Get position of dragable object, relative to a div - javascript

Here is the jsFiddle, where I have a football field, where the user shall partition 10 players, in two five-membered teams. I want to know whether he dragged a player on the left or night side (assuming the center line of the field is border).
Here the js code:
$(".dragNdrop").draggable({
drag: function(){
var offset = $(this).offset();
var xPos = offset.left;
var yPos = offset.top;
console.log('x: ' + xPos);
console.log($('#footballField').width());
}
});
I've also tried with position() and offset(), but I can't seem to find the right formula to do it.
So, how will I find whether the players is positioned in the left or the right side of the div?
Related question: How to get the position of a draggable object

If $('#footballField').width() is the width of the field, you can check if the xPos of the dragNdrop element is less or higher than the footballField left + his width divided by 2:
$(".dragNdrop").draggable({
drag: function(){
var offset = $(this).offset();
var xPos = offset.left;
var yPos = offset.top;
console.log('x: ' + xPos);
//console.log('y: ' + yPos);
console.log('offset: ' + $('#footballField').offset().left);
var fieldLeft = $('#footballField').offset().left;
console.log($('#footballField').width());
if(xPos < fieldLeft + $('#footballField').width()/2){
console.log('I am at left');
}else{
console.log('I am at right');
}
}
});

Related

How to position the center of a div to the center of the mouse cursor on mouse movement with JS?

I'm trying to position the center of a div element to the center of the mouse cursor, that will follow along its movements.
Already I came up with the code below, but the problem with this one is, that the following div is not positioned at the center of my cursor, but with some offset off the cursor.
WORKFLOW
The basic idea behind my code is, when the mouse enters the .post-entry div element, the .pointer within the current item should be displayed and follow the cursor of the mouse. When the mouse leaves the div it should be hidden.
CODE
HTML post item:
<article class="col-md-4 col-sm-6 post-entry">
<a href="#" title="">
<figure class="post-thumb">
<img src="http://placehold.it/300x300" alt="">
<div class="pointer" style="background: red;"></div>
</figure><!-- End figure.post-thumb -->
</a>
</article><!-- End article.col-md-4 post-entry -->
JS:
$('.entry .post-entry').each(function() {
$(this).on("mouseenter", mouseEnter);
$(this).on("mousemove", mouseMove);
$(this).on("mouseleave", mouseLeave);
});
function mouseEnter(event) {
console.log('enter');
var target = $(this);
var dot = target.find('.pointer');
var mX = (event.clientX);
var mY = (event.clientY);
set(
dot, {
x: mX,
y: mY,
force3D: !0
}
);
};
function mouseMove(event) {
console.log('move');
var target = $(this);
var dot = target.find('.pointer');
// var offset = target.offset();
// var width = target.width();
// var height = target.height();
// var top = offset.top;
// var left = offset.left;
var mX = (event.clientX);
var mY = (event.clientY);
$(dot).css('-webkit-transform', 'translate3d(' + mX + 'px, ' + mY + 'px, 0)');
};
function mouseLeave(event) {
console.log('leave');
var target = $(this);
var dot = target.find('.pointer');
$(dot).css('-webkit-transform', 'translate3d(0, 0, 0) scale(0, 0)');
};
function onClick(event) {
event.preventDefault();
console.log('click');
};
function set(el, obj) {
var dot = $(el).css('-webkit-transform', 'translate3d(' + obj.x + 'px, ' + obj.y + 'px, 0px)');
return dot;
};
PROBLEM / DEMO
As mentioned before, the span is following the mouse cursor, only the span is not positioned to the center of the cursor. It will be offset the mouse. See live demo here
I tried already something like this for the mX and mY variables, but with no succes:
var mX = (event.clientX - $(this).offset().left) / $(this).width() * $(this).width() - .125 * $(this).width();
var mY = (event.clientY - $(this).offsetTop) / $(this).height() * $(this).height() - .125 * $(this).width();
Also the answer from #hiEven doesn't work and will let me with the same issue:
transform: calc(mX - 50%, mY - 50%)
I know I should do something with dividing the .pointer by half, but how I should implement that in the code is a big question mark for me.
UPDATE
I created two new Codepen projects:
Use without images: http://codepen.io/anon/pen/GqGOLv. When you hover over the first item you will see that the brown pointer is correctly following your mouse cursor - what I am looking for. But when hovering over the second one, you will see the red pointer, only when you are at the very left side of the item.
When I use images: http://codepen.io/anon/pen/QExOkx. The problem by this example is that when you at the very top of the first column, you will see the brown pointer. When hover at the top left corner of the second item you will see a little piece of the red pointer, the same as the example without images.
Both pointer should follow the mouse cursor correctly. And I am searching for a solution that works with the use of an image.
Beside these two examples, when I add to the first one, an extra margin-left to the first item, the brown pointer will not be in the center of the mouse cursor, only when it's set to margin-left zero.
So I don't know what's missing and why it only works with the first example (without images) and only for the first item?
Try the code below
<html>
<head>
<style>
#mouse_div{
position: absolute;
background-color: black;
}
</style>
<script>
var div_width = 100;
var div_height = 100;
var div_x, div_y;
function mouse_position(event){
var mouse_x = event.clientX;
var mouse_y = event.clientY;
document.getElementById("mouse_div").style.width = div_width + "px";
document.getElementById("mouse_div").style.height = div_height + "px";
div_x = mouse_x - (div_width / 2);
div_y = mouse_y - (div_height / 2);
document.getElementById("mouse_div").style.left = div_x + "px";
document.getElementById("mouse_div").style.top = div_y + "px";
}
</script>
</head>
<body onmousemove="mouse_position(event)" onload="mouse_position(event)">
<div id="mouse_div"></div>
</body>
</html>
This program gets the position of your mouse, the width, and the height of the div. Then, it takes the x and subtracts the div's width divided by two from it (this centres the div's x position on your mouse). The program then does the same thing for the mouse y. Once all of the variables are defined, I use JavaScript to access the CSS of the div to place the div where it needs to be.
Note: you must make sure that the position of the div is set to absolute or the program will not work.
I assume you want the circle being center of your mouse, right?
try do this
transform: `translate(calc(${mx}px - 50%), calc(${my}px - 50%))
here is the demo
Based on my latest update, I did not conform to the correct formula that is needed to center the element .pointer to the mouse.
In order to use the following calculation within mouseMove:
var mX = (event.clientX);
var mY = (event.clientY);
Should be changed to this:
var height = dot.height();
var width = dot.width();
var offset = target.offset();
var w = target.width();
var h = target.height();
var top = offset.top;
var left = offset.left;
var mX = (event.clientX - left) - width / 2 - 15; // 15 = padding
var mY = (event.clientY - top) - height / 2;
So this formule is considering that the following DOM element .pointer will follow the mouse movements of the user. I don't know exactly why this working, but the offset from the previous item will be decreased from the current clientX coordinates, so the position of the second item is reset to zero, so the pointer will start at the left side of each item.
Here is a working demo of above code: http://codepen.io/anon/pen/AXdxZO?editors=0110

moving a div according to mouse position

I am trying to create and effect where you have a vertical list, and when you hover it with your mouse, a separate "cursor" div should travel up and down vertically along this list, horizontally aligned with your pointer.
I am using this code:
$(document).mousemove( function(e) {
mouseY = e.pageY;
mouseX = e.pageX;
translateY = 'translateY(' + mouseY + 'px)';
translateX = 'translateX(' + mouseX + 'px)';
});
Then with jQuery:
$(".sidebarnav").mouseover(function(){
$('.sidebarnav .cursor').css({'transform': translateY});
});
All this kind of work, but the cursor div does not perfectly align with my mouse pointer. It does if you move real slow and with precision, but it doesn't if you move a bit faster. Is there any technical reason to this lack of precision, or is my code just wrong?
Here is a jsfiddle
http://jsfiddle.net/txks3wtj/
A fiddle would definitely help. But if I understand your code correctly I believe you can't just update the .cursor's position on mouseover of the .sidebarnav - instead you need to update its position on mousemove ie all the time.
Since you don't want the cursor to move when not hovering the sidebar you'd need to keep track of whether or not it is hovered. Something like:
var isOver = false;
$('.sidebarnav').mouseover(function () {
isOver = true;
}).mouseout(function () {
isOver = false;
});
$(document).mousemove( function(e) {
mouseY = e.pageY;
mouseX = e.pageX;
translateY = 'translateY(' + mouseY + 'px)';
translateX = 'translateX(' + mouseX + 'px)';
if (isOver) {
$('.sidebarnav .cursor').css({'transform': translateY});
}
});
Untested.
Edit: It would increase performance if you cached your queries as well;
var sidebar = $('.sidebarnav');
var cursor = sidebar.find('.cursor');
Edit2: You may have better results with mouseenter and mouseleave too I think. I think over/out triggers as soon as you hover a child of the element as well.

Subtract Display Pixels from Mouse Position

Full code can be viewed on JSBin - http://jsbin.com/inibAya/1/edit
So I'm working on a wysiwyg website designer and I added a crosshair to show the corrinates the mouse position is within the canvas. (NOTE: a div acts as the canvas not a html5 canvas element)
The div#canvas is positioned at...
#canvas {
position: absolute;
top:0; left:44px; right:291px; bottom:16px;
overflow: auto;
}
Whatever calculation I tried to remove the 44px from the canvas's display I got NaN or undefined. When the user moves their mouse I want it to start at 0 from the top left and move onwards. Does anyone know of anyway to get this to work?
Here's my JQuery/JavaScript:
// Crosshair
var cH = $('#crosshair-h'), cV = $('#crosshair-v');
$('#canvas').mousemove(function(e) {
cH.css('top', e.pageY);
cV.css('left', e.pageX);
$('#mousepos').text( "X: " + e.pageX + "px, Y: " + e.pageY + "px");
});
From e.pageX's documentation:
Description: The mouse position relative to the left edge of the document.
You will need to account for your canvas's offset (of 44px) to solve your problem.
var canvasPosition = $(canvas).position();
$(canvas).on('mousemove', function(e) {
var x = e.pageX - canvasPosition.left;
var y = e.pageY - canvasPosition.top;
cH.css('top', e.pageY);
cV.css('left', e.pageX);
$('#mousepos').text( "X: " + x + "px, Y: " + y + "px");
});
JSBin.

JavaScript coordinates showing as greater than the image width and height

I am trying to get the location of the mouse while hovering over an image in pixels from the top left corner of the image. I am currently using the pageX and pageY event attributes but this is returning a value greater than the width and height of the image itself.
var getImgCoord = function(e) {
var x = e.pageX,
y = e.pageY;
console.log(x + ' | ' + y);
}
$('.featuredImg').mousemove(function() {
getImgCoord(event);
});
Any help would be greatly appreciated.
pageX and pageY are the coordinates relative to the top left corner of the document not your image itself (the name already says it).
you need to subtract the offsets from your element:
$('.featuredImg').mousemove(function(e) {
var x = e.pageX - $(this).offset().left,
y = e.pageY - $(this).offset().top;
console.log(x + ' | ' + y);
});
http://jsfiddle.net/D5uuA/
var getImgCoord = function(e) {
var imageOffset = $(this).offset();
//or $(this).offset(); if you really just want the current element's offset
var x = e.pageX - imageOffset.left,
y = e.pageY - imageOffset.top;
console.log(x + ' | ' + y);
}
$('.featuredImg').mousemove(getImgCoord);

How to calculate mouse coordinates related to DIV position

I have a DIV and I can get the offset using .offset().
But I am trying to get the position of the mouse related to the div. When I hover the DIV i can get the x and y offsets of Mouse. But those will be calculated related to Document. But it should be calculated in below way.
For example DIV dimensions are 200 and 200.
then it should calculate offsets related to (0,200)(200,0),(200,200),(200,200).
Please help me on this. How I can do this.
Do you mean:
$('#someele').click(function(e) {
var offset = $(this).offset();
var x = Math.floor(e.pageX - offset.left);
var y = Math.floor(e.pageY - offset.top);
console.log('x pos:' + x + ' y pos:' + y);
});

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