I cannot seem to add a transform to the body element (having a mega brain block as to why its not working). I am trying to experiment with some scrolling effects.
Progress thus far:
document.addEventListener('scroll', function () {
var previousScrollPos = 0;
var currentScrollPos = document.body.scrollTop;
var transformValue = -500px;
if(currentScrollPos > previousScrollPos) {
document.body.style.transform = "translate-y(transformValue)";
}
}
UPDATE
This is now my working code
document.addEventListener('scroll', scroller)
function scroller() {
var previousScrollPos = 0;
var currentScrollPos = document.body.scrollTop;
var nextScrollPos = 0;
if (currentScrollPos > previousScrollPos) {
nextScrollPos = nextScrollPos - 100;
document.body.style.transform = "translateY(" + nextScrollPos + "vh)";
} else {
nextScrollPos = nextScrollPos + 100;
document.body.style.transform = "translateY(" + previousScrollPos + "vh)";
}
}
Your Syntax is wrong. translating the Y axis is written in camelcase like this:
transform: translateY(-500px);
So the right way to write it should be:
...
var transformValue = -500;
if(currentScrollPos > previousScrollPos) {
document.body.style.transform = "translateY(" + transformValue + "px)";
}
}
Related
I'm new to pure Javascript and struggling to change the opacity of an element when it's between 30% and 60% of the viewport. I would appreciate it if you could look through my code and point out any errors. Thanks!
var parent = document.documentElement;
var elements = document.getElementsByClassName('.text');
var elementHeight = document.getElementsByClassName('.text').clientHeight;
var gridTop = parent.clientHeight * .2;
var gridBottom = parent.clientHeight * .6;
window.addEventListener('scroll', function() {
for (var i = 0; i < elements.length; i++) {
var thisTop = elements[i].offsetTop - parent.scrollTop;
if (thisTop >= gridTop && (thisTop + elementHeight) <= gridBottom) {
elements.style.opacity = ".3";
} else {
elements.style.opacity = ".055";
}
};
});
I have a Javascript animation at http://dev17.edreamz3.com/css/
All code works, however, there are performance problems. on Desktop, its good, On mobile things are so slow that it's unusable. I want to optimize the animation so that it runs smoothly on mobile. It can take 20 seconds or more for the animation to render.
Right now the way the code is designed is in js/anim.js there is a render() function that gets executed every time a scroll event happens. The problem is that this routine is not efficient, that's what I think of. Each time render() executes it loops through all the paths and sections of the maze and redraws them, is there any alternative way or a strategy to get it working both on mobile as well as desktop.
var offPathTime = 1000;
window.offSection = -1;
function render() {
// var top = ($window.scrollTop() + (0.4 * $window.height())) / window.scale;
var top = ($('.parent-div').scrollTop() + (0.4 * $('.parent-div').height())) / window.scale;
top -= 660;
top /= mazeSize.h;
if (window.offSection != -1) {
$body.addClass("blockScroll");
$('.parent-div').addClass("blockScroll");
// var wtop = $window.scrollTop() / window.scale;
var wtop = $('.parent-div').scrollTop() / window.scale;
wtop -= 660;
wtop /= mazeSize.h;
var $offSection = $("#offSection" + window.offSection);
var $section = $("#section" + window.offSection);
$(".section").removeClass("sectionActive");
$offSection.addClass("sectionActive");
$section.addClass("sectionActive");
var sTop = 200 -(mazeSize.h * (window.offSections[window.offSection].cy - wtop));
$container.animate({
left: 290 -(mazeSize.w * window.offSections[window.offSection].cx) + "px",
top: sTop + "px"
}, offPathTime);
// Path
var lr = offPaths[window.offSection].x1 > offPaths[window.offSection].x0;
var dx = Math.abs(offPaths[window.offSection].x1 - offPaths[window.offSection].x0);
var dashw = (dx * mazeSize.w) | 0;
$offPaths[window.offSection].css("width", "0px");
$offPaths[window.offSection].show();
if (lr) {
$offPaths[window.offSection].animate({
width: dashw + "px"
}, offPathTime);
} else {
var x0 = offPaths[window.offSection].x0 * mazeSize.w;
var x1 = offPaths[window.offSection].x1 * mazeSize.w;
$offPaths[window.offSection].css("left", x0 + "px");
$offPaths[window.offSection].animate({
width: dashw + "px",
left: x1 + "px"
}, offPathTime);
}
return;
}
$body.removeClass("blockScroll");
$('.parent-div').removeClass("blockScroll");
$(".offPath").hide();
if ($container.css("top") != "0px") {
$container.animate({
left: "-1550px",
top: "0px"
}, 500);
}
var pathIdx = -1;
var path0 = paths[0];
var path1;
var inPath = 0;
var i;
var curTop = 0;
var found = false;
for (i=0; i<paths.length; i++) {
var top0 = (i == 0) ? 0 : paths[i-1].y;
var top1 = paths[i].y;
if (top >= top0 && top < top1) {
pathIdx = i;
path1 = paths[i];
inPath = (top - top0) / (top1 - top0);
found = true;
if (i > 0) {
var dy = paths[i].y - paths[i-1].y;
var dx = paths[i].x - paths[i-1].x;
var vert = dx == 0;
if (vert)
$paths[i-1].css("height", (dy * mazeSize.h * inPath) + "px");
$paths[i-1].show();
}
} else if (top >= top0) {
path0 = paths[i];
var dy = paths[i].y - top0;
var vert = dy != 0;
if (i > 0) {
if (vert)
$paths[i-1].css("height", (dy * mazeSize.h) + "px");
$paths[i-1].show();
}
} else {
if (i > 0) {
$paths[i-1].hide();
}
}
curTop = top1;
}
// Check for an active section
$(".section").removeClass("sectionActive");
var section;
for (i=0; i<sections.length; i++) {
var d = Math.abs(sections[i].cy - (top - 0.05));
if (d < 0.07) {
var $section = $("#section" + i);
$section.addClass("sectionActive");
}
}
}
1) At the very least - assign all DOM objects to variables outside of the function scope. Like this:
var $parentDiv = $('.parent-div');
var $sections = $(".section");
...
function render() {
...
2) Also you should probably stop animation before executing it again, like this:
$container.stop(true).animate({
...
If you are running render() function on scroll - it will run many times per second. stop() helps to prevent it somewhat.
3) If it will not be sufficient - you can switch from jQuery to Zepto(jQuery-like api, but much faster and uses css transitions for animations) or to Velocity(basically drop-in replacement for jQuery $.animate and much faster than original) or even to GSAP - much more work obviously, but it is very fast and featured animation library.
I built a magnifying glass in JavaScript, which works well when I click on it or click and dragging it, but it should not hide from the screen.
$(".menu-left-preview-box-preview").bind('click', function (e) {
window.location = "page" + ($(this).index() + 1) + ".html";
});
var native_width = 0;
var native_height = 0;
var magnifyIsMouseDown = false;
$(".magnify").parent().mousedown(function (e) {
magnifyIsMouseDown = true;
});
$(".magnify").mousemove(function (e) {
if (magnifyIsMouseDown) {
if (!native_width && !native_height) {
var image_object = new Image();
image_object.src = $(".small").attr("src");
native_width = image_object.width;
native_height = image_object.height;
} else {
var magnify_offset = $(this).offset();
var mx = e.pageX - magnify_offset.left;
var my = e.pageY - magnify_offset.top;
if (mx < $(this).width() && my < $(this).height() && mx > 0 && my > 0) {
$(".large").fadeIn(100);
} else {
$(".large").fadeOut(100);
}
if ($(".large").is(":visible")) {
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";
var px = mx - $(".large").width() / 2;
var py = my - $(".large").height() / 2;
$(".large").css({ left: px, top: py, backgroundPosition: bgp });
}
}
}
});
$(".magnify").parent().mouseup(function (e) {
magnifyIsMouseDown = false;
$(".large").fadeOut(100);
});
$(".magnify").parent().mouseleave(function (e) {
$(".large").fadeOut(100);
});
manageSlide();
By default the magnifying glass must be there on the screen. The magnifying glass can be dragged and after it's dropped it must remain there at it's dropped position.
On clicking and dragging the magnify glass is working well, but it should not hide from the screen. It should be there on screen.
Provide handle of magnify glass with that circle (in design).
Working example: http://jsfiddle.net/mohsin80/4ww8efx5/
I replaced the if (magnifyIsMouseDown) { by if (isDragging) { and created the following methods:
var isDragging = false;
$(".magnify").parent().mouseup(function(e) {
isDragging = false;
});
$(".magnify").parent().mousedown(function(e) {
isDragging = true;
});
To make a simulated drag event with jQuery.
Here is the fiddle. Hope it helped :)
I'm attempting to output on a page multiple 'labels' over an image using absolute positioned divs. Each of these divs has a unique number and are placed according to an x and y position on the map (these are percentage based so the image may be scaled).
As some of these labels may overlap, I need a way to either stop them from overlapping, or to essentially 'bump' them off eachother so they no longer overlap. (At this point, it doesn't matter if they are not in their correct position as long as they are near enough as there is a separate 'Pin' view).
They need to stay within the confines of their container and not overlap with eachother.
HTML:
<div id="labelzone">
<div class="label" style="left:0%;top:8%">001</div>
<div class="label" style="left:0%;top:11%">002</div>
<div class="label" style="left:1%;top:10%">003</div>
</div>
CSS:
#labelzone{
float:left;
width:500px;
height:500px;
border: 1px solid black;
position: relative;
}
.label{
position:absolute;
border:1px solid black;
background-color:white;
}
Jsfiddle: https://jsfiddle.net/79cco1oy/
There's a simple example of what I have as an output, these pins could be placed anywhere and there is no limit to how many is on the page, however there shouldn't be any occasion where there are too many to fit in the area.
I'm toying around with doing some form of collision detection and currently attempting to figure out an algorithm of some sort to get them to no longer overlap, and ensure they also don't overlap another item.
My solution is a bit more object oriented.
One object (LabelPool) will contain labels and will be in charge of storing and accomodating them so that they don't collide. You can customize the x/y values that you want to add/substract of the Label's positions in order to avoid their collision. The other object (Label) defines a Label and has some convenient methods. The collision algorithm that I used in LabelPool was taken from this post
var Label = function ($el) {
var position = $el.position(),
width = $el.outerWidth(true),
height = $el.outerHeight(true);
this.getRect = function () {
return {
x: position.left,
y: position.top,
width: width,
height: height
};
};
this.modifyPos = function (modX, modY) {
position.top += modY;
position.left += modX;
updatePos();
};
function updatePos() {
$el.css({
top: position.top,
left: position.left
});
}
};
var LabelPool = function () {
var labelPool = [];
function collides(a, b) {
return !(((a.y + a.height) < (b.y)) || (a.y > (b.y + b.height)) || ((a.x + a.width) < b.x) || (a.x > (b.x + b.width)));
}
function overlaps(label) {
var a = label.getRect();
return labelPool.some(function (other) {
return collides(a, other.getRect());
});
}
this.accomodate = function (label) {
while (labelPool.length && overlaps(label)) {
label.modifyPos(0, 1);// You can modify these values as you please.
}
labelPool.push(label);
};
};
var labelPool = new LabelPool;
$(".label").each(function (_, el) {
labelPool.accomodate(new Label($(el)));
});
Here's the fiddle.
Hope it helps.
Using js and jquery, you can find a basic collision engine based on left/top abs position and size of the label.
https://jsfiddle.net/Marcassin/79cco1oy/6/
Every time you want to add a Label, you check if the positionning is overlaping any existing div, in this case, you translate the new Label to position. This operation may not be the most beautiful you can find, there can be a long process time in case of lots of labels.
$(document).ready (function () {
addLabel (0, 8);
addLabel (0, 11);
addLabel (1, 10);
addLabel (2, 7);
});
function addLabel (newLeft, newTop)
{
var newLab = document.createElement ("div");
newLab.className = "label";
$(newLab).css({"left": newLeft+"%", "top": newTop + "%"});
var labels = $("#labelzone > div");
newLab.innerHTML = "00" + (labels.length + 1); // manage 0s
$("#labelzone").append (newLab);
var isCollision = false;
var cpt = 1;
do
{
isCollision = false;
$(labels).each (function () {
if (! isCollision && collision (this, newLab))
isCollision = true;
});
if (isCollision)
$(newLab).css({"left": (newLeft + cpt++) + "%",
"top": (newTop + cpt++) + "%"});
} while (isCollision);
}
function isInside (pt, div)
{
var x = parseInt($(div).css("left"));
var y = parseInt($(div).css("top"));
var w = $(div).width () + borderWidth;
var h = $(div).height ();
if (pt[0] >= x && pt[0] <= x + w &&
pt[1] >= y && pt[1] <= y + h)
return true;
return false;
}
function collision (div1, div2)
{
var x = parseInt($(div1).css("left"));
var y = parseInt($(div1).css("top"));
var w = $(div1).width () + borderWidth;
var h = $(div1).height ();
var pos = [x, y];
if (isInside (pos, div2))
return true;
pos = [x + w, y];
if (isInside (pos, div2))
return true;
pos = [x + w, y + h];
if (isInside (pos, div2))
return true;
pos = [x, y + h];
if (isInside (pos, div2))
return true;
return false;
}
Here's another implementation of collision detection close to what you asked for. The two main goals being:
move vertically more than horizontally (because boxes are wider than tall)
stay within a reasonable range from the origin
Here goes:
function yCollision($elem) {
var $result = null;
$('.label').each(function() {
var $candidate = $(this);
if (!$candidate.is($elem) &&
$candidate.position().top <= $elem.position().top + $elem.outerHeight() &&
$candidate.position().top + $candidate.outerHeight() >= $elem.position().top) {
$result = $candidate;
console.log("BUMP Y");
}
});
return $result;
}
function xCollision($elem) {
var $result = null;
$('.label').each(function() {
$candidate = $(this);
if (!$candidate.is($elem) &&
yCollision($elem) &&
yCollision($elem).is($candidate) &&
$candidate.position().left <= $elem.position().left + $elem.outerWidth() &&
$candidate.position().left + $candidate.outerWidth() >= $elem.position().left) {
$result = $candidate;
console.log("BUMP X");
}
});
return $result;
}
function fuzzyMoveY($elem, direction) {
var newTop = $elem.position().top + $elem.outerHeight() / 4 * direction;
// stay in the canvas - top border
newTop = (newTop < 0 ? 0 : newTop);
// stay in the canvas - bottom border
newTop = (newTop + $elem.outerHeight() > $("#labelzone").outerHeight() ? $("#labelzone").outerHeight() - $elem.outerHeight() : newTop);
// stay close to our origin
newTop = (Math.abs(newTop - $elem.attr("data-origin-top")) > $elem.outerHeight() ? $elem.attr("data-origin-top") : newTop);
$elem.css({'top': newTop});
}
function fuzzyMoveX($elem, direction) {
var newLeft = $elem.position().left + $elem.outerWidth() / 4 * direction;
// stay in the canvas - left border
newLeft = (newLeft < 0 ? 0 : newLeft);
// stay in the canvas - right border
newLeft = (newLeft + $elem.outerWidth() > $("#labelzone").outerWidth() ? $("#labelzone").outerWidth() - $elem.outerWidth() : newLeft);
// stay close to our origin
newLeft = (Math.abs(newLeft - $elem.attr("data-origin-left")) > $elem.outerWidth() ? $elem.attr("data-origin-left") : newLeft);
$elem.css({'left': newLeft});
}
function bumpY($above, $below) {
if ($above.position().top > $below.position().top) {
$buff = $above;
$above = $below;
$below = $buff;
}
fuzzyMoveY($above, -1);
fuzzyMoveY($below, 1);
}
function bumpX($left, $right) {
if ($left.position().left > $right.position().left) {
$buff = $right;
$right = $left;
$left = $buff;
}
fuzzyMoveX($left, 1);
fuzzyMoveX($right, -1);
}
$('.label').each(function() {
$(this).attr('data-origin-left', $(this).position().left);
$(this).attr('data-origin-top', $(this).position().top);
});
var yShallPass = true;
var loopCount = 0;
while (yShallPass && loopCount < 10) {
yShallPass = false;
$('.label').each(function() {
var $this = $(this);
$collider = yCollision($this);
if ($collider) {
bumpY($this, $collider);
yShallPass = true;
}
});
loopCount++;
}
console.log("y loops", loopCount);
var xShallPass = true;
var loopCount = 0;
while (xShallPass && loopCount < 10) {
xShallPass = false;
$('.label').each(function() {
var $this = $(this);
$collider = xCollision($this);
if ($collider) {
bumpX($this, $collider);
xShallPass = true;
}
});
loopCount++;
}
console.log("x loops", loopCount);
This is not production code obviously but please report back if it helps.
I am doing a small javascript animation. this is my code :
window.onload = function () {
var heading = document.getElementsByTagName('h1')[0];
heading.onclick = function () {
var divHeight = 250;
var speed = 10;
var myInterval = 0;
alert(divHeight);
slide();
function slide() {
if (divHeight == 250) {
myInterval = setInterval(slideUp, 30);
} else {
myInterval = setInterval(slideDwn, 30);
alert('i am called as slide down')
}
}
function slideUp() {
var anima = document.getElementById('anima');
if (divHeight <= 0) {
divHeight = 0;
anima.style.height = '0px';
clearInterval(myInterval);
} else {
divHeight -= speed;
if (divHeight < 0) divHeight = 0;
anima.style.height = divHeight + 'px';
}
}
function slideDwn() {
var anima = document.getElementById('anima');
if (divHeight >= 250) {
divHeight = 250;
clearInterval(myInterval);
} else {
divHeight += speed;
anima.style.height = divHeight + 'px';
}
}
}
}
i am using above code for simple animation. i need to get the result 250 on the first click, as well second click i has to get 0 value. but it showing the 250 with unchanged. but i am assigning the value to set '0', once the div height reached to '0'.
what is the issue with my code? any one help me?
Everytime you click on the div the divHeight variable is reset to 250, thus your code never calls slideDwn. Moving the divHeight declaration outside the event handler should do the trick.
Also, your div wont have the correct size when any of the 2 animations end. You're setting the divHeight variable to 250 or 0 correctly, but never actually setting anima.style.height after that.
I've rewritten your code into something simpler and lighter. The main difference here is that we're using a single slide() function here, and that the height of the div in question is stored in a variable beforehand to ensure that the element slides into the correct position.
Note that this is a very simplistic implementation and assumes that the div carries no padding. (The code uses ele.clientHeight and ele.style.height interchangeably, which admittedly, is a pretty bad choice, but is done here to keep the code simple)
var heading = document.getElementsByTagName('h1')[0],
anima = document.getElementById('anima'),
divHeight = anima.clientHeight,
speed = 10,
myInterval = 0,
animating = false;
function slide(speed, goal) {
if(Math.abs(anima.clientHeight - goal) <= speed){
anima.style.height = goal + 'px';
animating = false;
clearInterval(myInterval);
} else if(anima.clientHeight - goal > 0){
anima.style.height = (anima.clientHeight - speed) + 'px';
} else {
anima.style.height = (anima.clientHeight + speed) + 'px';
}
}
heading.onclick = function() {
if(!animating) {
animating = true;
var goal = (anima.clientHeight >= divHeight) ? 0 : divHeight;
myInterval = setInterval(slide, 13, speed, goal);
}
}
See http://www.jsfiddle.net/yijiang/dWJgG/2/ for a simple demo.
I've corrected your code a bit (See working demo)
window.onload = function () {
var heading = document.getElementsByTagName('h1')[0];
var anima = document.getElementById('anima');
var divHeight = 250;
heading.onclick = function () {
var speed = 10;
var myInterval = 0;
function slideUp() {
divHeight -= speed;
if (divHeight <= 0) {
divHeight = 0;
clearInterval(myInterval);
}
anima.style.height = divHeight + 'px';
}
function slideDwn() {
divHeight += speed;
if (divHeight >= 250) {
divHeight = 250;
clearInterval(myInterval);
}
anima.style.height = divHeight + 'px';
}
function slide() {
console.log(divHeight )
if (divHeight == 250) {
myInterval = setInterval(slideUp, 30);
} else {
myInterval = setInterval(slideDwn, 30);
}
}
slide();
}
}