We Keep Coding

Leaflet.draw how to draw circle with two mouse clicks

I'm using leaflet.draw
By default, to draw a circle :
You should click on map(this will be the center of the circle)
Then drag the mouse to draw the radius of a circle.
https://leaflet.github.io/Leaflet.draw/docs/examples/full.html
How can I change this to double click?
First, click will put the center
Second, fixed the radius?
Thank you

Drawing on canvas in Bootstrap

So I have been having this problem with HTML5 canvas and Bootstrap. Esentially, I inserted a canvas inside a Bootstrap template (put it in an element with the class of "jumbotron"). And I want to be able to draw inside that canvas using my mouse. But, my mouse position and the editable-canvas area seem off. I took a snap-shot (hope I uploaded it correctly), the canvas is the pale-yellow thing with the purple border and the actual mouse position is the arrow I drew with blue, the blue dot is where the page sees the mouse position and begins drawing the line. Also, it won`t let me use the whole canvas area, I can only draw in the green square I outlined in the photo...
HTML code:
<div class="jumbotron">
<canvas id="draw" width="800" height="800"></canvas>
</div>
JS code to activate the drawing:
function draw(e) {
ctx.beginPath();
ctx.moveTo(lastX, lastY);
ctx.lineTo(e.offsetX, e.offsetY);
ctx.stroke();
[lastX, lastY] = [e.offsetX, e.offsetY];
}
I also have to add that if I get the canvas into a new HTML (without Bootstrap), the code works perfectly (dot/line is following the mouse cursor fine). Also, if I delete the class "jumbotron", the mouse Position will be read correctly. I tried looking into the styles for "jumbotron", digged it up, tried using BoundingRect and others, but I could not figure this one out.
I am new here, so take me slow :) Many thanks in advance!

This happens because mouse position is relative to window. You must make some math to calculate coordinates relative to canvas. Some code for understanding
rect = canvas.getBoundingClientRect()
x = e.offsetX - rect.x
y = e.offsetY - rect.y
Then use x, y to draw something on canvas.
Also you can check my example where I draw with mouse without some additional calculations.
https://codepen.io/Profesor08/pen/aYJWRZ

Moving multiple objects simultaneously in createJS/easelJS

I've been using easelJS within the createJS framework for a project and have enjoyed it a lot until recently hitting a roadblock. I have multiple objects that I'd like to move simultaneously when one of the group is dragged. Here is my current situation:
What I'd like to do is when the red circle is moved, the red crosshairs would also move so that they appear to be "locked" to the circle. The same with the green circle.
I have been able to accomplish something very close to this by adding the circles and crosshairs to a container, as mentioned in the answers to this question:
Easeljs Scrollable Container
But the issue I encounter is that the container is actually a rectangle, such that I can click anywhere between the circle and crosshairs to move the various objects contained within the container. Instead I would like for the objects to be moved only when I click on a circle.
Does anyone have any idea how to accomplish this? Am I correct in thinking this can be accomplished somehow with easelJS containers?

Containers should be fine. You can turn off mouseEnabled on the cross-hair in order to make it ignore the mouse.
You could also just store the offset for each cross-hair/circle, and just set the cross-hair position when the circle moves.
Here is a quick demo:
http://jsfiddle.net/lannymcnie/kah9of6e/
// Set the offset when the circle is pressed
circle.on("mousedown", function(e) {
circle.offset = new createjs.Point(crosshair.x-circle.x, crosshair.y-circle.y);
});
// Add drag and drop to each shape
circle.on("pressmove", handleDrag);
crosshair.on("pressmove", handleDrag);
function handleDrag(e) {
// Move the target to the mouse
e.target.x = e.stageX; e.target.y = e.stageY;
// If the target is the circle, also move the cross-hair
if (e.target == circle) {
// Move the cross-hair
crosshair.x = circle.x + circle.offset.x;
x.y = circle.y + circle.offset.y;
}
}

HTML5 Canvas event listening [duplicate]

I am new in canvas can anyone please help to short this issue.
I create 5 canvas circle. When I hover on any circle I need to change canvas color only, when hover on circle I added one class on canvas but is it possible to change only color. I don't want to create canvas again change only color when hover.
$(document).ready(function(){
$('.menuballs').hover(function () {
$(".menuballs").children('canvas').toggleClass('hover-intro');
if($(this).is(':hover'))
{
var c = document.getElementsByClassName("hover-intro");
var graphics = c.getContext( '2d' );
graphics.fillStyle = 'green';
graphics.fill();
}
});
});
Try this as taking hover-intro class but its given HTMLElement, and I need CanvasElement to fill in circle.

Your :hover will never be triggered.
Circles drawn on html canvas are not DOM elements. Instead they are like forgotten painted pixels on a canvas.
These are the steps to apply a hover-effect to your circle
Keep track of your circle's definition (x,y,radius,etc) in a javascript object.
Listen for mousemove events and test if the mouse is inside your circle
When the mouse enters or leaves your circle, redraw your circle
This is how those steps might look in code:
Demo: http://jsfiddle.net/m1erickson/rV9cZ/
Keep track of your circle's definition (x,y,radius,etc) in a javascript object.
var myCircle={
x:150,
y:150,
radius:25,
rr:25*25, // radius squared
hovercolor:"red",
blurcolor:"green",
isHovering:false
}
Listen for mousemove events and test if the mouse is inside your circle
function handleMouseMove(e){
mouseX=parseInt(e.clientX-offsetX);
mouseY=parseInt(e.clientY-offsetY);
var dx=mouseX-myCircle.x;
var dy=mouseY-myCircle.y;
// math to test if mouse is inside circle
if(dx*dx+dy*dy<myCircle.rr){
// change to hovercolor if previously outside
if(!myCircle.isHovering){
myCircle.isHovering=true;
drawCircle(myCircle);
}
}else{
// change to blurcolor if previously inside
if(myCircle.isHovering){
myCircle.isHovering=false;
drawCircle(myCircle);
}
}
}
When the mouse enters or leaves your circle, redraw your circle
function drawCircle(circle){
ctx.beginPath();
ctx.arc(circle.x,circle.y,circle.radius,0,Math.PI*2);
ctx.closePath();
ctx.fillStyle=circle.isHovering?circle.hovercolor:circle.blurcolor;
ctx.fill();
}

Fabric.js group coordinates with panned canvas

I have a canvas that's initially panned so that the 0,0 point is in the middle of the screen. I'm trying to move a programmatically created group, but for some reason the group moves relative to the upper left corner of the visible canvas instead of the 0,0 point of the canvas. After that first movement the panning works correctly and the group moves around that position, until I discard it and create it again, and then it's relative to the upper left corner again, without taking the pan into account. If I create a group selection using the selection tool, it works correctly every time.
I pan the canvas with this:
var offsetX = -canvas.getWidth()/2;
var offsetY = -canvas.getHeight()/2;
canvas.absolutePan(new fabric.Point(offsetX, offsetY));
This is how I create the group:
var group = new fabric.Group();
objects.forEach(function (o) {
group.addWithUpdate(o);
canvas.remove(o);
});
canvas.add(group);
Then I try to move it with this:
group.set("left", 0);
canvas.renderAll();
And then the group is right at the left edge of the canvas element. But if I select the group with my mouse and use this instead, it appears right where it should be - in the center:
canvas.getActiveGroup().set("left", 0);
canvas.renderAll();
So, how do I get this to work properly? I know I could just calculate an offset from the canvas transformations, but I feel like this should be compensated for in the library itself and I'm either somehow using it wrong or it's a bug.