Version 5.0 The LEDA User Manual

17.9 Windows for 3d visualization ( d3 window )
1. Definition
The data type d3 window supports three-dimensional visualization. It uses a LEDA
window to visualize and animate three-dimensional drawings of graph. For this purpose
we need to assign positions in 3d space to all nodes of the graph (see init-operations
and set position-operation). The edges of the visualized graph are drawn as straight-linesegments
between the 3d positions of their source and target nodes. Note all edges of the
graph must have a reversal edge.
If the graph to be shown is a planar map the faces can be shaded in different grey scales
(if the solid flag is true).
The graph can be drawn with the draw-operation and animated with the move-operation.
The draw-operation draws a frontal projection of the graph on the output window. The
move-operation starts a simple animation mode. First it draws the graph, then it rotates
it (the rotation depends on the x rotation and y rotation flags and the mouse position)
and finally returns the pressed mouse button.
Every object of type d3 window maintains a set of parameters:
• x rotation (type bool); if true, rotation about the x-axis is enabled during a move
operation
• y rotation (type bool); if true, rotation about the y-axis is enabled during a move
operation
• elim (type bool); if true, hidden lines will be eliminated
• solid (type bool); if true, faces have to be drawn in different grey scales
• draw edges (type bool) enables/disables the redraw of edges
• message (type string) is the message that will be displayed on top of the drawing
area of the output window
In addition, a d3 window stores information assigned to the nodes and edges of the visualized
graph.
• color (type color) information for nodes and edges
• position (three-dimensional vectors) information for the nodes
• arrow (type bool) information for the edges (define whether or not edges have to be
drawn as arrows)