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When calling some functions of the LVectorBase LEADTOOLS C++ Class Library classes, particularly those that affect the vector itself, then notification messages are sent through the LVectorBase::StartChanging and LVectorBase::EndChanging member functions. These functions are called before and after executing the function that changes the bitmap. This gives you more control over the operation in progress. In order to use this feature, you must override the virtual functions for StartChanging and EndChanging. In the LVectorBase::StartChanging function, if you return an error code, the change operation will halt the calling function and will return the same error code. In the LVectorBase::EndChanging function you will be notified that the calling function's operation is complete. This gives you a chance to do other processing such as updating the display.
The following sections describe the change notifications and the notification categories:
The following is a list of all the notification messages and the functions that send them:
The following is a list of all the notification categories:
| Notification Message | Function In Progress |
|---|---|
| NCAT_VECTOR | LVectorBase functions for setting view and object characteristics |
| NCAT_VECTOR_DIALOG | LVectorDialog dialog generation |