Class: Curve

• Inheritance
• Description
• Related information
• Class protocol
  • instance creation
• Instance protocol
  • accessing
  • converting
  • displaying
  • helpers
  • queries
  • testing
• Examples

Inheritance:

   Object
   |
   +--Geometric
      |
      +--Curve

Package:

stx:libbasic2

Category:

Graphics-Geometry-Objects

Version:

rev: 1.8 date: 2009/06/06 10:12:21

user: cg

file: Curve.st directory: libbasic2

module: stx stc-classLibrary: libbasic2

Author:

Claus Gittinger

Description:

A Curve is a conic section determined by three points
that interpolates the first and the third and is tangent to the angle formed
by the three points at the first and third points.

Related information:

    Rectangle
    Polygon
    EllipticalArc
    Circle
    Spline
    Point
    LineSegment
    ArrowedSpline
    Arrow
    GraphicsContext
    StrokingWrapper
    FillingWrapper

Class protocol:

 from: startPoint to: endPoint through: middlePoint

return a new curve, passing through the three given points

 start: startPoint middle: middlePoint end: endPoint

return a new curve, passing through the three given points

 with: startPoint with: middlePoint with: endPoint

return a new curve, passing through the three given points

Instance protocol:

 end

return the endPoint

 start

return the startPoint

 start: p1 middle: p2 end: p3

set the startPoint, middlePoint and the endPoint

 asPointArray

return an array containing my points.

 asPolygon

return a polygon, approximating the spline

 displayFilledOn: aGC

draw the receiver as a filled curve in a graphicsContext, aGC

 displayStrokedOn: aGC

draw the receiver as a unfilled curve in a graphicsContext, aGC

 computeLineSegments

compute the lines which approxiamte this curve

 bounds

return the smallest enclosing rectangle

usage example(s):

(Curve from:10@10 to:50@100 through:50@50) bounds (Curve from:10@10 to:50@100 through:100@50) bounds

 canBeFilled

return true, if the receiver can be drawn as a filled geometric.
Always true here.

Examples:

  |v c|

  v := (View extent:100@100) openAndWait.

  c := Curve start:(20@20) middle:(80@80) end:(20@80).

  v paint:Color blue.
  c displayFilledOn:v.

  v paint:Color red.
  c displayStrokedOn:v.

  |v c|

  v := (View extent:200@100) openAndWait.

  v lineStyle:#dashed.
  v displayLineFrom:(20@0) to:(20@200).
  v displayLineFrom:(180@0) to:(180@200).

  v displayLineFrom:(0@20) to:(200@20).
  v displayLineFrom:(0@80) to:(200@80).

  v lineStyle:#solid.
  c := Curve start:(20@20) middle:(180@80) end:(20@80).

  v paint:Color blue.
  c displayFilledOn:v.

  v paint:Color red.
  c displayStrokedOn:v.

  v paint:(Color black).
  v displayLineFrom:(20@20) to:(180@80).
  v displayLineFrom:(20@80) to:(180@80).