ITT Rule IDL Version 7.0 Manuel d'utilisateur télécharger pdf (Page 219)

Chapter 8: Creating a Manipulator 219

iTool Developer’s Guide Creating a New Manipulator

; the retrieved IDLitVisImage object.

self.oImage = (*self.pSelectionList)[0]

ENDIF ELSE BEGIN

RETURN

ENDELSE

; Record the current values for the selected images.

iStatus = self->RecordUndoValues()

; *** Interact with the visualization based upon key press.

; ...

; Commit this transaction.

iStatus = self->CommitUndoValues()

; Write information to the status bar

; using inherited IDLitIMessaging ProbeStatusMessage method.

self->ProbeStatusMessage, 'Some manpulation information'

; Update the window to reflect the changes made.

oWin->Draw

END

Discussion

The OnKeyboard method will customarily contain portions of code from any

implemented mouse transaction methods. In this example, if a button press event

occurred, access the list of selected items and verify that the first item is an image. If

so, call IDLitManipulator::RecordUndoValues, as was previously shown in the

OnMouseDown method. Interact with the visualization as defined in an

OnMouseDown or OnMouseMotion method. After making modifications, call

CommitUndoValues to commit the transaction to the undo/redo buffer, previously

shown in the OnMouseUp method. Use the IDLitIMessaging::ProbeStatusMessage

method to write information to the status bar of the iTool and access the

oWin

parameter to update the window, as was previously shown in the OnMouseMotion

method.

Creating a RegisterCursor Method

It is a useful visual indication to the user that a manipulator has been activated if the

cursor changes. You can define a pre-existing cursor for a manipulator using the

DEFAULT_CURSOR property during initialization as described in “Example Init

Method” on page 210 or using the SetProperty method. If none of the predefined

cursors suit your needs, you can create a custom cursor by calling a method that

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ITT Rule IDL Version 7.0 Manuel d'utilisateur Page 219