Interface AutoexposeHelper
- All Known Implementing Classes:
- ViewportAutoexposeHelper
GraphicalEditPart. Certain
 DragTrackers tools and native drop listeners will make use of
 autoexpose helpers to reveal any potential drop areas that are currently not
 visible to the user. An example of this is scrolling a container to reveal
 unexposed area. Another example is a bunch of stacked containers in a "tab
 folder" arrangement, whever hovering over a tab should switch which container
 is on top.
 Autoexpose helpers are obtained from editparts that are target of whatever operation is being performed. If the target provides no helper, its parent chain is traversed looking for helpers. A helper will be obtained under conditions deemed appropriate by the caller, such as when the mouse has paused for some amount of time in the current location.
 An autoexpose helper may be short-lived or long-running. A short-lived helper
 would be something like the example described above when a "page" is being
 flipped. A long-running example is auto-scrolling. A helper requests to
 remains active by returning true from its step(Point)
 method for as long as necessary. An active helper can remain active even as
 the mouse is moving. The client may stop calling step(Point) at
 any time, even if false was never returned, such as when the
 user releases the mouse.
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Nested Class SummaryNested ClassesModifier and TypeInterfaceDescriptionstatic classUsed with EditPartViewers to find the AutoexposeHelper at a Point.
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Method Summary
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Method Details- 
detectReturnstrueif the specified location is interesting to the helper. This method gets called as part of the search for an AutoexposeHelper. The helper should do something if it returnstrue, or it may wait forstep(Point)to be called later.- Parameters:
- where- the mouse's current location in the viewer
- Returns:
- trueif the location is interesting
 
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stepPerforms the autoexpose and returns a hint indicating that the helper would like to remain active. The client will continue to call step() for as long as it previously returnedtrue, and the conditions are deemed appropriate to continue the autoexpose process.The client may stop calling this method at any time, even if the previous invocation returned true. The return value is a hint.- Parameters:
- where- the current location of the mouse in the viewer
- Returns:
- a hint indicating whether this helper should continue to be invoked
 
 
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