[Gzz-commits] manuscripts/xupdf article.rst

[Janne V. Kujala]

CVSROOT:        /cvsroot/gzz
Module name:    manuscripts
Changes by:     Janne V. Kujala <address@hidden>        03/02/13 09:23:21

Modified files:
        xupdf          : article.rst 

Log message:
        buoys

CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/manuscripts/xupdf/article.rst.diff?tr1=1.80&tr2=1.81&r1=text&r2=text

Patches:
Index: manuscripts/xupdf/article.rst
diff -u manuscripts/xupdf/article.rst:1.80 manuscripts/xupdf/article.rst:1.81
--- manuscripts/xupdf/article.rst:1.80  Thu Feb 13 08:39:30 2003
+++ manuscripts/xupdf/article.rst       Thu Feb 13 09:23:20 2003
@@ -253,7 +253,7 @@
 - the view should animate continuously when the focus moves
 
 Furthermore,
-It is important to maintain orientation locally,
+it is important to maintain orientation locally,
 that is, going in one direction should result in arriving from 
 the opposite direction, so that the local spatial structure
 does not change too much.
@@ -284,33 +284,38 @@
 leaving more space at the left and right sides than on the top and bottom.
 XXX: left and right hand???
 
-We choose the geometry as follows:
+From the above principles, we have chosen a simple geometry
+depicted in Fig. [ref-figbuoygeom]_.
+The buoys are placed on a circle with diameter little less 
+than the screen heighand tcentered at the focus.
+Thus, the buoys are equally close to the focus, matching 
+the fisheye focus shape.
+Additionally, a circle arc provides more area for the buoys than,
+e.g., a straight line.
+
+The position of a right-end buoy on the circle is obtained by 
+projecting a line from a constant point on the left side of the view
+through the anchor point and to the circle, and similarly
+for the left-end buoys.
+The resulting layout placed the buoys close to the anchor
+while maintaining the left-right orientation.
+Also, such line projections are easy to perceive for humans,
+because it is analogous to 3D perspective.
+
+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
+is large and gets linearly smaller as it approaches the circle.
+
+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. 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.
 
-  - buoys are placed on a circle centered at the focus and diameter 
-    little less than the screen height
+.. how does this interact with the perception of the projection?
 
-       - buoys equally close to the focus, matching the fisheye focus shape
-
-       - provides more space for the buoys than, e.g., a straight line
-         (a circle arc is longer)
-
-  - buoys anchored outside the buoy-circle are drawn near the anchor instead,
-    to prevent awkward view-cutting long lines and to yield more space
-    for the layout of buoys anchored closer to the focus
-
-  - the position on the circle is obtained by projecting from a constant 
-    point (on left/right) through the anchor to right/left side of the circle
-
-       - buoys placed close to the anchor
-
-       - such line projections are easy to track for humans,
-         because it is analogous to 3d perspective
-
-  - final positions may need be adjusted to prevent too much overlap
-
-       - how does this interact with the perception of the projection?
-
-  - buoy scale is relative to the anchor's distance from the circle
 
 .. raw:: latex
 
@@ -321,7 +326,9 @@
    \label{figbuoygeom}
    Buoy layout geometry: XXX}  
    \end{figure}
- 
+
+   %
+
 The above design produces good results and is very simple if not 
 the simplest way to meet the layout requirements.