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How to scale a container keeping its bottom right corner fixed?

I have a red container which initially is at bottom right of black container. I have a scale function that gradually scales the container. I want to make the bottom right position of red container to be fixed and scale it towards top left. How can I do that?
const box = document.getElementById("box")
const initHeight = 200
const initWidth = 200
const centerX = initWidth / 2
const centerY = initHeight / 2
function transform(scale, translate) {
if (translate) {
translate[0] = -centerX + translate[0]
translate[1] = -centerY + translate[1]
}
box.style.transform = `scale(${scale})${
translate ? ` translate(${translate.map((x) => x + "px").toString()})` : ""
}`
}
let initX = initWidth
let initY = initHeight
let scaleVal = 0.5
transform(scaleVal, [initX, initY])
function scale() {
scaleVal = scaleVal + 0.01
transform(scaleVal, [
initX - scaleVal * initWidth,
initY - scaleVal * initHeight
])
if (scaleVal <= 1) {
setTimeout(() => {
requestAnimationFrame(scale)
}, 50)
}
}
scale()
* {
box-sizing: border-box;
}
.box {
height: 200px;
width: 200px;
background-color: black;
position: absolute;
}
.box:nth-child(2) {
background-color: red;
}
<div id="app">
<div class="box"></div>
<div class="box" id="box"></div>
</div>

To lock the bottom right corner of the red box to the bottom right of the black box this snippet does two things: positions red box right bottom relative to the parent app container and sets the transform-origin to that spot too (normally transform origin is at the center of an element). It then uses a CSS animation to expand the red box and contract it again using scale.
This method does not need JS as it is a simple scaling transform, but of course some of the subtleties of the original transformations are lost because of tying the corner down.
* {
box-sizing: border-box;
}
body {
position: relative;
width: 100vw;
height: 100vh;
}
#app {
position: absolute;
height: 200px;
width: 200px;
}
.box:nth-child(1) {
height: 200px;
width: 200px;
background-color: black;
position: absolute;
top: 0;
left: 0;
}
#box {
background-color: red;
width: 100px;
height: 100px;
position: absolute;
bottom: 0;
right: 0;
transform-origin: right bottom;
animation: scale 5s 1 ease-in-out;
}
#keyframes scale {
0% {
transform: scale(1);
}
50% {
transform: scale(2);
}
100% {
transform: scale(1);
}
}
<div id="app">
<div class="box"></div>
<div class="box" id="box"></div>
</div>

Okay so I finally figured it out,
const box = document.getElementById("box")
let scale = 0
const initWidth = 50
const initHeight = 50
function fixed(num, fix = 1) {
return Number(parseFloat(num).toFixed(fix))
}
function scaleBox() {
const [x, y] = [
fixed((initWidth - scale * initWidth) / 2),
fixed((initHeight - scale * initHeight) / 2)
]
box.style.transform = `translate(${x}px, ${y}px) scale(${scale})`
scale = scale + 0.1
if (scale < 1) {
setTimeout(() => {
requestAnimationFrame(scaleBox)
}, 500)
}
}
scaleBox()
* {
box-sizing: border-box;
}
.box {
height: 50px;
width: 50px;
background-color: black;
position: absolute;
}
.box:nth-child(2) {
background-color: red;
transform: translate(0, 0) scale(0);
}
<div id="app">
<div class="box"></div>
<div class="box" id="box"></div>
</div>
Explanation
The trick is to translate the container in such a way that when its scaled after the translation, it always places itself in the bottom right of purple container.
To figure out the translation amount, let's first scale the container to 0.5 without any translation. It looks like this,
As you can see the container's width is 25 as 0.5(scale) * 50(init_width)=25 and position from container from all sides(top left, bottom left, top right, bottom right) will be (25/2, 25/2)=(12.5,12.5) since the container is scaled equally from all sides.
Since the position from bottom right is (12.5,12.5), we need to translate the container to (+12.5,+12.5) and then scale it to exactly place it at bottom right.

You can achieve many things using display:flex, it's great!
This is how I would approach your problem:
const handleClick = () => {
const blackDiv = document.getElementById("black-div");
const redDiv = document.getElementById("red-div");
let widthRatio = 0;
let heightRatio = 0;
const scaleUpTimer = setInterval(() => {
if (widthRatio === 1 || heightRatio === 1) clearInterval(scaleUpTimer);
widthRatio = redDiv.offsetWidth / blackDiv.offsetWidth;
heightRatio = redDiv.offsetHeight / blackDiv.offsetHeight;
redDiv.style.width = widthRatio * 100 + 2 + "%";
redDiv.style.height = heightRatio * 100 + 2 + "%";
}, 10);
};
#black-div {
width: 200px;
height: 200px;
background-color: rgb(0, 0, 0);
display: flex;
align-items: flex-end;
justify-content: flex-end;
}
#red-div {
background-color: red;
width: 50%;
height: 50%;
}
<div id='black-div'>
<div id='red-div' onclick={handleClick()}></div>
</div>
EDIT: I used onclick here but obviously you would have to handle the situations where someone clicks the red square and its already scaled up to avoid setting unnecessary timers. Or you could just call the function directly, without having to click anything.

make the video fill the screen width and and remove the frame

I have created this frame for playing the movie which resizes based on the user's screen size.
Now I want to be able to remove the frame and fill the whole width of the user screen using another function but each time I failed.
Now I'm using injectViewportSizes() function. I want a new function to do this:
remove the frame completely without affecting anything else.
stretch the width of the movie until it fills the whole width of the screen.
of course stretching the movie is much simpler for me than removing the frame ... each time I've tried to remove it the whole movie removes or a distortion occurs for the rest of the elements.
Here is the code:
const clipSource = `https://langfox.ir/movie/movieclip/My_name_is_Edward_Bloom.mp4`;
const content = document.querySelector('.content');
const box = document.getElementById("box");
let video = document.createElement('video');
content.appendChild(video);
video.id = 'clip';
let clip = document.getElementById("clip");
clip.currentTime = 0;
let source = document.createElement('source');
source.src = clipSource;
source.type = 'video/mp4';
video.appendChild(source);
video.load();
setTimeout(() => {
injectViewportSizes(); // or goFull();
clip.play();
}, 3000);
function goFull(){
// Remove the frame and make the video fill the while 'Width' of the screen
}
function injectViewportSizes(){
let screenWidth = screen.width;
let screenHeight = screen.height;
let vwPixels = screenWidth / 100;
let clipWidth = clip.videoWidth;
let clipHeight = clip.videoHeight;
screenWidth = screenWidth - (screenWidth * 0.10); // available space to put the clip inside
screenHeight = screenHeight - (screenHeight * 0.10);
let clipWidthNew;
let clipHeightNew;
if(clipWidth > clipHeight){
clipWidthNew = clipWidth;
let ratio = clipWidth / clipHeight;
while(screenWidth < clipWidthNew) {
clipWidthNew--;
}
clipHeightNew = clipWidthNew / ratio;
} else {
clipHeightNew = clipHeight;
let ratio = clipWidth / clipHeight;
while(screenHeight < clipHeightNew) {
clipHeightNew--;
}
clipWidthNew = clipHeightNew * ratio;
}
let viewPortClipWidth = clipWidthNew * (100 / document.body.clientWidth);
let viewPortClipHeight = clipHeightNew / vwPixels;
document.querySelector('.box .content').style.width = `${viewPortClipWidth}vw`;
document.querySelector('.box .content').style.height = `${viewPortClipHeight}vw`;
}
video {
position: absolute;
top: 0;
left: 0;
max-width: 100%;
max-height: 100%;
width: 100%;
height: 100%;
-o-object-fit: cover;
object-fit: cover;
}
body {
height: 100vh;
display: flex;
align-items: center;
justify-content: center;
background-color: #0b0e12;
}
.box {
border-radius: 0.31vh;
position: relative;
overflow: hidden;
}
.box::after {
content: '';
position: absolute;
z-index: -1;
top: 0;
right: 0;
bottom: 0;
left: 0;
background: repeating-linear-gradient(-45deg, white 0 0.48828125vw, #f00c36 0 0.9765625vw) 0 0/1.380859375vw 1.380859375vw;
width: calc(100vw + 1.380859375vw);
height: calc(100vh + 1.380859375vw);
}
.box .content {
position: relative;
max-width: 100vw;
max-height: 100vh;
box-shadow: 0 0 0.262vh black, 0 0 0.6553vh rgba(0, 0, 0, 1), inset 0 0 0.6553vh rgba(0, 0, 0, 1);
margin: 0.45vh;
}
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="style.css">
</head>
<body>
<div id='box' class="box">
<div class="content"></div>
</div>
</body>
</html>
Note: it seems that this code snippet can't show the original frame correctly but it works in a raw HTML file locally.

How do I make an image move when i scroll down?

Here is an example of what i want to achieve:
https://www.flambette.com/en/
I have tried to change the css properties of images but that effect does not satisfy my needs.
I have tried the following code:
mydocument.on('scroll',function() {
if (mydocument.scrollTop() > 10 && mydocument.scrollTop() < 200 ) {
$('#first').css('top', '320px');
$('#first').css('left', '215px');
$('#first').css('transition', '0.5s');
}
else {
$('#first').css('top', '300px');
$('#first').css('left', '200px');
$('#first').css('transition', '0.5s');
}
});
This is supposed to move an image when you scroll between 10 and 200 px.

var container = document.getElementById('container');
var windowHeight = window.innerHeight;
var windowWidth = window.innerWidth;
var scrollArea = 1000 - windowHeight;
var square1 = document.getElementsByClassName('square')[0];
var square2 = document.getElementsByClassName('square')[1];
// update position of square 1 and square 2 when scroll event fires.
window.addEventListener('scroll', function() {
var scrollTop = window.pageYOffset || window.scrollTop;
var scrollPercent = scrollTop/scrollArea || 0;
square1.style.left = scrollPercent*window.innerWidth + 'px';
square2.style.left = 800 - scrollPercent*window.innerWidth*0.6 + 'px';
});
body {
overflow-x: hidden;
}
.container {
width: 100%;
height: 1000px;
}
.square {
position: absolute;
}
.square-1 {
width: 100px;
height: 100px;
background: red;
top: 600px;
}
.square-2 {
width: 120px;
height: 120px;
background: black;
left: 800px;
top: 800px;
}
<div class="container" id="container">
<div class="square square-1"></div>
<div class="square square-2"></div>
</div>
Hope to help you.
Here you can see more examples about movable elements and scroll events.

How to simulate rays emerging from an image/div to another image/div using HTML and CSS

I want to build a page to show a blown-up version of an image.
I have the smaller image and the bigger image built out. I am not sure how to build the in between portion that looks like rays coming out of the smaller image.
HTML
<div class="flex">
<div class="exp" tabindex="0">
<img class="image" src="http://via.placeholder.com/50x50">
</div>
<div class="big-image">
<img class="image" src="http://via.placeholder.com/350x550">
</div>
</div>
CSS
.exp {
margin: 5px;
width: 100px;
height: 100px;
background-color: #ded3c0;
border-radius: 100%;
line-height: 80px;
align-items: center;
display: flex;
justify-content: center;
}
.exp .image {
width: 50px;
height: 50px;
}
.big-image {
border: 1px solid #000;
padding: 20px;
border-radius: 19px;
}
.flex {
display: flex;
align-items: center;
justify-content: space-around;
}
Any pointers on how to do this is helpful.
Here is jsfiddle https://jsfiddle.net/npkeq7ut/

If you need only lines you can achieve this with JS and skew transform:
let topLine = document.getElementById('top-line');
let bottomLine = document.getElementById('bottom-line');
function updateLines()
{
let b = document.getElementById('b').getBoundingClientRect();
let a = document.getElementById('a').getBoundingClientRect();
let left = a.right;
let width = b.left - a.right;
let tHeight = a.top - b.top;
let tTop = tHeight / 2 + b.top;
let tAngle = Math.atan(tHeight / width) * 180 / Math.PI;
let bHeight = b.bottom - a.bottom;
let bTop = bHeight / 2 + a.bottom - bottomLine.offsetHeight;
let bAngle = Math.atan(bHeight / width) * 180 / Math.PI;
topLine.style.top = tTop + "px";
topLine.style.left = left + "px";
topLine.style.width = width + "px";
topLine.style.transform = "skewY("+(-tAngle)+"deg)";
bottomLine.style.top = bTop + "px";
bottomLine.style.left = left + "px";
bottomLine.style.width = width + "px";
bottomLine.style.transform = "skewY("+(bAngle)+"deg)";
}
updateLines();
Fiddle: https://jsfiddle.net/JacobDesight/f40yeuqe/2/
#EDIT
If you want trapeze with background then here is example using canvas: https://jsfiddle.net/JacobDesight/f40yeuqe/3/

This could be a starting point for you.
Code by thecodeplayer.
http://thecodeplayer.com/walkthrough/magnifying-glass-for-images-using-jquery-and-css3
$(document).ready(function() {
var native_width = 0;
var native_height = 0;
//Now the mousemove function
$(".magnify").mousemove(function(e) {
//When the user hovers on the image, the script will first calculate
//the native dimensions if they don't exist. Only after the native dimensions
//are available, the script will show the zoomed version.
if (!native_width && !native_height) {
//This will create a new image object with the same image as that in .small
//We cannot directly get the dimensions from .small because of the
//width specified to 200px in the html. To get the actual dimensions we have
//created this image object.
var image_object = new Image();
image_object.src = $(".small").attr("src");
//This code is wrapped in the .load function which is important.
//width and height of the object would return 0 if accessed before
//the image gets loaded.
native_width = image_object.width;
native_height = image_object.height;
} else {
//x/y coordinates of the mouse
//This is the position of .magnify with respect to the document.
var magnify_offset = $(this).offset();
//We will deduct the positions of .magnify from the mouse positions with
//respect to the document to get the mouse positions with respect to the
//container(.magnify)
var mx = e.pageX - magnify_offset.left;
var my = e.pageY - magnify_offset.top;
//Finally the code to fade out the glass if the mouse is outside the container
if (mx < $(this).width() && my < $(this).height() && mx > 0 && my > 0) {
$(".large").fadeIn(100);
} else {
$(".large").fadeOut(100);
}
if ($(".large").is(":visible")) {
//The background position of .large will be changed according to the position
//of the mouse over the .small image. So we will get the ratio of the pixel
//under the mouse pointer with respect to the image and use that to position the
//large image inside the magnifying glass
var rx = Math.round(mx / $(".small").width() * native_width - $(".large").width() / 2) * -1;
var ry = Math.round(my / $(".small").height() * native_height - $(".large").height() / 2) * -1;
var bgp = rx + "px " + ry + "px";
//Time to move the magnifying glass with the mouse
var px = mx - $(".large").width() / 2;
var py = my - $(".large").height() / 2;
//Now the glass moves with the mouse
//The logic is to deduct half of the glass's width and height from the
//mouse coordinates to place it with its center at the mouse coordinates
//If you hover on the image now, you should see the magnifying glass in action
$(".large").css({
left: px,
top: py,
backgroundPosition: bgp
});
}
}
})
})
/*Some CSS*/
* {
margin: 0;
padding: 0;
}
.magnify {
width: 200px;
margin: 50px auto;
position: relative;
}
/*Lets create the magnifying glass*/
.large {
width: 175px;
height: 175px;
position: absolute;
border-radius: 100%;
/*Multiple box shadows to achieve the glass effect*/
box-shadow: 0 0 0 7px rgba(255, 255, 255, 0.85), 0 0 7px 7px rgba(0, 0, 0, 0.25), inset 0 0 40px 2px rgba(0, 0, 0, 0.25);
/*Lets load up the large image first*/
background: url('http://thecodeplayer.com/uploads/media/iphone.jpg') no-repeat;
/*hide the glass by default*/
display: none;
}
/*To solve overlap bug at the edges during magnification*/
.small {
display: block;
}
<!-- Lets make a simple image magnifier -->
<div class="magnify">
<!-- This is the magnifying glass which will contain the original/large version -->
<div class="large"></div>
<!-- This is the small image -->
<img class="small" src="http://thecodeplayer.com/uploads/media/iphone.jpg" width="200"/>
</div>
<!-- Lets load up prefixfree to handle CSS3 vendor prefixes -->
<script src="http://thecodeplayer.com/uploads/js/prefixfree.js" type="text/javascript"></script>
<!-- You can download it from http://leaverou.github.com/prefixfree/ -->
<!-- Time for jquery action -->
<script src="http://thecodeplayer.com/uploads/js/jquery-1.7.1.min.js" type="text/javascript"></script>

Can't use jQuery to override inline style generated by jQuery?

My code is forking this pen, I also include my code in the stack snippet under this post.
what I want to achieve are:
When the cursor is not inside the body, the eyeball would move randomly ( achieved ).
When the cursor enters the body, the eyeball follows the cursor ( achieved ).
When the cursor leaves the body, the eyeball starts moving randomly again ( not achieved ).
I called the function which is used to move the eyeball randomly in on("mouseleave") event, and it does move to a random position but it will immediately go back to the last cursor position, rather than staying at the new position. Can anyone point me to the right direction to fix the problem?
Thanks!
var
mouseOvering = false,
pupil = $("#pupil"),
eyeball = $("#iris"),
eyeposx = 40,
eyeposy = 20,
r = $(pupil).width()/2,
center = {
x: $(eyeball).width()/2 - r,
y: $(eyeball).height()/2 - r
},
distanceThreshold = $(eyeball).width()/2 - r,
mouseX = 0,
mouseY = 0;
$("body").ready( function(){
if ( !mouseOvering ) {
moveRandomly();
}
});
$("body").on('mouseleave', function(){
mouseOvering = false;
moveRandomly();
console.log("mouseleave");
});
$("body").on('mousemove', function(e){
mouseOvering = true;
console.log("mouseovering");
followCursor(e);
});
function moveRandomly() {
var loop = setInterval(function(){
var xp = Math.floor(Math.random()*80);
var yp = Math.floor(Math.random()*80);
pupil.animate({left:xp, top:yp});
}, 3500);
}
function followCursor(e) {
var d = {
x: e.pageX - r - eyeposx - center.x,
y: e.pageY - r - eyeposy - center.y
};
var distance = Math.sqrt(d.x*d.x + d.y*d.y);
if (distance < distanceThreshold) {
mouseX = e.pageX - eyeposx - r;
mouseY = e.pageY - eyeposy - r;
} else {
mouseX = d.x / distance * distanceThreshold + center.x;
mouseY = d.y / distance * distanceThreshold + center.y;
}
var xp = 0, yp = 0;
var loop = setInterval(function(){
// change 1 to alter damping/momentum - higher is slower
xp += (mouseX - xp) / 1;
yp += (mouseY - yp) / 1;
pupil.css({left:xp, top:yp});
}, 2);
}
body {
background-color: #D1D3CF;
}
#container {
display: inline;
height: 400px;
width: 400px;
}
#eyeball {
background: radial-gradient(circle at 100px 100px, #EEEEEE, #000);
height: 300px;
width: 300px;
border-radius: 100%;
position: relative;
}
#iris {
top: 10%;
left: 10%;
background: radial-gradient(circle at 100px 100px, #4DC9EF, #000);
height: 80%;
width: 80%;
border-radius: 100%;
position: absolute;
}
#pupil {
top: 10%;
left: 10%;
background: radial-gradient(circle at 100px 100px, #000000, #000);
height: 55%;
width: 55%;
border-radius: 100%;
position: absolute;
}
#keyframes move {
50% {
transform: translate(-50px, 50px);
}
}
#keyframes move2 {
50% {
transform: translate(-20px, 20px);
}
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<link rel="stylesheet" href="style.css">
</head>
<body>
<div id="container">
<div id="eyeball">
<div id="iris">
<div id="pupil"></div>
</div>
</div>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="script.js"></script>
</body>
</html>

With Javascript you can only track where the cursor is on the webpage. If you shift your cursor outside the body, it's not possible for your code to know where the cursor is.
This is the reason the eye tracking your cursor stops moving when you move your cursor outside the window.

The problem is that once the followcursor function was started it kept on moving back to the last known mouse position, even after the mouse had left the body. I just put a check on your mouseOvering variable inside your followcursor function:
var
mouseOvering = false,
pupil = $("#pupil"),
eyeball = $("#iris"),
eyeposx = 40,
eyeposy = 20,
r = $(pupil).width()/2,
center = {
x: $(eyeball).width()/2 - r,
y: $(eyeball).height()/2 - r
},
distanceThreshold = $(eyeball).width()/2 - r,
mouseX = 0,
mouseY = 0;
$("body").ready( function(){
if ( !mouseOvering ) {
moveRandomly();
}
});
$("body").on('mouseleave', function(){
mouseOvering = false;
console.log("mouseleave");
});
$("body").on('mousemove', function(e){
mouseOvering = true;
console.log("mouseovering");
followCursor(e);
});
function moveRandomly() {
var loop = setInterval(function(){
var xp = Math.floor(Math.random()*80);
var yp = Math.floor(Math.random()*80);
if (!mouseOvering) {
pupil.animate({left:xp, top:yp});
}
}, 3500);
}
function followCursor(e) {
var d = {
x: e.pageX - r - eyeposx - center.x,
y: e.pageY - r - eyeposy - center.y
};
var distance = Math.sqrt(d.x*d.x + d.y*d.y);
if (distance < distanceThreshold) {
mouseX = e.pageX - eyeposx - r;
mouseY = e.pageY - eyeposy - r;
} else {
mouseX = d.x / distance * distanceThreshold + center.x;
mouseY = d.y / distance * distanceThreshold + center.y;
}
var xp = 0, yp = 0;
var loop = setInterval(function(){
// change 1 to alter damping/momentum - higher is slower
xp += (mouseX - xp) / 1;
yp += (mouseY - yp) / 1;
if (mouseOvering) {
pupil.css({left:xp, top:yp});
}
}, 2);
}
body {
background-color: #D1D3CF;
}
#container {
display: inline;
height: 400px;
width: 400px;
}
#eyeball {
background: radial-gradient(circle at 100px 100px, #EEEEEE, #000);
height: 300px;
width: 300px;
border-radius: 100%;
position: relative;
}
#iris {
top: 10%;
left: 10%;
background: radial-gradient(circle at 100px 100px, #4DC9EF, #000);
height: 80%;
width: 80%;
border-radius: 100%;
position: absolute;
}
#pupil {
top: 10%;
left: 10%;
background: radial-gradient(circle at 100px 100px, #000000, #000);
height: 55%;
width: 55%;
border-radius: 100%;
position: absolute;
}
#keyframes move {
50% {
transform: translate(-50px, 50px);
}
}
#keyframes move2 {
50% {
transform: translate(-20px, 20px);
}
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<link rel="stylesheet" href="style.css">
</head>
<body>
<div id="container">
<div id="eyeball">
<div id="iris">
<div id="pupil"></div>
</div>
</div>
</div>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="script.js"></script>
</body>
</html>