Dojo in XPages – 15: Modifying the Rate of Animation with Easing Functions

In the last few posts, we’ve looked at dojo code to perform pre-defined animations and custom animations. By default, the animations progress in a linear fashion, but the rate of animation can be changed. In this post, we’ll take a look at the easing functions that are available to modify animations.

Dojo in XPages Series

Dojo in XPages — All Blog Posts

Built-In Easing Functions

The easing property of an animation defines the rate of the animation.

You can write your own function to use, but there are 31 built-in functions already available to save you some time.

The default is linear — it performs the transition evenly throughout. The other methods are mathematical calculations that change the rate of the transition at the beginning or end (or both).

Easing Function Effect on Transition
linear No effect — even throughout
quadIn, quadOut, quadInOut rate by power of 2
cubicIn, cubicOut, cubicInOut rate by power of 3
quartIn, quartOut, quartInOut rate by power of 4
quintIn, quintOut, quintInOut rate by power of 5
sineIn, sineOut, sineInOut rate by sine function over time
expoIn, expoOut, expoInOut exponential effect
circIn, circOut, circInOut circular effect
backIn, backOut, backInOut start away from target, then move toward it
elasticIn, elasticOut, elasticInOut back and forth, then toward target
bounceIn, bounceOut, bounceInOut bounce near the beginning or end

Naming Convention

The functions are all named consistently. They specify the affect and at which end(s) the effect will be applied.

  • The *In functions start slowly and then speed up toward the end
  • The *Out functions start faster and end slowly (the opposite of the *In functions)
  • The *InOut functions start slowly, speed up, then end slowly

Dojo Modules to Include

The easing functions are part of the dojo.fx.easing module, so you’ll need to include it on your page in order to use them. (This is in addition to including dojo.fx if you’re using a function in that module.)

Example

Here’s an example that will take a div called myDiv on the page and move it, using the bounceIn easing function:

dojo.fx.slideTo({
  node:"myDiv",
  top: 100,
  left: 400,
  easing: dojo.fx.easing.bounceIn,
  duration: 3000
}).play();

More Examples

There’s a good demo already set up in the Dojo documentation that allows you to test each one of these easing functions.

https://dojotoolkit.org/reference-guide/1.8/dojo/fx/easing.html#examples

Just click the Play button and you can choose a function to try. Test them out and use whatever suits your needs best

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