SVG Path Hit-Testing - javascript

I am having problems detecting mouseover events on SVG path elements. It seems that the smaller the strokeWidth for the path element, the less success I have in detecting the mouseover.
Also, I am using jquery-svg plugin to do the drawing.
Below is a fiddle of trying to detect using a jquery mouseover event on the path element.
Mouseover Fiddle
Below is a fiddle of trying to detect by attaching a mousemove listener to svg, then using document.getElementFromPoint.
getElementFromPoint Fiddle
Neither of these seem to work reliably, especially if the mouse is moving fast. Is it possible to make either of these more sensitivity to better detect the mouseover? Or perhaps a better way of doing this?

The way browsers work, you don't get mouseover events continuously, but you get one each time the operating system updates the cursor position. And if the mouse is moving fast, you will get a events a few pixels apart. The mouse doesn't slide over the document, it jumps. Here's a jsfiddle showing where each event occurs. There's nothing that you can do to get mouseover events for all the elements between two consecutive positions of the cursor.
You could do something different: remember the previous location of the mousemove event, compute the line between that point and the current mouse position, and compute all the intersections between this line and all the other shapes in the document. But that is going to be resource-intensive, since there's no API available for that, you'll have to compute intersections yourself. There is a library that can help you.

Related

Adobe Animate CC Canvas mouse actions on the stage are laggy and intermittent

In Adobe Animate CC HTML5 Canvas (createJS), I'm trying to do something very simple, to trigger an animated rollover when the entire stage of an ad is moused over, and to trigger an animated rollout when the mouse leaves the stage. It should be very simple, but it's not. Using mouseenter and mouseleave on the stage is laggy and only works intermittently. It's the same with mouseover and mouseout.
Here's the code that's laggy and intermittent:
stage.addEventListener("mouseenter", fl_MouseOverHandler.bind(this));
stage.addEventListener("mouseleave", fl_MouseOutHandler.bind(this));
function fl_MouseOverHandler(){
this.btnOverAnim.gotoAndPlay("on");
}
function fl_MouseOutHandler(){
this.btnOverAnim.gotoAndPlay("off");
}
I also tried mouseover and mouseout on a button the entire size of the stage and I got the same issue. (Also doing it this way doesn't work at all from inside a frame, and the ad is served inside a frame). I put the var frequency way up to 90 to see if that would help with the lagging, it didn't.
This was the simple mouseover / mouseout code I tried:
var frequency = 90;
stage.enableMouseOver(frequency);
this.bgCta.addEventListener("mouseover", fl_MouseOverHandler.bind(this));
this.bgCta.addEventListener("mouseout", fl_MouseOutHandler.bind(this));
On the createJS website it says "You can monitor whether the pointer is over the canvas by using stage.mouseInBounds AND the mouseleave / mouseenter events." So I'm wondering if using stage.mouseInBounds will help (but I can't find an example anywhere of how to use it). But I actually don't think it'll help because I think this whole problem is about createJS not reading where the mouse is fast enough.
Does anyone know how to fix this lagginess and intermittent firing? A work around? Why does createJS not just monitor the mouse events constantly like pure js?
Also mouseenter and mouseleave on the stage in createJS do not work on tablets or mobile and that's a problem, so it would be better to do this with mouseover and mouseout on a button the entire size of the stage. I did try using mouseover and mouseout and having 3 pixels space around the button between the edge of the button and the edge of the ad banner, this helped, but it was still firing intermittently.
Your thoughts and ideas please.
Mouseover checks are expensive. A canvas is essentially just a bitmap, so EaselJS can't use mouse events from the browser (you just get one for the entire canvas). Instead, mouseover in EaselJS requires every element to be drawn to a 1x1 pixel canvas, and then checked for fill. This gives pixel-perfect detection, but is costly if you are either checking a lot of content, or checking too often.
Reduce your frequency:
It looks like you have set the frequency to 90. This is really high (11 ms between checks, which is basically trying to achieve 90 fps). The default is 10, which is slower than a good framerate, but fast enough to feel responsive. You can probably bring it down to 20 or so to give you a peppy check without it being unnecessarily high.
Modify interactivity: Another thing you can do is filter out exactly what gets checked. By default, all display objects get checked -- but you can reduce this by turning off mouseEnabled on anything you don't care about (omitting them from the check), and turning off mouseChildren on containers that you want to treat as a single object (so something like a complex button is drawn once, instead of all its contents being drawn individually).
// Example
myBackground.mouseEnabled = false;
myButton.mouseChildren = false;
Hope that helps!
Friends, I know this was asked 4 years ago, but the lagginess in Adobe Animate CC V.21 is no different (horrible) regarding mouseenter, mouseleave, mouseover and mouseout. After 10 times of rolling over/out the page becomes unresponsive. I was able to alleviate this using stage.mouseInBounds on a setInterval. The original poster could not find an example, so here is what I did:
// Place this in a keyframe on the timeline where the named cta exists.
setInterval(function(scope){
if(stage.mouseInBounds){
createjs.Tween.get(scope.cta).to({scaleX:1.1, scaleY:1.1}, 150);
}
else{
createjs.Tween.get(scope.cta).to({scaleX:1, scaleY:1}, 150);
}
}, 150, this );
Make sure to pass this into the end of the setInterval function as an argument for the callback function as to not lose scope. I am guessing this can be reworked to use gotoAndPlay() on the timeline, in this instance the built-in tweener for CreateJS sufficed for what I needed.

hoverOut() interferes with drag function when dragging too fast in Raphael

I have a shape that has hoverIn() and hoverOut() function and it can be dragged at the same time. My problem is when I drag too fast (not like really really fast), the mouse pointer may go outside of the shape boundary before the shape is actually moved. This cause hoverOut to be fired and it messes up with my dragging function. When I drag slow, this doesn't happened since the shape displacement is small and the mouse is always inside.
How can I handle the fact that if I'm dragging I don't want to deal with hoverOut. I tried the unHoverfunction(), it partially worked but now after dragging and leaving the shape the hoverOut function is not fired as it should be.
I've just created a flag, it seems like no built-in solution exist. Thanks for your time.

mouse moves faster than tooltip

I have an angular directive wrapped around a D3 graph. I have created a tooltip and i handle the visibility in 'mouseover' and 'mouseout' of the parent element, i also handle the tooltip position in 'mousemove' so that it moves with the mouse.
The tooltip is absolute.
The issue is, when i move my mouse pointer fast enough, the mouseout event of the parent gets called , even though the mouse pointer is still within the specified area. I logged and found out , it is happening because sometimes the mouse pointer (when moving fast, the tooltip position hasn't updated so quick) hovers over the tooltip , which is absolutely positioned and not part of the parent.
This creates some difficulties as on mouseout of the parent element i am also changing the visibility of another element, so it gives a fluctuating/flicker kind of effect on fast mouse move.
I am not sure whether this is the expected behavior or if it is specific to D3 or angular.
Here is a fiddle:
http://jsfiddle.net/6bQA8/5/
initially the text and polylines are shown, they would hide when hovered over any of the pie slices.
on hover over any of the pie slices, you will get a tooltip, if you move your mouse, the tooltip also moves, if you move your mouse fast enough, check the console and you will see "tooltip hovered" ,also on the UI you would see the flickering text and polylines which should be visible on mouseout from the slices.
In ideal case, "tooltip hovered" should never be called as the tooltip always updates with the mouse and it is not below the pointer.
P.S: one way to solve the problem is to add pointer-events:none to the tooltip or to increase the offset of tooltip from the pointer, but i am more interested in knowing why this happens and if this is a limitation of the framework or the browser or something wrong in the code. Also, since i am re-using the same tooltip object later for clicking purpose, so at that time i would have to remove the pointer-events:none, and increasing the offset does not look really good in the UI. Also, both these methods are actually hacks and not probably the correct solution.
Since you are asking a solution apart from the pointer-events:none i have done it this way:
slices.on("mouseout", function(d) {
//return if the mouse out is triggered by the tooltip-menu
if(d3.select(d3.event.toElement).classed("tooltip_menu")){
return;//if the to element is tooltip_menu
}
working fiddle here
Javascript can not block mouse until it does all calculations and DOM manipulations, that's why, there is dealy in moving the tooltip.
In modern browsers operations happens at least with 4ms delay, as setTimeout/setInterval minimum delay is 4ms.

Handle mouse event on irregular shaped objects with event delegation

I need to handle mouse events on a page where there are multiple irregular-shaped objects (for example, houses) are stacked on top of each other. If I use the normal way of event delegation jQuery .on(), the event source reported will always be the top most object, even if user clicked on the transparent part of the object (or image).
Example: <img> tag that contains the red triangle will always be the event source even if I click at the X position.
I can detect that mouse click is not inside the triangle. What I need is a way to "forward" the event to the green triangle below.
EDIT: My current approach is to catch the events on a big div that wraps everything, then use jQuery selector and compare coordinates to find out which object is under the mouse, then check if the mouse is in transparent part or not. It works fine, but seems to be slow and consume a lot of memory, especially with mouse move events being fired continuously.
EDIT 2:
This image was extracted from Building a game engine with jQuery, and my approach was almost identical to that. And now, this is the question:
Are you drawing complex graphics using plain HTML elements? Not sure about your exact needs, but it might make more sense to use SVG or Canvas, where catching click events on shapes becomes much easier.

Simple JavaScript drag and drop witout the help of a library

I am simply looking for a way of using drag and drop without jquery or any other library. If a dragged object is dropped on another element the later element should start an event (in FF - better would be browser independent).
I know that drag and drop for JavaScript was discussed sometimes before but the previous postings didn't help me.
Although I found some examples it is not clear to me if there is a "drop" or "dragdrop" events exist but these things don't work:
<p ondrop='alert("It worked");'>Text</p>
<p ondragdrop='alert("It worked");'>Text</p>
How could this be done?
Many thanks in advance.
I agree with the other answers. A library will save you a lot of time and headache. This is coming from someone who just recently created a drag-and-drop control from scratch.
If you insist though this is what you'll need to do:
Bind a onmousedown event to the div you want to drag (div.onmousedown).
Change the div's position style to absolute (div.style.position = 'absolute')
Begin capturing mouse movement (document.onmousemove).
On mouse move update the div's position (div.style.top|left = '[location]px')
On the div's onmouseup event (or the document's) unbind all the handlers and do any other cleanup (null out position changes, etc).
Some problems a library will probably solve:
While dragging you will select text on the page (looks ugly).
Binding to events is different between browsers.
You have to calculate the size of the element being dragged if you want to show placeholders and to make it not "pop" when you begin dragging the control (since changing to absolute positioning will remove the element from flow).
You will probably want your dragged element to move fluidly so you will have to store some mouse offset when selecting the element or automatically center the element to the mouse.
If you want to drag an item in a list you'll have to write a ton more custom code for that list to accept the dragged item.
You'll have to take into consideration dragging when the window is scrolled and possibly dragging inside other elements that are positioned strangely.
I am simply looking for a way of using drag and drop without jquery or any other library.
I'm sorry, but there are no such thing as simply drag and drop without any library. You can write it all yourself, but that will be a lot of JS to make it work in all browsers.
Hmm. It's probably not that simple that you'd want to do it yourself, but I would look at Peter Michaux's FORK Javascript drag and drop library -- unlike JQuery or all those big libraries, FORK's modules are decoupled from each other, and are simple enough that you could probably look at Peter's source code and figure out the bits you need. (edit: I'd just use FORK.Drag as it's really small: 7.6KB total minified)
While I agree that library is the way to go, the answer you want is onmousedown, onmousemove, onmouseup. You have to handle those three events.
In onmousedown you'd find the target (event.target or similar in different browsers) and set draggedObject = event.target. You'd also start handling the onmousemove event.
Whenever the onmousemove event fired, you'd move the dragged element based on the difference in position since last time the onmousemove event fired.
In the onmouseup event, you'd clear your draggedObject variable and stop handling onmousemove.
It's not very crossbrowser, but it's the core of what you'd need to do for dragging and dropping.

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