Overview
In web design, "croll animation" might be a typo or a misunderstanding. If you meant "scroll animation," it refers to animations triggered as a user scrolls down or up a webpage. These animations can include elements fading in, sliding into view, or changing size or position in response to the user's scrolling behavior. They are often used to enhance user experience by making the website more dynamic and engaging.
Animation-timeline in CSS
In CSS, the animation-timeline property is used to create scroll-based animations. It allows you to connect an element, called the "subject," to a view progress timeline. This timeline tracks how much of the subject is visible within its nearest scrollable container.
There are two main types of view progress timelines:
Anonymous View Progress Timeline:
- This timeline is created directly on the subject element itself by setting animation-timeline: view().
- You can specify the scroll axis (vertical or horizontal) to track progress and a padding value to adjust the area considered "in view" for the subject.
Named View Progress Timeline:
- This involves explicitly naming the timeline using the view-timeline-name property (or the shorthand view-timeline) on an element.
- Then, you link the element you want to animate by setting its animation-timeline property to the name you created.
Essentially, animation-timeline lets you control how an animation progresses based on how much of the element is scrolled into view.
View() In CSS
The view() function in CSS animation-timeline defines an anonymous view progress timeline. This timeline determines how an animation progresses based on the visibility of an element (the subject) relative to its nearest scrollable container.
Here's a breakdown of how it works:
- Subject Element: You apply the animation-timeline: view(parameters); property to the element whose animation you want to control based on scrolling. This element is called the subject.
- Parameters:
- The view() function takes two arguments (both optional)
- Axis (x or y): This specifies the scroll axis (horizontal or vertical) that will be tracked to determine the animation progress. By default, it's vertical (y).
- Padding Value: This value defines a padding area around the viewport. The element is considered "in view" only if part of it lies within this padded viewport area. A padding of 0px means the entire element must be visible.
- Animation Timeline: The view() function creates a timeline based on the subject's visibility within the scroll container. As the element scrolls into view (along the specified axis and considering the padding), the animation progresses accordingly.