Hi,
When I add lines into canvas, there are two ways to setup the position of the points. First, set local coordinate to line point through 'canvas.addLinePoint()', then set transform to canvas through 'canvas.addTransform()'; Second, calculate screen position=transform*local coordinate, then set screen position to line point through 'canvas.addLinePoint()'. The first way, I cannot get intersection with lines through 'canvas.getLineIntersection()'. The second way, it works.
There are two examples in attach files. 'canvas_03' shows the first way. 'canvas_04' shows the second way.
canvas_03.cpp
canvas_03.world
canvas_04.cpp
canvas_04.world