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To place a figure at a new location in the document, generator
figures are used. Vispatch currently implements two types of
generator figures. The first of these is called GenRotate and
looks like a small circle around an X. The second type of generator
figure is called GenXY and looks like a small square that
encloses an X. To illustrate the difference in how these generators create new points, the applet below includes a rule that draws two triangles in response to a mouse drag. The left scope figures contains several examples of figures produced by this rule. The red arrow in each example shows the length and direction of the mouse drag that the rule processed. |
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Both GenRotate and GenXY produce points that depend on the start and
end points of the mouse drag. Points generated with GenRotate
rotate with the direction of the mouse drag and scale proportionately
with the length of the mouse drag. This can be seen by looking at the smaller triangles,
which were created by GenRotate. In contrast, GenXY produces points that scale independently in the X and Y directions such that they are proportional to the X and Y distances covered by the mouse drag. For example, the larger triangles formed from dashed lines (i.e. equiv line figures) were created by GenXY. Notice how they become compressed horizontally as the mouse drag covers less X distance in the examples labeled "Same Y". Notice also that horizontal and vertical mouse drags cause GenXY to produce points that fall on the same line as the mouse drag. In the figure above, this causes the larger triangle to be hidden (mostly) below the red arrow. |