1.92 class line

Description

Straight line segment connecting two points. A line may have a line->pen (thickness) and a graphical->texture (dash-pattern). A line may have joint->arrows on both sides, see class joint and class arrow for attaching arrows to a line.

Bugs:

There are no provisions to display a label in a line. In the application-area of PCE, this would be a useful extension.

See also

class connection

1.92.1 Instance variables

joint <- first_arrow: graphical*

Arrow displayed on the start-point.

See also

- joint->first_arrow
- joint->arrows

joint <- second_arrow: graphical*

Arrow displayed on the end-point.

See also

- joint->second_arrow
- joint->arrows

1.92.2 Send methods

line ->copy: line

Copy the attributes from class graphical and the arrows. This method is used by class connection to instantiate itself from the related link.

line ->end: point

Inherits description from: line<-end

See also

line->points

line ->end_x: int

Inherits description from: line<-end_x

See also

line->points

line ->end_y: int

Inherits description from: line<-end_x

See also

line->points

joint ->first_arrow: graphical*

@see line-first_arrow @see class arrow

line ->initialise: start_x=[int], start_y=[int], end_x=[int], end_y=[int], arrows=[{none,first,second,both}]

Create a line from X1,Y1 to X2,Y2 with specified joint->arrows. A default line has line->pen: 1 and graphical->texture: none.

line ->orientation: {north_west,south_west,north_east,south_east}

Redefined from graphical: no-op.

line ->normalise:

Succeed without side-effect. Normalising a line could change the direction as a line is defines to go from

<-x, <-y towards <-x + <-width, <-y + <-height

See also

line->orientation

line ->points: start_x=[int], start_y=[int], end_x=[int], end_y=[int]

Set line->start from the first X-Y couple and line->end from the second. Any default value leaves the corresponding line parameter unchanged. See also graphical->set.

See also

- line->start_x
- line->start_y
- line->end_y
- line->end_x
- line->start
- line->end

joint ->second_arrow: graphical*

@see line-second_arrow @see class arrow

line ->start: point

Inherits description from: line<-end

See also

line->points

line ->start_x: int

Inherits description from: line<-start_x

See also

line->points

line ->start_y: int

Inherits description from: line<-start_x

See also

line->points

1.92.3 Get methods

line <-angle: origin=[point] -> degrees=real

Return the angle of the line with the positive X-axe in degrees counter clockwise.

line <-distance: to=graphical|point|event, segment=[bool] -> int

If the argument is a point object, this method computes the distance to the the infinitely extended line (if segment is @default or @off) or the line segment if segment is @on.

If the argument is an event object, act as above using the position of the event in the coordinate space of the graphical<-device.

If the argument is a graphical objects, it invokes area<-distance using the areas of both graphicals.

See also graphical->in_event_area.

line <-start: -> point

line <-end: -> point

Unlike normal graphicals, lines are in general not specified using their graphical<-width and graphical<-height but using line<-start and line<-end.

See also

line<-start

line <-intersection: with=line -> point

Return a new point object describing the intersection point of both infinitely extended lines. Fails if the lines are parallel.

line <-length: -> int

Distance between the points line<-start and line<-end. See also point<-distance.