ITT Rule IDL Version 7.0 Manuel d'utilisateur télécharger pdf (Page 217)

Chapter 8: Creating a Manipulator 217

iTool Developer’s Guide Creating a New Manipulator

If the manipulator supports undo/redo functionality, call RecordUndoValues prior to

modifying the visualization in response to scroll wheel actions, and call

CommitUndoValues prior to exiting the method. See “Manipulators and the

Undo/Redo System” on page 202 for details.

The parameters of the OnWheel method return information about the location of the

mouse pointer when the scroll wheel is scrolled (

X and Y), information about the

direction and distance the wheel is scrolled (

Delta), and information on any

modifier keys the user held down while scrolling (

Modifiers). See

“IDLitManipulator::OnWheel” (IDL Reference Guide) for details.

Example OnWheel Method

The following example shows an OnWheel method that changes the zoom value of

the current window. (Note that this behavior is the default when the Zoom

manipulator is selected.)

PRO ExampleManip::OnWheel, oWin, X, Y, Delta, Modifiers

; Get the object reference to the current iTool.

oTool = self->GetTool()

IF (~OBJ_VALID(oTool)) THEN RETURN

; Get the object reference to the current view.

oWin = oTool->GetCurrentWindow()

oScene = OBJ_VALID(oWin) ? oWin->GetScene() : OBJ_NEW()

oView = OBJ_VALID(oScene) ? oScene->GetCurrentView() : OBJ_NEW()

IF (~OBJ_VALID(oView)) THEN RETURN

; Retrieve previous zoom factor.

oView->GetProperty, CURRENT_ZOOM=zoom

; Increase or decrease the current zoom by a factor of

; 1.25, depending on which direction the scroll wheel was

; scrolled.

zoomFactor = (delta GT 0) ? 1.25d : 1/1.25d

zoom *= zoomFactor

; Perform the ViewZoom operation.

zoom = STRTRIM(zoom*100, 2) + '%'

void = oTool->DoAction('TOOLBAR/VIEW/VIEWZOOM', OPTION=zoom)

END

Discussion

This OnWheel method simply increases or decreases the View Zoom when the

mouse wheel is scrolled. The zoom is modified by the same factor (1.25) whenever a

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ITT Rule IDL Version 7.0 Manuel d'utilisateur Page 217