Advanced Authoring in GeoGebra: Constraining Movements

Anthony OR 柯志明, Jul 18, 2019

GeoGebra Global Gathering 2019

Table of Contents

  1. Cover
    1. 0. Cover
  2. Examples
    1. 1. Constrain movement by DynamicCoordinates command
    2. 2. Constrain Movement by Scripting
    3. 3. Constrain Segments to Integer Length and to 5° Intervals
  3. Appendix
    1. Demo: draggable bar (for barchart etc)

1.

Cover

  • 1. 0. Cover

1.1.

0. Cover

– Anthony OR 柯志明

2.

Examples

  • 1. 1. Constrain movement by DynamicCoordinates command
  • 2. 2. Constrain Movement by Scripting
  • 3. 3. Constrain Segments to Integer Length and to 5° Intervals

2.1.

1. Constrain movement by DynamicCoordinates command

To constrain the movement of the free point P on gird only, the following [b]DynamicCoordinates[/b] command is used to define P.[br][b]P = [/b][b]DynamicCoordinates(B, round(x(B)), round(y(B)))[br][/b]where B is a hidden free point.
– Anthony OR 柯志明

2.2.

–

2.3.

–

3.

Appendix

  • 1. Demo: draggable bar (for barchart etc)

3.1.

Demo: draggable bar (for barchart etc)

Define the polygon like this:[br][code]Polygon(P, Q, (0, y(Q)), (0, y(P)))[/code][br][br]and then add this as its On Update script to make sure it stays at the same height and can't go negative:[br][code]SetCoords(P, If(x(P) < 0, 0, x(P)), 1)[br]SetValue(Q, P + (0, 1))[br][/code][br]and then make sure "Selection Allowed" is unchecked for 3 of the segments. Also set Algebra -> Increment to eg 1 for Points P and Q (for keyboard control)[br][br]Try changing the "snap to grid" settings in the style bar.[br][br]Thanks to [url=https://www.geogebra.org/u/orchiming]Anthony Or[/url] for the idea, as shown at #ggbconf2019. Here's a full example to show how it can be used [url=https://www.geogebra.org/m/vmbuztsg]geogebra.org/m/vmbuztsg[/url][br][br]
– Michael Borcherds

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