Printer4Lazarus not working

[asmx]

I followed this page (https://wiki.freepascal.org/Using_the_printer) to write a print test program, but it doesn't work properly.

Code: Pascal  [Select][+][-]

1. program PrintUtil;
2.  
3. uses
4.   SysUtils, printers;
5.  
6. const
7.   LEFTMARGIN = 100;
8.   HEADLINE = 'I Printed My Very First Text On ';
9. var
10.   YPos, LineHeight, VerticalMargin: integer;
11.   SuccessString: string;
12. begin
13.   with Printer do
14.   try
15.     BeginDoc;
16.     Canvas.Font.Name := 'Courier New';
17.     Canvas.Font.Size := 10;
18.     Canvas.Font.Color := $0;
19.     LineHeight := Round(1.2 * Abs(Canvas.TextHeight('I')));
20.     VerticalMargin := 4 * LineHeight;
21.     // There we go
22.     YPos := VerticalMargin;
23.     SuccessString := HEADLINE + DateTimeToStr(Now);
24.     Canvas.TextOut(LEFTMARGIN, YPos, SuccessString);
25.   finally
26.     EndDoc;
27.   end;
28.  
29. end.
30.  

AccessViolationException is thrown directly when running to BeginDoc.

[wp]

The wiki article you are referring to is meant for printing out of a Lazarus GUI application. You are testing printing, however, in a console application. The difference is that a console application by-passes the Lazarus widgetset architecture and does not know about the LCL. The elemental step to make the LCL available in a consolue application is to add the unit "Interfaces" to the uses clause. But then you need another unit: "OSPrinters" to make the printer units of your operating system available.

So, in total, modify your uses clause as follows, and your application will work (tested on Windows):

Code: Pascal  [Select][+][-]

1. program PrintUtil;
2.  
3. uses
4.   Interfaces,    // <--- ADDED
5.   SysUtils, printers,
6.   osprinters;    // <--- ADDED
7.   //, printer4lazarus;          // <--- Not needed in "uses", but only in "required packages" of project
8.  
9. const
10.   LEFTMARGIN = 100;
11.   HEADLINE = 'I Printed My Very First Text On ';
12. var
13.   YPos, LineHeight, VerticalMargin: integer;
14.   SuccessString: string;
15. begin
16.   with Printer do
17.   try
18.     BeginDoc;
19.     Canvas.Font.Name := 'Courier New';
20.     Canvas.Font.Size := 10;
21.     Canvas.Font.Color := $0;
22.     LineHeight := Round(1.2 * Abs(Canvas.TextHeight('I')));
23.     VerticalMargin := 4 * LineHeight;
24.     // There we go
25.     YPos := VerticalMargin;
26.     SuccessString := HEADLINE + DateTimeToStr(Now);
27.     Canvas.TextOut(LEFTMARGIN, YPos, SuccessString);
28.   finally
29.     EndDoc;
30.   end;
31.  
32. end.

[AlexTP]

I added this new info (for me) to wiki:
https://wiki.freepascal.org/Using_the_printer#Printing_from_console_application

[Thaddy]

If you want simple printing from a console app, use the unit printer, not printers.
It is limited to what was possible in DOS times, but does the job.

[asmx]

The wiki article you are referring to is meant for printing out of a Lazarus GUI application. You are testing printing, however, in a console application. The difference is that a console application by-passes the Lazarus widgetset architecture and does not know about the LCL. The elemental step to make the LCL available in a consolue application is to add the unit "Interfaces" to the uses clause. But then you need another unit: "OSPrinters" to make the printer units of your operating system available.

So, in total, modify your uses clause as follows, and your application will work (tested on Windows):

Code: Pascal  [Select][+][-]

1. program PrintUtil;
2.  
3. uses
4.   Interfaces,    // <--- ADDED
5.   SysUtils, printers,
6.   osprinters;    // <--- ADDED
7.   //, printer4lazarus;          // <--- Not needed in "uses", but only in "required packages" of project
8.  
9. const
10.   LEFTMARGIN = 100;
11.   HEADLINE = 'I Printed My Very First Text On ';
12. var
13.   YPos, LineHeight, VerticalMargin: integer;
14.   SuccessString: string;
15. begin
16.   with Printer do
17.   try
18.     BeginDoc;
19.     Canvas.Font.Name := 'Courier New';
20.     Canvas.Font.Size := 10;
21.     Canvas.Font.Color := $0;
22.     LineHeight := Round(1.2 * Abs(Canvas.TextHeight('I')));
23.     VerticalMargin := 4 * LineHeight;
24.     // There we go
25.     YPos := VerticalMargin;
26.     SuccessString := HEADLINE + DateTimeToStr(Now);
27.     Canvas.TextOut(LEFTMARGIN, YPos, SuccessString);
28.   finally
29.     EndDoc;
30.   end;
31.  
32. end.

Thank you for reply , It worked!

[asmx]

Thanks every one!