Using Printer Escapes w/PS Printers on Windows NT & Win32s

• Microsoft Win32 Application Programming Interface (API) included with:

      - Microsoft Windows NT versions 3.1, 3.5, and 3.51
      - Microsoft Win32s versions 1.1, 1.15, 1.15a, and 1.2
  

SUMMARY

To identify and print to PostScript printers from a Win32-based application under Windows NT and under Win32s, you need to special-case your code. This is because the printer drivers respond to different Printer Escapes under Windows NT and Windows/Win32s.

This article discusses how to identify and print to PostScript printers on both Windows NT and Win32s.

MORE INFORMATION

Identification

To identify the printer as a PostScript printer, use this code:

   int gPrCode = 0;  // Set according to platform.

   if( Win32s ) // Using the Win16 driver.
   {
      gPrCode = PASSTHROUGH;
      if((Escape(printerIC, GETTECHNOLOGY, NULL, NULL, (LPSTR)szTech) &&
         !lstrcmp(szTech, "PostScript")) &&
         Escape(printerIC, QUERYESCSUPPORT, sizeof(int),
            (LPSTR)gPrCode, NULL )
      {
      // The printer is PostScript.
         ...
      }
   }
   else // Using Win32 driver under Windows NT.
   {
      gPrCode = POSTSCRIPT_PASSTHROUGH; // Fails with Win16 driver
      if( Escape(printerIC, QUERYESCSUPPORT, sizeof(int), (LPSTR)gPrCode,
          NULL))
      {
      // The printer is PostScript.
         ...
      }
   }

Printing

To send PostScript data to the printer on either platform, use this code:

// Assuming a buffer, szPSBuf, of max size MAX_PSBUF containing
// nPSData bytes of PostScript data.

   char szBuf[MAX_PSBUF+sizeof(short)];

// Store length in buffer.
   *((short *)szBuf) = nPSData;

// Store data in buffer.
   memcpy( (char *)szBuf + sizeof(short), szPSBuf, nPSData );

// Note that gPrCode (set when identifying the printer) depends on
// the platform.
   Escape( printerDC, gPrCode, (int) nPSData, szBuf, NULL );

The origin and scale for Windows printer drivers is not the PostScript default (bottom left/72 dpi) but is instead at the upper left and at the device scale(300 dpi). Therefore, before sending data to the printer, you may need to send a couple of PostScript commands to scale or translate the matrix. For example, for scaling, send the following escape to scale the PostScript transform to 72 dpi:

   xres = GetDeviceCaps(printerDC, LOGPIXELSX);
   yres = GetDeviceCaps(printerDC, LOGPIXELSY);

// Two leading spaces for the following operation.
   wsprintf(szBuf, "  %d 72 div %d 72 div scale\n", xres, yres);

// Put actual size into buffer
   *((short *)szBuf) = strlen(szBuf)-2;
   Escape( printerDC, gPrCode, strlen(szBuf)-2, szBuf, NULL );