point
-- generate a graphical
point primitivepoint(
x, y)
defines a 2D point with the
coordinates x
and y
.
point(
x, y, z)
defines a 3D point with the
coordinates x
, y
and z
.
point(x, y <, Color = [r, g,
b]>)
point(x, y, z <, Color = [r, g,
b]>)
x, y, z |
- | real numbers |
Color = [r, g,
b] |
- | sets an RGB color given by the amount of red, green,
and blue. The parameters r , g , b
must be real numbers between 0 and 1. |
an object of type DOM_POINT
.
plot
, plot::Point
, plot2d
, plot3d
, plotfunc2d
, plotfunc3d
, polygon
, RGB
point
defines a 2D or 3D point. It can be displayed
graphically via plot2d
/plot3d
using the list format
[Mode = List, [..points..]]
.The coordinates and color values must be numerical
expressions that can be converted to real floating point numbers.
Symbolic expressions such as PI + 1
,
exp(sqrt(2))
etc. are accepted and converted to floating
point numbers automatically. Note, however, that expressions involving
symbolic identifiers are not accepted! Cf. example 3.
plot
library
provides the alternative point primitive plot::Point
. This object is more
flexible than the kernel object generated by point
. The
first can be used with all functions of the plot
library, whereas the latter can
only be used in a call to plot2d
or plot3d
.point
is a function of the system kernel.[r, g, b]
r
, g
, b
must be numerical expressions that can be converted to real floating
point numbers from the interval [0.0, 1.0]. An error occurs
if any of these values is not in this range. Symbolic expressions such
as PI - 2
, exp(-sqrt(2))
etc. are accepted.
Note, however, that expressions involving symbolic identifiers are not
accepted! Cf. example 3.RGB
contains many pre-defined colors.The first two, respectively three, operands of a point are the
coordinates. The last operand is the list [r, g, b]
defining the point color. This operand is NIL
if no color was specified.
point
with two arguments defines a 2D
point:
>> point(1, PI)
point(1, 3.141592654)
Points generated by point
represent
graphical primitives that can be displayed via plot2d
and plot3d
using the list format
[Mode = List, [..points..]]
:
>> plot2d(Scaling = UnConstrained, PointWidth = 30, [Mode = List, [point(i/10, sin(i/10)) $ i=0..63]])
Points may be defined with a given color:
>> point(0, 1, PI, Color = [1/2, 0, PI - 2*sqrt(2)])
point(0, 1, 3.141592654, Color = [0.5, 0.0, 0.3131655288])
The domain RGB
contains many pre-defined
colors:
>> point(1.0, 0.0, 1.0, Color = RGB::Red)
point(1.0, 0.0, 1.0, Color = [1.0, 0.0, 0.0])
Symbolic coordinates or colors are not accepted:
>> point(x, y, z)
Error: Illegal argument [point]
>> point(1, 2, Color = [r, g, b])
Error: Illegal color specification [point]
However, one can create lists of points using symbolic loop variables:
>> mypoints := [point(i/40, exp(-i/40), Color = [1 - 1/i, i/(1 + i), exp(-i/40)]) $ i = 1..40]: plot2d(PointWidth = 30, [Mode = List, mypoints])
>> delete mypoints:
PI
, exp(-sqrt(2))
etc. are
now accepted and converted to floats automatically.