Kig (software)

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Kig

Developer(s)	KDE
Initial release	2 August 2006 (2006-08-02)
Stable release	23.08.3[1]  / 9 November 2023; 7 months ago (9 November 2023)
Repository	invent.kde.org/education/kig
Written in	Interactive geometry software
License	GPL
Website	https://apps.kde.org/kig/

KIG is

1. The center of curvature and osculating circle of a curve;
2. The
   affinity, inversion, projective application, homography and harmonic homology
   ;
3. The hyperbola with given asymptotes;
4. The Bézier curves (2nd and 3rd degree);
5. The
   polar line of a point and pole of a line with respect to a conic section
   ;
6. The asymptotes of a hyperbola;
7. The
   cubic curve
   through 9 points;
8. The cubic curve with a
   double point
   through 6 points;
9. The cubic curve with a cusp through 4 points.

Scripting language

Inside the figure

Another object is available inside Kig, it is a Python language script. It can accept Kig objects as variables, and always return one object.

For example, if there is already a numeric object inside the figure, for example 3, the following Python object can yield its square (9):

def square(arg1):
    return DoubleObject(arg1.value() ** 2)

The variables are always called arg1, arg2 etc. in the order they are clicked upon. Here there is only one variable arg1 and its numerical value is obtained with arg1.value().

If no one wants to implement the square of a complex number (represented by a point in the

def csquare(arg1):
    x = arg1.coordinate().x
    y = arg1.coordinate().y
    z = x * x - y * y
    y = 2 * x * y
    x = z
    return Point(Coordinate(x, y))

The

is ${\displaystyle x^{2}-y^{2}}$ as can be seen by expanding ${\displaystyle (x+iy)^{2}=x^{2}-y^{2}+i(2xy)}$, Coordinate(x,y) creates a Python list made of the two coordinates of the new point. And Point creates the point which

coordinates

are precisely given by this list.

But a Python object inside a figure can only create one object and for more complex figures one has to build the figure with a script:

Figure created by a script

Kig comes up with a little program (written in Python) called pykig.py which can

1. load a Python script, e.g. MyScript.py
2. build a Kig figure, described by this script
3. open Kig and display the figure.

For example, here is how a

from random import *
kigdocument.hideobjects()
A = Point(0, 2)
A.show()
B = Point(-2, -1)
B.show()
C = Point(2, -1)
C.show()
M = Point(.1, .1)
for i in range(1, 1000):
    d = randrange(3)
    if d == 0:
        s = Segment(A, M)
        M = s.midpoint()
    if d == 1:
        s = Segment(B, M)
        M = s.midpoint()
    if d == 2:
        s = Segment(C, M)
        M = s.midpoint()
    M.show()

• Official website
• The Kig Handbook
• Thomas G. Pfeiffer: Erstellen geometrischer Skizzen mit kig. Freies Magazin, December 2009 (German)
• Mike Diehl: Teaching Math with the KDE Interactive Geometry Program. Linux Journal, 2009-09-19
• Abdul Halim Abdullah, Mohini Mohamed: The Use Of Interactive Geometry Software (IGS) To Develop Geometric Thinking. Jurnal Teknologi 49(1), December 2008, DOI: 10.11113/jt.v49.212