Master CSS: CSS Transition Generator
Tags: css, beginners, tutorial
Published: 2022-02-05 16:37:20

CSS transitions give us the ability to smoothly transition from one set of styles to another. Without them, your hover, click, and transform effects can look janky and sudden. To illustrate a CSS transition, below are two emojis. Click on them to see the difference:

{% codepen https://codepen.io/smpnjn/pen/eYeBNXG %}

## CSS Transition Generator
As part of this tutorial, **I've created a CSS transition generator which will let you play around with a transition and see how it works**. Use this tool to generate your own custom transitions. Timing in transitions is controlled either by keywords, such as ease-in, or by the cubic bezier function, which you can manipulate below. If you want to learn more, read the rest of this article!

{% codepen https://codepen.io/smpnjn/pen/zYPoGBZ %} 

##When are CSS Transitions fired?
When a user initiates a new state, i.e. focuses or hovers over an element with `:focus` or `:hover`, styles will change. Similarly, if you add a new class with Javascript to an HTML element which adds new styles, the style will similarly change.

In both of these situations, CSS transitions will be fired. Essentially, then, a transition is fired when a CSS element changes, whether through an event, or by adding a class.

##How to use CSS Transitions
CSS Transitions can be added using the transition CSS property. Typically, we just use this shorthand property, which can be sumarised as:

`transition: [transition-property] [transition-duration] [transition-timing-function] [transition-delay]`

Let's think about what each of these means:

1. **transition-property** - this is the property we want to transition. It can be set to all or any CSS property, i.e. background or padding
2. **transition-duration** - this is the length of the transition. It can be set to a time, usually in seconds, i.e. 5s.
3. **transition-timing-function** - this is the timing function. It is usually a keywords, which can be ease, linear, ease-in, ease-out or ease-in-out. There are others, but we'll look at those later.
4. **transition-delay** - this is the delay at the start. If a user hovers, and we have this set to 0.5s, then the hover effect will only start 0.5s after the hover begins.

By default, we only really need to give the first two properties, i.e the following assumes an ease timing function, and no delay:

```css
div {
    transition: background 2s;
}
```
As discussed, transition is a short hand, the following shows both short form and long form of the transition property:
```css
div {
    transition: background 3s ease-in 0.5s;
    /* Equivalent to.. */
    transition-property: background;
    transition-duration: 3s;
    transition-timing-function: ease-in;
    transition-delay: 0.5s;
}
```
##An example of a CSS Transition
Let's take a look at a hover transition effect. If you hover over the the div below, you'll see the slow transition to the new styles:
```css
div {
    color: white;
    text-decoration: underline;
    font-size: 1.25rem;
    background: transparent;
    padding: 0.25rem;
    box-shadow: none;
    cursor: pointer;
    /* The transition property: */
    transition: all 0.5s ease-out;
}
div:hover {
    padding: 0.5rem;
    background: white;
    color: black;
    box-shadow: 0 2px 25px rgba(255,255,255,0.5);
}
```

{% codepen https://codepen.io/smpnjn/pen/QWOGbRG %}

##Other easing functions
We've spoken a little bit about easing functions, and the keywords we can use, but those aren't the only ones we can use. There are also a few other easing functions which can be quite useful for creating varied transition effects.

##Cubic Bezier Curves
One of the most used transition timing functions is a cubic bezier curve. An example of that is shown below:

```css
div {
    transition: all 0.5s cubic-bezier(.17,.67,1,-0.52);
}
```
This allows us to have transitions go back and forwards based on the curve shape. The above transition can be seen below:

{% codepen https://codepen.io/smpnjn/pen/QWOGbRG %}
If you want to generate your own cubic bezier curves, you can do it through various tools found online, or via the Google Chrome Dev tools when editing a transition property.

##Steps
Less used, but equally useful. It breaks the transition into a set of evenly spaced steps, giving a sort of jumpy effect when transitioning between two states.

Steps are defined as a number of steps, and a keyword. The keyword determines whether the jump starts at the beginning of the CSS change (jump-start) or if it aligns with the end instead (jump-end), or both (jump-both).

```css
div {
    transition: all 2s step(6, jump-start);
}
```
This allows us to have transitions go back and forwards based on the curve shape. The above transition can be seen below:
{% codepen https://codepen.io/smpnjn/pen/YzEpXmb %}

##Conclusion
I hope you've enjoyed this guide on CSS transitions. You can use our CSS Transition generator above to generate your own custom cubic bezier transitions, and test them out. Check out our other tutorials and guides for more.