CSS animated element animates on wrong place after touch-move transform

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I am using CSS to define a ball animation with certain class. This works fine when adding the class on click, the ball just jumps on one place.

However, when I add the class after moving the ball using touchmove/mousedrag and transform, the ball jumps on its original position, instead its new position I have moved it to.

Is there any way I can make the ball jump on the new position but still keep the jump animation nicely in the CSS?

Thanks if you're reading this.

fiddle here: https://jsfiddle.net/9bvucd3q/

code here:

<html>

<head>
  <!--<meta name="viewport" 
    content="width=device-width, 
    initial-scale=1.0, 
    user-scalable=no" />
  <title>Drag/Drop/Bounce</title>-->
  <style>
#item {
  width: 100px;
  height: 100px;
  background-color: rgb(245, 230, 99);
  border: 10px solid rgba(136, 136, 136, .5);
  border-radius: 50%;
  touch-action: none;
  user-select: none;
  position: absolute;
}
.bugout{animation: card-out 0.6s cubic-bezier(.8,.2,.1,0.8);}
@keyframes card-out {
    0% { z-index: 20; transform: translateY(0%) rotate(0deg); }
    5% { z-index: 20; transform: translateY(-5%) rotate(-4deg); }
    49% { z-index:20;transform: translateY(-120%) ; }
    100% { z-index:5;transform: translateY(-120%) ; }
}
#box1 {
  width: 200px;
  height: 200px;
  background-color: red;
}

  </style>
</head>

<body>
<h1>Drag and Drop</h1>
<div id="item"></div>
<div id="box1">
</div>

  <script>
var dragItem = document.querySelector("#item");
var box1 = document.querySelector("#box1");
var container = dragItem;
//Declare Variables
var active = false;
var currentX;
var currentY;
var initialX;
var initialY;
var xOffset = 0;
var yOffset = 0;

//Add Event Listeners for Touchscreens
container.addEventListener("touchstart", dragStart, false);
container.addEventListener("touchend", dragEnd, false);
container.addEventListener("touchmove", drag, false);

//Add Event Listeners for Mice
container.addEventListener("mousedown", dragStart, false);
container.addEventListener("mouseup", dragEnd, false);
container.addEventListener("mousemove", drag, false);

function dragStart(e) { //when the drag starts
  if (e.type === "touchstart") { //if its a touchscreen
    initialX = e.touches[0].clientX - xOffset; //set initial x-cordinate to where it was before drag started
    initialY = e.touches[0].clientY - yOffset; //set initial y-cordinate to where it was before drag started
  } else { //if its not a touchscreen (mouse)
    initialX = e.clientX - xOffset; //set initial x-cordinate to where it was before drag started
    initialY = e.clientY - yOffset; //set initial y-cordinate to where it was before drag started
  }
  if (e.target === dragItem) { //if user is dragging circle
    active = true; //the drag is active
    dragItem.classList.remove('bugout');
  }
}

function dragEnd(e) { //when the drag ends
  const box1Size = box1.getBoundingClientRect(); //the size of box1
  const elementSize = dragItem.getBoundingClientRect(); //the size of the circle
  
  if (elementSize.left >= box1Size.left && elementSize.right <= box1Size.right && elementSize.top >= box1Size.top && elementSize.bottom <= box1Size.bottom) { //if the circle is in box1
    initialX = currentX; //set the initial x-cordinate to where it is now
    initialY = currentY; //set the initial y-cordinate to where it is now
    dragItem.classList.add('bugout');
  } 
  else { //if the circle is in neither box1 nor box2
    currentX = 0;
    currentY = 0;
    initialX = 0;
    initialY = 0;
    xOffset = 0;
    yOffset = 0;
    setTranslate(0, 0, dragItem);
    
  }
  
  active = false; //the drag is no longer active
}

function drag(e) { //when the circle is being dragged
  if (active) { //if the drag is active
    e.preventDefault(); //the user cant do anything else but drag
  
    if (e.type === "touchmove") { //if its a touchscreen
      currentX = e.touches[0].clientX - initialX; //set current x-cordinate to where it is now
      currentY = e.touches[0].clientY - initialY; //set current y-cordinate to where it is now
    } else { //if its not a touchscreen (mouse)
      currentX = e.clientX - initialX; //set current x-cordinate to where it is now
      currentY = e.clientY - initialY; //set current y-cordinate to where it is now
    }
    
    //Im not sure what this does but it dosnt work without it
    xOffset = currentX;
    yOffset = currentY;
    setTranslate(currentX, currentY, dragItem);
  }
}

function setTranslate(xPos, yPos, el) { //Im not sure what this does but it dosnt work without it
  el.style.transform = "translate3d(" + xPos + "px, " + yPos + "px, 0)";
}
  </script>
</body>

</html>```
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There are 1 answers

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Tyler On

So in the end I have decided to use GSAP, a really fast animation lib which also supports dragging via its Draggable plugin. It's just simpler if I have to code the animations in JS as opposed as to having them nicely in CSS.