Scroll Direction - javascript

Trying to make div move with mousescroll in opposite direction of scroll from top right to bottom left hand corner.
Right now its going from bottom left to top right
#block {
position: absolute;
top: 400px;
left: 100px;
<script>
$(function(){
var lastScrollYPos = 0;
$(window).on('scroll', function(){
var $this = $(this),
$block = $('#block'),
// retrieves the top and left coordinates
position = $block.offset(),
// X and Y factors allows to change the diagonal movement direction and
// degree. Negative values inverts the direction.
factorX = 1,
factorY = 1,
// retrieves current vertical scrolling position and calculate the
// relative offset
scrollYPos = $this.scrollTop(),
offset = Math.abs(scrollYPos - lastScrollYPos),
// mouse wheel delta is inverted respect to the direction, so we need to
// normalize it against the direction
direction = scrollYPos > lastScrollYPos ? -1 : 1,
// calculates the new position. NOTE: if integers only are used for factors,
// then `Math.floor()` isn't required.
newTop = position.top + Math.floor(direction * offset * factorY),
newLeft = position.left - Math.floor(direction * offset * factorX);
// moves the block
$block.offset({ top: newTop, left: newLeft });
lastScrollYPos = scrollYPos;
});
});
</script>

I've flipped it around, by inverting the direction (as is commented) and then adding the last Y position instead of subtracting it (i've commented that)
$(function() {
var lastScrollYPos = 0;
$(window).on('scroll', function() {
var $this = $(this),
$block = $('#block'),
// retrieves the top and left coordinates
position = $block.offset(),
// X and Y factors allows to change the diagonal movement direction and
// degree. Negative values inverts the direction.
factorX = -1,
factorY = -1,
// retrieves current vertical scrolling position and calculate the
// relative offset
scrollYPos = $this.scrollTop(),
// ---- Flip around the offset calculation
offset = Math.abs(scrollYPos + lastScrollYPos),
// mouse wheel delta is inverted respect to the direction, so we need to
// normalize it against the direction
direction = scrollYPos > lastScrollYPos ? -1 : 1,
// calculates the new position. NOTE: if integers only are used for factors,
// then `Math.floor()` isn't required.
newTop = position.top + Math.floor(direction * offset * factorY),
newLeft = position.left - Math.floor(direction * offset * factorX);
// moves the block
$block.offset({
top: newTop,
left: newLeft
});
lastScrollYPos = scrollYPos;
});
});
.body {
height: 1500px;
width: 1000px;
}
#block {
height: 750px;
width: 500px;
background: blue;
position: absolute;
top: -700px;
left: 400px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="body">
<div id="block"></div>
</div>

Related

Making a box move smoothly and slowly to a set position in JavaScript

<html>
<div id="my_box_realtime" style="background-color: red; position: absolute; min-width: 100px; min-height: 100px"></div>
<script type="text/javascript">
var x = bottom
var y = right
var d = document.getElementById('my_box_realtime');
var position = 0;
setInterval(function() {}, 500)
position += 1;
d.style.top = position + 'px';
d.style.left = position + 'px';
function my_box_realtime() {
if (position)
}
</script>
</html>
The box needs to move smoothly and slowly to a set coordinate of bottom 0 and right 0.
Any help would be great. Very new to this and it's an assignment I have.
For your problem, we need to:
maintain top & left values separately
Check on Every Interval if the Boxes Bottom & Right have reached the Target Distance in relation to the window
Update the Top & Left Values if necessary
Finally, when the Box is at the Target Location, Clear the Interval.
var d = document.getElementById('my_box_realtime');
var x = 0; // Bottom Target in px
var y = 0; // Right Target in px
var positionTop = 0;
var positionLeft = 0;
let interval = setInterval(function() {
const {
bottom,
right
} = d.getBoundingClientRect();
const clientW = window.innerWidth;
const clientH = window.innerHeight;
if (clientH - bottom !== x) {
positionTop += 1;
d.style.top = positionTop + 'px';
}
if (clientW - right !== y) {
positionLeft += 1;
d.style.left = positionLeft + 'px';
}
if (right === clientW && bottom === clientH) {
clearInterval(interval);
}
}, 50);
<div id="my_box_realtime" style="background-color: red; position: absolute; min-width: 100px; min-height: 100px"></div>

Image that follows mouse

I'm trying to create a zoomed visual box with the possibility to move the visual on the Y avis from top to bottom with the mouse following.
My problem is that I need to limit the navigation to the top and the bottom of the visual to avoid white spaces over and below the image while navigate with the mouse to the extremes.
Here is my code :
HTML
<div class="follower-container">
<img src="https://picsum.photos/400/600?image=1083" class="follower-image" alt="" />
</div>
CSS
.follower-container {
position: relative;
height: 100vh;
max-width: 600px;
overflow: hidden;
border: 1px solid blue;
}
.follower-image {
position: absolute;
top: 50%;
left: 0; right: 0;
width: 100%;
display: block;
width: 100%;
height: auto;
transform: translateY(-50%);
}
JS
var mouse = { x:0, y:0 };
var image_position = { x:0, y:0 };
// Get mouse position
function getMouse(e){
mouse.x = e.clientX || e.pageX;
mouse.y = e.clientY || e.pageY;
}
$('.follower-container').mousemove(function(e){
getMouse(e);
});
// Move visual regarding mouse position
function moveImage(){
var distY = mouse.y - image_position.y;
image_position.y += distY/5;
$('.follower-image').css({
'top': image_position.y + "px"
});
}
setInterval(moveImage, 20);
My jsfiddle : https://jsfiddle.net/balix/hc2atzun/22/
You can use a combination of Math.min() and Math.max() to restrict the position to a certain range.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/max
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/min
Math.max() will return the larger of the two passed numbers:
Math.max(0, 100); // 100
Math.max(12, 5); // 12
Math.min() will return the smaller of the two passed numbers:
Math.min(0, 100); // 0
Math.min(12, 5); // 5
By combining them, you can restrict a given number to be within a range. If it is outside of the range, it will max out (or min out) at the ends of the range:
function keepInRange(n, minNum, maxNum) {
return Math.min(Math.max(minNum, n), maxNum);
}
keepInRange(-12, 0, 100); // 0
keepInRange(30, 0, 100); // 30
keepInRange(777, 0, 100); // 100
Now, you just need to figure out the math behind what number range to keep your top CSS value inside of. I highly, highly recommend that you give a go at that yourself.
If you really can't figure out the solution on your own, here it is for this case: https://jsfiddle.net/oeynjcpL/
Animation gets even better with requestAnimationFrame ;)
var mouse = { x:0, y:0 };
var image_position = { x:0, y:0 };
// Get mouse position
function getMouse(e){
mouse.x = e.clientX || e.pageX;
mouse.y = e.clientY || e.pageY;
}
$('.follower-container').mousemove(function(e){
getMouse(e);
});
// Returns number n if is inside of minNum and maxNum range
// Otherwise returns minNum or maxNum
function keepInRange(n, minNum, maxNum) {
return Math.min(Math.max(minNum, n), maxNum);
}
// Move visual regarding mouse position
function moveImage(){
var distY = mouse.y - image_position.y;
image_position.y += distY/5;
// minHeight is the containing element's height minus half the height of the image
var minHeight = $('.follower-container').height() - $('.follower-image').height() / 2;
// maxHeight is half the height of the image
var maxHeight = $('.follower-image').height() / 2;
$('.follower-image').css({
'top': keepInRange(image_position.y, minHeight, maxHeight) + "px"
});
requestAnimationFrame(moveImage);
}
requestAnimationFrame(moveImage);

JQuery Draggable - Prevent grid objects from going in the same position

I'm using JQuery Draggable to move items round a grid. Objects snap to a 32x32 grid area. I want to be able to cancel a grid snap if an object is in the same position.
The drag cannot be cancelled, it must just be prevented from entering the square. After it is prevented and moved back to the previous position, if the user continues to drag into a new unoccupied grid position, it must snap to that one.
I've created a demo which serves the purpose explained above however the image glitches when it tries to enter the new position but is then cancelled back to the old position.
https://jsfiddle.net/dtx7my4e/1/
Here's the code in that fiddle:
HTML:
<div class="drop-target">
<div class="drag-item" object-id="0"></div>
<div class="drag-item" style="left: 32px;" object-id="1"></div>
</div>
Javascript:
var objects = [
[0, 0],
[1, 1]
];
$(function() {
$(".drag-item").draggable({
grid: [ 32, 32 ],
containment: '.drop-target',
drag: function (event, obj){
let objectId = $(this).attr('object-id');
var objectPositionX = $(this).position().left / 32;
var objectPositionY = $(this).position().top / 32;
var previousPositionX = Math.floor(objects[objectId][0]);
var previousPositionY = Math.floor(objects[objectId][1]);
if (objectPositionX != previousPositionX || objectPositionY != previousPositionY) {
if(!isObjectInPosition(objects, [objectPositionX, objectPositionY])) {
objects[objectId] = [objectPositionX, objectPositionY];
} else {
obj.position.left = previousPositionX * 32;
obj.position.top = previousPositionY * 32;
}
}
}
});
});
function isObjectInPosition(arrayToSearch, positionToFind)
{
for (let i = 0; i < arrayToSearch.length; i++) {
if (arrayToSearch[i][0] == positionToFind[0]
&& arrayToSearch[i][1] == positionToFind[1]) {
return true;
}
}
return false;
}
CSS:
.drag-item {
background-image: url("http://i.imgur.com/lBIWrWw.png");
background-size: 32px auto;
width: 32px;
height: 32px;
cursor: move;
}
.drop-target {
background: whitesmoke url("http://i.imgur.com/uUvTRLx.png") repeat scroll 0 0 / 32px 32px;
border: 1px dashed orange;
height: 736px;
left: 0;
position: absolute;
top: 0;
width: 736px;
}
Thank you, any help is greatly appreciated.
Toby.
If you're willing to modify draggable itself, I think it would make the logic easier to apply. Once the drag event is triggered you can do lots of things, but you have much more control if you modify the _generatePosition method of draggable. It may look more complicated at first but for this kind of behavior, it's sometimes easier to work.
Basically, you can run your isInPosition function after the check for grid and containment has been applied. Normally next step is to set the new position, but if your isInPosition returns true, you prevent dragging. Something like this:
'use strict'
// This is the function generating the position by calculating
// mouse position, different offsets and option.
$.ui.draggable.prototype._generatePosition = function(event, constrainPosition) {
var containment, co, top, left,
o = this.options,
scrollIsRootNode = this._isRootNode(this.scrollParent[0]),
pageX = event.pageX,
pageY = event.pageY;
// Cache the scroll
if (!scrollIsRootNode || !this.offset.scroll) {
this.offset.scroll = {
top: this.scrollParent.scrollTop(),
left: this.scrollParent.scrollLeft()
};
}
/*
* - Position constraining -
* Constrain the position to a mix of grid, containment.
*/
// If we are not dragging yet, we won't check for options
if (constrainPosition) {
if (this.containment) {
if (this.relativeContainer) {
co = this.relativeContainer.offset();
containment = [
this.containment[0] + co.left,
this.containment[1] + co.top,
this.containment[2] + co.left,
this.containment[3] + co.top
];
} else {
containment = this.containment;
}
if (event.pageX - this.offset.click.left < containment[0]) {
pageX = containment[0] + this.offset.click.left;
}
if (event.pageY - this.offset.click.top < containment[1]) {
pageY = containment[1] + this.offset.click.top;
}
if (event.pageX - this.offset.click.left > containment[2]) {
pageX = containment[2] + this.offset.click.left;
}
if (event.pageY - this.offset.click.top > containment[3]) {
pageY = containment[3] + this.offset.click.top;
}
}
if (o.grid) {
//Check for grid elements set to 0 to prevent divide by 0 error causing invalid argument errors in IE (see ticket #6950)
top = o.grid[1] ? this.originalPageY + Math.round((pageY - this.originalPageY) / o.grid[1]) * o.grid[1] : this.originalPageY;
pageY = containment ? ((top - this.offset.click.top >= containment[1] || top - this.offset.click.top > containment[3]) ? top : ((top - this.offset.click.top >= containment[1]) ? top - o.grid[1] : top + o.grid[1])) : top;
left = o.grid[0] ? this.originalPageX + Math.round((pageX - this.originalPageX) / o.grid[0]) * o.grid[0] : this.originalPageX;
pageX = containment ? ((left - this.offset.click.left >= containment[0] || left - this.offset.click.left > containment[2]) ? left : ((left - this.offset.click.left >= containment[0]) ? left - o.grid[0] : left + o.grid[0])) : left;
}
if (o.axis === "y") {
pageX = this.originalPageX;
}
if (o.axis === "x") {
pageY = this.originalPageY;
}
}
// This is the only part added to the original function.
// You have access to the updated position after it's been
// updated through containment and grid, but before the
// element is modified.
// If there's an object in position, you prevent dragging.
if (isObjectInPosition(objects, [pageX - this.offset.click.left - this.offset.parent.left, pageY - this.offset.click.top - this.offset.parent.top])) {
return false;
}
return {
top: (
pageY - // The absolute mouse position
this.offset.click.top - // Click offset (relative to the element)
this.offset.relative.top - // Only for relative positioned nodes: Relative offset from element to offset parent
this.offset.parent.top + // The offsetParent's offset without borders (offset + border)
(this.cssPosition === "fixed" ? -this.offset.scroll.top : (scrollIsRootNode ? 0 : this.offset.scroll.top))
),
left: (
pageX - // The absolute mouse position
this.offset.click.left - // Click offset (relative to the element)
this.offset.relative.left - // Only for relative positioned nodes: Relative offset from element to offset parent
this.offset.parent.left + // The offsetParent's offset without borders (offset + border)
(this.cssPosition === "fixed" ? -this.offset.scroll.left : (scrollIsRootNode ? 0 : this.offset.scroll.left))
)
};
}
var objects = [
[0, 0],
[1, 1]
];
$(function() {
$(".drag-item").draggable({
grid: [32, 32],
containment: '.drop-target',
// on start you remove coordinate of dragged item
// else it'll check its own coordinates
start: function(event, obj) {
var objectId = $(this).attr('object-id');
objects[objectId] = [null, null];
},
// on stop you update your array
stop: function(event, obj) {
var objectId = $(this).attr('object-id');
var objectPositionX = $(this).position().left / 32;
var objectPositionY = $(this).position().top / 32;
objects[objectId] = [objectPositionX, objectPositionY];
}
});
});
function isObjectInPosition(arrayToSearch, positionToFind) {
for (let i = 0; i < arrayToSearch.length; i++) {
if (arrayToSearch[i][0] === (positionToFind[0] / 32) && arrayToSearch[i][1] === (positionToFind[1] / 32)) {
return true;
}
}
return false;
}
https://jsfiddle.net/bfc4tsrh/1/

Calculating child div top position - why does parent offsetHeight need to be subtracted?

I have created a magnifier in pure js. What I discovered in needing to translate the mouse position of a div relative to its parents is that in calculating the top for the overlaying magnifier div, the offsetTop works differently than the offsetLeft. After adjusting for what should be the top, I need to subtract the whole container div's offsetHeight.
The line in the code in question is this:
magnifier.style.top = yPosition - container.offsetHeight + "px";
Why do I need to subtract container.offsetHeight?
I know I've read something regarding this, but can't find it.
Disclaimers This code is working. I am asking so I (and those following) can understand how the box model works.
I know there are jQuery alternatives that are more cross browser reliable. I like to code it myself so that I can learn how it all works. If you see something which is not compatible for a modern browser, feel free to comment.
Lastly, For anyone using this, I removed code from this example to adjust for transforms. For example, if the wrapper has a transform: translate(-50%, 0); to center the wrapper horizontally, you will need to add the resulting amount of the translation (which translates to the wrapper's left position) back into the calculation.
I have created a jsfiddle here. I left more comments in the Fiddle as to methodology if anyone is interested.
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="../css/ms.js"></script>
<style type="text/css">
/********************/
body {
background-color: #FFF;
margin-left: 30px;
margin-top: 10px;
}
.wrapper {
position: absolute;
left: 100px;
}
#container {
width: 527px;
height: 450px;
border: 5px black solid;
overflow: hidden;
background-color: #F2F2F2;
cursor: pointer;
}
#image {
width: 527px;
height: 450px;
}
#magnifier {
width: 250px;
height: 250px;
overflow:hidden;
position:relative;
z-index: 1000;
border: solid 1px;
}
#magnifier img {
position: absolute;
}
</style>
</head>
<body>
<div class="wrapper" id="wrapper">
<div id="container">
<img id="image" src="../docs/grade-2/jpg/g2-bb-saints-francis.jpg">
<div id="magnifier" class="magnifier">
<img id="imagecopy">
</div>
<br>
</div>
<input type="button" value="Zoom" onClick="initmagnifier('magnifier', 'image', 'imagecopy');"><br>
</div>
<script>
function initmagnifier(magnifier, image, imagecopy){
var magnifier = document.getElementById("magnifier");
var container = document.getElementById("container");
var wrapper = document.getElementById("wrapper");
var img = document.getElementById(image);
var imgcopy = document.getElementById(imagecopy);
var zoom = 2;
container.addEventListener("mousemove",
function(e){
movemagnifier(e, img, imgcopy, magnifier, container, wrapper, zoom)
}, false);
var src = img.src;
imgcopy.src = src;
var src2 = imgcopy.src;
imgcopy.height = img.height * zoom;
imgcopy.width = img.width * zoom ;
}
function movemagnifier(e, img, imgcopy, magnifier, container, wrapper, zoom) {
// to get the left & top of the magnifier
// position needs to be adjusted for WRAPPER & CONTAINER top and left
// gets the top and left of the container
var containerPosition = getPosition(e.currentTarget);
// adjust out the CONTAINER's top / left
// Then takes 1/2 the hight of the MAGNIFIER and subtracts it from the MOUSE position to center MAGNIFIER around the MOUSE cursor
var xPosition = e.clientX - containerPosition.x - (magnifier.clientWidth / 2);
var yPosition = e.clientY - containerPosition.y - (magnifier.clientHeight / 2);
magnifier.style.left = xPosition + "px";
magnifier.style.top = yPosition - container.offsetHeight + "px";
// Adjust for zoom
// adjust the MAGNIFIER's top/left at an equal pace to the zoom amount
var yTravel = (e.clientY - containerPosition.y ) * (zoom - 1);
var yimgPosition = -(yPosition - container.clientTop + yTravel);
imgcopy.style.top = yimgPosition + "px";
var xTravel = (e.clientX - containerPosition.x) * (zoom - 1); // * 1.5
var ximgPosition = -(xPosition + xTravel);
imgcopy.style.left = ximgPosition + "px";
console.log('****');
console.log(e.clientY); // MOUSE POSTION
console.log(containerPosition.y);
console.log(wrapper.offsetTop);
console.log(wrapper.clientHeight);
console.log(container.offsetTop);
console.log(container.clientHeight);
console.log(yPosition);
console.log(container.offsetHeight);
console.log(magnifier.style.top);
}
function getPosition(element) {
var xPosition = 0;
var yPosition = 0;
// element is the CONTAINER
// This calculates the postion of the element (CONTAINER) TOP & LEFT relative to ALL parents
while (element) {
// if transform: translate in place for x and y,
// add it back as it skews the offsetLeft offsetTop values by the translate amount
xPosition += ((element.offsetLeft) - element.scrollLeft);
yPosition += ((element.offsetTop) - element.scrollTop);
element = element.offsetParent;
}
return { x: xPosition, y: yPosition };
}
</script>
</body>
</html>
It took me longer than I care to admit, but I have found the reason. In your fiddle you position the #magnifier-element relative, which means you have to move it from its 'natural' position, which is below the image inside the container.
So with every move you have to compensate for this, by pulling the #magnifier to the top/left position of the container, the left position already matches, but the 'natural' top position of the #magnifier is the full height of the container, as you calculate from the top/left position of the #container, you need to subtract the #container height.
A simple fix is to add position: relative to the #container and change position: relative on the #magnifier to position: absolute.
This will give you the expected coordinate system for the #magnifier as top: 0; left: 0 for the absolute positioned element is the top left corner of the its relative parent (the first positioned parent element, in this case #container).
a working example without the need to to subtract container.offsetHeight.
While I'm at it, you may want to look into the Element.getBoundingClientRect function, as you can get all information you need to determine the position in a single call.

mousemove parallax only move slightly instead of mouse position

I'm wanting the plane and rocket to only move approx 5% from their original place when the mouse hits the hero-panel area.
this current code makes both images follow and offset where the mouse position is.
Please assist.
$(document).ready(function () {
$('#hero-panel').mousemove(function (e) {
parallax(e, document.getElementById('plane'), 1);
parallax(e, document.getElementById('rocket'), 2);
});
});
function parallax(e, target, layer) {
var layer_coeff = 10 / layer;
var x = ($(window).width() - target.offsetWidth) / 4 - (e.pageX - ($(window).width() / 4)) / layer_coeff;
var y = ($(window).height() - target.offsetHeight) / 4 - (e.pageY - ($(window).height() / 4)) / layer_coeff;
$(target).offset({ top: y ,left : x });
};
https://jsfiddle.net/jc0807/c5yke2on/
Thanks
Ok, I think I understand what you're looking for:
fiddle
$(document).ready(function () {
var plane = document.getElementById('plane');
var rocket = document.getElementById('rocket');
plane.homePos = { x: plane.offsetLeft, y: plane.offsetTop };
rocket.homePos = { x: rocket.offsetLeft, y: rocket.offsetTop };
$('#hero-panel').mousemove(function (e) {
parallax(e, document.getElementById('plane'), 10);
parallax(e, document.getElementById('rocket'), 20);
});
});
function parallax(e, target, layer) {
var x = target.homePos.x - (e.pageX - target.homePos.x) / layer;
var y = target.homePos.y - (e.pageY - target.homePos.y) / layer;
$(target).offset({ top: y ,left : x });
};
What we're doing here is recording the starting position of the plane and the rocket as a new property 'homePos' on the plane and rocket objects. This makes it easy to apply the parallax effect as an offset from the original positions based on the mouse distance from the object homePos.
If you modify the layer value passed to parallax, the amount of movement will change (we're dividing the mouse offset from the middle of the object's starting position by it, to calculate the new object offset amount).
I guess my question is somehow related to the one above and I didn't want to create a duplicate.
I am using the code bellow to "navigate" into an image on mousemove. The problem is that I cannot manage to make the image fill all the viewable screen area. I've added a red background to the container to show what I mean. The desired result would be to no red background visible.
HTML
<div class="m-scene" id="main">
<div class="scene_element">
<img class="body" src="http://www.planwallpaper.com/static/images/nature-background-images2.jpg" />
</div>
</div>
JS
$(document).ready(function() {
$('img.body').mousemove(function(e) {
parallax(e, this, 1);
});
});
function parallax(e, target, layer) {
var layer_coeff = 20 / layer;
var x = ($(window).width() - target.offsetWidth) / 2 - (e.pageX - ($(window).width() / 2)) / layer_coeff;
var y = ($(window).height() - target.offsetHeight) / 2 - (e.pageY - ($(window).height() / 2)) / layer_coeff;
$(target).offset({
top: y,
left: x
});
};
CSS
.m-scene {
background-color: red;
overflow: hidden;
width: 100%;
}
.scene_element {
margin-left: auto;
margin-right: auto;
overflow: hidden;
}
.scene_element img {
width: 100%;
height: auto;
margin-left: auto;
margin-right: auto;
}
My jsFiddle is: fiddle
Thank you!

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