Develop Reference

Improve hovering over points to display tooltip

I am developing a datetime series line chart of efficiencies (in percentage) over time.
I need a tooltip to display information about each point on the chart, but I am finding that it is difficult to hover over points which coincide with the line or marker of another series.
The chart will be static in nature in that users will not be able to remove series from the chart - so they wouldn't be able to remove a series in order to be able to get more easily hover over the desired point.
In this demo - https://jsfiddle.net/slaws/37y4cteq/10/ - it takes many attempts moving the cursor in that area to get the tooltip for the last point in the series with the black markers to show.
Here
I moved my cursor around the area marked in red, but couldn't get the tooltip for any points other than one shown to display.
I had to follow a specific procedure and get my cursor to a specific point to be able to hover over the black marker and get the tooltip to display. Here
I had to hover over the second to last black marker and then move the cursor to the point indicated to get the tooltip for the last marker to display.
I have tried using the findNearestPointBy (x, y and xy) in combination with stickyTracking (true and false), with no improvement.
"stickyTracking": false,
"findNearestPointBy": 'y'
I read something about a direct hover mode rather than nearest neighbor but found no details about how to implement that.
Any guidance on how I can make it easier for my users to display the tooltips in my use case would be greatly appreciated!

Setting tooltip.snap as 0 and setting back stickyTracking to default options fixes your issue.
Demo: https://jsfiddle.net/BlackLabel/54q2eubd/
API: https://api.highcharts.com/highcharts/tooltip.snap

Change style of Leaflet Draw rectangle while drawing

I'm using Leaflet Draw to draw rectangles on a Leaflet map. The rectangles get added to a FeatureGroup once they are created, and their styles are updated based on their size. For example, the rectangles are filled red if their area exceeds a certain threshold and green if their area is within the threshold.
I'm leveraging the "draw:created" callback to inspect the completed rectangle's size. I'm also able to update the rectangle's style during editing by leveraging the "draw:editresize" and "draw:editmove" callbacks. By doing this, users can easily see if their rectangles fall within the correct area requirements while they are resizing them.
Here is my problem: I haven't been able to find a callback that allows me to style the rectangle during its initial creation. Have I overlooked a callback? I've tried all of the logical ones from the doc's: https://leaflet.github.io/Leaflet.draw/docs/leaflet-draw-latest.html#l-draw-event.
There's not really any code to show other than the following event handlers, which currently work while editing a rectangle.
this.map.on('draw:editmove', function (e) {
self.setROIStyle(e);// works
});
this.map.on('draw:editresize', function (e) {
self.setROIStyle(e);//works
});
Thanks,
Ray

jCanvas - start y from bottom left

I have created different layers, for example, a roof, a grid and various panels that are set.
I would like to start the y coordinate of the bottom left. Is there an already existing function for this, or is there an elegant solution to this problem?

You would wrap all your calls to jcanvas with a decorator that will "convert" the y-axis values.
Note that you cannot use rotation by 180° since the rotate is applied after positionning.

Tricky raphael svg animation

I've created a 'donut' chart originally from this jsfiddle, using raphael.
I have tweaked this script to suit my needs and currently have this being rendered.
My aim is to animate each slice (at the same time); for example make the blue slice grow to 60%; and the red slice shrink to 40%.
I have been able to redraw the slices by removing the existing one and quickly re-rendering a new one with adjusted values (e.g. 51, 49). But the problem here is that it is instant.
My question is,
(a) Can I animate this without the need to redraw the object (and how)?
(b) If not, how I can animate this effect using a redraw logic?

Yes. There is an example of doing this very thing on the Raphael demos page where you got the pie chart. See the Growing Pie demo.
You should separate the code in which you generate the path into a standalone function so you can use it later to return new paths. In order to use animate(), you'll need to define a function on the customAttributes object; it should return (at least) an object with the path property set to your slice's new path.
Since you have labels, you'll probably want to modify the code such that the pie slices expand/shrink relative to their center, so that you don't have to move the labels, too, since the labels are centered on their slice's "axis."
Update
Here's a JSFiddle with a simple example, pretty much the same as Dmitri's Growing Pie demo, except more like your chart. I export a setValue() method to change slice sizes and call it when the page loads. See his blog post about adding customAttributes, too.
In my last paragraph above, I was off the mark a bit. Your chart wasn't the one with labels; I had them mixed up. Also, it would be harder to keep slices centered, so I didn't do that after all. The animate() function sets each segment to its new starting and ending points on the circle, and Raphael figures out the intermediate points. As you can see, you can pass multiple arguments in an array.
this.customAttributes.slice = function(a0, a1) { /*...*/ }
// ...
chart.push(paper.path().attr({slice:[0, Math.PI/2 ]})

Can't see all the fiddle because I'm on iPod however it sounds like you need to have an animate call inside a function that you will need to write
Use the callback parameter that calls the function it sits inside.
Code your recursively called function so it eventually completes when all the work is done.
Each call to the function will happen at the end of every elapssed time interval you specify...

An HTML5 Canvas Problem

I'm working on a script to do several things. In a nutshell, here's what it needs to do:
Read the coordinates from a page and be able to pop up a box within a specific region.
The pop up box needs to be able to follow the mouse around.
I need to be able to modify the box to look however I want (I was thinking a div container that is set to display:hidden, and then the JS sets the display to block when your mouse is in the specified region).
I need to be able to modify it easily (aka, add and subtract objects and coordinate sets)
I was originally using HTML maps (), and that worked great, until I resized my browser, and the div that I had following the mouse no longer lined up correctly. Something about the offset not working correctly, and I couldn't get it to work correctly, so I switched to an HTML canvas.
And now I've got the coordinates in the canvas correctly, I just can't figure out how to get something to pop up when the mouse is inside of a certain section. Here's my current code:
function drawLines(numbers, color){
//poly [x,y, x,y, x,y.....];
var poly=numbers;
context.fillStyle = color;
context.beginPath();
context.moveTo(poly[0], poly[1]);
for( item=2 ; item < poly.length-1 ; item+=2 )
{context.lineTo( poly[item] , poly[item+1] )};
context.closePath();
context.fill();
}
I've got each region inside of an array, which I then pass to the function one by one. The color was a test, and I can easily get each region to show up as a specified color, but that doesn't solve my problem. Any ideas? Thanks!

Seems strange to jump to canvas over a style issue, but ignoring that...
You could bind mousemove events on the canvas element and then do hit tests on your region to see if the mouse is inside the region.
Doing the hit test efficiently might be tricky depending on the number of regions your testing, but it's definitely doable.
The canvas is just like any other block level element, so the same events apply and are bound in the same way.
Here's one example of mouse events interacting with canvas. In this example, the events are bound to the document, but similar ideas apply.
http://dev.opera.com/articles/view/blob-sallad-canvas-tag-and-javascrip/