Tutorial:Responsive Applets
When designing a GeoGebra applet you should make sure it will work nicely on all devices. This article gives you some advice how to ensure your applets will display correctly and perform better.
Most important point: test as you go in HTML5, don’t author in Java and then test at the end (obviously if you identify something that seems slower than expected, please let the developers know and they will check it out). At the moment, HTML5 is generally slower than Java running on the same hardware.
General advice
- https://tinypng.com/ reduces the file size of PNGs a lot (typically 80-90%!)
- Avoid any commands which need to load the CAS engine eg Simplify[], Factor[], Expand[], Asymptote[]. You can generally use Polynomial[] instead of Simplify[] / Expand[]
- Any user interface elements that are not needed should be hidden
- Only use fancy styling (hatching, background image) if necessary
- Do not place texts inside the applet unless necessary -- note that on GeoGebra you may place instructions for using the worksheet above and below the applet
- Avoid showing unnecessary labels of objects
- Grid and axes should be hidden if not needed
- If a computed value is used multiple times, it should be assigned to a variable and that variable name should be used
- Algebra View:
- If you only need algebraic descriptions of a few objects, create dynamic texts and hide the Algebra View
- You may also reduce the time needed to draw Algebra View updates, by collapsing some of the categories (eg switch Algebra to sort by type and hide all lists) or marking objects as auxiliary
Scripting tips
- use JavaScript scripting not GeoGebraScript where possible
SetValue[a,c+b]will be much faster thana = c + b(to avoid the whole construction being rebuilt) but ggbApplet.setValue() will be even faster as it will need less parsing.SetValue[a, If[x<3,4,5]]is better thanIf[x<3,SetValue[a,4],SetValue[a,5]].
Lists
The Sequence[ ] and Zip[] commands are currently quite slow in some cases. The team is working on some ideas to speed this up, in the meantime it’s worth trying out the spreadsheet for building sequences, and using “Conditon to Show Object” to simulate Sequence[ ]
Animations
If you have a multi-step animation, build it as separate objects driven by separate sliders, not as one big object driven by one slider
Here’s an example of an efficent way to solve ODEs (by using a variable slider speed) which is much quicker than using scripts/on update events. http://www.geogebra.org/student/m23587
LaTeX
Best to use the TableText Command & FormulaText Command but basic LaTeX also works well in HTML5: http://www.geogebra.org/student/m33487?mobile=true
Images
Make sure you’re not using hi-res images when a smaller one would do (especially in Sequence commands) es:Tutorial:Creando Applets fr:Tutoriel:Appliquettes_réactives it:Tutorial:Progettare_applet_efficienti
