as well.



Also, it would be really nice if virtual methods (signals) wouldn't be like 
this (the C way):

virtual void on_set_focus(Widget* focus);   // set_focus signal for 
Gtk::Window

But rather like this (the C++ way):

virtual void on_set_focus(Gtk::Widget* focus);  (or const Gtk::Widget& 
focus.. whatever)

And same goes for all other signals.



Any thoughs?

Rich


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