Reorganization of Expansions

[z3dev]

WORK IN PROGRESS. DO NOT MERGE.

This pull request adds the expansion functions as a seperate module. The goals are:

• Convert to V2 math
• Standardize API; names, parameter passing, error checks, etc.
• Full test coverage

Expansions:

expand

• [X] code complete
• [X] tests complete, 89.47% coverage (87.5 / 90.0 / 84.44% coverage internally)
• [X] reveiw complete

Fixes #66

offset

• [X] code complete
• [X] tests complete, 87.5% coverage (98.8 / 100 / 100% coverage internally)
• [X] reveiw complete

Fixes #75 Fixes #131 Fixes OpenJSCAD #351

Some small changes to math and geometry modulese are included.

• Added geom2.toOutlines()
• Added intersect() of two line segments to math/utils/
• Added area() under any number of ordered points to math/utils

[z3dev]

Examples of offset on paths.

• black path is the original
• green path is the offset path +3 delta
• red path is the offset path -3 delta

Segments of 0 (chamfer)

Segments of 1 (edges meet at intersection)

Segments of 32 (fillet with with rounded segments)

[kaosat-dev]

This is gorgeous @z3dev ! Reviewing asap !

[z3dev]

(This is actually from a wood working website.)

[z3dev]

For CAG V1, here's what expand() does to a shape with a hole (10x10 square with 5x5 hole). Notice that the hole is getting smaller, not larger.

    let obj1 = CAG.rectangle({radius: [10,10]});
    obj1 = obj1.subtract(CAG.rectangle({radius: [5,5]}));

    let obj2 = obj1.expand(1.0, 8);

[z3dev]

For V2, I think the same functionality should be offset. (See expand below)

  let obj1 = primitives.square({size: 10})
  obj1 = booleans.subtract(obj1, primitives.rectangle({size: [5, 5], center: [0,0]}))
  obj1.color = [1,1,0,1] // YELLOW

  let obj2 = expansions.offset({delta: 1}, obj1)
  obj2.color = [0,1,0,1] // GREEN

[z3dev]

For V2, the expand makes the whole shape expand (enlarge), including the holes. Note, this is very simular to scale however scale cannot chamfer corners.

  let obj1 = primitives.square({size: 10})
  obj1 = booleans.subtract(obj1, primitives.rectangle({size: [5, 5], center: [0,0]}))
  obj1.color = [1,1,0,1] // YELLOW

  let obj2 = expansions.expand({delta: 1}, obj1)
  obj2.color = [0,1,0,1] // GREEN

[z3dev]

@kaosat-dev please review the changes to the API again.

Summary:

• added 'corners' option, which accepts 'edge', 'chamfer', 'round'
• corrected useage of 'segments' options, which is now only used for creating round corners

In addition, poly2 geometry has been created. And, all expansion functions now use poly2 for measureArea and arePointsInside.

[z3dev]

@kaosat-dev please merge. :)