Wumpus.Basic.Geometry.Paths

Path algorithms for elementary shapes - rectangle, diamond, polygon.

Documentation

data PathAlg u

A vector chain building a path.

The vectors are relative to the predecessor, so the rendering of a PathAlg iterates the start point.

A polygon PathAlg should have steps for all sides of the polygon with the end point generated by the last vector coinciding with thet start point.

runPathAlgPoint :: Num u => Point2 u -> PathAlg u -> [Point2 u]

runPathAlgVec :: PathAlg u -> (Maybe (Vec2 u), [Vec2 u])

drawVertexPathAlg :: InterpretUnit u => DrawStyle -> PathAlg u -> LocGraphic u

pathStartIsStart :: [Vec2 u] -> PathAlg u

Create a PathAlg from the vertex list.

When the PathAlg is run the supplied point will be the start of the path.

pathStartIsLocus :: [Vec2 u] -> PathAlg u

Create a PathAlg from the vector list - the first vector displaces the start point the subsequent vectors displace the current tip. Figuratively, this is rather like Logo turtle drawing.

When the PathAlg is run, the supplied point is the locus of the path and it does not form part of the path proper.

This constructor is typically used to make shape paths where the supplied point is the center and the generated path is the border.

pathIterateLocus :: Num u => [Vec2 u] -> PathAlg u

Note this creates a path where the first vector represents a moveto, then the subsequence vectors represent linetos.

Create a PathAlg from the vector list - each vector in the input list iterates to the start point rather then the cumulative tip.

When the PathAlg is run, the supplied point is the locus of the path and it does not form part of the path proper.

Like pathStartIsLocus, this constructor is typically used to make shape paths. Some shapes are easier to express as iterated displacements of the center rather than turtle drawing.

rectanglePathAlg :: Fractional u => u -> u -> PathAlg u

Implicit start point is center, the genearated moves are counter-clockwise so the move-list is

 [ moveto_bl, moveto_br, moveto_tr, moveto_tl ]

blRectanglePathAlg :: Num u => u -> u -> PathAlg u

Implicit start point is bottom-left, subsequent moves are counter-clockwise so the move-list is:

 [ moveto_br, moveto_tr, moveto_tl, moveto_bl ]

diamondPathAlg :: Num u => u -> u -> PathAlg u

diamondPathAlg : half_width * half_height -> PathAlg

isoscelesTriPathAlg :: Floating u => u -> u -> PathAlg u

isoscelesTriPathAlg : base_width * height -> PathAlg

Start point is centtroid not incenter.

polygonPathAlg :: Floating u => Int -> u -> PathAlg u

polygonPathAlg : num_points * radius -> PathAlg

arcPathAlg :: Floating u => u -> Radian -> Radian -> PathAlg u

arcPathAlg : radius * angle1 * angle2 -> PathAlg

circlePathAlg :: (Fractional u, Floating u) => u -> PathAlg u

parallelogramPathAlg :: Floating u => u -> u -> Radian -> PathAlg u

 width * height * bottom_left_angle

isoscelesTrapeziumPathAlg :: Floating u => u -> u -> u -> PathAlg u

 base_width * top_width * height