Develop Reference

element flickering when it gets dragged

Hello guys i have following problem:
Whenever i drag an element it flickers and it looks very annoying. I couldnt find the root of the problem.
Here is my code snippet:
moveElement(element, e) {
let clientX = e.clientX;
let clientY = e.clientY;
let offsetX = e.offsetX;
let offsetY = e.offsetY;
let height = element.getBoundingClientRect().height;
let width = element.getBoundingClientRect().width;
window.requestAnimationFrame(function() {
element.style.setProperty("left", clientX - (width - offsetX) + "px");
element.style.setProperty("top", clientY - (height - offsetY) + "px");
});
}
Here is he full code:
class Dragger{
constructor() {
this.drags = [];
this.drops = [];
this.mover = null;
this.collectDragAndDrop();
}
dragItem(element) {
element.style.setProperty("position", "fixed");
this.mover = this.moveElement.bind(null, element);
element.addEventListener("mousemove", this.mover);
}
moveElement(element, e) {
let clientX = e.clientX;
let clientY = e.clientY;
let offsetX = e.offsetX;
let offsetY = e.offsetY;
let height = element.getBoundingClientRect().height;
let width = element.getBoundingClientRect().width;
window.requestAnimationFrame(function() {
element.style.setProperty("left", clientX - (width - offsetX) + "px");
element.style.setProperty("top", clientY - (height - offsetY) + "px");
});
}
dropItem(element) {
element.removeEventListener("mousemove", this.mover);
}
collectDragAndDrop() {
document.querySelectorAll("[drag]").forEach(element => {
let name = element.attributes.drag.nodeValue;
let findDup = this.drags.some(el => el.name === name);
if (findDup) throw Error("Duplicated drag attribute: " + name);
this.drags.push({
element,
name
});
element.addEventListener("mousedown", this.dragItem.bind(this, element));
element.addEventListener("mouseup", this.dropItem.bind(this, element));
});
}
}
new Dragger();
.box1 {
background: black;
width: 100px;
height: 100px;
color: white;
}
.box2 {
background: red;
width: 100px;
height: 100px;
position: fixed;
right: 100px;
}
<div class="box1" drag="test"></div>
<div class="box2" drag="test2"></div>
Can somebody tell me why this flickers so much?

Your math is wonky. You're only accounting for the current mouse position instead of calculating the amount of movement that has occurred. The only reason your boxes are moving at all is because the function is waiting for the animation frame so there is some change in those coordinates while it waits.
You should also consider that if the mouseup occurs while the mouse is no longer over the element, the element won't get the event and thus will continue dragging when you mouse back over it. It's better to set a flag that keeps track of the mouse state.
var isMouseDown = false;
addEventListener("mousedown", ()=>isMouseDown = true);
addEventListener("mouseup", ()=>isMouseDown = false);
document.querySelectorAll("[drag]").forEach(element=>{
element.addEventListener("mousemove", e=>{
if(!isMouseDown) return;
requestAnimationFrame(function() {
var rect = element.getBoundingClientRect();
element.style.left = rect.x + e.movementX + "px";
element.style.top = rect.y + e.movementY + "px";
});
});
});
.box1 {
background: black;
width: 100px;
height: 100px;
color: white;
position: absolute
}
.box2 {
background: red;
width: 100px;
height: 100px;
position: fixed;
right: 100px;
}
<div class="box1" drag="test"></div>
<div class="box2" drag="test2"></div>

get jquery touch position every x milliseconds

is there a way to get the touch position in a touchmove event every x milliseconds and then execute a function, when the x-coordinate at the moment and the one at the start are differing e.g. 50px?
Thanks

Try the below ;
$('document').ready(function() {
var touch,
action,
diffX,
diffY,
endX,
endY,
startX,
startY,
timer,
timerXseconds = 500, // Change to the Time(milliseconds) to check for touch position
xDifferenceX = 50, // Change to difference (px) for x-coordinates from starting point to run your function
xDifferenceY = 50; // Change to difference (px) for y-coordinates from starting point
function getCoord(e, c) {
return /touch/.test(e.type) ? (e.originalEvent || e).changedTouches[0]['page' + c] : e['page' + c];
}
function testTouch(e) {
if (e.type == 'touchstart') {
touch = true;
} else if (touch) {
touch = false;
return false;
}
return true;
}
function onStart(ev) {
if (testTouch(ev) && !action) {
action = true;
startX = getCoord(ev, 'X');
startY = getCoord(ev, 'Y');
diffX = 0;
diffY = 0;
timer = window.setInterval(checkPosition(ev), timerXseconds); // get coordinaties ever X time
if (ev.type == 'mousedown') {
$(document).on('mousemove', onMove).on('mouseup', onEnd);
}
}
}
function onMove(ev) {
if (action) {
checkPosition(ev)
}
}
function checkPosition(ev) {
endX = getCoord(ev, 'X');
endY = getCoord(ev, 'Y');
diffX = endX - startX;
diffY = endY - startY;
// Check if coordinates on Move are Different than Starting point by X pixels
if (Math.abs(diffX) > xDifferenceX || Math.abs(diffY) > xDifferenceY) {
// console.log('Start is :' + startX + ' End is : ' + endX + 'Difference is : ' + diffX);
$(this).trigger('touchend');
// here Add your function to run...
}
}
function onEnd(ev) {
window.clearInterval(timer);
if (action) {
action = false;
if (ev.type == 'mouseup') {
$(document).off('mousemove', onMove).off('mouseup', onEnd);
}
}
}
$('#monitor')
.bind('touchstart mousedown', onStart)
.bind('touchmove', onMove)
.bind('touchend touchcancel', onEnd);
});
body {
margin: 0;
padding: 0;
}
#monitor {
height: 500px;
width: 500px;
position: relative;
display: block;
left: 50px;
top: 50px;
background: green;
}
.box {
position: absolute;
top: 0;
left: 0;
right: 0;
text-align: center;
font-weight: bold;
bottom: 0;
background: white;
width: 50px;
height: 50px;
margin: auto;
font-size: 16px;
line-height: 23px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id='monitor'>
<div class='box'>start here</div>
</div>
Read this post for a more detailed answer

This can be done in a few functions.
The first function is called when there is a movement of the touch event, this event stores the x and y of the touch in a separate variable.
Then we have a function that runs every X miliseconds, this function gets the x and y from the move event and dispatches then to your code.
Functions 3, 4 and 5 are used to handle the start, stop and cancel dragevents, and start/stop the second function:
var timerid;
var x;
var y;
var tick = 0;
function handleStart(evt) {
console.log("handleStart");
evt.preventDefault();
timerid = window.setInterval(timer, 50); // Replace 50 here with X
}
function handleEnd(evt) {
console.log("handleEnd");
evt.preventDefault();
window.clearInterval(timerid);
}
function handleCancel(evt) {
console.log("handleCancel");
evt.preventDefault();
window.clearInterval(timerid);
}
function handleMove(evt) {
console.log("handleMove");
evt.preventDefault();
// Select last point:
var point = evt.changedTouches[evt.changedTouches.length - 1];
x = point.pageX;
y = point.pageY;
}
function timer() {
console.log("timer");
tick++;
document.getElementById("output").innerHTML = "tick: " + tick + " x: " + x + " y:" + y;
}
var el = document.getElementById("canvas");
el.addEventListener("touchstart", handleStart, false);
el.addEventListener("touchend", handleEnd, false);
el.addEventListener("touchcancel", handleCancel, false);
el.addEventListener("touchmove", handleMove, false);
<canvas id="canvas" width="300" height="300" style="border:solid black 1px;"></canvas>
<p id=output></p>
As long as the user is pressing the screen, the code will print out the x and the y coordinate to the screen. You can also integrate the reading of the x and y into your existing game loop instead of having a separate function if that is needed for your project.

Take a look at hammer.js, it has exactly what you need. It supports "touchmove" called pan, that is being called every few milliseconds when you pan. Also there is a threshold property which determine a length in pixels you have to pan before recognizing it as a pan.

Resizing div top left corner using jquery

I have a div which I want to resize from all sides and corners, i.e. nw, n, ne, e, w, sw, s, se. I have tried jquery ui's resizable plugin but in my code that is not working. I have removed complexity from my code and placed it in a very basic fiddle.
I have tried to resize only north-west corner of a div and put that logic in fiddle. Logic seems correct to me but mouse interaction is working in a weird way.
Can you guys tell me what am I doing wrong here? If I get it correct for top left corner I can manage for the remaining ones. Thanks.
HTML:
<div id="box">
<div id="nw"></div>
<div id="n"></div>
<div id="ne"></div>
<div id="w"></div>
<div id="e"></div>
<div id="sw"></div>
<div id="s"></div>
<div id="se"></div>
</div>
<p class="one"></p>
<p class="two"></p>
CSS:
#box{border:1px solid #000;width:100px;height:100px;background-color:red;position:absolute;top:100px;left:100px}
#box > div{height:10px;width:10px;background-color:#000;position:absolute}
#nw{top:-5px;left:-5px;cursor:nw-resize}
#n{top:-5px;left:45px;cursor:n-resize}
#ne{top:-5px;right:-5px;cursor:ne-resize}
#w{top:45px;left:-5px;cursor:w-resize}
#e{top:45px;right:-5px;cursor:e-resize}
#sw{bottom:-5px;left:-5px;cursor:sw-resize}
#s{bottom:-5px;left:45px;cursor:s-resize}
#se{bottom:-5px;right:-5px;cursor:se-resize}
p{margin-top:250px;font-size:8px}
JS:
$(function(){
var mousepress = false;
$("#box > div").mousedown(function(e){
mousepress = true;
});
$("#box > div").mousemove(function(e){
if(mousepress) {
var boxX = $("#box").position().left;
var boxY = $("#box").position().top;
var boxW = $("#box").width();
var boxH = $("#box").height();
var x = boxX - e.pageX;//$(this).position().left;
var y = boxY - e.pageY;//$(this).position().top;
$("p.two").append("x: "+x+"<br />");
$(this).css({
"top":y+"px",
"left":x+"px"
});
$("#box").css({
"top":(boxY+y-5)+"px",
"left":(boxX+x-5)+"px",
"width":(boxW+x)+"px",
"height":(boxH+y)+"px",
});
}
});
$("#box > div").mouseup(function(){
mousepress = false;
});
});
**JSFIDDLE: **http://jsfiddle.net/ashwyn/v8qoLj76/2/

I didn't quite understand how you calculated the size and position of the box, without knowing which of the inside divs the user pressed.
I have changed it to use the mouse event position.
I also moved the mousemove and mouseup events to the document, because when dragging using the mouse, it may move faster then the DOM and got out of the box.
I also changed positions of inside divs to use 50% so it will always be in the middle. You may need to add a bit of margin to have it better centered. (See north vs south - I added margin-left to one of them)
This works fine for me.
http://jsfiddle.net/v8qoLj76/4/
var prev_x = -1;
var prev_y = -1;
var dir = null;
$("#box > div").mousedown(function(e){
prev_x = e.clientX;
prev_y = e.clientY;
dir = $(this).attr('id');
});
$(document).mousemove(function(e){
if (prev_x == -1)
return;
var boxX = $("#box").position().left;
var boxY = $("#box").position().top;
var boxW = $("#box").width();
var boxH = $("#box").height();
var dx = e.clientX - prev_x;
var dy = e.clientY - prev_y;
//Check directions
if (dir.indexOf('n') > -1) //north
{
boxY += dy;
boxH -= dy;
}
if (dir.indexOf('s') > -1) //south
{
boxH += dy;
}
if (dir.indexOf('w') > -1) //west
{
boxX += dx;
boxW -= dx;
}
if (dir.indexOf('e') > -1) //east
{
boxW += dx;
}
$("#box").css({
"top":(boxY)+"px",
"left":(boxX)+"px",
"width":(boxW)+"px",
"height":(boxH)+"px",
});
prev_x = e.clientX;
prev_y = e.clientY;
});
$(document).mouseup(function(){
prev_x = -1;
prev_y = -1;
});

Is it something that you need (see the snippet below)?
$(function() {
var ORIGINAL_TOP = 100, ORIGINAL_LEFT = 100, ORIGINAL_WIDTH = 100, ORIGINAL_HEIGHT = 100, OFFSET = 5;
$('.top').css({top: (ORIGINAL_TOP - OFFSET) + 'px'});
$('.left').css({left: (ORIGINAL_LEFT - OFFSET) + 'px'});
$('.bottom').css({top: (ORIGINAL_TOP + ORIGINAL_HEIGHT - OFFSET) + 'px'});
$('.right').css({left: (ORIGINAL_LEFT + ORIGINAL_WIDTH - OFFSET) + 'px'});
$('.control-element').css({height: (2 * OFFSET) + 'px', width: (2 * OFFSET) + 'px'});
var moveMiddleControls = function(top, left, width, height) {
['top', 'bottom'].forEach(function(coordinate) {
$('#' + coordinate).css({left: (left + width / 2 - OFFSET) + 'px'});
});
['left', 'right'].forEach(function(coordinate) {
$('#' + coordinate).css({top: (top + height / 2 - OFFSET) + 'px'});
});
};
var resizeBox = function(top, left, width, height) {
$('#box').css({
top: top + 'px',
left: left + 'px',
width: width + 'px',
height: height + 'px'
});
};
var updateStatus = function(top, left, width, height) {
$('#status-top').html(Math.round(top));
$('#status-left').html(Math.round(left));
$('#status-width').html(Math.round(width));
$('#status-height').html(Math.round(height));
};
var updatePosition = function(top, left, width, height) {
resizeBox(top, left, width, height);
moveMiddleControls(top, left, width, height);
updateStatus(top, left, width, height);
};
var update = function() {
updatePosition(
$('#top').position().top + OFFSET,
$('#left').position().left + OFFSET,
$('#right').position().left - $('#left').position().left,
$('#bottom').position().top - $('#top').position().top
);
};
update();
var activeElement;
$('.control-element').mousedown(function(e) {
activeElement = this;
e.preventDefault();
return false;
});
$(document).mousemove(function(e) {
if(activeElement !== undefined) {
['top', 'bottom'].forEach(function(className) {
if($(activeElement).hasClass(className)) {
$('.' + className).css({top: e.pageY + 'px'});
}
});
['left', 'right'].forEach(function(className) {
if($(activeElement).hasClass(className)) {
$('.' + className).css({left: e.pageX + 'px'});
}
});
update();
}
});
$(document).mouseup(function() {
activeElement = undefined;
});
});
#box {
border:1px solid #000;
background-color:red;
position: fixed;
}
.control-element {
background-color: #000;
position: fixed;
}
#top-left {
cursor: nw-resize;
}
#top {
cursor:n-resize;
}
#top-right {
cursor:ne-resize;
}
#left {
cursor:w-resize;
}
#right {
cursor:e-resize;
}
#bottom-left {
cursor:sw-resize;
}
#bottom {
cursor:s-resize;
}
#bottom-right {
cursor: se-resize;
}
.status {
position:fixed;
right: 5px;
bottom: 10px;
width: 80px;
height: 80px;
z-index: 999;
font-size:8px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<div id="box"></div>
<div id="top-left" class="control-element top left"></div>
<div id="top" class="control-element top"></div>
<div id="top-right" class="control-element top right"></div>
<div id="right" class="control-element right"></div>
<div id="bottom-right" class="control-element bottom right"></div>
<div id="bottom" class="control-element bottom"></div>
<div id="bottom-left" class="control-element bottom left"></div>
<div id="left" class="control-element left"></div>
<div class="status">
<div>top: <span id="status-top"></span>px</div>
<div>left: <span id="status-left"></span>px</div>
<div>width: <span id="status-width"></span>px</div>
<div>height: <span id="status-height"></span>px</div>
</div>

zooming a selected part of image with cursor event

I have this jsfiddle : http://jsfiddle.net/seekpunk/JDU9f/1/
what I want is when the user do a selection the selected part is zoomed in .Is there anyway to achieve this ?
this is the code so far :
var canvas = document.getElementById("MyCanvas");
var ctx = canvas.getContext('2d'),
w = canvas.width,
h = canvas.height,
x1,
y1,
isDown = false;
var img = new Image();
img.src = "http://www.stockfreeimages.com/static/homepage/female-chaffinch-free-stock-photo-106202.jpg";
canvas.onmousedown = function (e) {
var rect = canvas.getBoundingClientRect();
x1 = e.clientX - rect.left;
y1 = e.clientY - rect.top;
isDown = true;
}
canvas.onmouseup = function () {
isDown = false;
}
canvas.onmousemove = function (e) {
if (!isDown) return;
var rect = canvas.getBoundingClientRect(),
x2 = e.clientX - rect.left,
y2 = e.clientY - rect.top;
ctx.clearRect(0, 0, w, h);
ctx.drawImage(img, 0, 0, w, h);
ctx.strokeRect(x1, y1, x2 - x1, y2 - y1);
}
img.onload = function () {
ctx.drawImage(img, 0, 0, w, h);
};
I can make the selection but how can i zoom the selected part only ? like this example : http://canvasjs.com/docs/charts/basics-of-creating-html5-chart/zooming-panning/

For those looking for zooming functionality without the use of a canvas, here's a pretty foolproof solution using a simple <img />:
$(window).on("load",function() {
//VARS===================================================
var zoom = {
zoomboxLeft:null, zoomboxTop:null, //zoombox
cursorStartX:null, cursorStartY:null, //cursor
imgStartLeft:null, imgStartTop:null, //image
minDragLeft:null,maxDragLeft:null, minDragTop:null,maxDragTop:null
};
//KEY-HANDLERS===========================================
$(document).keydown(function(e) {
if (e.which==32) {e.preventDefault(); if (!$(".zoombox img").hasClass("moving")) {$(".zoombox img").addClass("drag");}} //SPACE
});
$(document).keyup(function(e) {
if (e.which==32) {if (!$(".zoombox img").hasClass("moving")) {$(".zoombox img").removeClass("drag");}} //SPACE
});
//RESET IMAGE SIZE=======================================
$(".reset").on("click",function() {
var zoombox = "#"+$(this).parent().attr("id")+" .zoombox";
$(zoombox+" img").css({"left":0, "top":0, "width":$(zoombox).width(), "height":$(zoombox).height()});
}).click();
//ZOOM&DRAG-EVENTS=======================================
//MOUSEDOWN----------------------------------------------
$(".zoombox img").mousedown(function(e) {
e.preventDefault();
$(".zoombox img").addClass("moving");
var selector = $(this).next();
var zoombox = $(this).parent();
$(zoombox).addClass("active");
//store zoombox left&top
zoom.zoomboxLeft = $(zoombox).offset().left + parseInt($(zoombox).css("border-left-width").replace(/\D+/,""));
zoom.zoomboxTop = $(zoombox).offset().top + parseInt($(zoombox).css("border-top-width").replace(/\D+/,""));
//store starting positions of cursor (relative to zoombox)
zoom.cursorStartX = e.pageX - zoom.zoomboxLeft;
zoom.cursorStartY = e.pageY - zoom.zoomboxTop;
if ($(".zoombox img").hasClass("drag")) {
//store starting positions of image (relative to zoombox)
zoom.imgStartLeft = $(this).position().left;
zoom.imgStartTop = $(this).position().top;
//set drag boundaries (relative to zoombox)
zoom.minDragLeft = $(zoombox).width() - $(this).width();
zoom.maxDragLeft = 0;
zoom.minDragTop = $(zoombox).height() - $(this).height();
zoom.maxDragTop = 0;
} else {
//set drag boundaries (relative to zoombox)
zoom.minDragLeft = 0;
zoom.maxDragLeft = $(zoombox).width();
zoom.minDragTop = 0;
zoom.maxDragTop = $(zoombox).height();
//activate zoom-selector
$(selector).css({"display":"block", "width":0, "height":0, "left":zoom.cursorStartX, "top":zoom.cursorStartY});
}
});
//MOUSEMOVE----------------------------------------------
$(document).mousemove(function(e) {
if ($(".zoombox img").hasClass("moving")) {
if ($(".zoombox img").hasClass("drag")) {
var img = $(".zoombox.active img")[0];
//update image position (relative to zoombox)
$(img).css({
"left": zoom.imgStartLeft + (e.pageX-zoom.zoomboxLeft)-zoom.cursorStartX,
"top": zoom.imgStartTop + (e.pageY-zoom.zoomboxTop)-zoom.cursorStartY
});
//prevent dragging in prohibited areas (relative to zoombox)
if ($(img).position().left <= zoom.minDragLeft) {$(img).css("left",zoom.minDragLeft);} else
if ($(img).position().left >= zoom.maxDragLeft) {$(img).css("left",zoom.maxDragLeft);}
if ($(img).position().top <= zoom.minDragTop) {$(img).css("top",zoom.minDragTop);} else
if ($(img).position().top >= zoom.maxDragTop) {$(img).css("top",zoom.maxDragTop);}
} else {
//calculate selector width and height (relative to zoombox)
var width = (e.pageX-zoom.zoomboxLeft)-zoom.cursorStartX;
var height = (e.pageY-zoom.zoomboxTop)-zoom.cursorStartY;
//prevent dragging in prohibited areas (relative to zoombox)
if (e.pageX-zoom.zoomboxLeft <= zoom.minDragLeft) {width = zoom.minDragLeft - zoom.cursorStartX;} else
if (e.pageX-zoom.zoomboxLeft >= zoom.maxDragLeft) {width = zoom.maxDragLeft - zoom.cursorStartX;}
if (e.pageY-zoom.zoomboxTop <= zoom.minDragTop) {height = zoom.minDragTop - zoom.cursorStartY;} else
if (e.pageY-zoom.zoomboxTop >= zoom.maxDragTop) {height = zoom.maxDragTop - zoom.cursorStartY;}
//update zoom-selector
var selector = $(".zoombox.active .selector")[0];
$(selector).css({"width":Math.abs(width), "height":Math.abs(height)});
if (width<0) {$(selector).css("left",zoom.cursorStartX-Math.abs(width));}
if (height<0) {$(selector).css("top",zoom.cursorStartY-Math.abs(height));}
}
}
});
//MOUSEUP------------------------------------------------
$(document).mouseup(function() {
if ($(".zoombox img").hasClass("moving")) {
if (!$(".zoombox img").hasClass("drag")) {
var img = $(".zoombox.active img")[0];
var selector = $(".zoombox.active .selector")[0];
if ($(selector).width()>0 && $(selector).height()>0) {
//resize zoom-selector and image
var magnification = ($(selector).width()<$(selector).height() ? $(selector).parent().width()/$(selector).width() : $(selector).parent().height()/$(selector).height()); //go for the highest magnification
var hFactor = $(img).width() / ($(selector).position().left-$(img).position().left);
var vFactor = $(img).height() / ($(selector).position().top-$(img).position().top);
$(selector).css({"width":$(selector).width()*magnification, "height":$(selector).height()*magnification});
$(img).css({"width":$(img).width()*magnification, "height":$(img).height()*magnification});
//correct for misalignment during magnification, caused by size-factor
$(img).css({
"left": $(selector).position().left - ($(img).width()/hFactor),
"top": $(selector).position().top - ($(img).height()/vFactor)
});
//reposition zoom-selector and image (relative to zoombox)
var selectorLeft = ($(selector).parent().width()/2) - ($(selector).width()/2);
var selectorTop = ($(selector).parent().height()/2) - ($(selector).height()/2);
var selectorDeltaLeft = selectorLeft - $(selector).position().left;
var selectorDeltaTop = selectorTop - $(selector).position().top;
$(selector).css({"left":selectorLeft, "top":selectorTop});
$(img).css({"left":"+="+selectorDeltaLeft, "top":"+="+selectorDeltaTop});
}
//deactivate zoom-selector
$(selector).css({"display":"none", "width":0, "height":0, "left":0, "top":0});
} else {$(".zoombox img").removeClass("drag");}
$(".zoombox img").removeClass("moving");
$(".zoombox.active").removeClass("active");
}
});
});
/*CONTAINER-------------------*/
#container {
width: 234px;
height: 199px;
margin-left: auto;
margin-right: auto;
}
/*ZOOMBOX=====================*/
/*IMAGE-----------------------*/
.zoombox {
position:relative;
width: 100%;
height: 100%;
border: 2px solid #AAAAAA;
background-color: #666666;
overflow: hidden;
}
.zoombox img {position:relative;}
.zoombox img.drag {cursor:move;}
.zoombox .selector {
display: none;
position: absolute;
border: 1px solid #999999;
background-color: rgba(255,255,255, 0.3);
}
/*CONTROL---------------------*/
.reset {float:left;}
.info {float:right;}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div id="container">
<!--ZOOMBOX-->
<div class="zoombox">
<img src="http://www.w3schools.com/colors/img_colormap.gif" />
<div class="selector"></div>
</div>
<input type="button" class="reset" value="Reset" /><span class="info">Press SPACE to drag</span>
</div>
jsfiddle: http://jsfiddle.net/2nt8k8e6/
The container element can be anything, just place the .zoombox on your webpage and it should work.
You should even be able to put multiple .zoomboxes next to each other in the same container-element. I haven't tested it though.
It's not too complicated, there's not a whole lot of comments, but the variable names are pretty self-explanatory and make the code easy enough to read, and all the jquery-functions can be looked up.
The code is essentially divided into three handlers: .mousedown(), .mousemove(), .mouseup().
- In mousedown some values are stored into variables (like the start-coordinates for the selector), which are used in mousemove and mouseup as a reference.
If you want to know exactly what's happening, just have a look at the code, as I said it's not too difficult.

Move child element with mousemove

I'd like to know if there's a way to explore the content of a div by moving mouse? like for example having a 1000px*1000px pic inside a 500px*500px div content in overflow:hidden and being able to see the rest of the picture by putting the cursor in the right-bottom side of the div.
And if there's a way how should I proceed ?

Something nice and smooth?
jQuery(function($) {
const $mmGal = $('#mmGal'),
$mmImg = $('#mmImg'),
damp = 10; // 1 = immediate, higher number = smoother response
let X = 0, Y = 0,
mX = 0, mY = 0,
wDiff = 0, hDiff = 0,
zeno, tOut;
// Get image size after it's loaded
$mmImg.one('load', function() {
wDiff = (this.width / $mmGal.width()) - 1;
hDiff = (this.height / $mmGal.height()) - 1;
}).each(function() {
if (this.complete) $(this).trigger("load");
});
$mmGal.on({
mousemove(ev) {
mX = ev.pageX - this.offsetLeft;
mY = ev.pageY - this.offsetTop;
},
mouseenter() {
clearTimeout(tOut);
clearInterval(zeno);
zeno = setInterval(function() { // Zeno's paradox "catching delay"
X += (mX - X) / damp;
Y += (mY - Y) / damp;
// Use CSS transition
$mmImg.css({transform: `translate(${-X * wDiff}px, ${-Y * hDiff}px)`});
// If instead you want to use scroll:
// $mmGal[0].scrollTo(X * wDiff, Y * hDiff);
}, 26);
},
mouseleave() {
// Allow the image to move for some time even after mouseleave
tOut = setTimeout(function() {
clearInterval(zeno);
}, 1200);
}
});
});
#mmGal {
position: relative;
margin: 0 auto;
width: 500px;
height: 220px;
overflow: hidden;
background: #eee;
}
#mmImg {
display: block;
}
<div id="mmGal">
<img id="mmImg" src="https://i.stack.imgur.com/BfcTY.jpg">
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
Here's another similar approach to mousemove element in opposite direction
http://en.wikipedia.org/wiki/Zeno%27s_paradoxes

give widht and height to div wrapped for the image
here is the DEMO
on :hover add overflow: visible; to the div

This is almost what you want. See this fiddle http://jsfiddle.net/sajith/RM9wK/
HTML
<div id="container"><img src="http://farm4.staticflickr.com/3668/12858161173_8daa0b7e54_b.jpg"/></div>
CSS
#container {
width:300px;
height:300px;
overflow: hidden;
}
#container img {
position: relative;
}
Javascript
$(function() {
$( "#container" ).mousemove(function( event ) {
var width = $("#container img").width();
var height = $("#container img").height();
var divWidth = $("#container").width();
var divHeight = $("#container").height();
var xPos = (width / divWidth - 1) * event.pageX
var yPos = (height / divHeight -1) * event.pageY
$("#container img").css('left', '-'+ xPos+'px');
$("#container img").css('top', '-'+ yPos+'px');
});
});

I would use "triggers" (hot spot) ~ add some small div element and set their position as you want, now when mouse enter trigger some events....
Simple Example: jsfiddle
CSS
div.container {
position:relative;
width:100px;
height:100px;
overflow:hidden;
}
.trigger {
right:0;
bottom:0;
position:absolute;
z-index:2;
width:10px;
height:10px;
background-color:transparent;
}
HTML
<div class='container'>
<img src='http://static.adzerk.net/Advertisers/12f0cc69cd9742faa9c8ee0f7b0d210e.jpg' />
<div class='trigger'></div>
</div>
jQuery
$('.trigger').mouseenter(
function(){
$(this).parent('.container').css({
'width':'220px',
'height':'250px'
});
});
$('.container').mouseleave(
function(){
$(this).css({
'width':'100px',
'height':'100px'
});
});