TL;DR
I want to use HTML5 drag and drop of an element to a container with drag Hammer.js events. However, there are conflicts.
Detailed description:
As presented in the attached figure, I have two containers:
Left: container with draggable elements
Right: container with Hammer.js events, namely drag, dragstart and dragend.
I want to drag and drop elements from the left container to the right one.
However, while dragging, when entering on the right container, the Hammer.js dragstart event is activated. After dropping the element, I apply the drag event on the right container. However, the Hammer.js drag event is activated and it considers the deltaX and deltaY from the previous dragstart event.
Hammer.js is being used with preventDefault: true:
Hammer(this.container, {preventDefault: true}).on('dragstart', function (event) { ... }
I have already used event.preventDefault() and event.stopPropagation() on the dragstart of the draggable element, without success.
I have also partially solved the problem. In the dragstart event of the Hammer.js container, I have added the following verification, in order to check if the source element and the target are the same. However, the drag in the right container only works on the second action, since the first one is ignored.
if (event.gesture.startEvent.srcEvent.srcElement != event.gesture.target) {
return false;
}
Any idea on how to prevent Hammer.js events while dragging elements using the HTML5 drag and drop API?
I want to use flags as a last resort, since Hammer.js events should be developed by third-parties.
Thanks for your help.
Hammer.js events should only be captured if they have previously been bound.
Try using a case statement...(this is from an app that I built recently) I can case the statement then break out or return false etc to prevent things. Theoretically though, if I unbind or exclude the event "drag" it should work anyway.
<script>
var hammertime = Hammer(document.getElementById('image-wrapper'), {
transform_always_block: true,
transform_min_scale: window.initScale,
transform_max_scale: 1,
drag_block_horizontal: true,
drag_block_vertical: true,
drag_min_distance: 0
});
//console.log(hammertime);
var posX = window.calcLeft, posY = window.calcTop,
lastPosX = window.calcLeft, lastPosY = window.calcTop,
bufferX = 0, bufferY = 0,
scale = window.initScale, last_scale,
rotation = window.rotationNeeded, last_rotation, dragReady = 0;
hammertime.on('touch drag dragend transform release mouseleave transformend pinchin pinchout', function (ev) {
elemRect = document.getElementById('the-image');
manageMultitouch(ev);
});
function manageMultitouch(ev) {
var pinchDirection;
ev.stopPropagation();
//console.log(ev.type);
switch (ev.type) {
case 'touch':
last_scale = scale;
last_rotation = rotation;
break;
case 'drag':
posX = ev.gesture.deltaX + lastPosX;
posY = ev.gesture.deltaY + lastPosY;
break;
case 'pinchin':
console.log('pinchin');
pinchDirection = "in";
break;
case 'pinchout':
console.log('pinchout');
pinchDirection = "out";
break;
case 'transform':
rotation = window.rotationNeeded;// rotation + ev.gesture.rotation;//we can change this to snap rotation eventually.
//console.log('Last Scale: ', last_scale);
scale = Math.max(hammertime.options.transform_min_scale, Math.min(last_scale * ev.gesture.scale, 1));
var propsImage = document.getElementById('the-image').getBoundingClientRect();
//console.log(propsImage);
var propsBox = document.getElementById('image-wrapper').getBoundingClientRect();
//console.log(propsBox);
break;
case 'transformend':
console.log('We are finished transforming.');
//when they finish transforming, we need to determinw what the new left reset position would be.
var propsImage = document.getElementById('the-image').getBoundingClientRect();
var propsBox = document.getElementById('image-wrapper').getBoundingClientRect();
//window.calcLeft = Math.round(window.preBounds.left - propsImage.left);
//console.log(ev.type);
//if (pinchDirection = "out") {
window.calcLeft = Math.round(window.calcLeft + ((propsImage.width - propsBox.width) / 2));
//} else if (pinchDirection = "in") {
//window.calcLeft = Math.round(window.calcLeft - ((propsImage.width - propsBox.width) / 2));
//}
//window.calcTop = Math.round(window.calcTop + ((propsImage.top - propsBox.top) / 2));
//console.log(window.calcLeft);
break;
case 'dragend':
//console.log('We are finished dragging.');
//console.log(window.calcLeft);
lastPosX = posX;
lastPosY = posY;
checkBounds();
break;
case 'mouseleave':
//console.log('Release!', posX, posY);
//checkBounds();
break;
}
<script>
Related
I am using Here's Maps API for JavaScript and trying to achieve a scrolling behavior on mobile similar to what Google Map's API's has.
When I want to scroll by touching the map, scrolling the page should not be always prevented, only if the Map's DRAGGING behavior is disabled.
I have tried calling window.scroll() with the corresponding Y parameters extracted from pointer events, but it is not as smooth as the browser's default scrolling.
How should I use drag or some other event targeting the Map to scroll the page?
This code should work for you:
let mapevents = new mapsjs.mapevents.MapEvents(map),
behavior = new mapsjs.mapevents.Behavior(mapevents);
let startY, endY = 0;
map.addEventListener('dragstart', function(evt) {
if (evt.currentPointer.type == 'touch' && evt.pointers.length < 2) {
startY = evt.currentPointer.viewportY;
behavior.disable(H.mapevents.Behavior.DRAGGING);
}
});
map.addEventListener('drag', function(evt) {
if (evt.currentPointer.type == 'touch' && evt.pointers.length < 2) {
endY = evt.currentPointer.viewportY;
window.scrollBy(0, (startY - endY));
}
});
map.addEventListener('dragend', function(evt) {
behavior.enable(H.mapevents.Behavior.DRAGGING);
});
In dragstart and drag callbacks the scrolling is disabled only when pointer's type is touch and number of pointers is 1. That makes it possible to zoom & pan the map with two fingers on touch device and also with mouse on desktops / laptops.
Note, that method behavior.isEnabled(feature) doesn't disable the feature. For that you need to use behavior.disable(opt_features) See https://developer.here.com/documentation/maps/topics_api/h-mapevents-behavior.html
You can allow scrolling on the map by:
Disable the map's dragging behavior on dragstart and capture the Y coordinate.
Enable the map's dragging behavior on dragend and capture the Y coordinate.
Scroll the page by the difference of the start and end Y coordinates on dragend.
var mapEvents = new H.mapevents.MapEvents(map);
var beh = new H.mapevents.Behavior(mapEvents);
var startY, endY = 0;
map.addEventListener("dragstart", function(evt) {
startY = evt.currentPointer.viewportY;
beh.disable(H.mapevents.Behavior.DRAGGING);
});
map.addEventListener("dragend", function(evt) {
endY = evt.currentPointer.viewportY;
window.scrollBy(0, (startY - endY));
beh.enable(H.mapevents.Behavior.DRAGGING);
});
I would like selectable objects to snap their center to my mouse cursor on click. The only modification allowed to the user in this case is moving the object, no scaling, rotating, etc. Simply updating the position of the object on mousedown or selected will update its position only until the moving event is fired, where the object will snap to its original position and then begin following the mouse.
rect.on('moving', moveHandler);
function moveHandler(evt) {
var mousePnt = $canvas.getPointer(evt.e);
rect.set({
left:mousePnt.x - rect.width*0.5 , top:mousePnt.y - rect.height*0.5});
this.setCoords();
}
This is what I've come up with to center a selectable rectangle on the cursor, but I'm certain it's firing two movement events. Is there a way to override that original positioning. Or should I instead write my own mousedown, mouseup, and moving listeners to mimic the default dragging behavior?
You solution is fine if no rotating or scaling is involved.
You are not executing anything more than necessary if not the .setCoords that during a movement is optional since it will be called on mouseUp when the translation is finished.
If you want to take the mouseDown approach, changing the position once for all, you can use this logic:
var canvas = new fabric.Canvas('c');
canvas.add(new fabric.Rect({width: 50, height: 50}));
canvas.on('mouse:down', function(opt) {
if (this._currentTransform && opt.target) {
var target = opt.target;
target.top = this._currentTransform.ey - target.height/2;
target.left = this._currentTransform.ex - target.width/2;
this._currentTransform.left = target.left;
this._currentTransform.offsetX = this._currentTransform.ex - target.left;
this._currentTransform.offsetY = this._currentTransform.ey - target.top;
this._currentTransform.top = target.top;
this._currentTransform.original.left = target.left;
this._currentTransform.original.top = target.top;
this.renderAll();
}
})
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.7.18/fabric.min.js"></script>
<canvas id="c" ></canvas>
You have to modify all the transform information that fabric noted down on the mouseDown event before the your mousedown handler is executed.
Hi I know we can trigger click event . but I want to know that can we trigger mousemove event without any actual mouse movement by user.
Description :
I want to show a message when user select something. on canvas ,my canvas is of full height and width,when user click on a button the canvas shows up. when user do mouse movement he see a message "Click and drag on any part of the web page". this message follows the mouse movement of the user.
What I want to do :
When user click the button he should see the message that "Click and drag on any part of the web page". and message must follow wherever user moves the mouse.
Problem :
User is not able to see the message after click until he/she moves his mouse.
Code:
function activateCanvas() {
var documentWidth = jQ(document).width(),
documentHeight = jQ(document).height();
jQ('body').prepend('<canvas id="uxa-canvas-container" width="' + documentWidth + '" height="' + documentHeight + '" ></canvas><form method="post" id="uxa-annotations-container"></form>');
canvas = new UXAFeedback.Canvas('uxa-canvas-container', {
containerClass: 'uxa-canvas-container',
selection: false,
defaultCursor: 'crosshair'
});
jQ(function() {
var canvas = jQ('.upper-canvas').get(0);
var ctx = canvas.getContext('2d');
var x,y;
var tooltipDraw = function(e) {
ctx.save();
ctx.setTransform(1, 0, 0, 1, 0, 0);
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.restore();
x = e.pageX - canvas.offsetLeft;
y = e.pageY - canvas.offsetTop;
var str = 'Click and drag on any part of the webpage.';
ctx.fillStyle = '#ddd';
ctx.fillRect(x + 10, y - 60, 500, 40);
ctx.fillStyle = 'rgb(12, 106, 185)';
ctx.font = 'bold 24px verdana';
ctx.fillText(str, x + 20, y - 30, 480);
};
canvas.addEventListener('onfocus',tooltipDraw,0);
canvas.addEventListener('mousemove',tooltipDraw,0);
canvas.addEventListener('mousedown', function() {
canvas.removeEventListener('mousemove', tooltipDraw, false);
ctx.save();
ctx.setTransform(1, 0, 0, 1, 0, 0);
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.restore();
}, false);
});
}
jQ('body').on('click', '.mood_img_div', function() {
// alert("soemthing");
toggleOverlay();
activateCanvas();
});
I have made a function which is called after click but the message is not visible. Is there any way to call it for the first time with message and show is everytime when user uses mouse.
I have replaced jQuery with jQ because I am making my own plugin(this is not causing the problem)
A good native approach is to use dispatchEvent method on EventTarget.
It dispatches an Event at the specified EventTarget, invoking the affected EventListeners in the appropriate order. The normal event processing rules (including the capturing and optional bubbling phase) also apply to events dispatched manually with dispatchEvent().
Try
// 1. Add an event listener first
canvas.addEventListener('mousemove', tooltipDraw ,0);
// 2. Trigger this event wherever you wish
canvas.dispatchEvent(new Event('mousemove'));
in your case it should trigger mousemove event on canvas element.
(Triggering events in vanilla JavaScript article can be also useful):
var elem = document.getElementById('elementId');
elem.addEventListenter('mousemove', function() {
// Mousemove event callback
}, 0);
var event = new Event('mousemove'); // (*)
elem.dispatchEvent(event);
// Line (*) is equivalent to:
var event = new Event(
'mousemove',
{ bubbles: false, cancelable: false });
jQuery:
Try this with jQuery trigger method:
$('body').bind('mousemove',function(e){
// Mousemove event triggered!
});
$(function(){
$('body').trigger('mousemove');
});
OR (if you need triggering with coords)
event = $.Event('mousemove');
// coordinates
event.pageX = 100;
event.pageY = 100;
// trigger event
$(document).trigger(event);
OR
Try using .mousemove() jQuery method
let coordX = 0; // Moving from the left side of the screen
let coordY = window.innerHeight / 2; // Moving in the center
function move() {
// Move step = 20 pixels
coordX += 20;
// Create new mouse event
let ev = new MouseEvent("mousemove", {
view: window,
bubbles: true,
cancelable: true,
clientX: coordX,
clientY: coordY
});
// Send event
document.querySelector('Put your element here!').dispatchEvent(ev);
// If the current position of the fake "mouse" is less than the width of the screen - let's move
if (coordX < window.innerWidth) {
setTimeout(() => {
move();
}, 10);
}
}
// Starting to move
move();
Albeit it is probably possible to mimic such an event as shown in Andrii Verbytskyi's answer, most of the time, when you want to do it, it is because of an "X-Y problem".
If we take OP's case for instance, here we absolutely don't need to trigger this mousemove event.
Pseudo-code of current implementation :
function mousemoveHandler(evt){
do_something_with(evt.pageX, e.pageY);
}
element.addEventListener('mousemove', mousemoveHandler)
function clickHandler(evt){
do_something_else();
}
element.addEventListener('click', clickHandler);
And what we want is to also call do_something_with in the click handler.
So OP spends some time to find a way to trigger a fake mousemove, spends another amount of time trying to implement it, while all that is needed is to add a call to do_something_with in clickHandler.
Both mousemove and click events have these pageX and pageY properties, so the event can be passed has is, but in other case, we could also just want to pass it with a fake object containing required properties.
function mousemoveHandler(evt){
do_something_with(evt.pageX, evt.pageY);
}
element.addEventListener('mousemove', mousemoveHandler)
function clickHandler(evt){
do_something_else();
do_something_with(evt.pageX, evt.pageY);
}
element.addEventListener('click', clickHandler);
// here we won't have pageX nor pageY properties
function keydownHandler(evt){
do_something_else();
// create a fake object, which doesn't need to be an Event
var fake_evt = {pageX: someValue, pageY: someValue};
do_something_with(fake_evt.pageX, fake_evt.pageY);
}
element.addEventListener('keydown', keydownHandler);
Note : you are mixing jQuery.on and element.addEventListener, so you might need to pass the originalEvent property of the jQuery event object.
The basic functionality I'm going for is...
Tap (mousedown) on the stage to create and add a child at that location.
*EDIT: I'm also trying to solve for multitouch, so multiple balls can be created at the same time.
As you hold down you can drag (pressmove) that child around and it grows (using regX/regY/scaleX/scaleY) until you release (pressup), at which point it falls (using a tick cycle).
I have everything sort of working, but I've hit a snag wherein I can't add a child and have it immediately register mousedown without releasing and pressing again.
Is there a way to manually trigger mousedown after adding, or some other workaround that makes more sense? dispatchEvent doesn't seem to be working.
Here's my stage event listener and touch bits:
stage.enableMouseOver(10);
createjs.Touch.enable(stage, false, false);
stage.preventSelection = false;
stage.addEventListener("stagemousedown", spawnsnowball);
And here are my functions. The spawnsnowball one includes displayObject event listeners verging on desperate, but the only way I've been able to get the pressmove and pressup working is to click on the same snowball again. releasesnowball right now just releases all instances of them (using a 'stagemouseup' listener), but if I can get it triggering off of pressup then I'll rewrite it to target just the event target.
function spawnsnowball(evt){
var ball = new createjs.Bitmap(loader.getResult("snowball"));
ball.crossOrigin="Anonymous";
ball.name="ball";
ball.scaleX = 0.5;
ball.scaleY = ball.scaleX;
ball.regX = ball.image.width/2;
ball.regY = ball.image.height/2;
ball.x = evt.stageX;
ball.y = evt.stageY;
ball.type = balltype;
ball.holding = 1;
ball.velX = 0;
ball.velY = 0;
ball.addEventListener("pressup",releasesnowball);
ball.addEventListener("pressmove",dragsnowball);
ball.onPress = function(mouseEvent) {};
stage.addChild(ball);
ball.dispatchEvent("mousedown");
ball.dispatchEvent("pressdown");
}
function dragsnowball(evt){
evt.target.x = evt.stageX;
evt.target.y = evt.stageY;
}
function releasesnowball(evt){
for(var i=0;i<stage.getNumChildren();i++){
var shape = stage.getChildAt(i);
if(shape.type == balltype){
if(shape.holding){
shape.holding = 0;
var dX = shape.x - shape.oldX;
var dY = shape.y - shape.oldY;
if(Math.abs(dY)>8)
dY = 8*dY/Math.abs(dY);
if(Math.abs(dX)>3)
dX = 3*dX/Math.abs(dX);
}
}
}
}
The pressmove event is special because it basically stores off the target of the last mousedown event, and then remembers it for pressmove and pressup events.
This means you can't really fake the event by forcing mouse events. Dispatching a mouse event from the target will not do the trick.
Instead, consider just handling the initial drag manually. You already know what you want to be the target of the pressmove, so you can listen for the stagemousemove event, and handle it yourself:
// Listen to the stagemousemove and manually call the event.
var initialDrag = stage.on("stagemousemove", function(event) {
event.target = ball; // Re-target the event so your other method works fine.
dragsnowball(event);
});
// When done, remove the move listener.
// The off() method supports a "once" parameter so you don't have to unsubscribe that listener.
stage.on("stagemouseup", function(event) {
stage.off("stagemousemove", initialDrag);
}, null, true); // Fires one time
Here is a quick sample using your code as the base: http://jsfiddle.net/3qhmur82/
I also added some comments in the demo which might be useful.
Hope that helps!
I have an HTML5 canvas based Javascript component that needs to capture and release mouse events. In the control the user clicks an area inside it and drags to affect a change. On PC I would like the user to be able to continue dragging outside of the browser and for the canvas to receive the mouse up event if the button is released outside of the window.
However, according to my reading setCapture and releaseCapture aren't supported on Chrome.
Is there a workaround?
An article written in 2009 details how you can implement cross-browser dragging which will continue to fire mousemove events even if the user's cursor leaves the window.
http://news.qooxdoo.org/mouse-capturing
Here's the essential code from the article:
function draggable(element) {
var dragging = null;
addListener(element, "mousedown", function(e) {
var e = window.event || e;
dragging = {
mouseX: e.clientX,
mouseY: e.clientY,
startX: parseInt(element.style.left),
startY: parseInt(element.style.top)
};
if (element.setCapture) element.setCapture();
});
addListener(element, "losecapture", function() {
dragging = null;
});
addListener(document, "mouseup", function() {
dragging = null;
}, true);
var dragTarget = element.setCapture ? element : document;
addListener(dragTarget, "mousemove", function(e) {
if (!dragging) return;
var e = window.event || e;
var top = dragging.startY + (e.clientY - dragging.mouseY);
var left = dragging.startX + (e.clientX - dragging.mouseX);
element.style.top = (Math.max(0, top)) + "px";
element.style.left = (Math.max(0, left)) + "px";
}, true);
};
draggable(document.getElementById("drag"));
The article contains a pretty good explanation of what's going on, but there are a few gaps where knowledge is assumed. Basically (I think), in Chrome and Safari, if you handle mousemove on the document then, if the user clicks down and holds the mouse, the document will continue receiving mousemove events even if the cursor leaves the window. These events will not propagate to child nodes of the document, so you have to handle it at the document level.
Chrome supports setPointerCapture, which is part of the W3C Pointer events recommendation. Thus an alternative would be to use pointer events and these methods.
You might want to use the jquery Pointer Events Polyfill to support other browsers.