csdl_shapes.itcl

# -----------------------------------*-Tcl-*--------------------------
#
#  shapes.itcl
#
#  These Incr Tcl classes define the shapes of transmission
#  line cross section structures.
#
#  Bob Techentin
#  January 23, 2000
#
#  Copyright 2000-2004 Mayo Foundation.  All Rights Reserved.
#  $Id: csdl_shapes.itcl,v 1.3 2004/02/09 18:56:01 techenti Exp $
#
# --------------------------------------------------------------------

package require Itcl
package require units

package provide csdl 1.0.1

# --------------------------------------------------------------------
#
#  itcl::class Shape 
#
#    Defines a shape of a structure in a transmission line
#    cross section.  While we can't exactly declare a 
#    virtual class, we can document the expected
#    functionality of an object of type Shape.
#
#    A shape doesn't know _where_ it is, but it does
#    know its height and width and color.
#
#    Shapes don't do much interesting, but they can accept
#    a visitor class which can do interesting things like
#    draw them.
#
# options
#
#  -color
#    Each shape has an intrinsic color, which is defined
#    by the object which creates it.  Note that some simulators,
#    (i.e., BEM MMTL) depend upon color to properly identify
#    the type of structure.  (blue==ground)
#
#  -description
#    A text description, set by the creator.  This text is
#    displayed when the Shape draws itself.  The creator
#    would typically use this description to display the
#    name and/or attributes of the structure.
#
# methods
#
#  width
#  height
#  area
#  circumference
#    These methods return the width, height, area, or 
#    circumference of the shape, as a floating point number, 
#    scaled to the default length units, as defined in the variable 
#    ::units::default(Length)
#
#    These are useful for drawing routines which operate
#    on lists of Shapes.  Since the caller doesn't know the
#    specific gemoetry of any given shape, it can just ask
#    the shape for the amount of space that it needs.
#
# --------------------------------------------------------------------

itcl::class Shape {
    public variable name ""
    public variable color ""
    public variable description ""
    method accept { visitor x y } {
	#  Cleverly call a visitor based on our class name
	scan [info class] "::%s" myClass
	$visitor visit$myClass $this $x $y
    }
    method width {}
    method height {}
    method area {}
    method circumference {}
}

itcl::class Rectangle {
    inherit Shape
    public variable width 0.0
    public variable height 0.0
    constructor {args} {
	eval configure $args
    }
    method width {}
    method height {}
    method area {}
    method circumference {}
}

itcl::class Trapezoid {
    inherit Shape
    public variable topWidth 0.0
    public variable bottomWidth 0.0
    public variable height 0.0
    constructor {args} {
	eval configure $args
    }
    method width {}
    method height {}
    method area {}
    method circumference {}
}

itcl::class Circle {
    inherit Shape
    public variable diameter 0.0
    constructor {args} {
	eval configure $args
    }
    method width {}
    method height {}
    method area {}
    method circumference {}
}

itcl::class Layer {
    inherit Shape
    public variable thickness 0.0
    constructor {args} {
	eval configure $args
    }
    method width {}
    method height {}
    method area {}
    method circumference {}
}



# --------------------------------------------------------------------
#  Rectangle methods
# --------------------------------------------------------------------

itcl::configbody Rectangle::width {check_length $width "width"}
itcl::configbody Rectangle::height {check_length $height "height"}

itcl::body Rectangle::width {} {return [length $width]}

itcl::body Rectangle::height {} {return [length $height]}

itcl::body Rectangle::area {} {
    return [expr {[length $width]*[length $height]}]
}

itcl::body Rectangle::circumference {} {
    return [expr {2.0*([length $width]+[length $height])}]
}


# --------------------------------------------------------------------
#  Trapezoid methods
# --------------------------------------------------------------------

itcl::configbody Trapezoid::topWidth {check_length $topWidth "top width"}
itcl::configbody Trapezoid::bottomWidth {check_length $bottomWidth "bottom width"}
itcl::configbody Trapezoid::height {check_length $height "height"}

itcl::body Trapezoid::width {} {
    if {[length $topWidth]>[length $bottomWidth]} {
	return [length $topWidth]
    } else {
	return [length $bottomWidth]
    }
}

itcl::body Trapezoid::height {} {return [length $height]}

itcl::body Trapezoid::area {} {
    set h [length $height]
    set tw [length $topWidth]
    set bw [length $bottomWidth]
    return [expr {$h * ($tw + $bw)/2.0}]
}
itcl::body Trapezoid::circumference {} {
    #
    #       +-------------+      +
    #      /               \     | h = height
    #     /                 \    |
    #    +-------------------+   +
    #                     +--+ base
    set h [length $height]
    set tw [length $topWidth]
    set bw [length $bottomWidth]
    set base [expr {0.5*abs($tw-$bw)}]
    set sidelength [expr {sqrt($h*$h + $base*$base)}]
    return [expr {$tw + $bw + 2.0*$sidelength}]
}


# --------------------------------------------------------------------
#  Circle methods
# --------------------------------------------------------------------

itcl::configbody Circle::diameter {check_length $diameter "diameter"}

itcl::body Circle::width {} {return [length $diameter]}

itcl::body Circle::height {} {return [length $diameter]}

itcl::body Circle::area {} {
    set pi 3.14159265358979323846
    set d [length $diameter]
    return [expr {$pi * $d*$d / 4.0}]
}

itcl::body Circle::circumference {} {
    set pi 3.14159265358979323846
    set d [length $diameter]
    return [expr {$pi * $d}]
}


# --------------------------------------------------------------------
#  Layer methods
# --------------------------------------------------------------------

itcl::configbody Layer::thickness {check_length $thickness "thickness"}

itcl::body Layer::width {} {
    #  as far as anybody checking on the width of all the
    #  cross section structures  is concerned, the layer
    #  width is 2x the thickness.  But we draw it "wide"
    #  when compared to the width of all the other layers
    #  and structures.
    return [expr {[length $thickness]*2}]
}

itcl::body Layer::height {} {return [length $thickness]}



set ::units::default(Length) meter
set ::units::default(Time) second

proc check_length { value name } {
    global units::default
    if { $value == "" } {
	error "'$name' value is required"
    }
    if { [catch {units::convert $value $units::default(Length)} result] } {
	error "Invalid Dimension '$name':  $result"
    }
    if { $result < 0.0 } {
	error "Invalid '$name':  Negative dimensions are not allowed"
    }
}

proc length { value } {
    # add default units, if necessary
    if { [string is double $value] } {
	append value $units::default(Length)
    }
    units::convert $value $units::default(Length)
}

proc time { value } {
    # add default units, if necessary
    if { [string is double $value] } {
	append value $units::default(Time)
    }
    units::convert $value $units::default(Time)
}