I have written a program that uses FindNextPrinterChangeNotification to monitor changes in print jobs on a printer and log the information to a database. I am having a problem, however, that sometimes the paper size is reported as 8"x11" when the printed document is actually much larger.

I check the dmPaperWidth and dmPaperLength values of the DEVMODE (provided through JOB_NOTIFY_FIELD_DEVMODE in the PRINTER_NOTIFY_INFO_DATA structure) but often times these values are not used and dmPaperSize is set instead.

In these cases I use the following code to request the Paper Size dimensions (based on the dmPaperSize value) from the printer driver usiing DeviceCapabilites. It works in most cases, but occasionally the DEVMODE reports PaperSize as "1" and DeviceCapabilities says that this means 8"x11" even though this is not the correct size.


        // find out how many paper names there are
      PaperSizeCount = DeviceCapabilities(PrinterName, port, DC_PAPERNAMES, NULL, devMode);
      
      if(PaperSizeCount < 0) {
            ErrorMessage((string)"Error: DeviceCapabilities failed: " + ToString(GetLastError()));
      }

      // make sure we have atleast one paper name
      else if (PaperSizeCount > 0) {

            PaperNames = new char[PaperSizeCount*64];
            DeviceCapabilities(PrinterName, port, DC_PAPERNAMES, PaperNames,
                                    devMode);
            if(PaperNames==NULL) ErrorMessage("Error: need more memory for paper names");

            PaperIds = new WORD[PaperSizeCount];
            DeviceCapabilities(PrinterName, port, DC_PAPERS, (char*)PaperIds,
                                    devMode);
            if(PaperIds==NULL) ErrorMessage("Error: need more memory for paper ids");

            PaperSizes = new POINT[PaperSizeCount];
            DeviceCapabilities(PrinterName, port, DC_PAPERSIZE, (char*)PaperSizes,
                                    devMode);
            if(PaperSizes==NULL) ErrorMessage("Error: need more memory for paper sizes");

            ErrorMessage("Notice: Found " + ToString(PaperSizeCount) + " PaperSize Defintions for " + PrinterName);
            
            // pointer to loop through PaperIds
            WORD* p = PaperIds;

            for (long i = 0; i < PaperSizeCount; i++) {
                  if(*p==devMode->dmPaperSize) {
                        memcpy(&ret, &PaperSizes[i], sizeof(POINT));
                        char temp[65];
                        memcpy(temp, &PaperNames[i*64], 64);
                        temp[64] = '\0';
                        ErrorMessage((std::string)"Notice: Found matching Paper Size Definition for " + ToString(devMode->dmPaperSize) + " on " + PrinterName + " : " + temp + " ("  + ToString(ret.x) + "\" x " + ToString(ret.y) + "\")");
                        break;
                  }
                  p++;
            }
            if(i==PaperSizeCount) ErrorMessage("Warning: No match for for Paper Size Code: " + ToString(devMode->dmPaperSize));

      } else {
            ErrorMessage((std::string)"Warning: No Paper Size Codes found for " + PrinterName);
      }

The cases where the paper size is reported incorrectly seems to happen intermittently an unpredictably. I know the problem is happening on our KIP 8000 print driver and our HP 1055 driver because these are large format plotters. It is possible that other printer drivers are also reporting the wrong size, but I have not confirmed this yet.

It seems to me like the problem is in the software that is printing selecting dmPaperSize 1 when it prints yet actually printing a larger document. The drivers seem to accept this without complaint. Is there a better way to obtain the dimensions of the document being printed? Does anyone have any ideas about how I could improve my code to get the correct values in these cases?