book

Creating Web Animations

by Kirupa Chinnathambi

March 2017

Beginner

210 pages

English

O'Reilly Media, Inc.

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Know Your Basic HTML, CSS, and JavaScriptAbout Authoring ToolsUsing the Code ExamplesO’Reilly SafariGetting Help/Contacting the AuthorContacting O’ReillyAcknowledgments
What Is an Animation?The Start and End StatesInterpolationAnimations on the WebConclusion
Creating a Simple AnimationWhat Just HappenedThe NameDuration and KeyframesLoopingThe Longhand VersionConclusion
Creating a Simple TransitionWhat Just HappenedThe Longhand VersionConclusion
What Is a Timing Function?Timing Functions in CSSTiming Functions in CSS AnimationsTiming Functions in CSS TransitionsMeet the Timing Function CurveThe cubic-bezier Timing FunctionThe step Timing FunctionConclusion
What Is a Smooth Animation?Creating Responsive 60 fps AnimationsMeet the Animation-Friendly PropertiesPush Element Rendering to the GPUConclusion
It’s Just Property ChangesThe ExampleInitial State Using CSS, Changes Using JSWhat Just Happened?A Tale of Two Styling ApproachesSetting the Style DirectlyAdding and Removing Classes Using JavaScriptAnimating with requestAnimationFrameConclusion
SimilaritiesDifferencesTriggeringLoopingDefining Intermediate Points/KeyframesSpecifying Properties Up FrontInteraction with JavaScriptConclusion

The Starting PointAnimated UnderlineSimple Background Color ChangeCooler Background Color ChangeConclusion
The ExampleThe CSS AnimationThe Easing FunctionConclusion
How the Sliding Menu WorksCreating the Sliding MenuThe Initial PageAdding the MenuMaking the Menu WorkAdding Some Finishing TouchesConclusion
The Basic IdeaThe ContentIt’s Scrolling TimeIdentifying the ElementsModifying the ElementsBuilding It All OutListening to the Scroll EventDetecting When Elements Are VisiblePutting It All TogetherSome Performance ConsiderationsConclusion
The Full HTML and CSSDeconstructing This EffectLooking at the CSSFaking RandomnessSlightly Different Variants of Style Rules + KeyframesAltering Some CSS Properties and Their Values…Inline!Conclusion
Overview of How the Parallax Effect WorksGetting StartedAdding Our Background ElementsThe JavaScriptConclusion
Creating the Sprite SheetThe Actual ImplementationIt’s Animation TimeThe Steps Easing Function in ActionConclusion
Overview of How It WorksThe ContentThe Content (For Realz This Time)What You Just DidClipping the ContentThe Navigation LinksMaking the Content Actually SlideAdding the JavaScriptAdding the TransitionUnderstanding the Code (and More!)What’s Really Going OnThe Role of the data-pos AttributeIt’s All About the JavaScriptConclusion
Until Next Time

Content preview from Creating Web Animations

Chapter 3. Introduction to CSS Transitions

When you’re interacting with UIs, a lot of the animations you’ll see won’t be of the CSS animation kind with its predefined keyframes. They will instead be reactions to the things you are doing. Examples of such reactions include a link underlining when you hover over it, a menu flying in when you tap on a button, or a text element getting bigger when it has focus. For animating these kinds of behaviors, you will use CSS transitions.

To better understand CSS transitions, let’s take a moment to see one in action on our friendly hexagon shape:

Notice that the image smoothly scales up and rotates when your mouse cursor is over it. It then smoothly scales and rotates back to its original state when your mouse cursor goes elsewhere. All of this is made possible thanks to the magic of CSS transitions, and in the following sections, you’ll learn the basics of how to use them.

Creating a Simple Transition

Just like with CSS animations earlier, the way you’ll learn about CSS transitions is simple. We are going to dive head first and just use them. The first thing we’ll need to do is create a new HTML document and add the following things into it:

<!DOCTYPE html>
<html>
 
<head>
  <title>CSS Transitions!</title>
 
  <style>
    #container {
      width: 100%;
      height: 290px;
      background-color: #EEE;
 
      display: flex ...