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Match image container width with image width after it is rendered - React

I am using react-image-marker which overlays marker on image inside a div.
<ImageMarker
src={props.asset.url}
markers={markers}
onAddMarker={(marker) => setMarkers([...markers, marker])}
className="object-fit-contain image-marker__image"
/>
The DOM elements are as follows:
<div class=“image-marker”>
<img src=“src” class=“image-marker__image” />
</div>
To make vertically long images fit the screen i have added css to contain the image within div
.image-marker {
width: inherit;
height: inherit;
}
.image-marker__image {
object-fit:contain !important;
width: inherit;
height: inherit;
}
But now the image is only a subpart of the entire marker area. Due to which marker can be added beyond image bounds, which i do not want.
How do you think i can tackle this. After the image has been loaded, how can i change the width of parent div to make sure they have same size and markers remain in the image bounds. Please specify with code if possible

Solved it by adding event listeners in useLayoutEffect(). Calculating image size info after it is rendered and adjusting the parent div dimensions accordingly. Initially and also when resize occurs.
If you think you have a better solution. Do specify.
useLayoutEffect(() => {
const getRenderedSize = (contains, cWidth, cHeight, width, height, pos) => {
var oRatio = width / height,
cRatio = cWidth / cHeight;
return function () {
if (contains ? (oRatio > cRatio) : (oRatio < cRatio)) {
this.width = cWidth;
this.height = cWidth / oRatio;
} else {
this.width = cHeight * oRatio;
this.height = cHeight;
}
this.left = (cWidth - this.width) * (pos / 100);
this.right = this.width + this.left;
return this;
}.call({});
}
const getImgSizeInfo = (img) => {
var pos = window.getComputedStyle(img).getPropertyValue('object-position').split(' ');
return getRenderedSize(true,
img.width,
img.height,
img.naturalWidth,
img.naturalHeight,
parseInt(pos[0]));
}
const imgDivs = reactDom.findDOMNode(imageCompRef.current).getElementsByClassName("image-marker__image")
if (imgDivs) {
if (imgDivs.length) {
const thisImg = imgDivs[0]
thisImg.addEventListener("load", (evt) => {
if (evt) {
if (evt.target) {
if (evt.target.naturalWidth && evt.target.naturalHeight) {
let renderedImgSizeInfo = getImgSizeInfo(evt.target)
if (renderedImgSizeInfo) {
setOverrideWidth(Math.round(renderedImgSizeInfo.width))
}
}
}
}
})
}
}
function updateSize() {
const thisImg = imgDivs[0]
if (thisImg){
let renderedImgSizeInfo = getImgSizeInfo(thisImg)
if (renderedImgSizeInfo) {
setOverrideWidth((prev) => {
return null
})
setTimeout(() => {
setOverrideWidth((prev) => {
return setOverrideWidth(Math.round(renderedImgSizeInfo.width))
})
}, 390);
}
}
}
window.addEventListener('resize', updateSize);
return () => window.removeEventListener('resize', updateSize);
}, [])

Converting babel compiled code into regular js

I got an example code from codepen and I wanted to understand it better. I noticed that the js code is compiled with Babel. Since I'm quite new to JS I would be more comfortable to look at a standard javascript code, so I wanted to ask you if there's some way to convert a babel js into a regular js. I did some research but I couldn't find anything
By the way, this is the Babel code
const parent = document.getElementById("projects");
const closeButton = document.getElementById("project-close");
const projectItems = document.querySelectorAll(".project-item");
closeButton.addEventListener("click", onProjectClose);
projectItems.forEach(item => item.addEventListener("click", onProjectClick));
function onProjectClick(event) {
const { target } = event;
const { width, height, top, left } = target.getBoundingClientRect();
const clone = document.createElement("div");
clone.style.height = height + "px";
clone.style.width = width + "px";
clone.style.top = top + "px";
clone.style.left = left + "px";
clone.style.position = "absolute";
clone.style.zIndex = 10;
clone.classList.add("project-item");
clone.classList.add("clone");
clone.innerHTML = target.innerHTML;
document.body.appendChild(clone);
gsap.timeline().
to(clone, 1.5, {
position: "fixed",
top: 0,
left: 0,
width: "100%",
height: "100vh",
ease: Expo.easeInOut }).
add(() => document.body.classList.add("project-page")).
set(clone, {
overflow: "auto" });
}
function onProjectClose() {
document.body.classList.remove("project-page");
const clone = document.querySelector(".clone");
gsap.to(clone, 1, {
clipPath: "inset(100% 0 100% 0)",
ease: Sine.easeInOut,
onComplete() {
clone.remove();
} });
gsap.to(clone.querySelector("img"), 1, {
scale: 0.7,
ease: Sine.easeInOut });
}

jquery plugin, settimeout and div not being append, simple weird case

I'm writing a jquery plugin the code below is not working (I mean the setTimeout is working but nothing is append)
var self = this;
for (var i=0; i<=10; i++) {
setTimeout(function() {
self.append(bubble);
}, 1000);
}
And the code below is working:
for (var i=0; i<=10; i++) {
this.append(bubble);
}
this is a jquery selection. I really don't get what's going on. It can't be scope issue .. can it be ? I don't get it. Thanks in advance for you help
Edit: bubble is a simple div (" ")
Below the whole plugin code:
(function($) {
'use strict';
$.fn.randomBubble = function(options) {
var self = this;
var settings = $.extend({
color: 'blue',
backgroundColor: 'white',
maxBubbleSize: 100
}, options);
var frame = {
height: this.height(),
width: this.width(),
}
var bubble = "<div class='randomBubble'> </div>";
this.getLeft = function(width) {
var left = Math.random() * frame.width;
if (left > (frame.width / 2)) {
left -= width;
} else {
left += width;
}
return left
}
this.getTop = function(height) {
var top = Math.random() * frame.height;
if (top > (frame.height / 2)) {
top -= height;
} else {
top += height;
}
return top
}
this.removeBubbles = function() {
var currentBubbles = this.find('.randomBubble');
if (currentBubbles.length) {
currentBubbles.remove();
}
}
window.oh = this;
for (var i = 0; i <= 10; i++) {
var timer = Math.random() * 1000;
setTimeout(function() {
window.uh = self;
self.append(bubble);
console.log("oh");
}, 1000);
}
this.randomize = function() {
//self.removeBubbles();
var allBubbles = this.find('.randomBubble');
allBubbles.each(function(i, el) {
var height = Math.random() * settings.maxBubbleSize;
var width = height;
$(el).css({
color: settings.color,
backgroundColor: settings.backgroundColor,
zIndex: 1000,
position: 'absolute',
borderRadius: '50%',
top: self.getTop(height),
left: self.getLeft(width),
height: height,
width: width
});
});
}
this.randomize();
//var run = setInterval(self.randomize, 4000);
return this.find('.randomBubble');
}
})(jQuery);

Because the bubbles are appended later due to the setTimeout(), this selector in your randomize() function comes up empty:
var allBubbles = this.find('.randomBubble');
That is why appending them in a simple for loop works fine.
If you really want to use the setTimout() to append your bubbles, one option is to style them when you add them:
setTimeout(function() {
var height = Math.random() * settings.maxBubbleSize;
var width = height;
var b = $(bubble).css({
color: settings.color,
backgroundColor: settings.backgroundColor,
zIndex: 1000,
position: 'absolute',
borderRadius: '50%',
top: self.getTop(height),
left: self.getLeft(width) ,
height: height,
width: width
});
self.append(b);
}, 1000);
Fiddle

Is it because you still call randomize() right away, even when you postpone the creation for one second?
You will also return an empty selection in that case, for the same reason.
Also, you probably want to use the timer variable in setTimeout() instead of hardcoding all to 1000 ms?

this is a javascript selection, the selector in jquery is $(this)
$.fn.randomBubble = function(options) {
var self = $(this);
};

How much of an element is visible in viewport

There's a div (brown rectangle) on the page. The page is higher than the viewport (orange rectangle) so it can be scrolled, which means that the div might only partially show up or not at all.
What's the simplest algorithm to tell how much % of the div is visible in the viewport?
(To make things easier, the div always fits into the viewport horizontally, so only the Y axis needs to be considered at the calculations.)

See one more example in fiddle:
https://jsfiddle.net/1hfxom6h/3/
/*jslint browser: true*/
/*global jQuery, window, document*/
(function ($) {
'use strict';
var results = {};
function display() {
var resultString = '';
$.each(results, function (key) {
resultString += '(' + key + ': ' + Math.round(results[key]) + '%)';
});
$('p').text(resultString);
}
function calculateVisibilityForDiv(div$) {
var windowHeight = $(window).height(),
docScroll = $(document).scrollTop(),
divPosition = div$.offset().top,
divHeight = div$.height(),
hiddenBefore = docScroll - divPosition,
hiddenAfter = (divPosition + divHeight) - (docScroll + windowHeight);
if ((docScroll > divPosition + divHeight) || (divPosition > docScroll + windowHeight)) {
return 0;
} else {
var result = 100;
if (hiddenBefore > 0) {
result -= (hiddenBefore * 100) / divHeight;
}
if (hiddenAfter > 0) {
result -= (hiddenAfter * 100) / divHeight;
}
return result;
}
}
function calculateAndDisplayForAllDivs() {
$('div').each(function () {
var div$ = $(this);
results[div$.attr('id')] = calculateVisibilityForDiv(div$);
});
display();
}
$(document).scroll(function () {
calculateAndDisplayForAllDivs();
});
$(document).ready(function () {
calculateAndDisplayForAllDivs();
});
}(jQuery));
div {
height:200px;
width:300px;
border-width:1px;
border-style:solid;
}
p {
position: fixed;
left:320px;
top:4px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="div1">div1</div>
<div id="div2">div2</div>
<div id="div3">div3</div>
<div id="div4">div4</div>
<p id="result"></p>

Here's a snippet illustrating how you can calculate this.
I've put the % values in the boxes for readability, and it even kinda "follows" the viewport ^^ :
Fiddle version
function listVisibleBoxes() {
var results = [];
$("section").each(function () {
var screenTop = document.documentElement.scrollTop;
var screenBottom = document.documentElement.scrollTop + $(window).height();
var boxTop = $(this).offset().top;
var boxHeight = $(this).height();
var boxBottom = boxTop + boxHeight;
if(boxTop > screenTop) {
if(boxBottom < screenBottom) {
//full box
results.push(this.id + "-100%");
$(this).html("100%").css({ "line-height": "50vh" });
} else if(boxTop < screenBottom) {
//partial (bottom)
var percent = Math.round((screenBottom - boxTop) / boxHeight * 100) + "%";
var lineHeight = Math.round((screenBottom - boxTop) / boxHeight * 50) + "vh";
results.push(this.id + "-" + percent);
$(this).html(percent).css({ "line-height": lineHeight });
}
} else if(boxBottom > screenTop) {
//partial (top)
var percent = Math.round((boxBottom - screenTop) / boxHeight * 100) + "%";
var lineHeight = 100 - Math.round((boxBottom - screenTop) / boxHeight * 50) + "vh";
results.push(this.id + "-" + percent);
$(this).html(percent).css({ "line-height": lineHeight });
}
});
$("#data").html(results.join(" | "));
}
$(function () {
listVisibleBoxes();
$(window).on("scroll", function() {
listVisibleBoxes();
});
});
body {
background-color: rgba(255, 191, 127, 1);
font-family: Arial, sans-serif;
}
section {
background-color: rgba(175, 153, 131, 1);
height: 50vh;
font-size: 5vh;
line-height: 50vh;
margin: 10vh auto;
overflow: hidden;
text-align: center;
width: 50vw;
}
#data {
background-color: rgba(255, 255, 255, .5);
left: 0;
padding: .5em;
position: fixed;
top: 0;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<section id="one"></section>
<section id="two"></section>
<section id="three"></section>
<section id="four"></section>
<section id="five"></section>
<section id="six"></section>
<div id="data">data here</div>

After playing around a bit I think I've found perhaps the simplest way to do it: I basically determine how much the element extends over the viewport (doesn't matter in which direction) and based on this it can easily be calculated how much of it is visible.
// When the page is completely loaded.
$(document).ready(function() {
// Returns in percentages how much can be seen vertically
// of an element in the current viewport.
$.fn.pvisible = function() {
var eTop = this.offset().top;
var eBottom = eTop + this.height();
var wTop = $(window).scrollTop();
var wBottom = wTop + $(window).height();
var totalH = Math.max(eBottom, wBottom) - Math.min(eTop, wTop);
var wComp = totalH - $(window).height();
var eIn = this.height() - wComp;
return (eIn <= 0 ? 0 : eIn / this.height() * 100);
}
// If the page is scrolled.
$(window).scroll(function() {
// Setting the opacity of the divs.
$("div").each(function() {
$(this).css("opacity", Math.round($(this).pvisible()) / 100);
});
});
});
html,
body {
width: 100%;
height: 100%;
}
body {
background-color: rgba(255, 191, 127, 1);
}
div {
width: 60%;
height: 30%;
margin: 5% auto;
background-color: rgba(175, 153, 131, 1);
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
A little illustration to help understand how it works:

Chrome now supports Intersection Observer API
Example (TypeScript):
export const elementVisibleInPercent = (element: HTMLElement) => {
return new Promise((resolve, reject) => {
const observer = new IntersectionObserver((entries: IntersectionObserverEntry[]) => {
entries.forEach((entry: IntersectionObserverEntry) => {
resolve(Math.floor(entry.intersectionRatio * 100));
clearTimeout(timeout);
observer.disconnect();
});
});
observer.observe(element);
// Probably not needed, but in case something goes wrong.
const timeout = setTimeout(() => {
reject();
}, 500);
});
};
const example = document.getElementById('example');
const percentageVisible = elementVisibleInPercent(example);
Example (JavaScript):
export const elementVisibleInPercent = (element) => {
return new Promise((resolve, reject) => {
const observer = new IntersectionObserver(entries => {
entries.forEach(entry => {
resolve(Math.floor(entry.intersectionRatio * 100));
clearTimeout(timeout);
observer.disconnect();
});
});
observer.observe(element);
// Probably not needed, but in case something goes wrong.
const timeout = setTimeout(() => {
reject();
}, 500);
});
};
const example = document.getElementById('example');
const percentageVisible = elementVisibleInPercent(example);

Please note that the Intersection Observer API is available since then, made specifically for this purpose.

Setting Column Widths using Javascript

I'm Trying to Figure out how to set column widths and heights using javascript so that i can set them according to the browser window. i figured the following code. but its not working. please help
<script type="javascript">
function size()
{
document.getElementById("body").style.width=window.innerWidth;
document.getElementById("body").style.height=window.innerHeight;
var width=document.getElementById("body").style.width;
var height=document.getElementById("body").style.height;
document.getElementById("header").style.height=(.15*height);
document.getElementById("loginbox").style.height=(.15*height);
document.getElementById("navigation").style.height=(.05*height);
document.getElementById("leftpanel").style.height=(.70*height);
document.getElementById("contentarea").style.height=(.75*height);
document.getElementById("addcolumn").style.height=(.75*height);
document.getElementById("footer").style.height=(.10*height);
document.getElementById("header").style.width=(.75*width);
document.getElementById("loginbox").style.width=(.25*width);
document.getElementById("navigation").style.width=(width);
document.getElementById("leftpanel").style.width=(.20*width);
document.getElementById("contentare").style.width=(.65*width);
document.getElementById("addcolumn").style.width=(.15*width);
document.getElementById("footer").style.width=(width);
}
</script>
i use css to float the columns according to requirement.
and then i'm calling the function size() in body ( onload=size() )
but not working

style attributes are strings and need a unit in the end:
document.getElementById("addcolumn").style.width=(width + "px");
Chances are you've also need to set width and height as:
var width = window.innerWidth;
var height = window.innerHeight

I would suggest a different way to accomplish this, which will be easily mantainable:
function size() {
var props = {
header: {
width: .75,
height: .15
},
loginbox: {
width: .25,
height: .15
},
navigation: {
width: 1,
height: .05
},
leftpanel: {
width: .2,
height: .7
},
contentarea: {
width: .65,
height: .75
},
addcolumn: {
width: .15,
height: .75
},
footer: {
width: 1,
height: .1
}
},
bodyElement = document.getElementById('body'),
width = bodyElement.style.width = window.innerWidth,
height = bodyElement.style.height = window.innerHeight;
for (var id in props) {
if (!props.hasOwnProperty(id)) continue;
var element = document.getElementById(id),
prop = props[id];
element.width = (width * prop.width) + "px";
element.height = (height * prop.height) + "px";
}
}
Note: I haven't tested it, but it should work.

Why not use simple css, make the width a percentage,
width: 75%;