GtkAda. Printing

GtkAda. Printing

[ldries46]

I have a good working procedure procedure Draw_Grid(CR : Cairo_Context); 
which draws the contents of a Drawing Area.

Now I want that drawing on my printer. The examples I can find on internet 
all result in problems. In one g_signal_connect is called used together with 
G_CALLBACK But I have no idea which package they belong to. In another, 
using Gtkada.printing they use On_Draw_Page for connecting the draw_page 
event with a handler routine. In that case I use

On_Draw_Page(Print_Op, Draw_Page); here Draw_Page is the name of a routine 
that overwrites the value of the routine in the package.

My version is:

procedure Draw_Page(Op : Gtk_Print_Operation_Record; Context : 
Gtk_Print_Context;
                    Page_nr : Gint) is
   CR : Cairo_Context;
begin
   CR := Get_Cairo_Context (Print_CR);
   Draw_Grid(CR);
end Draw_Page;

But in building the compiler gives an error on Draw_Page with the messages 
for On_Draw_Page

190:07: missing argument for parameter "Slot" in call to "On_Draw_Page" 
declared at gtk-print_operation.ads:769
190:20: expected an access type with designated type 
"Gtk_Print_Operation_Record" defined at gtk-print_operation.ads:98
190:20: found type "Gtkada_Print_Operation" defined at 
gtkada-printing.ads:104
190:20:   ==> in call to "On_Draw_Page" at gtk-print_operation.ads:765
190:30: no candidate interpretations match the actuals:
190:30: context requires function call, found procedure name
190:30:   ==> in call to inherited operation "On_Draw_Page" at 
gtkada-printing.ads:102

With Draw_Page relaced by Draw_Page'Access it gives the same errors.

The error on 190.07 and 190.20 look like the result of the one in 190.30 
because
there are two instances op On_Draw_Page one with two and one with three 
parameters, I use the one with two and in other procedures and functions I 
can without an error set a value of type Gtk_Print_Operation at a location 
that expect Gtk_Print_Operation_Record.

What is the correct way to present the handler routine in On_Draw_Page, 
because that is my preference.

L. Dries

Re: GtkAda. Printing

[Dmitry A. Kazakov]

On 2016-08-03 09:02, ldries46 wrote:

> 190:07: missing argument for parameter "Slot" in call to "On_Draw_Page"
> declared at gtk-print_operation.ads:769
> 190:20: expected an access type with designated type
> "Gtk_Print_Operation_Record" defined at gtk-print_operation.ads:98
> 190:20: found type "Gtkada_Print_Operation" defined at
> gtkada-printing.ads:104

The compiler told you everything you need. You use an instance of 
Gtkada_Print_Operation instead of access Gtk_Print_Operation_Record.

The types are declared as follows:

type Gtkada_Print_Operation_Record is
    new Gtk_Print_Operation_Record with private;
type Gtkada_Print_Operation is access all Gtkada_Print_Operation_Record;

P.S. Granted, it seems a glitch in the GtkAda bindings which should have 
used access Gtk_Print_Operation_Record'Class instead. But nothing you 
could not workaround with an explicit type conversion...

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

Re: GtkAda. Printing

[ldries46]

Yes Print is declared as Gtkada_Print_Operation; and still in the Call to 
routine Set_N_Pages(Print_Op, 1); the compiler does not find an error while 
the declaration is

procedure Set_N_Pages
   (Self    : not null access Gtk_Print_Operation_Record;
    N_Pages : Gint);

and

type Gtkada_Print_Operation_Record is new
  Gtk_Print_Operation_Record with private;
type Gtkada_Print_Operation is access all Gtkada_Print_Operation_Record;

I expect that in the compiler to react the same in simular cases. Therefore 
I think that the error in lines 190:30 is the real error and the one I asked 
about.

"Dmitry A. Kazakov"  schreef in bericht news:nns747$s6g$1@gioia.aioe.org...

On 2016-08-03 09:02, ldries46 wrote:

> 190:07: missing argument for parameter "Slot" in call to "On_Draw_Page"
> declared at gtk-print_operation.ads:769
> 190:20: expected an access type with designated type
> "Gtk_Print_Operation_Record" defined at gtk-print_operation.ads:98
> 190:20: found type "Gtkada_Print_Operation" defined at
> gtkada-printing.ads:104

The compiler told you everything you need. You use an instance of
Gtkada_Print_Operation instead of access Gtk_Print_Operation_Record.

The types are declared as follows:

type Gtkada_Print_Operation_Record is
    new Gtk_Print_Operation_Record with private;
type Gtkada_Print_Operation is access all Gtkada_Print_Operation_Record;

P.S. Granted, it seems a glitch in the GtkAda bindings which should have
used access Gtk_Print_Operation_Record'Class instead. But nothing you
could not workaround with an explicit type conversion...

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

Re: GtkAda. Printing

[Dmitry A. Kazakov]

On 2016-08-03 12:25, ldries46 wrote:
> Yes Print is declared as Gtkada_Print_Operation; and still in the Call
> to routine Set_N_Pages(Print_Op, 1); the compiler does not find an error
> while the declaration is
>
> procedure Set_N_Pages
>   (Self    : not null access Gtk_Print_Operation_Record;
>    N_Pages : Gint);
>
> and
>
> type Gtkada_Print_Operation_Record is new
>  Gtk_Print_Operation_Record with private;
> type Gtkada_Print_Operation is access all Gtkada_Print_Operation_Record;
>
> I expect that in the compiler to react the same in simular cases.
> Therefore I think that the error in lines 190:30 is the real error and
> the one I asked about.

That depends on whether the operation is primitive or type specific. A 
primitive operation is inherited. Draw_Page parameter types are

    access Gtk_Print_Operation_Record'Class;
    not null access Gtk_Context_Record'Class;
    Gint

not

    Gtk_Print_Operation_Record;
    Gtk_Print_Context;
    Gint

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

Re: GtkAda. Printing

[ldries46]

To check what you said I tried the following just added an extra 
declaration:
Print_OpR : Gtkada_Print_Operation_Record;
and replaced Print_Op with it: The error stayed
Then I changed Print_OpR in On_Draw_Page with Print_OpR'Access.
The Error stayed nut said they expected Gtk_Print_Operation_record.
When I Changed the declaration accordingly The Error said they expected 
Gtkada_Print_Operation_Record
This looks like an infinite loop, and again, my experience wiyh GPS ia that 
somtimes the compiler tries several ways to resolve a problem abd you have 
to find out which of the several Error messages is the solution for you. I 
stll think It is the last one

: expected type "Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void" defined 
at gtk-print_operation.ads:754
: found type access to procedure "Draw_Page" defined at line 191
:   ==> in call to inherited operation "On_Draw_Page" at 
gtkada-printing.ads:102

I still cannot find how to address the draw_page routine ib there

"Dmitry A. Kazakov"  schreef in bericht news:nnsij4$1ddn$1@gioia.aioe.org...

On 2016-08-03 12:25, ldries46 wrote:
> Yes Print is declared as Gtkada_Print_Operation; and still in the Call
> to routine Set_N_Pages(Print_Op, 1); the compiler does not find an error
> while the declaration is
>
> procedure Set_N_Pages
>   (Self    : not null access Gtk_Print_Operation_Record;
>    N_Pages : Gint);
>
> and
>
> type Gtkada_Print_Operation_Record is new
>  Gtk_Print_Operation_Record with private;
> type Gtkada_Print_Operation is access all Gtkada_Print_Operation_Record;
>
> I expect that in the compiler to react the same in simular cases.
> Therefore I think that the error in lines 190:30 is the real error and
> the one I asked about.

That depends on whether the operation is primitive or type specific. A
primitive operation is inherited. Draw_Page parameter types are

    access Gtk_Print_Operation_Record'Class;
    not null access Gtk_Context_Record'Class;
    Gint

not

    Gtk_Print_Operation_Record;
    Gtk_Print_Context;
    Gint

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

Re: GtkAda. Printing

[Dmitry A. Kazakov]

On 2016-08-04 07:33, ldries46 wrote:

> I still cannot find how to address the draw_page routine ib there

You must use correct types. That's all. If Draw_Page does not match 
expected parameters profile wrap it into another subprogram.

GtkAda has examples (testgtk). Read the example of printing 
(create_print.adb). Modify it for your case.

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

Re: GtkAda. Printing

[ldries46]

I tried the various files from the Gtkada examples but they use almost the 
same methods I do.
The only thing I cannot find in these files is how to use On_Draw_Page and 
that is the point that causes my trouble.
When outcommenting the all works correct can see the Print dialog and I even 
can start the print. This print is empty, because the draw_page event is not 
connected with the Draw_Page routine. To create that the On_Draw_Page 
routine is necessary. And that still is creating the troubles.
The Call rouine is of the following type : 
Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void. Describes as

type Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void is not null access 
procedure
  (Self    : access Gtk_Print_Operation_Record'Class;
   Context : not null access 
Gtk.Print_Context.Gtk_Print_Context_Record'Class;
   Page_Nr : Gint);

Until now I have tried Draw_Page and Draw_Page'Access

L. Dries

"Dmitry A. Kazakov"  schreef in bericht news:nnup8m$6jg$1@gioia.aioe.org...

On 2016-08-04 07:33, ldries46 wrote:

> I still cannot find how to address the draw_page routine ib there

You must use correct types. That's all. If Draw_Page does not match
expected parameters profile wrap it into another subprogram.

GtkAda has examples (testgtk). Read the example of printing
(create_print.adb). Modify it for your case.

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

Re: GtkAda. Printing

[ldries46]

After looking at several places I found the following acc LRM (3.10) I must 
declare a parameter of the cb.... type
      Draw      : Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void
       := Draw_Page'Access;
and changing  On_Draw_Page to
On_Draw_Page(Print_Op, Draw);

Now the error changed to

: expected type "Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void" defined 
at gtk-print_operation.ads:754
: found type access to procedure "Draw_Page" defined at line 184

"ldries46"  schreef in bericht news:57a3297e$0$20642$e4fe514c@news.kpn.nl...

I tried the various files from the Gtkada examples but they use almost the
same methods I do.
The only thing I cannot find in these files is how to use On_Draw_Page and
that is the point that causes my trouble.
When outcommenting the all works correct can see the Print dialog and I even
can start the print. This print is empty, because the draw_page event is not
connected with the Draw_Page routine. To create that the On_Draw_Page
routine is necessary. And that still is creating the troubles.
The Call rouine is of the following type :
Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void. Describes as

type Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void is not null access
procedure
  (Self    : access Gtk_Print_Operation_Record'Class;
   Context : not null access
Gtk.Print_Context.Gtk_Print_Context_Record'Class;
   Page_Nr : Gint);

Until now I have tried Draw_Page and Draw_Page'Access

L. Dries

"Dmitry A. Kazakov"  schreef in bericht news:nnup8m$6jg$1@gioia.aioe.org...

On 2016-08-04 07:33, ldries46 wrote:

> I still cannot find how to address the draw_page routine ib there

You must use correct types. That's all. If Draw_Page does not match
expected parameters profile wrap it into another subprogram.

GtkAda has examples (testgtk). Read the example of printing
(create_print.adb). Modify it for your case.

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

Re: GtkAda. Printing

[ldries46]

I got it right, The problem was in de Draw_Page Routinewhere a typing error 
prevented the compiler from recognizing the routine as an callback routine.

L. Dries

"ldries46"  schreef in bericht news:57a334d0$0$20655$e4fe514c@news.kpn.nl...

After looking at several places I found the following acc LRM (3.10) I must
declare a parameter of the cb.... type
      Draw      : Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void
       := Draw_Page'Access;
and changing  On_Draw_Page to
On_Draw_Page(Print_Op, Draw);

Now the error changed to

: expected type "Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void" defined
at gtk-print_operation.ads:754
: found type access to procedure "Draw_Page" defined at line 184

"ldries46"  schreef in bericht news:57a3297e$0$20642$e4fe514c@news.kpn.nl...

I tried the various files from the Gtkada examples but they use almost the
same methods I do.
The only thing I cannot find in these files is how to use On_Draw_Page and
that is the point that causes my trouble.
When outcommenting the all works correct can see the Print dialog and I even
can start the print. This print is empty, because the draw_page event is not
connected with the Draw_Page routine. To create that the On_Draw_Page
routine is necessary. And that still is creating the troubles.
The Call rouine is of the following type :
Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void. Describes as

type Cb_Gtk_Print_Operation_Gtk_Print_Context_Gint_Void is not null access
procedure
  (Self    : access Gtk_Print_Operation_Record'Class;
   Context : not null access
Gtk.Print_Context.Gtk_Print_Context_Record'Class;
   Page_Nr : Gint);

Until now I have tried Draw_Page and Draw_Page'Access

L. Dries

"Dmitry A. Kazakov"  schreef in bericht news:nnup8m$6jg$1@gioia.aioe.org...

On 2016-08-04 07:33, ldries46 wrote:

> I still cannot find how to address the draw_page routine ib there

You must use correct types. That's all. If Draw_Page does not match
expected parameters profile wrap it into another subprogram.

GtkAda has examples (testgtk). Read the example of printing
(create_print.adb). Modify it for your case.

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