requires: {#QuadraticBezierSegment. #CubicBezierSegment. #Point}.
"provides: {#UserPath}."
"This needs renamed"

Graphics addPrototype: #UserPath derivedFrom: {Trace}.
UserPath addSlot: #currentPoint valued: Point origin.
UserPath addSlot: #startPoint valued: Point origin.
UserPath addSlot: #segments valued: ExtensibleArray newEmpty.
UserPath addSlot: #closed valued: False.

up@(UserPath traits) copy
[|newUP|
  newUP: up clone.
  newUP segments: up segments copy.
  newUP closed: up closed.
  newUP currentPoint: up currentPoint.
  newUP startPoint: up startPoint.
  newUP
].

up@(UserPath traits) penFlatness
[up context penFlatness].

up@(UserPath traits) curveFlatness
[up context curveFlatness].

up@(UserPath traits) penTo: p@(Point traits)
"Sets the starting point"
[
  up currentPoint: p.
  up startPoint: p.
  up
].

up@(UserPath traits) lineTo: p@(Point traits)
"Add a LineSegment to an absolute Point"
[
  up segments add: (LineSegment newFrom: up currentPoint to: p).
  up currentPoint: p.
  up
].

up@(UserPath traits) relativeLineTo: p@(Point traits)
"Add a LineSegment to a relative Point"
[|ap|
  ap: p + up currentPoint.
  up lineTo: ap.
  up
].

up@(UserPath traits) curveTo: p@(Point traits) via: v1@(Point traits) via: v2@(Point traits)
"Add a cubic bezier to the path."
[
  up segments add: (CubicBezierSegment newFrom: up currentPoint to: p via: v1 via: v2).
  up currentPoint: p.
  up
].

up@(UserPath traits) curveTo: p@(Point traits) via: v@(Point traits)
"Add a quadratic bezier to the path."
[
  up segments add: (QuadraticBezierSegment newFrom: up currentPoint to: p via: v).
  up currentPoint: p.
  up
].

up@(UserPath traits) closePath
"Draws a line from the current point to the start point"
[
"TODO: Check if the current and endpoints are the same first"
  up segments add: (LineSegment newFrom: up currentPoint to: up startPoint).
  up currentPoint: up startPoint.
  up closed: True.  
  up
].

up@(UserPath traits) end
"Ends this path"
[].

up@(UserPath traits) stroke
"Strokes the current path"
"Converts the UserPath into one or more PolyLines, strokes, caps
and joins them, then passes them as polygons to the tessilator"
[|newP pen|
  pen: (Pen newWidth: up penWidth flatness: up penFlatness).
  newP: up segments collect: [|:each| each strokeWithPen: pen flatness: up curveFlatness].
  newP doAllButLast: [|:each| each joinToNext].
  up closed
    ifTrue: [newP joinLastToFirst]
    ifFalse: [newP cap].
  newP: (newP as: Polygon).
  newP renderOn: up medium.
].


up@(UserPath traits) fill
"Turns the path into a filled polygon"
"TODO: Beware of gaps"
[|poly|
  poly: (up segments as: Polygon).
  poly renderOn: up medium.
  up
].

"Draw Shapes on a Surface using a Medium"
"Shape = geometric object"
"Surface = anything you can draw on"
"Medium = the drawing context"

"A Surface can provide an appropriate Medium"

"
shape renderOn: medium &pen: aWeirdConvexPolygon &ink: aFunkyPattern.
shape renderFilledOn: medium &ink: Color red.

StandardMedium - a platform independent medium which is converted to platform specific ones when used
X11Medium - a medium which knows how to draw on X11 Drawables

"