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Size of points

Inherited | Positive output size |

`PointSize`

determines the physical size of
points. The value should be specified as an absolute physical length
including a length unit such as ```
PointSize
= 1.5*unit::mm
```

. Numbers without a physical unit give the
size in mm.

Typical points have a size of only a few pixels on the screen.
Hence, the renderers cannot always react to small changes of the `PointSize`

,
because the actual size of the graphical points can attain only discrete
values.

Depending on your hardware, there is a maximal size of the graphical
points that can be rendered in 3D. If the `PointSize`

is
too large, the 3D renderer uses the maximal size that is supported.

Many graphical objects such as curves, surfaces etc. are approximated
by a numerical mesh. With `PointsVisible`

= `TRUE`

,
the points of this mesh become visible. These points react to `PointSize`

.

`PointSize`

cannot be animated.

We plot a cluster of points with random sizes within the unit square:

r := frandom: plot(plot::Point2d(r(),r(), PointSize = 2*r()*unit::mm) $ i = 1 .. 200)

delete r:

Due to pixelation, there is only a discrete number of `PointSize`

values
that the renderers can display faithfully. Further, note that the
large points may protrude over the edges of the viewing box without
being clipped:

plot(plot::Point2d([i, 5], PointSize = i*0.1*unit::mm, Color = RGB::Red) $ i = 1 .. 30, plot::Point2d([3*i, 15], PointSize = i*unit::mm, Color = RGB::Green) $ i = 1 .. 10, plot::Point2d([9*i , 30], PointSize = i*unit::cm, Color = RGB::Blue) $ i in [0.3, 0.5, 0.8, 1.3, 2, 3], ViewingBox = [0 .. 30, 0 .. 35], Axes = Boxed)

Here are the same points in 3D. Note the threshold for `PointSize`

beyond
which the graphical points do not grow:

plot(plot::Point3d([i, 5, 0], PointSize = i*0.1*unit::mm, Color = RGB::Red) $ i = 1 .. 30, plot::Point3d([3*i, 15, 0], PointSize = i*unit::mm, Color = RGB::Green) $ i = 1 .. 10, plot::Point3d([9*i , 30, 0], PointSize = i*unit::cm, Color = RGB::Blue) $ i in [0.3, 0.5, 0.8, 1.3, 2, 3], ViewingBox = [0 .. 30, 0 .. 35, -1 .. 1], Axes = Boxed, CameraDirection = [0, -10, 1000], YXRatio = 2/3)

We can access the `PointSize`

attribute from
a point and change it:

p := plot::Point2d(1, 2): p::PointSize := 4*unit::inch: p::PointSize

delete p:

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