Step 3: Modifying and Saving a Bitmap
Editing capabilities will now be added to the Bitmap Editor application. The basic editing function needed can change the color of a pixel in the BitmapDocument.
In Views, editing is done through the use of interactor objects. Interactor objects can be associated with a view or with a graphic object and can handle events to perform actions on these objects.
In most Document/View applications, modifications to the document are done through their view. The user performs some action on the view, which results in a modification of the document through a command call. Once the command is executed, the document notifies the views so that they can reflect the changes. The commands that are executed on a document are kept in memory to enable Undo/Redo operations.
Implementing pixel edition requires the following steps:
Defining a subclass of
IlvDvCommand that changes the color of a pixel in the
BitmapDocument. In particular, the
doIt and
undo methods will have to be implemented.
Defining a subclass of
IlvInteractor that is associated with the
IlvZoomableIcon object. This interactor will handle the user events on
BitmapView and call the above command.
Adding notification on the document views.
Enabling Undo/Redo with the Application Framework Editor.
BitmapView uses an
IlvZoomableIcon object to display the
BitmapDocument. In order to edit a pixel of the document, you need to associate an
IlvInteractor object that will handle the mouse events and call the appropriate command.
Published date: 05/24/2022
Last modified date: 02/24/2022