Performant Animations Using KUTE.js: Part 4, Animating Text

In the second tutorial of this series, you learned how to animate different CSS properties of the elements on a webpage using KUTE.js. You learned how to animate all the transform properties as well as properties like border-radius and border-color. You can also use the CSS plugin to animate CSS properties like font-size, line-height, letter-spacing, and word-spacing.

KUTE.js also has a Text plugin which allows you to animate the text inside different elements, either by increasing or decreasing a number like in a countdown or by writing a string character by character.

In this tutorial, you will learn how to animate the text inside different elements on a webpage using the CSS and Text plugins in KUTE.js.

Animating CSS Text Properties

As I mentioned earlier, you can use the KUTE.js CSS plugin to animate four different text-related CSS properties. These properties are font-size, line-height, letter-spacing, and word-spacing. We will also use some properties from the core engine discussed in the first tutorial to animate individual letters. Let's see how we can use all these concepts together to create the vibrating HELLO text in the following demo.

Here is the code that was used to create the above animation:

var theLetters = document.querySelectorAll("span");
var h = document.querySelector(".h");
var e = document.querySelector(".e");
var la = document.querySelector(".la");
var lb = document.querySelector(".lb");
var o = document.querySelector(".o");
var startButton = document.querySelector(".start");

var animateColor = KUTE.allFromTo(
  theLetters,
  { color: 'white' },
  { color: 'red' },
  { offset: 200, duration: 50}
);

var animateFontSize = KUTE.allFromTo(
  theLetters,
  { fontSize: '2em' },
  { fontSize: '4em' },
  { offset: 100, duration: 200, repeat: 10, yoyo: true}
);

var animateSkewing = KUTE.allTo(
  theLetters,
  { skewX: -15},
  { offset: 200, duration: 200 }
);

var animateH = KUTE.to(
  h,
  { color: '#009688' }
);

var animateE = KUTE.to(
  e,
  { translateY: -40, color: '#E91E63' }
);

var animateLA = KUTE.to(
  la,
  { color: '#8BC34A' }
);

var animateLB = KUTE.to(
  lb,
  { translateY: 20, color: '#FFC107' }
);

var animateO = KUTE.to(
  o,
  { color: '#FF5722' }
);

var lettersSqueezed = KUTE.allTo(
  theLetters,
  { letterSpacing: '-15px' },
  { offset: 0, duration: 200 }
);

animateColor.chain(animateFontSize);
animateFontSize.chain(animateSkewing);
animateSkewing.chain(animateH, animateE, animateLA, animateLB, animateO);
animateE.chain(lettersSqueezed);

startButton.addEventListener(
  "click",
  function() {
    animateColor.start();
  },
  false
);

Each letter of the word is wrapped inside a span tag and has its own unique class. The first tween animates the color of all the letters from white to red with an offset of 200ms. This is also the first animation that is played after clicking on Start Animation. The animateFontSize tween has been chained to animateColor. This way, the font-size animation begins as soon as the color animation ends. 

You might have noticed that I have used two attributes called repeat and yoyo to control the behavior of the animation. The yoyo attribute is used to reverse the animation that is currently being played repeatedly. This can avoid sudden jumps in the values of different properties during the animation and make it appear smooth.

The font-size animation has been chained with animateSkewing, which skews all the letters by -15 degrees. The skewX and skewY properties are available within the core engine itself.

All the tweens for animating the color of different letters have been chained to animateSkewing at once. This way, you can make sure that all the chained color animations start playing as soon as the skew animation ends. Finally, the lettersSqueezed tween reduces the spacing between different letters by 15 px.

You can create more interesting effects by using different combinations of properties.

Animating Numbers

You can also animate numbers in KUTE.js. However, you will have to include an additional text plugin to create the animation. 

The process of animating numbers is actually very simple. You just need to specify the selector where the animating numbers should be shown as well as the final number at which the animation should end. 

Here is a basic example that shows the total number of airports in the USA in 2016 using animation.

var usa = document.querySelector(".usa");
var startButton = document.querySelector(".start");

var animateUSA = KUTE.to(
  usa,
  { number: 19536 }
);

startButton.addEventListener(
  "click",
  function() {
    animateUSA.start();
  },
  false
);

You can also apply the usual tween options like duration, repeat, and delay to customize the behavior of the animation. The code we just wrote will result in the following animation:

Writing Text Character by Character

This is a very popular effect that you can find on quite a few websites. The KUTE.js text plugin allows you to specify the new sentence that should replace the original sentence one character at a time. 

Before replacing the initial characters with their final value, random characters are animated like the numbers example you just saw. The embedded CodePen demo should make it clearer:

Here is the code that you need to write in order to create the above animation:

var animateHeading = KUTE.to(
  heading,
  { text: '70% Surface of Earth is Covered with Water.' },
  { duration: 5000}
);

startButton.addEventListener(
  "click",
  function() {
    animateHeading.start();
  },
  false
);

The character animation for the whole sentence is finished within 5 seconds. As you might have noticed, the initial and final sentences don't need to have the same number of characters. This gives us a lot of liberty when setting the value of the text parameter.

You can also include HTML tags inside the value of the text parameter and then use CSS to change the appearance of the text that you just animated.

var animateHeading = KUTE.to(
  heading,
  { text: '70% SURFACE OF <span class="earth">EARTH</span> IS COVERED WITH <span class="water">WATER</span>.' },
  { duration: 10000, textChars: 'upper' }
);

There will be a delay in the appearance of Earth after of has already appeared. This happens because the plugin also writes <span class="earth"> using the same character animation, but none of those characters are actually visible to the user. The delay may or may not be desirable based on your preferences.

The intermediate characters that are shown during the animation are lowercase alphabetical values by default. This can be an issue when the characters that you want to animate are all uppercase letters or numbers. Which intermediate characters are used for the animation is determined by the value of the textChars parameter. It accepts six different values:

• alpha: In this case, the intermediate characters will be lowercase letters.
• upper: In this case, the intermediate characters will be uppercase letters.
• numeric: In this case, numerical characters are used for the animation. This is different from animating a number as the values won't increase sequentially.
• symbols: In this case, the plugin will use characters like #, %, and $ for the animations.
• all: You can use this value if you want the intermediate characters to be a mix of alphabetic, numeric, and symbols.
• If nothing else works for you, KUTE.js gives you the option of specifying your own custom list of characters that should be used during the animation.

The following example shows how you can animate text inside a heading using uppercase intermediate characters.

Final Thoughts

In this tutorial, you learned how to use the CSS and Text plugins in KUTE.js to animate the text inside an element. When you want to animate the appearance of the text, you need to use the CSS plugin. This will allow you to use properties like font-size, letter-spacing, etc. When you want to change the actual characters inside any element, you need to use the text plugin.

If you’re looking for additional JavaScript resources to study or to use in your work, check out what we have available on Envato Market.

I hope you learned something new in this tutorial. If you have any questions, please let me know in the comments.

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