This callback function is used to get information about metadata items received during a READ filter operation.
Declaration:
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typedef VOID (LPACCUAPI LPAFT_IG_METAD_ITEM_GET_CB)( LPVOID lpPrivate, AT_MODE FormatID, LPCHAR ItemName, DWORD ItemID, AT_MODE ItemType, LPVOID ItemValue, AT_MODE ValueType, DWORD ValueLength, AT_BOOL ReadOnlyValue ); |
Arguments:
Name | Type | Description |
lpPrivate | LPVOID | Private callback data. |
FormatID | AT_MODE | The ID of the format filter that will send or get the item (IG_FORMAT_... constant). |
ItemName | LPCHAR | Name of the item. |
ItemID | DWORD | Numerical ID of the item. |
ItemType | AT_MODE |
Specifies the type of the item and reflects the status of the given record. Possible values are:
|
ItemValue | LPVOID | If ItemType = IG_METAD_VALUE_ITEM then ItemValue contains the actual value of the item of the type specified by the ValueType parameter. Value is stored as array of elements where each element contains values of type ValueType. Length of array is provided in parameter ValueLength. |
ValueType | AT_MODE | Type of element stored in array ItemValue. |
ValueLength | DWORD | Length of array of elements stored in ItemValue. |
ReadOnlyValue | AT_BOOL | If this argument is TRUE, then the actual value of the item cannot be changed by the callback function, and the value is passed for informational purposes only. If FALSE then the value of the item can be changed, and the application can provide a new value through the next three parameters. |
Return Value:
None
Supported Raster Image Formats:
This function does not process image pixels.
Sample:
JPEG
Example:
See example for IG_fltr_metad_callback_set() function.
Remarks:
The ReadOnlyValue parameter is used to inform the application that the value of a given item is for information only and cannot be changed during future operations.
See also IG_fltr_metad_callback_get(), IG_fltr_metad_callback_set(), LPAFT_IG_METAD_ITEM_ADD_CB, LPAFT_IG_METAD_ITEM_SET_CB functions and the section Using Filter Callback Functions to Process Non-Image Data.