Add bezierArrowShaft that can draw an arrow shaft with its ends at parameterized angles.

app/Rendering.hs

@@ -81,6 +81,12 @@ arg1ResT len _ = (alignR $ circle (len / 2), mempty)
 arg1ResH :: (RealFloat n) => ArrowHT n
 arg1ResH len _ = (alignL $ circle (len / 2), mempty)
 
+bezierShaft angle1 angle2 = fromSegments [bezier3 c1 c2 x] where
+  scaleFactor = 0.5
+  x = r2 (1,0)
+  c1 = rotate angle1 (scale scaleFactor unitX)
+  c2 = rotate angle2 (scale scaleFactor unitX) ^+^ x
+
 getArrowOpts :: (RealFloat n, Typeable n) => (EdgeEnd, EdgeEnd) -> [EdgeOption]-> ArrowOpts n
 getArrowOpts (t, h) opts = arrowOptions
   where

todo.txt

@@ -1,4 +1,6 @@
 -- TODO Now --
+-- Improve line routing. Draw curved lines with outgoing lines at fixed angles.
+--  - connectPerim might be useful for this.
 
 -- TODO Later --
 -- Add documentation.
@@ -7,7 +9,7 @@
 Fix the arrowheads being too big for SyntaxGraph darwings.
 
 -- Visual todos:
--- Put the function name in nested apply in a colored box.
+-- Consider putting the function name in nested apply and pattern apply in a colored box.
 -- Make an icon font/library with labeled ports. E.g. the apply icon would have text labels "function", "result", "arg 0", "arg 1", etc.
 -- Fix rotation missing edges to nested diagrams.
 -- Don't rotate text and nested icons, give them rectangualar bounding boxes in GraphViz. (Perhaps use a typeclass for isRotateAble)
@@ -18,11 +20,8 @@ Fix the arrowheads being too big for SyntaxGraph darwings.
 -- Let each bool, value pair in Guard icon be flipped to reduce line crossings. Do the same for case.
 -- Let lines connect to ports in multiple locations (eg. case value, or guard result)
 -- Rotate icons based on the outgoing line's difference from ideal angle, not line distance.
--- Improve line routing. Draw curved lines with outgoing lines at fixed angles.
---  - connectPerim might be useful for this.
 -- For nested apply, cycle through different colors and line styles (eg. dashed, solid, wavy)
 -- - for each nesting level. This will help distinguish what is an argument to which funciton.
--- Investigate arrows not being drawn
 
 -- Translate todos:
 Fix y = f (g y) embedding. See todo for findParentThatWillEmbed in GraphAlgorithms.