Fluid Visualization Of Spreadsheet Structures Page 5

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a) An arrow grows
b) The user can change
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when the control key is
the direction of the arrow
pressed.
using left/right arrow keys.
Figure 7. Direct editing of dataflow graphs .
The user can transform the dataflow graph
in ways similar to editing in object-oriented
drawing editors. In this example, the user
grabs a handle and drags it to scale two
parts of the graph.
7 Visual editing
c) The current cell indicator
d) The user can then
flies to the destination cell
continue navigating from
when the up arrow key is
the destination cell.
In previous sections, we discussed techniques to visually
pressed.
present the underlying dataflow structure of a spreadsheet. In
this section, we will introduce techniques to visually edit the
Figure 6. Semantic navigation of dataflow
dataflow structure underlying the textual formulas. This
graphs. The user can navigate through the
dataflow graph using arrow keys by holding
visual editing functionality works surprisingly well in
down a control key.
constructing dataflow structures that are spatially regular and
simple, but complicated to specify textually. Direct editing
1. The user begins semantic navigation by pressing the
of dataflow graphs allows the user to edit the dataflow
control key.
structure in a way similar to object-oriented drawing editors,
and interactive graphical induction enables the user to
2. A large arrow sprouts from the current cell, growing to
construct regular formulas for a series of cells interactively.
point to one of the semantically connected cells
(incoming or outgoing cells). We call the cell that the
7.1 Direct editing of dataflow graphs
arrow is pointing to a destination cell (Figure 6a).
3. The user can select the destination cell among the
Direct editing of dataflow graphs is a straightforward
semantically connected cells using the left and right
application of dataflow graph visualization. It allows the user
arrow keys (Figure 6b).
to move, scale, and delete the visualized dataflow graphs
using standard direct manipulation techniques [27]. These
4. The user can jump to the destination cell by pressing
editing operations cause the textual formulas to be updated
the up arrow key (Figure 6c). The user can then
accordingly. It is especially useful to edit multiple dataflow
continue to navigate through the dataflow graph by
graphs directly at a time. (Excel allows graphical editing, but
repeating 3 and 4 (Figure 6d).
only of one region at a time.)
5. When the control key is released, the cursor keys once
When the static global view is in effect or the user
again function for normal spatial navigation.
enters editing mode by clicking a cell in the transient
Every visual effect is presented in an animated manner
visualization mode, dataflow graphs are made visible. The
to aid the user’s comprehension of the navigation. The
user can grab a graph by clicking it, move the selected
arrowhead moves continuously and the current cell indicator
constraint by dragging it, and scale it by dragging the
flies smoothly. This semantic navigation mechanism not only
handles that appear at its corners. Multiple graphs can be
reduces the number of keystrokes, but also promotes better
activated by clicking them with shift key pressed, causing all
understanding of the dataflow structure. Easy access to
active graphs to move and scale simultaneously (Figure 7).
logically connected cells makes the user feel that the cells are
close to each other, even if they are spatially distant. In other
7.2 Interactive graphical induction
words, semantic navigation visualizes the hidden topology of
the dataflow graph through its characteristic interaction.
The visual representation of dataflow graphs makes it
possible to understand the structure as a collection of regular

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