Mentaer: Created page with 'To implement a new cursortool, the best way is to study and subclass existant cursortools with a similar behaviour: * for example cursortool #DragTool if your tool needs a mouse…'

2009-10-18T21:55:06Z

Created page with 'To implement a new cursortool, the best way is to study and subclass existant cursortools with a similar behaviour: * for example cursortool #DragTool if your tool needs a mouse…'

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To implement a new cursortool, the best way is to study and subclass existant cursortools with a similar behaviour:
* for example cursortool #DragTool if your tool needs a mouse drag;
* or cursortool#NClickTool if your tool uses several clicks

(see Jump Developer's Guide chapter 6. for more informations on cursortool classes)

Let's create a simple cursortool that displays cursor coordinates in a java console, each time we click once in the layerViewPanel (not a very useful tool...):

<pre>
public class CoordinateCursorTool extends AbstractCursorTool{
private Coordinate actualCoord = new Coordinate();
public RasterQueryCursorTool() //constructor does nothing special here

public Icon getIcon() {
return IconLoader.icon("My_toolbar_Icon.gif");
//specify here the toolbar icon file (button image) to use%
}

public Cursor getCursor() {
return createCursor(IconLoader.icon("My_Cursor.gif")
.getImage()); //specify here the cursor image file to use
}

public void deactivate() {
}

public boolean isRightMouseButtonUsed() {
return false;
}

public void mouseClicked(MouseEvent e) {
try {//add here the code to execute when the mouse is clicked%
actualCoord = getPanel().getViewport().toModelCoordinate(
e.getPoint());
system.out.println(actualCoord); //Display coordinates as a string
} catch (NoninvertibleTransformException e1) {
e1.printStackTrace();
}
fireGestureFinished(); //Notify that mouse gesture is finished
}

public boolean isGestureInProgress() {
return false;
}

public void cancelGesture() {
}

public String getName() {
return "CoordinateTool";
}

protected Shape getShape() throws Exception {
return null; //because nothing should be drawn here
}

protected void gestureFinished() throws Exception {
reportNothingToUndoYet();

}}

</pre>

Then we add our cursortool to the workbench toolbar. This can be done in the initialize() method of a new plugin:

<pre>
public void initialize(PlugInContext context){
WorkbenchFrame frame = context.getWorkbenchContext()
.getWorkbench().getFrame();

frame.getToolBar().addCursorTool(new CoordinateCursorTool());

//etc...
</pre>

In the workbench, you have now a new button. Press it and the CoordinateCursortool becomes active (the #activate method is called). Have fun!

<hr>

Thanks to Paul Plouy for writing up the tutorial above. Note that there are some subclasses of AbstractCursorTool that you can subclass to get additional power for free; for example: MultiClickTool, SpecifyFeaturesTool, etc. For examples of their use, see the classes in com.vividsolutions.jump.workbench.ui.cursortool [Jon Aquino 2005-09-22]

<hr>

There are several good examples of CursorTools in the OpenJUMP source code. Check out the cursortools folder. [Jon Aquino 2005-11-04]

Implementing cursortools - Revision history

Mentaer: Created page with 'To implement a new cursortool, the best way is to study and subclass existant cursortools with a similar behaviour: * for example cursortool #DragTool if your tool needs a mouse…'