Question

我需要一种便宜的方法来为我的应用程序创建PDF文件。因此，我直接使用Windows API的打印功能（CreateDC()，StartDoc()，StartPage()，EndPage()，EndDoc()等），然后选择 Microsoft Print to PDF 打印机驱动程序。

此外，我发现如果将lpszOutput结构的DOCINFO成员设置为文件名，驱动程序会将PDF文件写入命名文件，而不会提示用户输入名称。

到目前为止，太好了。但是，我怎么知道何时创建PDF文件？有后台处理程序API，但不一定仅由于完成后台处理程序而完成了驱动程序。或者，我可以创建一个循环来查找文件，但是当然它会在实际完成之前存在。我还考虑过尝试在循环中对文件进行锁定，如果该文件尚不存在或仍在写入中，则该尝试将失败。

但是我不禁想知道是否还有更直接的方法来知道PDF文件何时准备就绪。

Answer 1

如果您使用的是GDI打印API（wingdi.h），则此link显示用于查询打印机上打印作业状态的示例代码。

我包括了链接中的代码，但是您可能也想阅读这篇文章。

#include <Windows.h>
#include <wingdi.h>

BOOL GetJobs(HANDLE hPrinter,        /* Handle to the printer. */

             JOB_INFO_2 **ppJobInfo, /* Pointer to be filled.  */
             int *pcJobs,            /* Count of jobs filled.  */
             DWORD *pStatus)         /* Print Queue status.    */

{

  DWORD               cByteNeeded,
    nReturned,
    cByteUsed;
  JOB_INFO_2          *pJobStorage = NULL;
  PRINTER_INFO_2       *pPrinterInfo = NULL;

  /* Get the buffer size needed. */
  if (!GetPrinter(hPrinter, 2, NULL, 0, &cByteNeeded)) {
    if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
      return FALSE;
  }

  pPrinterInfo = (PRINTER_INFO_2 *)malloc(cByteNeeded);
  if (!(pPrinterInfo))
    /* Failure to allocate memory. */
    return FALSE;

  /* Get the printer information. */
  if (!GetPrinter(hPrinter,
                  2,
                  (LPSTR)pPrinterInfo,
                  cByteNeeded,
                  &cByteUsed)) {
    /* Failure to access the printer. */
    free(pPrinterInfo);
    pPrinterInfo = NULL;
    return FALSE;
  }

  /* Get job storage space. */
  if (!EnumJobs(hPrinter,
                0,
                pPrinterInfo->cJobs,
                2,
                NULL,
                0,
                (LPDWORD)&cByteNeeded,
                (LPDWORD)&nReturned)) {
    if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
      free(pPrinterInfo);
      pPrinterInfo = NULL;
      return FALSE;
    }
  }

  pJobStorage = (JOB_INFO_2 *)malloc(cByteNeeded);
  if (!pJobStorage) {
    /* Failure to allocate Job storage space. */
    free(pPrinterInfo);
    pPrinterInfo = NULL;
    return FALSE;
  }

  ZeroMemory(pJobStorage, cByteNeeded);

  /* Get the list of jobs. */
  if (!EnumJobs(hPrinter,
                0,
                pPrinterInfo->cJobs,
                2,
                (LPBYTE)pJobStorage,
                cByteNeeded,
                (LPDWORD)&cByteUsed,
                (LPDWORD)&nReturned)) {
    free(pPrinterInfo);
    free(pJobStorage);
    pJobStorage = NULL;
    pPrinterInfo = NULL;
    return FALSE;
  }

  /*
  *  Return the information.
  */
  *pcJobs = nReturned;
  *pStatus = pPrinterInfo->Status;
  *ppJobInfo = pJobStorage;
  free(pPrinterInfo);

  return TRUE;

}

BOOL IsPrinterError(HANDLE hPrinter) {

  JOB_INFO_2  *pJobs;
  int         cJobs,
    i;
  DWORD       dwPrinterStatus;

  /*
  *  Get the state information for the Printer Queue and
  *  the jobs in the Printer Queue.
  */
  if (!GetJobs(hPrinter, &pJobs, &cJobs, &dwPrinterStatus))
    return FALSE;

  /*
  *  If the Printer reports an error, believe it.
  */
  if (dwPrinterStatus &
    (PRINTER_STATUS_ERROR |
     PRINTER_STATUS_PAPER_JAM |
     PRINTER_STATUS_PAPER_OUT |
     PRINTER_STATUS_PAPER_PROBLEM |
     PRINTER_STATUS_OUTPUT_BIN_FULL |
     PRINTER_STATUS_NOT_AVAILABLE |
     PRINTER_STATUS_NO_TONER |
     PRINTER_STATUS_OUT_OF_MEMORY |
     PRINTER_STATUS_OFFLINE |
     PRINTER_STATUS_DOOR_OPEN)) {
    free(pJobs);
    return TRUE;
  }

  /*
  *  Find the Job in the Queue that is printing.
  */
  for (i = 0; i < cJobs; i++) {
    if (pJobs[i].Status & JOB_STATUS_PRINTING) {
      /*
      *  If the job is in an error state,
      *  report an error for the printer.
      *  Code could be inserted here to
      *  attempt an interpretation of the
      *  pStatus member as well.
      */
      if (pJobs[i].Status &
        (JOB_STATUS_ERROR |
         JOB_STATUS_OFFLINE |
         JOB_STATUS_PAPEROUT |
         JOB_STATUS_BLOCKED_DEVQ)) {
        free(pJobs);
        return TRUE;
      }
    }
  }

  /*
  *  No error condition.
  */
  free(pJobs);
  return FALSE;

}

如何判断Microsoft Print to PDF打印机驱动程序何时完成？

1 个答案: