0.2.0

GeoGebra#

GeoGebra builds the construction, the slides supply the dramaturgy. A job can sit on every step: set values, show or hide objects, change colours, move the viewport, start a motion.

Quick start#

geogebra() puts an applet on the slide. The commands that drive it stand in the same slide body and produce no output of their own.

#import "@preview/typstage:0.2.0": *

#presentation(
  slide([Remote controlled], {
    geogebra(app: "classic", perspective: "G", height: 240pt,
             link: "https://www.geogebra.org/calculator")
    ggb-run("a=1", "f(x)=a*x^2")
    ggb-set((a: 3), at: 2)
  }),
)

The parabola is there from the start; on step 2 a becomes 3.

Every command takes at, the step selector known from anim; the default is "1-". The applet frame has no step of its own, so bullet points beside it still start on step one.

Which applet is meant#

With one applet on the slide the commands find it themselves. Two applets need names, and the commands then need target — a string or a label:

#geogebra(<left>, height: 200pt)
#geogebra(<right>, height: 200pt)
#ggb-run("A=(0,0)", target: <left>)
#ggb-run("B=(1,1)", target: "right")

With no applet, or with more than one and no target, nothing is guessed. The build stops and names what it found:

error: panicked with: typstage: 2 applets on this slide
(left, right) — say which one is meant, e.g. target: "left".

Building the construction#

ggb-run hands GeoGebra commands to evalCommand, one at a time. The order counts: whatever is needed has to exist first.

#ggb-run(at: "1-",
         "k: x^2+y^2=4", "t=Slider(0,6.283,0.01)",
         "P=(2cos(t),2sin(t))", "s=Segment((0,0),P)")

Entering a slide and paging back reset the applet and repeat the run, so commands have to be repeatable. Fix the colour on "1-" for the same reason: on a rebuild GeoGebra would otherwise hand out the next colour of its palette.

#ggb-run("a=1", "f(x)=a*x^2", at: "1-")
#ggb-style("f", at: "1-", color: dark, thickness: 3)

Values, appearance, viewport#

ggb-set takes a dictionary of object name and value, ggb-show and ggb-hide any number of object names. Build everything at the start and reveal it when its turn comes:

#ggb-hide("P", "s", "t", at: "1-")
#ggb-show("P", "s", at: 2)
#ggb-set((a: 3), at: 2)
#ggb-set((a: -2, b: 0.5), at: 3)

Appearance#

ggb-style takes the object names and the settings to change. What is not named stays as it is.

color takes a Typst colour, so the construction carries the colours of the slides instead of GeoGebra’s palette.

#ggb-style("P", at: 2, color: accent, point-size: 6)
#ggb-style("s", at: 2, color: dark, thickness: 3)
#ggb-style("d", at: 3, color: accent, filling: 0.18, thickness: 4)

Viewport#

ggb-view sets the visible range as well as the grid and the axes. x and y take effect only together; each is a pair of smallest and largest value.

#ggb-view(at: 2, x: (-3, 3), y: (-3, 3), grid: false)
#ggb-view(at: 3, axes: false)

Without ggb-view the visible range follows from width and height.

Motion#

Two ways to set something moving, and they do different things.

ggb-animate starts GeoGebra’s own animation: back and forth without end until the slide is left. trace switches on the trace of the named objects, speed sets the pace, playing: false stops it.

#ggb-animate("t", at: 3, speed: 1.2, trace: ("P",))

ggb-tween moves a value once from A to B and stops. Everything that depends on it follows along — a segment whose endpoint travels, an arc whose angle grows — and that is how a construction draws itself. from gives the starting value, duration the time in milliseconds, easing the shape.

#ggb-run("t_1=0", "s=Segment(A,(4*t_1,0))", at: "1-")
#ggb-tween("t_1", at: 2, to: 1, duration: 700)

From the next step on the value sits on its target, so paging back shows the finished drawing instead of the motion again.

On paper#

There is no applet in the PDF. A labelled placeholder keeps the size of the frame, and link puts the way to the live applet beneath it.

#geogebra(height: 90pt, link: "https://www.geogebra.org/calculator")

Better is a drawing of your own. fallback takes any content: an image, a table, above all a drawing with CeTZ.

#geogebra(height: 120pt, link: "https://www.geogebra.org/calculator",
  fallback: cetz.canvas(length: 0.8cm, {
    import cetz.draw: *
    line((-2.6, 0), (2.6, 0), stroke: luma(70%))
    line((0, -0.4), (0, 2.6), stroke: luma(70%))
    line(..range(0, 45).map(i => (-2.2 + i * 0.1, 0.5 * calc.pow(-2.2 + i * 0.1, 2))),
         stroke: dark + 1.6pt)
  }))

Both take effect in the PDF only.

How the applet looks#

seamless: true, the default, takes the frame off the applet and puts its drawing area in the colour of the slide. It then looks like part of the slide rather than a window inside a window. background sets that colour.

#geogebra(height: 240pt, background: rgb("#f4f1ea"))
#geogebra(height: 240pt, seamless: false)   // with GeoGebra's own frame

background: auto, the default, takes the paper of the theme in force, so an applet on a dark theme comes up dark.

font-size counts in points of the slide, like width and height, so the applet’s font grows with the slide instead of staying physically the same size on a projector. The default is 17, one above GeoGebra’s 16.

#geogebra(height: 240pt, font-size: 22)      // larger axis numbers
#geogebra(height: 240pt, pan: true)          // viewport by hand

grid and axes follow GeoGebra’s own default while they are auto and force one or the other otherwise. perspective: "G" shows the graphics view alone, app chooses the GeoGebra app (default "classic"), language the interface language, and animation-button shows GeoGebra’s play button.

Size#

width and height count in the measurements of the slide, not in screen pixels, and width: 100% is the usual case. What keeps every window showing the same crop is the visible range: it is set from the box the first time the applet appears, and after that ggb-view decides.

From the speaker view#

The speaker window runs a copy of every applet. m switches its pointer from the pen to the embedded frame; the applet in front of you is then the live one, and the copy on the canvas follows what you do to it.

Only what a hand has touched travels: a dragged point, a slider, the panned view. Creating, deleting or renaming sends the whole construction. An animation running on both sides sends nothing.

Point(k) is a point on the path that a hand can take; Point(k, 0.3) is pinned to that parameter and cannot be dragged at all. Where it should start is said with position:. examples/geogebra-sprecher.typ is a deck built around exactly this: Thales with a point that walks along the half circle and leaves its trace, and a parabola with two sliders.

The keyboard#

Click the applet and it holds the focus; every key then lands inside it. The keys the talk uses are handed back out of the frame — see “A frame that has the focus”. Without a toolbar and without an algebra input, no key changes the construction anyway.

Whose applet this is#

This package does not ship GeoGebra. The browser fetches what runs in the frame from codebase, https://www.geogebra.org/apps/ by default. Three things follow:

1. Without a network the frame stays empty. Whoever presents offline puts GeoGebra’s files beside the deck and points codebase at them.
2. The applet stands under GeoGebra’s terms, not under this package’s MIT licence, which covers the Typst and runtime code here. For commercial use, read GeoGebra’s.
3. The viewer’s browser talks to geogebra.org. Where that is unwanted — a firewall, a data protection requirement — codebase sends it elsewhere.