342 |
and if the buoy would be inside this ellipse, its position |
and if the buoy would be inside this ellipse, its position |
343 |
and size is calculated differently. |
and size is calculated differently. |
344 |
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|
345 |
The size falls |
The position is calculated by *projecting* the anchor to the circle |
346 |
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from the leftmost point of the ellipse. |
347 |
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This places the buoys in a predictable and comprehensible way: |
348 |
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the human eye is good at understanding pencils of lines, due to perspective. |
349 |
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The size of the projected buoys |
350 |
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falls linearly with the distance of the anchor from the |
351 |
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center up to the edge of the ellipse, |
352 |
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|
353 |
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For left-link-end buoys the preceding discussion should |
354 |
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be reversed. |
355 |
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|
356 |
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.. Thus, the buoys are equally close to the focus, matching |
357 |
|
the fisheye focus shape. |
358 |
|
Additionally, a circle arc provides more area for the buoys than, |
359 |
|
e.g., a straight line. |
360 |
|
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The buoys are placed on an ellipse with diameter little less |
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than the screen heighand tcentered at the focus. |
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Thus, the buoys are equally close to the focus, matching |
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the fisheye focus shape. |
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Additionally, a circle arc provides more area for the buoys than, |
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|
e.g., a straight line. |
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|
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The position of a right-end buoy on the circle is obtained by |
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|
projecting a line from a constant point on the left side of the view |
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|
through the anchor point and to the circle, and similarly |
|
|
for the left-end buoys. |
|
361 |
The resulting layout placed the buoys close to the anchor |
The resulting layout placed the buoys close to the anchor |
362 |
while maintaining the left-right orientation. |
while maintaining the left-right orientation. |
363 |
Also, such line projections are easy to perceive for humans, |
If buoy anchors coincide or are very close to each other |
364 |
because it is analogous to 3D perspective. |
in the focused node, |
365 |
|
the final positions of the buoys need be adjusted to prevent. |
|
The buoy scale is chosen to be relative to the anchor's distance |
|
|
from the circle. That is, a buoy anchored at the center of the focus |
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|
is large and gets linearly smaller as it approaches the circle. |
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|
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Because the documents, even with the fisheye-distortion, can be larger |
|
|
than the buoy circle, buoys anchored far from the focus are drawn |
|
|
near the anchor instead (while maintaining the link direction). |
|
|
This is needed to prevent awkward view-cutting |
|
|
long lines and to yield more space for the layout of buoys anchored |
|
|
close to the focus. |
|
|
Furthermore, the final positions of the buoys may need be adjusted |
|
|
to prevent too much overlap. |
|
366 |
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|
367 |
.. how does this interact with the perception of the projection? |
.. how does this interact with the perception of the projection? |
368 |
|
|
372 |
|
|
373 |
Buoy layout geometry: XXX |
Buoy layout geometry: XXX |
374 |
|
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|
The above design produces good results and is very simple if not |
|
|
the simplest way to meet the layout requirements. |
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|
375 |
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|
376 |
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|
377 |
Paper |
Paper |
378 |
----- |
----- |
379 |
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|
380 |
Although the silhuettes of the buoys are different, |
The fragments of nodes seen in buoys are |
381 |
the fragments of the documents still seem quite similar. |
generally very similar in appearance. |
382 |
The user could identify the related documents by |
The user could identify the related documents by |
383 |
reading the text of a fragment, but that requires attention. |
reading the text of a fragment, but that requires attention. |
384 |
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|