Board index » cppbuilder » Switching printers causes data to go into black hole.

2004-07-07 05:50:51 AM
cppbuilder83
Using the example in Builder 5 Developer's Guide, I was able
to produce printed output from the IDE pretty easily on my
development machine. But the user has a printer that operates
via a USB cable. My output falls into a black hole, whereas
ordinary Notepad/Wordpad works fine. I do get a brief flash of
message that seems to be directing the printing toward the
printer, and the printer makes a little noise, but that's it.
Would you be kind enough to study my code? Why is there such
a difference between printers? Thanks!
char szDeviceName[CCHDEVICENAME], //Printer Name
szDriverName[MAX_PATH], //Dummy variable
szPortName[MAX_PATH]; //Dummy variable
THandle hPrnDevMode; //Dummy variable
int prtok; // For marking printing error.
// Get the name of the printer.
Printer()->GetPrinter(szDeviceName,szDriverName,szPortName,hPrnDevMode);
HANDLE hPrinter; // Printer handle
PRINTER_DEFAULTS pd; // Printer access rights for
// WinNT/Win2K only, ignored by Win9x
ZeroMemory(&pd, sizeof(pd)); // Initialize printer defaults
pd.DesiredAccess = PRINTER_ACCESS_USE; // Initialize access rights
// Open printer and get a handle to it (which is saved in hPrinter).
if(OpenPrinter(szDeviceName, &hPrinter,&pd))
{
DOC_INFO_1 docInfo1; // Document information
ZeroMemory(&docInfo1, sizeof(docInfo1)); // Init. doc info structure
// --- Setup the Doc1 information ---
// Name of the Doc (which is shown in the user's Print Manager)
docInfo1.pDocName = "Pantry Client Form";
docInfo1.pOutputFile = 0; // Port/File (not used)
// Data are sent in RAW format.
docInfo1.pDatatype = "RAW";
prtok = 1; // Initialize printing error flag.
if(!StartDocPrinter(hPrinter, 1, (LPBYTE)&docInfo1)) // Start the doc.
{
prtok = 0; // Mark the error.
}
else
{
if (!StartPagePrinter(hPrinter)) // Notify system that we want to print.
{
prtok = 0; // Mark the error.
}
}
if (prtok == 1) // If no error up to now ...
{
DWORD dwWritten; // Length of data actually sent
// Write the data to the Printer (including carrige
// returns and line feeds (New Lines))
String varbuf = "\0";
String one = "\r\n\n\n A.R. Nelson Christian Outreach Center\r\n";
String two = " Client Request Form\r\n ";
.
.
.
WritePrinter(hPrinter, (LPVOID)one.c_str(),
one.Length(), &dwWritten);
.
.
.
// Write a New Page to the Printer
String ff = "\f";
if(!WritePrinter(hPrinter, (LPVOID)ff.c_str(),
ff.Length(), &dwWritten))
{
prtok = 0;
}
// --------------------------------
// --- End of WritePrinter Code ---
// --------------------------------
// Tell the printer we're finished printing
if (!EndPagePrinter(hPrinter))
{
prtok = 0; // Mark the error.
}
// End the document
if(!EndDocPrinter(hPrinter))
{
prtok = 0;
}
// Close the printer
ClosePrinter(hPrinter);
}
 

Don Peterson wrote:
You are sending raw ascii data to the printer. Most USB printers are GDI
printers and cannot print ascii. They can only print in graphics mode.
The same applies to certain parallel printers.
Actually you should have posted this question in the nativeapi group.
Eelke
 

To answer my own question, apparently the printer to which I switched will not accept "raw" data, and must have pixel-based input. (It's a Lexmark Z35.) I was able to solve my problem by using Borland's Printer() object. The example given in the Sam's book is somewhat hairy, but by using mainly the Printer()->Canvas->TextOut function I succeeded. Hope this helps others.
 

{smallsort}