Pango in GtkAda Gtk version 3

Pango in GtkAda Gtk version 3

[ldries46]

Is their an equivalent of the "Hello World" program for using 'Pango' within 
a drawing area.
If so where can I find it?
I need it to learn using Pango within a program

L. Dries 

Re: Pango in GtkAda Gtk version 3

[Dmitry A. Kazakov]

On Fri, 31 Jan 2014 10:27:19 +0100, ldries46 wrote:

> Is their an equivalent of the "Hello World" program for using 'Pango' within 
> a drawing area.
> If so where can I find it?

Nowhere. GTK+ 3.x does not have drawing area anymore.

> I need it to learn using Pango within a program

To use a Pango font with Cairo, you should:

1. create a Pango_Layout on the given context (Create_Layout);
2. set Pango font there (Set_Font_Description);
3. set text to render into the layout (Set_Text);
4. draw the layout (Show_Layout_Line).

For further information see:

https://developer.gnome.org/pango/unstable/pango-Cairo-Rendering.html

Examples of use with GtkAda are here (require some adjustments for GTK
3.x).

http://www.dmitry-kazakov.de/ada/aicwl.htm

Since Pango fonts and Toy fonts are considerably different in their use,
the library has an abstraction layer in order to be able to use both.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

Re: Pango in GtkAda Gtk version 3

[ldries46]

After a while searching I could not find the procedure or function
Create_Layout. Finally I just found Show_Layout which shows a Layout in a 
CR.

procedure Show_Layout (Cr : Cairo_Context; Layout : Pango_Layout);

>To use a Pango font with Cairo, you should:

>1. create a Pango_Layout on the given context (Create_Layout);
>2. set Pango font there (Set_Font_Description);
>3. set text to render into the layout (Set_Text);
>4. draw the layout (Show_Layout_Line).

>Nowhere. GTK+ 3.x does not have drawing area anymore.

May be not but why is it then possible in Glade 3.14.2 to create one and you 
can write lines in it.

L. Dries 

Re: Pango in GtkAda Gtk version 3

[Dmitry A. Kazakov]

On Fri, 31 Jan 2014 15:09:25 +0100, ldries46 wrote:

> After a while searching I could not find the procedure or function
> Create_Layout.

I guess it is missing in GtkAda 3.4. Use this until AdaCore fixes that:

function Create_Layout (Context : Cairo_Context)
   return Pango_Layout is
   function Internal (Context : Cairo_Context) return Address;
   pragma Import (C, Internal, "pango_cairo_create_layout");
   Stub : Pango_Layout_Record;
begin
  return Pango_Layout (Get_User_Data (Internal (Context), Stub));
end Create_Layout;

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de