GendL Application

Object: ELLIPSE (The :GEOM-BASE Package)

Description

A curve which is the locus of all points in the plane the sum of whose distances from two fixed points (the foci) is a given positive constant. This is a simplified 3D ellipse which will snap to the nearest quarter if you make it a partial ellipse. For a full ellipse, do not specify start-angle or end-angle.

Input Slots (required)

MAJOR-AXIS-LENGTH number
Length of (generally) the longer ellipse axis

MINOR-AXIS-LENGTH number
Length of (generally) the shorter ellipse axis

RADIUS [from ARCOID-MIXIN] number
Distance from center to any point on the arc.

Input Slots (optional)

BOUNDING-BOX [from BASE-OBJECT] list of two 3d points
The left front bottom and right rear top corners, in global coordinates, of the rectangular volume bounding the tree of geometric objects rooted at this object.

END-ANGLE angle in radians
End angle of the ellipse. Defaults to 2pi for full ellipse.

HIDDEN? [from VANILLA-MIXIN] boolean*
Indicates whether the object should effectively be a hidden-object even if specified in :objects. Default is nil.

IMAGE-FILE [from BASE-OBJECT] pathname or string
Points to a pre-existing image file to be displayed instead of actual geometry for this object. Defaults to nil

LOCAL-BOX [from BASE-OBJECT] list of two 3d points
The left front bottom and right rear top corners, in global coordinates, of the rectangular volume bounding this geometric object.

OBLIQUENESS [from BASE-OBJECT] 3x3 orthonormal matrix of double-float numbers
This is synonymous with the `orientation`.

ONCLICK-FUNCTION [from BASE-OBJECT] lambda function of zero arguments, or nil
If non-nil, this function gets invoked when the user clicks the object in graphics front-ends which support this functionality, e.g. SVG/Raphael and X3DOM.

ROOT [from VANILLA-MIXIN] gdl instance*
The root-level node in this object's ``tree'' (instance hierarchy).

SAFE-CHILDREN [from VANILLA-MIXIN] list of gdl instances*
All objects from the :objects specification, including elements of sequences as flat lists. Any children which throw errors come back as a plist with error information

START-ANGLE angle in radians
Start angle of the ellipse. Defaults to 0 for full ellipse.

STRINGS-FOR-DISPLAY [from VANILLA-MIXIN] string or list of strings*
Determines how the name of objects of this type will be printed in most places. This defaults to the name-for-display (generally the part's name as specified in its parent), followed by an index number if the part is an element of a sequence.

VISIBLE-CHILDREN [from VANILLA-MIXIN] list of gdl instances*
Additional objects to display in Tatu tree. Typically this would be a subset of hidden-children. Defaults to NIL.

Input Slots (optional, defaulting)

CENTER [from BASE-OBJECT] 3d point
Indicates in global coordinates where the center of the reference box of this object should be located.

DISPLAY-CONTROLS [from BASE-OBJECT] plist
May contain keywords and values indicating display characteristics for this object. The following keywords are recognized currently: :color color keyword from the color-table parameter, or an HTML-style hexidecimal RGB string value, e.g. "#FFFFFF" for pure white. Defaults to :black. :line-thickness an integer, defaulting to 1, indicating relative line thickness for wireframe representations of this object. :dash-pattern (currently PDF/PNG/JPEG only). This is a list of two or three numbers which indicate the length, in pixels, of the dashes and blank spaces in a dashed line. The optional third number indicates how far into the line or curve to start the dash pattern.

ORIENTATION [from BASE-OBJECT] 3x3 matrix of double-float numbers
Indicates the absolute Rotation Matrix used to create the coordinate system of this object. This matrix is given in absolute terms (i.e. with respect to the root's orientation), and is generally created with the alignment function. It should be an orthonormal matrix, meaning each row is a vector with a magnitude of one (1.0).

Computed Slots

HEIGHT [from BASE-OBJECT] number
Z-axis dimension of the reference box. Defaults to zero.

LENGTH [from BASE-OBJECT] number
Y-axis dimension of the reference box. Defaults to zero.

WIDTH [from BASE-OBJECT] number
X-axis dimension of the reference box. Defaults to zero.

Examples

  
  (in-package :gdl-user)

  (define-object ellipse-sample (ellipse)
    :computed-slots
    ((minor-axis-length 10)
     (major-axis-length (* (the minor-axis-length) +phi+))
     (start-angle 0)
     (end-angle pi)))

  (generate-sample-drawing :objects (make-object 'ellipse-sample))

Package Documentation