This function has been deprecated and will be removed from the API in version 18 of ImageGear. Please use LPAFT_IG_METAD_ITEM_GET_CB instead.
Declaration:
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typedef BOOL (ACCUAPI LPFNIG_TAG_USER_GET) (
LPVOID lpPrivate,
LPAT_MODE lpUserTag,
LPAT_MODE lpDataType,
LPVOID32 FAR *lpTagData,
LPDWORD lpSize
);
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Arguments:
| lpPrivate | Far pointer to private data area, which can be used for anything you like, including the storage of the image's HIGEAR handle. |
| lpIGTag | Far pointer to an AT_MODE variable to receive a private tag number. Your value must be 32768 or higher. |
| lpDataType | Set to an IG_TAG_TYPE_ constant (these are listed in file accucnst.h) specifying the data type for this tag. |
| lpTagData | Return a pointer to your data. |
| lpSize | Tell ImageGear the size of your data. |
Return Value:
Return TRUE if returning a tag, in which case this callback function will be called again in case you have more tags to supply. Return FALSE if you are not returning a tag and are done returning tags.
Supported Raster Image Formats:
This function does not process image pixels.
Sample:
JPEG
Example:
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BOOL ACCUAPI TagUserGet( LPVOID lpPrivate, /* Private data passed in */ LPAT_MODE lpnIGTag, /* Tag ID from geartags.h */ LPAT_MODE lpType, /* Type of data lpTag points to */ LPVOID FAR* lpTag, /* Pointer to tag data */ LPDWORD lpSize /* Size of tag data (bytes) */ ) /* set Tag ID, data type, length, and pointer to your data */ { *lpSize = 0; if( (*lpnIGTag>=IGTAG_JPG_APPDATA) && (*lpnIGTag<=IGTAG_JPG_APPDATA_LAST) ) { if( (*lpnIGTag-IGTAG_JPG_APPDATA)==12 ) /* supplying only APP13 marker */ { /* supply application marker data */ *lpType = IG_TAG_TYPE_RAWBYTES; *lpTag = (LPVOID)(&TestData[0]); *lpSize = sizeof(TestData); return TRUE; } /* FALSE when no tag being returned */ } return FALSE; } ... IG_save_tag_CB_register( TagGet, TagUserGet, (LPVOID)&dwPrivateFlags ); ... |
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Remarks:
This function allows you to store a private TIFF tag with the image being saved.
This callback function is registered by calling IG_save_tag_CB_register(). In this callback, you supply a tag number, tag type, and tag data. Note that the value of your private tag number must be higher than 32768.
When ImageGear is going to save a file it will check to see if you have registered any applicable callbacks. If you have registered a callback of type LPFNIG_USER_TAG_GET(), it will be called until you set it to FALSE. While your callback is still set to TRUE, it will add your user-defined tags one at a time to the TIFF image being saved.
lpIGTag is a far pointer to an AT_MODE in which you store a privately defined tag ID#. lpDataType is a pointer to your Tag data type, lpTagData is a pointer to your tag data, and lpSize is the length of your tag data.
This callback function should return TRUE when supplying a tag, in which case it will be called again. Return FALSE when you are done supplying tags. This callback will be called at least once if it has been registered.