253 |
- the view should animate continuously when the focus moves |
- the view should animate continuously when the focus moves |
254 |
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|
255 |
Furthermore, |
Furthermore, |
256 |
It is important to maintain orientation locally, |
it is important to maintain orientation locally, |
257 |
that is, going in one direction should result in arriving from |
that is, going in one direction should result in arriving from |
258 |
the opposite direction, so that the local spatial structure |
the opposite direction, so that the local spatial structure |
259 |
does not change too much. |
does not change too much. |
284 |
leaving more space at the left and right sides than on the top and bottom. |
leaving more space at the left and right sides than on the top and bottom. |
285 |
XXX: left and right hand??? |
XXX: left and right hand??? |
286 |
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287 |
We choose the geometry as follows: |
From the above principles, we have chosen a simple geometry |
288 |
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depicted in Fig. [ref-figbuoygeom]_. |
289 |
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The buoys are placed on a circle with diameter little less |
290 |
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than the screen heighand tcentered at the focus. |
291 |
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Thus, the buoys are equally close to the focus, matching |
292 |
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the fisheye focus shape. |
293 |
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Additionally, a circle arc provides more area for the buoys than, |
294 |
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e.g., a straight line. |
295 |
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|
296 |
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The position of a right-end buoy on the circle is obtained by |
297 |
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projecting a line from a constant point on the left side of the view |
298 |
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through the anchor point and to the circle, and similarly |
299 |
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for the left-end buoys. |
300 |
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The resulting layout placed the buoys close to the anchor |
301 |
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while maintaining the left-right orientation. |
302 |
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Also, such line projections are easy to perceive for humans, |
303 |
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because it is analogous to 3D perspective. |
304 |
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|
305 |
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The buoy scale is chosen to be relative to the anchor's distance |
306 |
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from the circle. That is, a buoy anchored at the center of the focus |
307 |
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is large and gets linearly smaller as it approaches the circle. |
308 |
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|
309 |
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Because the documents, even with the fisheye-distortion, can be larger |
310 |
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than the buoy circle, buoys anchored far from the focus are drawn |
311 |
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near the anchor instead. This is needed to prevent awkward view-cutting |
312 |
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long lines and to yield more space for the layout of buoys anchored |
313 |
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close to the focus. |
314 |
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Furthermore, the final positions of the buoys may need be adjusted |
315 |
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to prevent too much overlap. |
316 |
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|
317 |
- buoys are placed on a circle centered at the focus and diameter |
.. how does this interact with the perception of the projection? |
|
little less than the screen height |
|
318 |
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- buoys equally close to the focus, matching the fisheye focus shape |
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- provides more space for the buoys than, e.g., a straight line |
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(a circle arc is longer) |
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- buoys anchored outside the buoy-circle are drawn near the anchor instead, |
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to prevent awkward view-cutting long lines and to yield more space |
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for the layout of buoys anchored closer to the focus |
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- the position on the circle is obtained by projecting from a constant |
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point (on left/right) through the anchor to right/left side of the circle |
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- buoys placed close to the anchor |
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|
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- such line projections are easy to track for humans, |
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because it is analogous to 3d perspective |
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|
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- final positions may need be adjusted to prevent too much overlap |
|
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|
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- how does this interact with the perception of the projection? |
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- buoy scale is relative to the anchor's distance from the circle |
|
319 |
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320 |
.. raw:: latex |
.. raw:: latex |
321 |
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|
326 |
\label{figbuoygeom} |
\label{figbuoygeom} |
327 |
Buoy layout geometry: XXX} |
Buoy layout geometry: XXX} |
328 |
\end{figure} |
\end{figure} |
329 |
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330 |
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% |
331 |
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|
332 |
The above design produces good results and is very simple if not |
The above design produces good results and is very simple if not |
333 |
the simplest way to meet the layout requirements. |
the simplest way to meet the layout requirements. |
334 |
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|