Handling "mousedown" event on different object - javascript

I am trying to change the length of two bars (div) by mouse dragging (extending one example in eloquetjavascript book chapter 14, which involves changing the length of one bar by dragging the mouse.) The intended behavior is clicking on any bar, moving the mouse when holding the left mouse key would change the length of that bar.
Here is my implementation (also available on JSfiddle)
<script>
var lastX; // Tracks the last observed mouse X position
var rect1 = document.getElementById("bar1");
var rect2 = document.getElementById("bar2");
rect1.addEventListener("mousedown", function(){watchmousedown(rect1)});
rect2.addEventListener("mousedown", function(){watchmousedown(rect2)});
function watchmousedown(rec) {
if (event.which == 1) {
lastX = event.pageX;
addEventListener("mousemove",function(){moved(rec)});
event.preventDefault(); // Prevent selection
} else {
removeEventListener("mousedown", watchmousedown)}
}
function moved(rec) {
if (event.which != 1) {
removeEventListener("mousemove", moved);
} else {
var dist = event.pageX - lastX;
var newWidth = Math.max(10, rec.offsetWidth + dist);
rec.style.width = newWidth + "px";
lastX = event.pageX;
}
}
</script>
The problem is I can only change the length of the bar where the first mouse click event happened. I assume I didn't handle the mousedown event correctly (probably need a reset some how).
I am new to javascript, help on programming style is also appreciated.
Thanks!

Add rec. to addEventListener("mousemove", function () { so that the event listener is bound to the rec you clicked on instead of to the window.
function watchmousedown(rec) {
if (event.which == 1) {
lastX = event.pageX;
rec.addEventListener("mousemove", function () {
moved(rec)
});
event.preventDefault(); // Prevent selection
} else {
rec.removeEventListener("mousedown", watchmousedown)
}
}
Edit: I there are some event handlers not being cleaned up properly. I don't know if this would be my final code, but this is closer to how I would do it:
var lastX; // Tracks the last observed mouse X position
var rect1 = document.getElementById("bar1");
var rect2 = document.getElementById("bar2");
var moveRect1 = function () {
console.log(arguments);
moved(rect1)
};
var moveRect2 = function() {
console.log(arguments);
moved(rect2);
}
var watchRect1 = function () {
console.log(arguments);
watchmousedown(moveRect1)
};
var watchRect2 = function () {
console.log(arguments);
watchmousedown(moveRect2)
};
rect1.addEventListener("mousedown", watchRect1);
rect2.addEventListener("mousedown", watchRect2);
window.addEventListener("mouseup", function() {
removeEventListener("mousemove", moveRect1);
removeEventListener("mousemove", moveRect2);
});
function watchmousedown(moverec) {
if (event.which == 1) {
lastX = event.pageX;
addEventListener("mousemove", moverec);
event.preventDefault(); // Prevent selection
}
}
function moved(rec) {
if (event.which == 1) {
var dist = event.pageX - lastX;
var newWidth = Math.max(10, rec.offsetWidth + dist);
rec.style.width = newWidth + "px";
lastX = event.pageX;
}
}
Edit: removed a line that didn't do anything

Related

Context-Menu on right click in the threejs scene?

I have an angular project wherein the three representation is using threeJs. I wish to add a context menu on right-click to the scene. This is what I have so far. I am also receiving an error called 'menu does not exist'.
window.addEventListener('mousedown', (e: MouseEvent) => { this.rightClickContextMenu(e); }, false);
if (document.addEventListener) {
document.addEventListener('contextmenu', function (e) {
e.preventDefault();
}, false);
} else {
(<any>document).attachEvent('oncontextmenu', function () {
window.event.returnValue = false;
});
}
public rightClickContextMenu(e: MouseEvent): void {
var rightclick;
if (!event) var event = window.event;
if ((<any>event).which) rightclick = ((<any>event).which == 3);
else if ((<any>event).button) rightclick = ((<any>event).button == 2);
if (!rightclick) return;
const x = e.clientX - this.rect.left;
const y = e.clientY - this.rect.top;
var intersect;
let scenePointer = new th.Vector2();
scenePointer.x = (x / this.canvas.clientWidth) * 2 - 1;
scenePointer.y = (y / this.canvas.clientHeight) * - 2 + 1;
// Determine the component in-focus using raycasting
this.raycaster.setFromCamera(scenePointer, this.camera);
var intersects = this.raycaster.intersectObjects(this.scene.children);
if (intersects.length) {
intersect = intersects[0].object;
menu.style.left = x + "px";
menu.style.top = y + "px";
menu.style.display = "";
}
else {
intersect = undefined;
}
}
So far, on left-click, the color of the mesh changes but nothing happens on right click. I was wondering how do I add on a context menu to the same on right click. Modifications to my code to highlight the correct one would be much appreciated from you guys. I apologise, I am very new to threejs in case this question sounds trivial.
Stop event propagation on the control where u want this feature and then capture the event and diplay

I am trying to make a drawImage change when mouseover and mouseout

I'm attempting to make it, so that when the mouse is within the boundaries set by var play, it changes image. I used the same method I've used for changing images on click, but mouseover and mouseout don't want to work here.
var play = {
x: 650,
y: 360,
width: 200,
height: 100
}
var playUpButton = new Image();
playUpButton.src = "images/PlayUp.png";
var playDownButton = new Image();
playDownButton.src = "images/PlayDown.png";
var playHovering = false;
thisCanvas.addEventListener('click', checkPlay);
thisCanvas.addEventListener('mouseover', hoverPlay, false);
thisCanvas.addEventListener('mouseout', hoverPlay, false);
function seen_move(e)
{
var bounding_box = thisCanvas.getBoundingClientRect();
mouseX = ((e.clientX-bounding_box.left) *(thisCanvas.width/bounding_box.width));
mouseY = ((e.clientY-bounding_box.top) * (thisCanvas.height/bounding_box.height));
}
function draw_start()
{
context.drawImage(menubg, menubg.x, menubg.y, menubg.width, menubg.height);
if(playHovering)
{
context.drawImage(playDownButton, play.x, play.y, play.width, play.height);
}
}
function mouseInArea(top, right, bottom, left)
{
if(mouseX >= left && mouseX < right && mouseY >= top && mouseY < bottom)
{
return true;
}
else
{
return false;
}
}
function hoverPlay()
{
if(mouseInArea(play.y, play.x + play.width, play.y + play.height, play.x))
{
console.log("Hovering");
if(playHovering)
{
playHovering = false;
}
else
{
playHovering = true;
}
}
}
It looks like the following is missing from your code.
var thisCanvas = document.getElementById("thisCanvas");
The function checkPlay also seems to be missing.
Take a look at these articles:
http://www.html5canvastutorials.com/advanced/html5-canvas-mouse-coordinates/
http://www.informit.com/articles/article.aspx?p=1903884&seqNum=6
You must call function seen_move(e) to get the mouse position.
BTW, I'm confused about what the extra code in seen_move is. I'm guessing you're making the mouse position relative to the bounding box. I just mention it in case that's also a problem:
// this usually get the mouse position
var bounding_box = thisCanvas.getBoundingClientRect();
mouseX = e.clientX-bounding_box.left;
mouseY = e.clientY-bounding_box.top;
// and you have this extra bit:
// *(thisCanvas.width/bounding_box.width)); and
// * (thisCanvas.height/bounding_box.height));
mouseX = ((e.clientX-bounding_box.left) *(thisCanvas.width/bounding_box.width));
mouseY = ((e.clientY-bounding_box.top) * (thisCanvas.height/bounding_box.height));

Javascript mouse event issue

Here's my simple code:
<!DOCTYPE html>
<html>
<head></head>
<body>
<style>
</style>
<script>
var exit = 0;
document.onmousedown = function (e) {
exit = 0;
document.onmousemove = function (e) {
if (exit == 1) {
return;
} else {
var x = e.pageX;
var y = e.pageY;
var e = document.createElement("div");
e.style.width = 10 + "px";
e.style.height = 10 + "px";
e.style.background = "red";
e.style.top = y + "px";
e.style.left = x + "px";
e.style.position = "absolute";
document.body.appendChild(e);
}
};
};
document.onmouseup = function (e) {
exit = 1;
};
</script>
</body>
</html>
It's like painter.You hold left mouse button down and when you move mouse, it should draw line made of div elements and when you release button, it stops.It actually works...sometimes.First time it works perfect, but after letting left mouse button go up, and after additional press, only one element is drawn and moving mouse does not do anything.To be exact- sometimes it does and sometimes doesn't.Best would be if you could try this code and see what happens.Thanks.
It seems to be because it conflicts dragging with selection. Both events involve mousedown and subsequent mousemove.
You will need to prevent default of event and then run your code.
Updated fiddle: http://jsfiddle.net/L4KhJ/2/
Prevent the default on both events, like this:
document.onmousedown = function (e) {
stopDefault(e); // *** prevent default here
exit = 0;
document.onmousemove = function (e) {
stopDefault(e); // *** prevent default here
if (exit == 1) { ...
Where stopDefault is:
function stopDefault(e) {
if (e && e.preventDefault) {
e.preventDefault();
}
else {
window.event.returnValue = false;
}
return false;
}
Code for above function taken from this thread here: https://stackoverflow.com/a/891616/1355315
When you add some log output, you see that sometimes after a mouseup event, you get a mousedown shortly after.
Maybe this is a timing related problem. I moved the assignment to onmousemove outside the onmousedown function and now it works properly
var exit = 1;
document.onmousemove = function (e) {
if (exit == 1)
return;
var x = e.pageX;
var y = e.pageY;
var el = document.createElement("div");
el.style.width = 10 + "px";
el.style.height = 10 + "px";
el.style.background = "red";
el.style.top = y + "px";
el.style.left = x + "px";
el.style.position = "absolute";
document.body.appendChild(el);
};
document.onmousedown = function (e) {
exit = 0;
};
document.onmouseup = function (e) {
exit = 1;
};
See JSFiddle

Dragging div does not work in IE 7 & 8

I am using the following function to drag a div by a handle:
function enableDragging(ele) {
var dragging = dragging || false,
x, y, Ox, Oy,
current;
enableDragging.z = enableDragging.z || 1;
var grabber = document.getElementById("myHandelDiv");
grabber.onmousedown = function(ev) {
current = ev.target.parentNode;
dragging = true;
x = ev.clientX;
y = ev.clientY;
Ox = current.offsetLeft;
Oy = current.offsetTop;
current.style.zIndex = ++enableDragging.z;
console.log(dragging);
window.onmousemove = function(ev) {
pauseEvent(ev);
if (dragging == true) {
var Sx = ev.clientX - x + Ox,
Sy = ev.clientY - y + Oy;
current.style.top = Sy + "px";
current.style.left = Sx + "px";
document.body.focus();
// prevent text selection in IE
document.onselectstart = function () { return false; };
// prevent IE from trying to drag an image
ev.ondragstart = function() { return false; };
return false;
}
};
window.onmouseup = function(ev) {
dragging && (dragging = false);
}
};
}
function pauseEvent(e){
if(e.stopPropagation) e.stopPropagation();
if(e.preventDefault) e.preventDefault();
e.cancelBubble=true;
e.returnValue=false;
return false;
}
I have two problems:
Does not work in IE 7 & 8, for some reason i get no errors whatsoever.
Text is selected on some browsers while dragging causing the drag to appear laggy
I initiate the drag like this:
var ele = document.getElementById("divDragWrapper");
enableDragging(ele);
Update, am now getting this error in IE:
SCRIPT5007: Unable to get value of the property 'target': object is
null or undefined
On this line: current = ev.target.parentNode;
You need to add ev = ev || window.event to all eventhander functions. Older IEs don't pass the event object within arguments. Also target is rather srcElement in those browsers.
For example:
grabber.onmousedown = function(ev) {
ev = ev || window.event;
var target = ev.target || ev.srcElement;
current = target.parentNode;
...
}
Another thing is, that older IEs can't attach onmousemove to the window. You can use document or document.body instead.
See the code in action at jsFiddle.

Create a draggable div in native javascript [duplicate]

This question already has answers here:
Moveable/draggable <div>
(9 answers)
Closed 5 years ago.
I want to create a movable/draggable div in native javascript without using jquery and libraries. Is there a tutorial or anythign?
OK, here's my personal code that I use for lightweight deployments (projects where using a library is either not allowed or overkill for some reason). First thing first, I always use this convenience function so that I can pass either an id or the actual dom element:
function get (el) {
if (typeof el == 'string') return document.getElementById(el);
return el;
}
As a bonus, get() is shorter to type than document.getElementById() and my code ends up shorter.
Second realize that what most libraries are doing is cross-browser compatibility. If all browsers behave the same the code is fairly trivial. So lets write some cross-browser functions to get mouse position:
function mouseX (e) {
if (e.pageX) {
return e.pageX;
}
if (e.clientX) {
return e.clientX + (document.documentElement.scrollLeft ?
document.documentElement.scrollLeft :
document.body.scrollLeft);
}
return null;
}
function mouseY (e) {
if (e.pageY) {
return e.pageY;
}
if (e.clientY) {
return e.clientY + (document.documentElement.scrollTop ?
document.documentElement.scrollTop :
document.body.scrollTop);
}
return null;
}
OK, the two functions above are identical. There're certainly better ways to write them but I'm keeping it (relatively) simple for now.
Now we can write the drag and drop code. The thing I like about this code is that everything's captured in a single closure so there are no global variables or helper functions littering the browser. Also, the code separates the drag handle from the object being dragged. This is useful for creating dialog boxes etc. But if not needed, you can always assign them the same object. Anyway, here's the code:
function dragable (clickEl,dragEl) {
var p = get(clickEl);
var t = get(dragEl);
var drag = false;
offsetX = 0;
offsetY = 0;
var mousemoveTemp = null;
if (t) {
var move = function (x,y) {
t.style.left = (parseInt(t.style.left)+x) + "px";
t.style.top = (parseInt(t.style.top) +y) + "px";
}
var mouseMoveHandler = function (e) {
e = e || window.event;
if(!drag){return true};
var x = mouseX(e);
var y = mouseY(e);
if (x != offsetX || y != offsetY) {
move(x-offsetX,y-offsetY);
offsetX = x;
offsetY = y;
}
return false;
}
var start_drag = function (e) {
e = e || window.event;
offsetX=mouseX(e);
offsetY=mouseY(e);
drag=true; // basically we're using this to detect dragging
// save any previous mousemove event handler:
if (document.body.onmousemove) {
mousemoveTemp = document.body.onmousemove;
}
document.body.onmousemove = mouseMoveHandler;
return false;
}
var stop_drag = function () {
drag=false;
// restore previous mousemove event handler if necessary:
if (mousemoveTemp) {
document.body.onmousemove = mousemoveTemp;
mousemoveTemp = null;
}
return false;
}
p.onmousedown = start_drag;
p.onmouseup = stop_drag;
}
}
There is a reason for the slightly convoluted offsetX/offsetY calculations. If you notice, it's just taking the difference between mouse positions and adding them back to the position of the div being dragged. Why not just use the mouse positions? Well, if you do that the div will jump to the mouse pointer when you click on it. Which is a behavior I did not want.
You can try this
HTML
<div id="one" style="height:50px; width:50px; border:1px solid #ccc; background:red;">
</div>
Js Script for draggable div
window.onload = function(){
draggable('one');
};
var dragObj = null;
function draggable(id)
{
var obj = document.getElementById(id);
obj.style.position = "absolute";
obj.onmousedown = function(){
dragObj = obj;
}
}
document.onmouseup = function(e){
dragObj = null;
};
document.onmousemove = function(e){
var x = e.pageX;
var y = e.pageY;
if(dragObj == null)
return;
dragObj.style.left = x +"px";
dragObj.style.top= y +"px";
};
Check this Demo
This code corrects the position of the mouse (so the dragged object doesn't jump when you start dragging) and works with touch screens/phones as well
var dragObj = null; //object to be moved
var xOffset = 0; //used to prevent dragged object jumping to mouse location
var yOffset = 0;
window.onload = function()
{
document.getElementById("menuBar").addEventListener("mousedown", startDrag, true);
document.getElementById("menuBar").addEventListener("touchstart", startDrag, true);
document.onmouseup = stopDrag;
document.ontouchend = stopDrag;
}
function startDrag(e)
/*sets offset parameters and starts listening for mouse-move*/
{
e.preventDefault();
e.stopPropagation();
dragObj = e.target;
dragObj.style.position = "absolute";
var rect = dragObj.getBoundingClientRect();
if(e.type=="mousedown")
{
xOffset = e.clientX - rect.left; //clientX and getBoundingClientRect() both use viewable area adjusted when scrolling aka 'viewport'
yOffset = e.clientY - rect.top;
window.addEventListener('mousemove', dragObject, true);
}
else if(e.type=="touchstart")
{
xOffset = e.targetTouches[0].clientX - rect.left; //clientX and getBoundingClientRect() both use viewable area adjusted when scrolling aka 'viewport'
yOffset = e.targetTouches[0].clientY - rect.top;
window.addEventListener('touchmove', dragObject, true);
}
}
function dragObject(e)
/*Drag object*/
{
e.preventDefault();
e.stopPropagation();
if(dragObj == null) return; // if there is no object being dragged then do nothing
else if(e.type=="mousemove")
{
dragObj.style.left = e.clientX-xOffset +"px"; // adjust location of dragged object so doesn't jump to mouse position
dragObj.style.top = e.clientY-yOffset +"px";
}
else if(e.type=="touchmove")
{
dragObj.style.left = e.targetTouches[0].clientX-xOffset +"px"; // adjust location of dragged object so doesn't jump to mouse position
dragObj.style.top = e.targetTouches[0].clientY-yOffset +"px";
}
}
function stopDrag(e)
/*End dragging*/
{
if(dragObj)
{
dragObj = null;
window.removeEventListener('mousemove', dragObject, true);
window.removeEventListener('touchmove', dragObject, true);
}
}
div{height:400px; width:400px; border:1px solid #ccc; background:blue; cursor: pointer;}
<div id="menuBar" >A</div>
<div draggable=true ondragstart="event.dataTransfer.setData('text/plain', '12345')">
drag me
</div>
<div ondragover="return false;" ondrop="this.innerHTML=event.dataTransfer.getData('text/plain')">
drop on me
</div>

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