#include "BITIFF.H"
BOOL CALLBACK IsRequiredTag(WORD wTag)
Description
Decides whether a tag is required in a tag list of an image or not. Document Imaging SDK uses this function in decoding functions, but you should use it in encoding functions. If a tag is required, it is not mandatory in an image, but if it presents, the value(s) it specifies must be correct. In most cases there are default value(s) for a required tag, so if it does not exist, the decoding function uses the default. Some tags has no default, so they must be present in the tag list of the image, otherwise the loader fails to load the image.
Most of the required tags are specified by the encoding functions, so you do not need to define them manually. Besides, it is not recommended to define or modify these tags. ASCII type tags are not part of the required tags, so they are freely defineable and modifiable. If you are unsure if a tag is required or not, just call this function, instead of making an image unreadable after saving.
Parameters
|
WORD |
wTag |
Identifier of the tag to get information about. |
Return values
Returns TRUE, if the specified tag is required, otherwise FALSE. The function does not change the error code.
Requirements
Header : Declared in BiTiff.h; include BiTiff.h.
Library : Use BiTIFF.lib.
DLLs : BiTiff.dll.
References to related functions
See DefineGeneralTags(), DefineTiffImageInfo(), DefineTiffImageInfoBuffer(), AddTiffTagToImage() and DeleteTiffTagOfImage().