We Keep Coding

Calculate position (X, Y) on cirlcle base on height

I think the title is a little bit confusing so I will try to say it better.
Image you have this code:
#NadrzFrontView:before {
--beginHeight: var(--startHeight);
--endHeight: var(--finishHeight);
animation: 2s fillin ease forwards;
content: "";
position: absolute;
bottom: 0;
width: 300px;
height: 0;
background-color: #00FFF5;
display: inline-block;
}
#NadrzFrontView {
width: 300px;
height: 300px;
border-radius: 50%;
border: 3px solid black;
position: relative;
overflow: hidden;
}
<div id="NadrzFrontView" style="--startHeight: 0%; --finishHeight: 50%;"> </div>
It looks like this:
Now, you can determent left, top position and height of an element using this script:
function getOffset(el) {
var rect = el.getBoundingClientRect();
return {
left: rect.left + window.pageXOffset,
top: rect.top + window.pageYOffset,
width: rect.width || el.offsetWidth,
height: rect.height || el.offsetHeight
};
}
Ok, when we are able to find these then we go to our problem:
function SomeFunction() {
var thickness = 1;
var color = '#000000';
var off_nadrz = getOffset(document.getElementById('NadrzFrontView'));
var elem = document.getElementById('NadrzFrontView');
var pseudoStyle = window.getComputedStyle(elem, ':before');
var off_pseudo_elem = getOffset(elem);
off_pseudo_elem.top += parseInt(pseudoStyle.top, 10);
off_pseudo_elem.left += parseInt(pseudoStyle.left, 10);
off_pseudo_elem.height = parseInt(pseudoStyle.height, 10);
//finding middle of the circle
var x1 = off_nadrz.left + (off_nadrz.width / 2);
var y1 = off_nadrz.top + (off_nadrz.height / 2);
//draw point in the middle of circle
document.getElementById("AllLines").innerHTML += CreateHtmlPoint(color, x1, y1);
//fincding point on the side of an element
var x2; //I need to find this -- see more in examples
var y2; //I need to find this -- see more in examples
document.getElementById("AllLines").innerHTML += CreateHtmlPoint(color, x2, y2); //This does not work
}
function CreateHtmlPoint(color, cx, cy) {
cx -= 5; // - 5, because width of point is 10
cy -= 5; // - 5, because height of point is 10
return "<div style='padding:0px; z-index: 2; margin:0px; height: 10px; width: 10px; background-color:" + color + "; line-height:1px; position:absolute; left:" + cx + "px; top:" + cy + "px; border-radius: 50%;' />";
}
So, now example of an x2 and y2 would look like this:
Basically, we know on what coordinades is top of circle (off_nadrz.top), bottom of circle (off_nadrz.top + (off_nadrz.height / 2)) and height of an circle (off_nadrz.height). We also know same things of an psuedo_element (blue thing in the circle). From this we need to calculate x2 and y2.
Thanks for every suggestion because I am fighting with this problem for 2 days now...

you have only to apply the circumference formula:
var y2 = y1 - ( off_pseudo_elem.height - off_nadrz.height / 2 );
once you have y2, calculate x2:
var r = off_nadrz.height / 2; // if the figure is a circle, not an ellipse
var x2 = x1 + Math.sqrt( r * r - ( y2 - y1 ) * ( y2 - y1 ) );

How to increase FPS parallax plugin?

In the script, the picture is very slow.
$(".holiday-face__item").each(function(i, el) {
var offset = parseInt($(el).data('offset'));
var translate = "translate3d(0px," + Math.round(offsetY * offset) + "px, 0px)";
var x = (e.pageX * -1 / 40),
y = (e.pageY * -1 / 25);
$(el).css({
'-webkit-transform': translate,
'transform': translate,
'moz-transform': translate
});
});
$(".holiday-face_parallax .holiday-face__item_5").each(function(i, el) {
var x = (e.pageX * -1 / 40), y = (e.pageY * -1 / 25);
$(this).css('background-position', x + 'px ' + y + 'px');
});
$(".holiday-face_parallax .holiday-face__item_4").each(function(i, el) {
var x = (e.pageX * -1 / 30), y = (e.pageY * -1 / 20);
$(this).css('background-position', x + 'px ' + y + 'px');
});
$(".holiday-face_parallax .holiday-face__item_3").each(function(i, el) {
var x = (e.pageX * -1 / 40), y = (e.pageY * -1 / 25);
$(this).css('background-position', x + 'px ' + y + 'px');
});
$(".holiday-face_parallax .holiday-face__item_2").each(function(i, el) {
var x = (e.pageX * -1 / 25), y = (e.pageY * -1 / 25);
$(this).css('background-position', x + 'px ' + y + 'px');
});
$(".holiday-face_parallax .holiday-face__item_1").each(function(i, el) {
var x = (e.pageX * -1 / 20), y = (e.pageY * -1 / 25);
$(this).css('background-position', x + 'px ' + y + 'px');
});
});
.holiday-face {
bottom: 0;
left: 0;
min-height: 540px;
min-width: 875px;
right: 0;
top: 0;
z-index: -1;
}
.holiday-face_parallax .holiday-face__item_5 {
background-image: url("../img/header-bg-ley2.png");
width: 100%;
height: 600px;
}
.holiday-face_parallax .holiday-face__item_4 {
width: 100%;
height: 600px;
background-image: url("../img/header-bg-ley3.png");
}
.holiday-face_parallax .holiday-face__item_3 {
background-image: url("../img/header-bg-ley4.png");
width: 100%;
height: 600px;
}
.holiday-face_parallax .holiday-face__item_2 {
background-image: url("../img/header-bg-ley5.png");
width: 100%;
height: 600px;
}
.holiday-face_parallax .holiday-face__item_1 {
background-image: url("../img/header-bg-ley1.png");
width: 100%;
height: 600px;
}
.holiday-face-words__link {
height: 100%;
left: 0;
margin: 0 auto;
position: absolute;
right: 0;
}
.holiday-face-words {
background: none no-repeat scroll center top rgba(0, 0, 0, 0);
height: 69px;
left: 0px;
position: absolute;
right: 0px;
top: 0%;
width:100%;
}
.b-page_holiday-face .holiday-face_parallax .holiday-face__item {
opacity: 1;
}
.holiday-face__item {
background-position: center center;
background-repeat: no-repeat;
background-size: cover;
bottom: 0;
left: 0;
margin: 0px 0;
position: absolute;
right: 0;
top: 0;
transition: opacity 0.1s ease 0s;
}
<div data-id="1" class="holiday-face holiday-face_parallax">
<div data-offset="20" class="holiday-face__item holiday-face__item_5"></div>
<div data-offset="70" class="holiday-face__item holiday-face__item_4"></div>
<div data-offset="30" class="holiday-face__item holiday-face__item_3"></div>
<div data-offset="20" class="holiday-face__item holiday-face__item_2"></div>
<div data-offset="50" class="holiday-face__item holiday-face__item_1"></div>
</div>
<div data-id="1" class="holiday-face holiday-face_parallax">
<div data-offset="20" class="holiday-face__item holiday-face__item_5"></div>
<div data-offset="70" class="holiday-face__item holiday-face__item_4"></div>
<div data-offset="30" class="holiday-face__item holiday-face__item_3"></div>
<div data-offset="20" class="holiday-face__item holiday-face__item_2"></div>
<div data-offset="50" class="holiday-face__item holiday-face__item_1"></div>
</div>
$(".holiday-face__item").each(function(i, el) {
var offset = parseInt($(el).data('offset'));
var translate = "translate3d(0px," + Math.round(offsetY * offset) + "px, 0px)";
var x = (e.pageX * -1 / 40),
y = (e.pageY * -1 / 25);
$(el).css({
'-webkit-transform': translate,
'transform': translate,
'moz-transform': translate
});
});
$(".holiday-face_parallax .holiday-face__item_5").each(function(i, el) {
var x = (e.pageX * -1 / 40), y = (e.pageY * -1 / 25);
$(this).css('background-position', x + 'px ' + y + 'px');
});
$(".holiday-face_parallax .holiday-face__item_4").each(function(i, el) {
var x = (e.pageX * -1 / 30), y = (e.pageY * -1 / 20);
$(this).css('background-position', x + 'px ' + y + 'px');
});
$(".holiday-face_parallax .holiday-face__item_3").each(function(i, el) {
var x = (e.pageX * -1 / 40), y = (e.pageY * -1 / 25);
$(this).css('background-position', x + 'px ' + y + 'px');
});
$(".holiday-face_parallax .holiday-face__item_2").each(function(i, el) {
var x = (e.pageX * -1 / 25), y = (e.pageY * -1 / 25);
$(this).css('background-position', x + 'px ' + y + 'px');
});
$(".holiday-face_parallax .holiday-face__item_1").each(function(i, el) {
var x = (e.pageX * -1 / 20), y = (e.pageY * -1 / 25);
$(this).css('background-position', x + 'px ' + y + 'px');
});
});

It looks like the values of
var x = (e.pageX * -1 / 30), y = (e.pageY * -1 / 20);
define the speed of the parallax. Your example does not work correctly, so I cannot test this out for sure.
Try changing the values of these assignments. A smaller value should make it go slower, where a larger value will make it faster.
To make it very slow, for example, try
var x = (e.pageX * -1 / 3000), y = (e.pageY * -1 / 2000);
Looks like each function gets its own speeds, so you can choose how fast or slow you want each photo to go.

Move a coordinate along an angled line using mouse movement

Please run the code snippet below - you will see an angled line derived from the corners of a box. Given mouse movement, I would like to move the marker along this line - where either:
movement in x will move along the line, and additional movement in y will accelerate
movement in x will move along the line and you can get from start to finish with it (whatever is simplest)
So far I haven't got anywhere but I'll update if I do and many thanks for any help.
PS doesn't really matter if it doesn't move exactly along the line - it's the algorithm to move along an angle I'm interested in.
Fiddle: http://jsfiddle.net/ngr3dbhx/3/
var boxEl = document.getElementById('box');
var lineEl = document.getElementById('line');
var markerEl = document.getElementById('marker');
var rad, deg;
// Draw an angled line for demonstration purposes.
function getElementOffset (el) {
var rect = el.getBoundingClientRect();
var docEl = document.documentElement;
var rectTop = rect.top + window.pageYOffset - docEl.clientTop;
var rectLeft = rect.left + window.pageXOffset - docEl.clientLeft;
return {
top: rectTop,
left: rectLeft
};
}
function calcAndDrawAngle () {
var boxOffset = getElementOffset(boxEl);
var x1 = boxOffset.left;
var y1 = boxOffset.top;
var x2 = boxOffset.left + boxEl.offsetWidth;
var y2 = boxOffset.top + boxEl.offsetHeight;
var deltaX = x2 - x1;
var deltaY = y2 - y1;
rad = Math.atan2(deltaY, deltaX);
deg = rad * (180 / Math.PI);
lineEl.style.transform = 'rotate(' + deg + 'deg) translate(-50%, 0)';
}
// On mouse move I want to move the marker along the anged line..
// Do something with rad or deg?
document.addEventListener('mousemove', function (e) {
markerEl.style.top = e.clientY + 'px';
markerEl.style.left = e.clientX + 'px';
});
calcAndDrawAngle();
window.addEventListener('resize', calcAndDrawAngle);
html,
body {
margin: 0;
width: 100%;
height: 100%;
overflow: hidden;
}
#box {
position: absolute;
top: 20%;
left: 30%;
width: 35%;
height: 30%;
border: 1px solid #999;
}
#line {
position: absolute;
top: 0;
left: 0;
transform-origin: top left;
height: 1px;
width: 9999em;
background-color: black;
}
#marker {
position: absolute;
width: 8px;
height: 8px;
background-color: red;
}
<div id="box">
<div id="line"></div>
</div>
<div id="marker"></div>

you mean this?
https://jsfiddle.net/2q1nLh3q/1/
The formula is basic mathematics:
y = k * x + d
Where k is deltaY / deltaX and d is the point where the line crosses the y axis.
So your function could look like this:
document.addEventListener('mousemove', function (e) {
window.requestAnimationFrame(function() {
var boxOffset = getElementOffset(boxEl);
var k = boxEl.offsetHeight / boxEl.offsetWidth;
var d = boxOffset.top - boxOffset.left * k;
var mouseY = k * e.clientX + d;
markerEl.style.top = mouseY + 'px';
markerEl.style.left = e.clientX + 'px';
});
});

Using fairly simple math, calculate y for any x within limited range (subtracted 4 to place rectangle at center):
//var canvas = document.getElementById('canvas');
var boxEl = document.getElementById('box');
var lineEl = document.getElementById('line');
var markerEl = document.getElementById('marker');
var rad, deg;
var coords;
// Draw an angled line for demonstration purposes.
function getElementOffset (el) {
var rect = el.getBoundingClientRect();
var docEl = document.documentElement;
var rectTop = rect.top + window.pageYOffset - docEl.clientTop;
var rectLeft = rect.left + window.pageXOffset - docEl.clientLeft;
return {
top: rectTop,
left: rectLeft
};
}
function calcAndDrawAngle () {
var boxOffset = getElementOffset(boxEl);
var x1 = boxOffset.left;
var y1 = boxOffset.top;
var x2 = boxOffset.left + boxEl.offsetWidth;
var y2 = boxOffset.top + boxEl.offsetHeight;
coords = [{x:x1,y:y2},{x:x2,y:y1}];
var deltaX = x2 - x1;
var deltaY = y2 - y1;
rad = Math.atan2(deltaY, deltaX);
deg = rad * (180 / Math.PI);
lineEl.style.transform = 'rotate(' + deg + 'deg) translate(-50%, 0)';
}
// On mouse move I want to move the marker along the anged line..
// Do something with rad or deg?
document.addEventListener('mousemove', function (e) {
var x = Math.min(Math.max(e.clientX, coords[0].x), coords[1].x) - 4;
var y = coords[0].y + ((coords[1].y - coords[0].y) * (coords[1].x - x) / (coords[1].x - coords[0].x));
markerEl.style.top = y + 'px';
markerEl.style.left = x + 'px';
});
calcAndDrawAngle();
window.addEventListener('resize', calcAndDrawAngle);
html,
body {
margin: 0;
width: 100%;
height: 100%;
overflow: hidden;
}
#box {
position: absolute;
top: 20%;
left: 30%;
width: 35%;
height: 30%;
border: 1px solid #999;
}
#line {
position: absolute;
top: 0;
left: 0;
transform-origin: top left;
height: 1px;
width: 9999em;
background-color: black;
}
#marker {
position: absolute;
width: 8px;
height: 8px;
background-color: red;
}
<div id="box">
<div id="line"></div>
</div>
<div id="marker"></div>

How to draw a lines in circle in different angles by using for loop

I used below code to draw a line in circle,Now I want to draw 12 lines in different angles with same space & lines should be touched to the circle.
<!DOCTYPE html>
<html>
<head>
<style>
#straight{
height: 30px;
border-right: 1px solid blue;
-webkit-transform: rotate(**" for loop value must be displayed"** deg);
transform: rotate(**" for loop value must be displayed"** deg);
position: absolute;
top:40px;
left:400px;
}
#circle {
height: 30px;
width: 31px;
margin-left: 81px;
margin-top: 0px;
background-color: #fff;
border: 2px solid blue;
border-radius: 65px;
position:absolute;
}
</style>
</head>
<body>
<div>
<div id="circle">
<div style="position:relative; top:-40px; left:-385px;">
<div id="straight"></div>
</div>
</div>
</body>
</html>
Please help me & thanks in advance

Check this fiddle.
It uses a function DrawLine(x1,y1,x2,y2) to draw a line between the given co-ordinates.
Basically, it creates divs with thin width and rotate them according the slope.
Looks like a wheel with spokes.
Here is a wheel in action if you need.
Here is the snippet.
drawNLines(12, 40, 40, 40);
function drawNLines(N, centreX, centreY, radius) {
for (i = 0; i < N; i++) {
angle = 360 / N;
x2 = centreX + radius * Math.cos(Math.PI * angle * i / 180);
y2 = centreY + radius * Math.sin(Math.PI * angle * i / 180);
DrawLine(centreX, centreY, x2, y2);
}
}
function DrawLine(x1, y1, x2, y2) {
if (y1 < y2) {
var pom = y1;
y1 = y2;
y2 = pom;
pom = x1;
x1 = x2;
x2 = pom;
}
var a = Math.abs(x1 - x2);
var b = Math.abs(y1 - y2);
var c;
var sx = (x1 + x2) / 2;
var sy = (y1 + y2) / 2;
var width = Math.sqrt(a * a + b * b);
var x = sx - width / 2;
var y = sy;
a = width / 2;
c = Math.abs(sx - x);
b = Math.sqrt(Math.abs(x1 - x) * Math.abs(x1 - x) + Math.abs(y1 - y) * Math.abs(y1 - y));
var cosb = (b * b - a * a - c * c) / (2 * a * c);
var rad = Math.acos(cosb);
var deg = (rad * 180) / Math.PI
htmlns = "http://www.w3.org/1999/xhtml";
div = document.createElementNS(htmlns, "div");
div.setAttribute('style', 'border:1px solid black;width:' + width + 'px;height:0px;-moz-transform:rotate(' + deg + 'deg);-webkit-transform:rotate(' + deg + 'deg);position:absolute;top:' + y + 'px;left:' + x + 'px;');
document.getElementById("circle").appendChild(div);
}
#circle {
height: 80px;
width: 80px;
margin-left: 30px;
margin-top: 30px;
background-color: #fff;
border: 2px solid blue;
border-radius: 80px;
position: absolute;
}
<div id="circle"></div>
Hope this helps. :)

Placing interactive box on top of the canvas on mouseleave

I'm trying to make a box follow the cursor on mousemove. However, it should stop following the mouse if
the user clicks the box
the user's mouse leaves the surrounding div
Here's what the current setup looks like:
$(function() {
$(document).mousemove(function(e) {
// assign the co-ords as vars so
var vert = e.pageY;
var horz = e.pageX;
// get co -ords for the center of the box
centx = Math.ceil($('div').width() / 2);
centy = Math.ceil($('div').height() / 2);
// checking to see if the cursor is outside the boudries of the box and stoping the circle moving past them
if (e.pageY + 53 > Math.ceil($('div').height())) var vert = Math.ceil($('div').height() - 47);
if (e.pageY - 53 < 0) vert = 53;
if (e.pageX + 53 > Math.ceil($('div').width())) var horz = Math.ceil($('div').width() - 47);
if (e.pageX - 53 < 0) horz = 53;
// work out the distance between the cursor and the center of box
disx = horz - centx;
disy = vert - centy;
// work out the scale of the shadow
sx = -disx * 0.1;
sy = -disy * 0.1;
// work out the shadow blur
b = (Math.abs(sx) + Math.abs(sy)) * 0.5;
//apply the css
$('p').css({
'top': vert - 53,
'left': horz - 53,
'-webkit-box-shadow': '#a0a0a0 ' + sx + 'px ' + sy + 'px ' + b + 'px, inset ' + sx + 'px ' + sy + 'px ' + b + 'px #e3e3e3'
});
});
});
body {
padding: 0px;
}
div {
position: relative;
width: 400px;
height: 400px;
background-color: #f0f0f0;
}
p {
background-color: orange;
height: 100px;
width: 100px;
position: absolute;
top: 100px;
left: 100px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.6.4/jquery.min.js"></script>
<div>
<p>set the location</p>
</div>
fiddle

edit
To restrict movement once the box is clicked, just use a helper variable:
var cond = false;
$(yourElement).click(function () {
cond = true;
})
Then, in the body of your mousemove function:
if (cond) return false;
You should check whether the mouse is within the div using Element.getBoundingClientRect:
var boundary = document.getElementById("theDiv").getBoundingClientRect()
var vert = e.pageY;
var horz = e.pageX;
if (boundary.top <= vert && vert <= boundary.bottom &&
boundary.left <= horz && horz <= boundary.right) {
/* the rest of your code */
}
Element.getBoundingClientRect returns an object like this:
{
bottom: 408,
height: 400,
left: 8,
right: 408,
top: 8,
width: 400,
}
If you want to use jQuery, you can instead use
var left = $(item).offset().left
, top = $(item).offset().top
, right = left + $(item).width()
, bottom = top + $(item).height()
;
and set up a similar if condition.
demo:
$(function() {
var cond = false;
$("#theDiv").click(function () {
cond = true;
})
$(document).mousemove(function(e) {
if (cond) return false;
var boundary = document.getElementById("theDiv").getBoundingClientRect()
// assign the co-ords as vars so
var vert = e.pageY;
var horz = e.pageX;
if (boundary.top <= vert && vert <= boundary.bottom && boundary.left <= horz && horz <= boundary.right) {
// get co -ords for the center of the box
centx = Math.ceil($('div').width() / 2);
centy = Math.ceil($('div').height() / 2);
// checking to see if the cursor is outside the boudries of the box and stoping the circle moving past them
if (e.pageY + 53 > Math.ceil($('div').height())) var vert = Math.ceil($('div').height() - 47);
if (e.pageY - 53 < 0) vert = 53;
if (e.pageX + 53 > Math.ceil($('div').width())) var horz = Math.ceil($('div').width() - 47);
if (e.pageX - 53 < 0) horz = 53;
// work out the distance between the cursor and the center of box
disx = horz - centx;
disy = vert - centy;
// work out the scale of the shadow
sx = -disx * 0.1;
sy = -disy * 0.1;
// work out the shadow blur
b = (Math.abs(sx) + Math.abs(sy)) * 0.5;
//apply the css
$('p').css({
'top': vert - 53,
'left': horz - 53,
'-webkit-box-shadow': '#a0a0a0 ' + sx + 'px ' + sy + 'px ' + b + 'px, inset ' + sx + 'px ' + sy + 'px ' + b + 'px #e3e3e3'
});
}
});
});
body {
padding: 0px;
}
div {
position: relative;
width: 400px;
height: 400px;
background-color: #f0f0f0;
}
p {
background-color: orange;
height: 100px;
width: 100px;
position: absolute;
top: 100px;
left: 100px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="theDiv">
<p>set the location</p>
</div>
fiddle