IG_ISIS_tag_get

Get the type of a tag.

Declaration:

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AT_ERRCOUNT ACCUAPI IG_ISIS_tag_get_type( HISISDRV hDriver, AT_MODE nTag, LPAT_MODE lpnType );

Arguments:

hDriver

The handle to the driver.

nTag

Specifies the tag for which to return the type.

lpnType

Points to the address which will contain the type of wTag after this function completes. lpnType is filled in with one of the following values:

IG_ISIS_TAG_TYPE_STRING - The tag consists of an ASCII string.
IG_ISIS_TAG_TYPE_BYTE - The tag consists of one or more signed byte values.
IG_ISIS_TAG_TYPE_SHORT - The tag consists of one or more signed integer values.
IG_ISIS_TAG_TYPE_LONG - The tag consists of one or more signed long values.
IG_ISIS_TAG_TYPE_RATIONAL - The tag consists of one or more rational values.

The TIFF specification normally treats all values as unsigned. Note also that the types IG_ISIS_TAG_TYPE_BYTE, IG_ISIS_TAG_TYPE_SHORT, and IG_ISIS_TAG_TYPE_LONG are all accessed as longs in toolkit functions to reduce the total number of functions needed.

Return Value:

Returns the number of ImageGear errors that occurred during this function call. If there are no errors, the return value is IGE_SUCCESS.

Supported Raster Image Formats:

This function does not process image pixels.

Remarks:

The IG_ISIS_tag_get_type function retrieves the type of the specified tag.

Use IG_ISIS_tag_get_type to determine the type of a tag before performing other functions such as IG_ISIS_tag_get_long, IG_ISIS_tag_get_long_default, etc., or IG_ISIS_choice_get_long, etc..

Example:

The following example returns a text string that indicates the type of a tag based on checking the tag inside a driver.

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char FAR GetTagText (HISISDRV hDriver, AT_MODE nTag) { DWORD dwLength ; LONG lTemp ; WORD wTemp ; AT_ISIS_RAT ratValue ; char FAR cpString ; if (IG_ISIS_tag_get_type (hDriver, nTag, &wTemp)) return NULL ; switch (wTemp) { case IG_ISIS_TAG_TYPE_STRING:IG_ISIS_tag_get_length (hDriver, nTag, &dwLength) ; if (NULL == (cpString = (char FAR ) malloc((ulLength + 1)))) return NULL ;IG_ISIS_tag_get_ascii (hDriver, nTag, dwLength, cpString) ; return cpString ; case IG_ISIS_TAG_TYPE_BYTE: case IG_ISIS_TAG_TYPE_SHORT: case IG_ISIS_TAG_TYPE_LONG: / Return only first value. / if (NULL == (cpString = (char FAR ) malloc(20))) return NULL ;IG_ISIS_tag_get_long (hDriver, nTag, 0, &lTemp) ; sprintf (cpString, "%d", lTemp, 0) ; return cpString ; case IG_ISIS_TAG_TYPE_RATIONAL: /* Return only first value. / if (NULL == (cpString = (char FAR ) malloc(20))) return NULL ;IG_ISIS_tag_get_long (hDriver, nTag, 0, &ratValue) ; lTemp = (LONG) (ratValue.Num / ratValue.Denom) ; sprintf (cpString, "%d", lTemp, 0) ; return cpString ; default: return NULL ; } }

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char FAR *GetTagText (HISISDRV hDriver, AT_MODE nTag)  {
  DWORD dwLength ;
  LONG lTemp ;
  WORD wTemp ;
  AT_ISIS_RAT    ratValue ;
  char   FAR *cpString ;
  if (IG_ISIS_tag_get_type (hDriver, nTag, &wTemp))
    return NULL ;
  switch (wTemp) {
    case IG_ISIS_TAG_TYPE_STRING:IG_ISIS_tag_get_length (hDriver, nTag, &dwLength) ;
      if (NULL == (cpString = (char FAR *) malloc((ulLength + 1))))
        return NULL ;IG_ISIS_tag_get_ascii (hDriver, nTag, dwLength, cpString) ;
      return cpString ;
    case IG_ISIS_TAG_TYPE_BYTE:
    case IG_ISIS_TAG_TYPE_SHORT:
    case IG_ISIS_TAG_TYPE_LONG:
      /* Return only first value. */
      if (NULL == (cpString = (char FAR *) malloc(20)))
        return NULL ;IG_ISIS_tag_get_long (hDriver, nTag, 0, &lTemp) ;
      sprintf (cpString, "%d", lTemp, 0) ;
      return cpString ;
    case IG_ISIS_TAG_TYPE_RATIONAL:
      /* Return only first value. */
      if (NULL == (cpString = (char FAR *) malloc(20)))
        return NULL ;IG_ISIS_tag_get_long (hDriver, nTag, 0, &ratValue) ;
      lTemp = (LONG) (ratValue.Num / ratValue.Denom) ;
sprintf (cpString, "%d", lTemp, 0) ;
return cpString ;
    default:
      return NULL ;
    }
  }