I am stuck on implementing a UI in React.
I want to trigger a state change when an element crosses the centre of the viewport.
Here's a prototype of the design: https://cln.sh/sNhueq
In this prototype, the box on the right is sticky so it stays on the screen. And the list on the left moves as we scroll. I want to know when a list item crosses that red line so I can change the content of the box.
I am using framer-motion and react-intersection-observer.
Here's what I tried:
I tried using the viewport prop of <motion.div> but it triggers when the element enters the whole viewport. Yes, we can set root prop to an element's ref but for that the root element has to be an ancestor which the red line is not.
I tried react-intersection-observer but got the same results (because the ancestor limitation comes from the IntersectionObserver API in general).
I ultimately thought of some hacky non-performant ways like having a scroll listener, checking the bounds of root and target and finding if they collide. But I really don't want to do that heavy computing.
Is there any way with IntersectionObserver or something else that is performant?
Any help is appreciated. Thank you! :)
Related
I'm implementing a carousel and I want to target the element at the center of the slider. So, I can make it pop a little.
How can I target this component? I have found ways to know if the element is inside the viewport or not but I want to know if it's horizontally centered.
Original Problem
Horizontal scroll and set state
Since you have no code my answer will be more theoretically how to do it.
So first off you should have a boolean state that you can toggle for the active state. This state should be controlled by the container. That way you can only activate one at a time.
Next you should get 2 values, the X scroll position of the container and the center point of the visible area of the gallery.
Then you can just calculate an offset on mount and then X scroll of the gallery.
So in theory it starts at 0 and your container is 500px you know that the active slide is at the 250px mark so you can calculate that with the position of the slide, it should be the last slide that passed that point. then just recalculate this value on scroll. (maybe throttle)
Possibly able to use react-hook-inview
I've used this react hook before on the Y axis. I'm not 100% sure that it works on the X scroll. But it can be a great way to trigger a state change on each of the slides. The only issue is that you'll be adding a event listener to each of your slides (possible performance hit).
You can see that lib here
This one lets each slide control it's own inView state.
I'm working on some sort of 'continuous' animation. Say a div translates from its current location 200px to the right. There's an option to change the distance of translation. While its animating, the user changes from 200px to 400px. The div should still move smoothly until it reaches its final point which is 400px from its previous location. I have done the basic moving animation, however I can't figure out how to make it continues without jumping when the distance changes.
Here's the codesandbox that I'm working on which best illustrates my point above and what I'm struggling with. Any ideas or help would be greatly appreciated. Thanks :))
Edit: Steps to reproduce the jumping problem:
Open the sandbox
Click the 'Toggle' button
Click the 'Add distance' button
While the red div animates, click 'Add distance' button again
And you should see the div jumping
There is probably a way to fix your code so that it works as you want, though I would suggest going in another direction. There are several animation libraries in React that can help you solve this problem. The resulting code is also going to be more portable.
For your specific need, I would suggest using a library called react-move. It is part of the react-tools which provides other cool libraries. I created a CodeSandbox with my take on your problem using react-move.
I only took the transform line for your code, since I wanted to focus on how you could integrate the library into your example.
To create the animation, I imported a component from react-move called Animate. It's the main component of the library. You use this component to wrap a function using the function as child pattern. This function will receive a state object with information regarding the animated element. It also consumes a start, update, enter, and leave function, that represents the state for those actions.
Inside you function as child function is where you define the animation. In our case, we want to translate the Box along its x axis, using the x value provided on the state object.
OBS: On my example the Box returns to the start (x === 0) when its offset value is bigger than the window's width.
I hope it helps.
swipeable navigation
Whats the best approach to make link area swipeable left and right?
Ive failed to find ready to use component that allows to do that.
Ive tried to use React Touch SyntheticEvent and transform translateX to navigation bar, but failed with calculations. So question is what are the ways to achieve that and is there any react components that can help me to make this work?
Maybe you need to have a look at there.
Although it only supports element swipeable up and down, you can refer to the code of how the author implements element swipeable with translate3d.
The main idea of swiper is to calculate the position of the element, and when to start translation. You can record scrollHeight/scrollWidth and offsetHeight/offsetWidth when you start move event, and compare the value of them when the event is end. Then you know where is the element, and you can control the transform of the element as you want.
So far as I know, maybe Iscroll is a good solution for you.
Using react-select 2, I'm trying to figure out the best way to display the opening direction, depending where on the page (and in the viewport) the select element is.
I've considered using the onMenuOpen prop to check how much space is below the select component and then add a class name when required - and handle the positioning in CSS, but I'm worried that could end up in an infinite loop.
The menuPlacement prop on its own won't work, as that will control the direction for all times, not when the component is near the bottom of the viewport (or conversely near the top of the viewport).
Does anyone know what I could do?
I have a basic plunker which shows the problem: http://plnkr.co/edit/L3rhEIdrnTucG0M7yGhO?p=preview. When you click on the button the first element is shown/hidden with a bouncy animation. This works fine, but the problem is that the items below it just jump to the new place which is quite ugly and jarring.
So, if you click on the button, item One slides away and then a second later items Two and Three jump up. I'd like everything to slide up while item One slides away. How can this be done? Do I need to drop animate.css and write my own custom animations? How would that work? (I don't really care about the bouncy animation, it should just slide away / back into view.)
The current bouncy animation that you have is using a transform property which isn't going to effect sibling elements. If you did something like animate the margin, other elements would move as well.
You could either change the animation method on your target element, or leave it and additionally animate the target's adjacent sibling. I modified your Plunker demonstrating the latter:
http://plnkr.co/edit/hMaPgRDYC8Z0EeCs6SHQ?p=preview
*This also demonstrations using transitions on the hide and keyframes on the show.
To select the adjacent sibling next to the one being effected by ng-hide, make a css selector with the + symbol:
.item.ng-hide-add + .item {...}
Then by transitioning/animating margin-top, the remaining item elements will get pushed around too.