Class Line

Lines use dots. A line object is either straight (two dots) or bezier curve (four dots).

Common values are canvas to draw and list of instance to calculate ID for XML.

Attributes -width, -outline, -fill for convenience, but without effect, -smooth (to make straight or curvy), -constraint for special properties.

Private data centerDot, group, dots

obj class line -common {
  canvas .c
  instances {}
} -configure {
  -width 2.0
  -outline black
  -fill ""
  -smooth no
  -constraint ""
}

obj constructor line args {
  set dots {}
  if {[string is double -strict [lindex $args 0]]} then {
    foreach {x y} $args {
      if {[string is double -strict $x]} then {
        set dot [new dot -x $x -y $y]
        lappend dots $dot
        $dot add $self
      } else {
        # Objekte zu Ende, ab hier Optionen
        $self configure $x $y
      }
    } 
  } else {
    while {[llength $args] > 0} {
      if {[string match -* $args]} break
      set args [lassign $args dot]
      lappend dots $dot
      $dot add $self
    }
    $self configure {*}$args
  }
  our instances [list {*}[our instances] $self]
  my centerDot [new dot]
  my group {}
  my dots $dots
  # $self calcCenter
}

obj destructor line {
  $self draw no
  foreach dot [$self dots] {
    $dot remove $self
  }
  set index [lsearch [our instances] $self]
  our instances [lreplace [our instances] $index $index]
}