think-cell technical report TC2003/01 A GUI-based Interaction ...

4.3 Specifying the User Interface INTERACTION CONCEPT
Selection Indication
Since smart elements exhibit an enhanced behavior as opposed to native PowerPoint
shapes, the user must be provided with feedback to distinguish these two kinds of
elements. I chose to show a different style for the outline and the dragging points of
selected elements. In addition, a lighter version of the selection indication displays
on mouse-over to provide some hint which elements are “smart” and can be selected.
Native PowerPoint shapes are not sensitive to mouse-over actions.
While PowerPoint shapes generally have eight dragging points – one in each
corner and one in the middle of each side – to modify their size in different dimen-
sions, smart elements offer similar functionality only for the corners. Because of
the difference in behavior with regard to the smart grid, I call my dragging points
anchorpoints. A detailed description of anchorpoints is given in section 4.3.4 where
there are also screenshots that show the appearance of a selected element (Fig. 33).
Outline-based Selection
While a traditional PowerPoint slide is built from basic shapes – rectangles, ovals,
arrows, text boxes – and from OLE objects that appear to PowerPoint as sim-
ple rectangles, in the smart grid approach the layout exhibits a hierarchical struc-
ture. In particular, charts and complex templates are replaced with smart elements.
Smart elements are complex compositions of basic shapes. In contrast to traditional
PowerPoint templates, smart elements appear to the user as one single PowerPoint
object. They configure themselves while interacting with the smart grid, generating
and moving their internal shapes as required. In contrast to OLE objects, smart
elements are edited “in place” without the need to switch to another application
first. 10
In order to facilitate user interaction with smart elements, I needed to extend the
PowerPoint notion of “selection”. For purposes like moving, resizing and copying,
smart elements can be selected like usual PowerPoint shapes. Any selection of a
shape that is part of a smart element, selects the entire smart element itself. On top
of that, those shapes of the smart element that offer some configurability present an
outline that look different from the PowerPoint selection. These shapes are called
features of the smart element. The outline of a feature is highlighted in red on
mouse-over and turns to blue when it is selected. Just as in PowerPoint, selection
is performed with a single click and the shift key can be used to create multiple
selections. But in this case, multiple selection is restricted to features of the same
type and within the same smart element.
The place to click in order to select a feature is its highlighted outline, not
its body as in ordinary PowerPoint. When a mouse click is detected on a feature
outline, that click is hidden from PowerPoint to circumvent the traditional selection
behavior.
10 For remarks on mode switch and OLE objects, see section 4.2.4.
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