Does PrintDocument sends whole document to printer or line by line?

Question

A little context: I'm developing a Windows Form app that contains a feature where the user prints some info.

The thing is that the size of that information can change from time to time: sometimes it can fit on a single page or sometimes it can be 20+ pages.

For the printings, I'm using .Net's PrintDocument

So I'm using e.HasMorePages to handle the possible multiple pages. Here's a simplified version of my code:

int printIndex = 0;

private void startPrinting(){
    PrintDocument printDoc = new PrintDocument();
    printDoc.PrinterSettings.PrinterName = "Ticket printer1"

    printDoc.PrintPage += new PrintPageEventHandler(printPage);
    printDoc.Print();
}

And the printPage method:

private void printPage(object sender, PrintPageEventArgs e)
{
    Graphics graphics = e.Graphics;
    int yPos = 0;
    Font regular = new Font(FontFamily.GenericSansSerif, 10.0f, FontStyle.Regular);

    for(int i = printIndex; i < data.Length; i++)
    {
        if (yPos + 30 >= e.PageBounds.Height)
        {
            e.HasMorePages = true;
            return;
        }
        else
        {
            e.HasMorePages = false;
        }
        graphics.DrawString(data[i], regular, Brushes.Black, yPos, 110);
        yPos += 20;
        printIndex++;
    }
    regular.Dispose();
    graphics.Dispose();
}

And this works just fine on virtual printers and even some physical printers here at the office. But when the user runs the app on his actual computer (with his actual printer) it prints no more than 3 pages.

I asked a peer and he suggested that Windows is sending the whole document to the printer and maybe some printers can't handle large documents due to low memory issues.

Is it how it works? and if it is: how can I fix it to print more than 3 pages?

I think this might depend on the print driver, though you might want to play with the print spool settings, `print after last page is spooled`, and `start printing immediately`. Postscript, PCL, HPGL, breaks up printing work into a special language that the printer understands, the Windows spools that work so the printer can deal with it in a orderly fashion. I'm not sure if this is the case, but it could be possible that the way you are doing this is trying to send 20 pages at once (as 1 page) to the printer and its running out of memory. — TheGeneral, Aug 22 '18 at 23:06
I haven't seen a printer than can't handle many more than 3 pages since the days of Windows 3.x, including old dot matrix and thermal receipt printers. — Ken White, Aug 23 '18 at 00:45
All those drawing classes you are using (Graphics, Font, etc.) are wrappers around Win32 GDI objects and are Disposable. If you don't Dispose those things, unexpected results can happen. Read up on the "using" statement and IDisposable, and make sure you clean things up properly. You aren't printing line by line; you are printing page by page (hence the PrintPage event). You should be able to print *a lot* of pages. — Flydog57, Aug 23 '18 at 01:43
@Flydog57 Edited the Question showing the way I'm disposing of those objects (I forgot earlier to include those lines but they are actually in my code) But I just realized most of the iterations those lines are not being called, thanks for the advice. It actually solved the issue, post it as an answer please to mark it as resolved. — Adan Sandoval, Aug 23 '18 at 17:27

score 1 · Accepted Answer · answered Aug 23 '18 at 18:35

Some hints:

All those drawing classes you are using (Graphics, Font, etc.) are wrappers around Win32 GDI objects and are Disposable. If you don't Dispose those things, unexpected results can happen. Read up on the "using" statement and IDisposable, and make sure you clean things up properly. You aren't printing line by line; you are printing page by page (hence the PrintPage event). You should be able to print a lot of pages.

Does PrintDocument sends whole document to printer or line by line?

1 Answers1