LPAFT_IG_METAD_ITEM_ADD

This callback function is used to insert new items during a WRITE filter operation.

Declaration:

	Copy Code
typedef AT_BOOL (LPACCUAPI LPAFT_IG_METAD_ITEM_ADD_CB)( LPVOID lpPrivate, AT_MODE FormatID, LPCHAR ItemName, DWORD ItemID, AT_MODE ItemType, LPVOID ItemValue, AT_MODE ValueType, DWORD ValueLength, AT_BOOL ReadOnlyValue );

Copy Code

typedef AT_BOOL (LPACCUAPI LPAFT_IG_METAD_ITEM_ADD_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	Provides the name of the new 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: IG_METAD_VALUE_ITEM - this value specifies that the current item is a value of the simplest type, and the field Value contains the actual value of the item, and ValueType contains the identifier of the type of this item. ReadOnly can be either TRUE (readonly) or FALSE (read/ write). The Name and/or Id contains textual and numerical identification of the item. IG_METAD_LEVEL_START - this value specifies that the current item opens a sublevel of items, and all next items up to the corresponding item with a LEVEL_END value belong to this sublevel. IG_METAD_LEVEL_END - this value closes the current sublevel and indicates that the next item belongs to a higher level.
ItemValue	LPVOID	Value of the new item. If ItemType = IG_METAD_VALUE_ITEM then ItemValue contains the actual value of the item of type specified by the ValueType parameter. The ItemValue is stored as an array of elements where each element contains values of type ValueType. Length of array is provided in parameter ValueLength.
ValueType	AT_MODE	If ItemType = IG_METAD_VALUE_ITEM then contains actual type of value stored in ItemValue pointer. See the Non-Image Data Format section for exact list of possible types.
ValueLength	DWORD	Length of array in ItemValue.
ReadOnlyValue	AT_BOOL	This parameter is not used.

Return Value:

Returns TRUE if a new value is added to item data; FALSE if it is not. A return of TRUE will cause the call of the Add callback function one more time.

Supported Raster Image Formats:

This function does not process image pixels.

Sample:

JPEG

Example:

See example for IG_fltr_metad_callback_set() function.

Remarks:

If the return value is TRUE then a new value is added; and if FALSE a new value is not added. ImageGear will be calling Add callback function while it returns TRUE, so the callback function should return TRUE if the provision of additional items is it not finished yet, and FALSE if it is finished. All parameters except of lpPrivate are used to get information about the new value.

ImageGear assumes that all tags passed via LPAFT_IG_METAD_ITEM_ADD_CB callback are writable, except for the tags that were sent by LPAFT_IG_METAD_ITEM_SET_CB, marked as read-only.