Class: LineSegment

• Inheritance
• Description
• Class protocol
  • instance creation
• Instance protocol
  • accessing
  • comparing
  • converting
  • displaying
  • printing
  • queries
  • testing
  • transforming
• Examples

Inheritance:

   Object
   |
   +--Geometric
      |
      +--LineSegment
         |
         +--Arrow
         |
         +--Bezier2Segment

Package:

stx:libbasic2

Category:

Graphics-Geometry-Objects

Version:

rev: 1.31 date: 2023/08/10 13:11:36

user: alkurz

file: LineSegment.st directory: libbasic2

module: stx stc-classLibrary: libbasic2

Description:

LineSegments represent a line consisting of start and endPoint
(actually, its a vector, since the direction makes a difference when
 instances are compared using #=).

copyright
COPYRIGHT (c) 1996 by Claus Gittinger
             All Rights Reserved

This software is furnished under a license and may be used
only in accordance with the terms of that license and with the
inclusion of the above copyright notice.   This software may not
be provided or otherwise made available to, or used by, any
other person.  No title to or ownership of the software is
hereby transferred.

Class protocol:

 from: start to: end

return a new lineSegment.

 with: p1 with: p2

return a new lineSegment; the smaller point is taken as startPoint.

Instance protocol:

 end

return the endPoint

 end: aPoint

set the endPoint

 endPoint: aPoint

set the endPoint

 setStart: p1 end: p2

set both the startPoint and the endPoint

 start

return the startPoint

 start: aPoint

set the startPoint

 start: p1 end: p2

set both the startPoint and the endPoint.
Obsolete - use setStart:end: for VW compatibility.

** This is an obsolete interface - do not use it (it may vanish in future versions) **

 startPoint: aPoint

set the startPoint

 = aLineSegment

return true, if the receiver represents the same lineSegment
as the argument, aLineSegment

 hash

return a number useul for hashing.
Redefined, since #= is redefined.

 asPointArray

return an array containing my points.

 displayFilledOn: aGC

raise an error - a lineSegment cannot be drawn filled

 displayStrokedOn: aGC

display the receiver in the graphicsContext, aGC

Usage example(s):

|v| v := View new openAndWaitUntilVisible. (LineSegment from:10@10 to:50@50) displayStrokedOn:v

 printOn: aStream

(comment from inherited method)
append a user printed representation of the receiver to aStream.
The format is suitable for a human - not meant to be read back.

The default here is to output the receiver's class name.
BUT: this method is heavily redefined for objects which
can print prettier.

 angle

return the receiver's angle (in degrees) in a polar coordinate system.
The angle is counted counter-clock-wise, starting with 0 for a horizontal
line (i.e. 0@0 -> 100@0 has an angle of 0 and 0@0 -> 0@100 has an angle of 90)

Usage example(s):

(LineSegment from:0@0 to:100@0) angle (LineSegment from:0@0 to:100@100) angle (LineSegment from:0@0 to:0@100) angle (LineSegment from:0@0 to:-100@100) angle (LineSegment from:0@0 to:-100@0) angle (LineSegment from:0@0 to:-100@-100) angle (LineSegment from:0@0 to:0@-100) angle

 center

(LineSegment from:(10@10) to:(20@10)) center
(LineSegment from:(10@10) to:(20@20)) center

 computeBounds

return the smallest enclosing rectangle

 dist: aPoint

the distance of aPoint to this segment.
That is the length of a line perpendicular to the line segment,
which hits aPoint.

Usage example(s):

(startPoint dist:aPoint)

Usage example(s):

(endPoint dist:aPoint)

Usage example(s):

(LineSegment from:(0@0) to:(10@10)) dist:0@0 (LineSegment from:(0@0) to:(10@10)) dist:10@10 (LineSegment from:(0@0) to:(10@10)) dist:11@10 (LineSegment from:(0@0) to:(10@10)) dist:-1@-1 (LineSegment from:(0@0) to:(10@10)) dist:5@5 (LineSegment from:(0@0) to:(10@10)) dist:6@4 (LineSegment from:(0@0) to:(10@10)) dist:5@0 (LineSegment from:(0@0) to:(10@0)) dist:5@0 (LineSegment from:(0@0) to:(10@0)) dist:5@1 (LineSegment from:(0@0) to:(10@0)) dist:5@3 (LineSegment from:(0@0) to:(10@0)) dist:5@-3 (LineSegment from:(0@0) to:(0@10)) dist:5@5 (LineSegment from:(0@0) to:(10@10)) dist:5@0

 isHorizontal

return true, if I am a horizontal line

 isVertical

return true, if I am a vertical line

 length

return the length of the vector

 isLineSegment

return true, if the receiver is a line segment

 roundedToNearestIntegerPoint

return a copy of the receiver, where all points are rounded to ly on the nearest integer coordinate

 scaledBy: amount

(comment from inherited method)
return a copy of the receiver, which is scaled by the argument, a point or number

 transformedBy: transformation

return a copy of the receiver, which is transformed using aMatrix

 translatedBy: amount

return a copy of the receiver which is translated (i.e. moved)
by amount, aPoint or Number

Examples:

  |v l|

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

  l := LineSegment from:10@10 to:90@90. 

  v paint:Color red.
  l displayStrokedOn:v.

  l setStart:90@10 end:10@90.
  v paint:Color blue.
  l displayStrokedOn:v.

  |v l|

  v := View extent:100@100.

  l := LineSegment from:10@10 to:90@90. 
  v addComponent:(StrokingWrapper on:l).

  l := LineSegment from:90@10 to:10@90. 
  v addComponent:((StrokingWrapper on:l) foregroundColor:(Color red)).

  v open.