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draw line with real-time measurement fabric.js

I'm having this problem in Fabric.Js when drawing line with measurement.
When I drag the line it must show the changing measurement at the end or in the middle of the line.
I can now measure the length of line but showing the measurement in error way. Thanks.
Heres the fiddle link: https://jsfiddle.net/ydtt94zm/
$(function(){
var line, isDown;
var arr = new Array();
var startx = new Array();
var endx = new Array();
var starty = new Array();
var endy = new Array();
var temp = 0;
var graphtype; trigger = "1";
var canvas = this.__canvas = new fabric.Canvas('canvas', { hoverCursor: 'pointer',selection: false});
fabric.Object.prototype.transparentCorners = false;
canvas.on('mouse:down', function(o){
if(trigger=="1"){
isDown = true;
var pointer = canvas.getPointer(o.e);
var points = [pointer.x, pointer.y, pointer.x, pointer.y];
startx[temp] = pointer.x;
starty[temp] = pointer.y;
line = new fabric.Line(points, {
strokeWidth: 2,
stroke: 'red',
originX: 'center',
originY: 'center'
});
canvas.add(line);
}else{
canvas.forEachObject(function(o){
o.setCoords();
});
}
});
canvas.on('mouse:move', function(o){
if (!isDown) return;
var pointer = canvas.getPointer(o.e);
line.set({ x2: pointer.x, y2: pointer.y });
endx[temp] = pointer.x;
endy[temp] = pointer.y;
if(trigger=="1"){
var px = Calculate.lineLength(startx[temp], starty[temp], endx[temp], endy[temp]).toFixed(2);
var text = new fabric.Text('Length ' + px, { left: endx[temp], top: endy[temp], fontSize: 12 });
canvas.add(text);
if(canvas.getActiveObject().get('type')==="text")
{
canvas.remove(text);
}
}
canvas.renderAll();
});
canvas.on('mouse:up', function(o){
var pointer = canvas.getPointer(o.e);
isDown = false;
});
canvas.on('mouse:over', function(e) {
e.target.setStroke('blue');
canvas.renderAll();
});
canvas.on('mouse:out', function(e) {
e.target.setStroke('red');
canvas.renderAll();
});
$("#selec").click(function(){
if(trigger == "1"){
trigger = "0";
}else{
trigger = "1";
}
});
var Calculate={
lineLength:function(x1, y1, x2,y2){//线长
//console.log(x1 + ", "+ y1 +", " + x2 + ", " + y2);
//clearRect(x2, y2);
return Math.sqrt(Math.pow(x2*1-x1*1, 2)+Math.pow(y2*1-y1*1, 2));
}
}
});

You need to remove the text element before re-adding it.
canvas.remove(text);
check this updated fiddler

resize rect doesnt not works once i add test within it,kinetic.js

I have code to resize rect in kinetic.js that works only once. after that it doesnt make rect resizable, here i am trying to add text within rect but once i set text within rect, click event on "box" not triggering on second time,pls suggest
var box = new Kinetic.Rect({
x : relativeX,
y : relativeY,
offset : [ 50, 25 ],
width : 100,
height : 50,
fill : 'yellow',
stroke : 'black',
strokeWidth : 1,
id:'comment'
});
group.add(box);
var simpleText = new Kinetic.Text({
x : relativeX - 48,
y : relativeY - 30,
text : 'Note',
fontSize : 15,
fontFamily : 'Calibri',
width:box.getWidth(),
height:box.getHeight(),
padding: 4,
fill : 'green',
id:"textBox"
});
group.add(simpleText);
var circle1 = new Kinetic.Circle({
x: relativeX+50,
y:relativeY+25,
radius: 4,
fill: 'red',
stroke: 'black',
strokeWidth: 1,
draggable: true,
visible:false
});
group.add(circle1);
layer.draw();
circle1.on("dragmove",function()
var pos = this.getPosition();
var x = pos.x;
var y = pos.y;
var rectX = box.getX();
var rectY = box.getY();
var x1= x - rectX;
var y1= y - rectY;
box.setSize(x1+50,y1+25);
var textX=simpleText.getX();
var textY=simpleText.getY();
var x2= x - textX;
var y2= y - textY;
simpleText.setSize(x2,y2);
var circle1X=circle1.getX();
var circle1Y=circle1.getY();
var x3=x-circle1X;
var y3=y-circle1Y;
circle1.setSize(x3,y3);
layer.draw();
});
box.on('mouseover', function() {
document.body.style.cursor = 'pointer'; });
box.on('mouseout', function() {
document.body.style.cursor = 'default'; });
circle1.on('mouseover', function() {
document.body.style.cursor = 'se-resize'; });
circle1.on('mouseout', function() {
document.body.style.cursor = 'default'; });
group.on('click', function(evt) {
var shape =circle1.getVisible();
if( shape==false)
{
circle1.show();
layer.draw();
$('html').on('keydown',function(e){
if(e.keyCode === 46){
group.destroy();
layer.draw();
}
});
}else{
circle1.hide();
layer.draw();
}
circle1.setVisible(false);
});
var canvas = document.getElementById('canDemo');
var canvas = document.getElementById('canDemo');
ctx = canvas.getContext('2d'),
font = '14px sans-serif',
hasInput = false;
box.on('dblclick', function() {
// canvas.onclick = function(e) {
if (hasInput) return;
addInput(e.clientX, e.clientY);
});
function addInput(x, y) {
var input = document.createElement('textarea');
input.id="comment_area";
input.type = 'textarea';
input.style.position = "absolute";
input.style.left = (x - 4) + 'px';
input.style.top = (y - 4) + 'px';
input.style.zIndex="3";
input.onkeydown = handleEnter;
document.body.appendChild(input);
input.focus();
hasInput = true; }
function handleEnter(e) {
var keyCode = e.keyCode;
if (keyCode === 27) {
simpleText.setText( $("#comment_area").val());
drawText(this.value, parseInt(this.style.left, 10), parseInt(this.style.top, 10));
document.body.removeChild(this);
hasInput = false;
}
}
$('#comment_area').keypress(function (e){
if(e.keyCode === 13){
e.preventDefault();
this.value = this.value.substring(0, this.selectionStart)+"\n";
}
});
function drawText(txt, x, y) {
ctx.textBaseline = 'top';
ctx.textAlign = 'left';
ctx.font = font;
ctx.fillText(txt, x - 4, y - 4);
layer.draw();}

Define x,y of line (start/end) connector for two shapes KineticJS/HTML5

I'm working in a small project where I'll need create a resizable parent shape and a resizable child shape with a connection line. I did​​ in KinecticJS.
But, I have a problem for calculate the x1, x2 (start connector) and x2,y2 (end connector) when the shape is resizing.
This calculate is in the function addConnection:
var x1 = parentNode.getX() + rectParent.getWidth()/2;
var y1 = parentNode.getY() + rectParent.getHeight()/2;
var x2 = childNode.getX() + rectChild.getWidth()/2;
var y2 = childNode.getY() + rectChild.getHeight()/2;
I put my working code in http://jsfiddle.net/geremora/nxDNH/
My Javascript code:
var stage = new Kinetic.Stage({
container: 'container',
width: 400,
height: 400
});
var groupRoot = new Kinetic.Group({
x: 100,
y: 50,
draggable: true,
});
var layer = new Kinetic.Layer();
layer.add(groupRoot);
stage.add(layer);
newRect(groupRoot);
var groupChild = new Kinetic.Group({
x: 270,
y: 100,
draggable: true
});
layer.add(groupChild);
newRect(groupChild);
var con = addConnection(groupRoot, groupChild);
layer.add(con);
con.moveToBottom();
stage.draw();
function newRect(group){
var rect = new Kinetic.Rect({
x: 0,
y: 0,
width: 50,
height: 50,
fill: 'blue',
stroke: 'black',
strokeWidth: 1,
name:'rect'
});
group.add(rect);
addAnchor(group, rect.x, rect.y, 'topLeft');
addAnchor(group, rect.getWidth(), rect.y, 'topRight');
addAnchor(group, rect.getWidth(), rect.getHeight(), 'bottomRight');
addAnchor(group, rect.x, rect.getHeight(), 'bottomLeft');
group.on('dragstart', function() {
this.moveToTop();
});
stage.draw();
}
function update(activeAnchor) {
var group = activeAnchor.getParent();
var topLeft = group.get('.topLeft')[0];
var topRight = group.get('.topRight')[0];
var bottomRight = group.get('.bottomRight')[0];
var bottomLeft = group.get('.bottomLeft')[0];
var rect = group.get('.rect')[0];
var anchorX = activeAnchor.getX();
var anchorY = activeAnchor.getY();
switch (activeAnchor.getName()) {
case 'topLeft':
topRight.setY(anchorY);
bottomLeft.setX(anchorX);
break;
case 'topRight':
topLeft.setY(anchorY);
bottomRight.setX(anchorX);
break;
case 'bottomRight':
bottomLeft.setY(anchorY);
topRight.setX(anchorX);
break;
case 'bottomLeft':
bottomRight.setY(anchorY);
topLeft.setX(anchorX);
break;
}
rect.setPosition(topLeft.getPosition());
var width = topRight.getX() - topLeft.getX();
var height = bottomLeft.getY() - topLeft.getY();
if(width && height) {
rect.setSize(width, height);
}
}
function addAnchor(group, x, y, name) {
var stage = group.getStage();
var layer = group.getLayer();
var anchor = new Kinetic.Circle({
x: x,
y: y,
stroke: '#666',
fill: '#ddd',
strokeWidth: 1,
radius: 5,
name: name,
draggable: true,
dragOnTop: false
});
anchor.on('dragmove', function() {
update(this);
layer.draw();
});
anchor.on('mousedown touchstart', function() {
group.setDraggable(false);
this.moveToTop();
});
anchor.on('dragend', function() {
group.setDraggable(true);
layer.draw();
});
anchor.on('mouseover', function() {
var layer = this.getLayer();
document.body.style.cursor = 'pointer';
this.setStrokeWidth(4);
layer.draw();
});
anchor.on('mouseout', function() {
var layer = this.getLayer();
document.body.style.cursor = 'default';
this.setStrokeWidth(2);
layer.draw();
});
group.add(anchor);
}
function addConnection(parentNode, childNode){
var connector = new Kinetic.Line({
drawFunc: function (canvas) {
var rectParent = parentNode.get('.rect')[0];
var rectChild = childNode.get('.rect')[0];
var ctx = canvas.getContext();
var x1 = parentNode.getX() + rectParent.getWidth()/2;
var y1 = parentNode.getY() + rectParent.getHeight()/2;
var x2 = childNode.getX() + rectChild.getWidth()/2;
var y2 = childNode.getY() + rectChild.getHeight()/2;
ctx.save();
ctx.strokeStyle = "red";
ctx.lineWidth = 3;
ctx.beginPath();
ctx.moveTo(x1, y1);
ctx.lineTo(x2, y2);
ctx.stroke();
ctx.restore();
},
points: [1, 1, 1, 3],
stroke: "red",
strokeWidth: 2,
lineCap: 'round',
lineJoin: 'round',
opacity: 1,
draggable: false
});
return connector;
}

Problem: when you are moving, for example, topLeft anchor, you are changing X position of rectange. But X position of group is not changing. So solution - add rect position when are are calculating position of connector:
var x1 = parentNode.getX() + rectParent.getX()+ rectParent.getWidth()/2;
var y1 = parentNode.getY() + rectParent.getY() + rectParent.getHeight()/2;
var x2 = childNode.getX() + rectChild.getX()+ rectChild.getWidth()/2;
var y2 = childNode.getY() + rectChild.getY() + rectChild.getHeight()/2;
http://jsfiddle.net/lavrton/pAQKx/

Smooth KineticJS animation, controlled speed

I am creating a simple plane animation in KineticJS for the fun of it.
Currently the animation runs a little jerky I would love to have some easing or tweening although I don't know how to begin.
Can anyone lend me a hand with the math?
<div id="container"></div>
<script src="http://www.html5canvastutorials.com/libraries/kinetic-v4.5.0-beta.js"></script>
<script defer="defer">
var stage = new Kinetic.Stage({
container: 'container',
width: 870,
height: 392
});
var layer = new Kinetic.Layer();
var xPos = 0;
var yPos = 126;
var growthFactorX = 6;
var growthFactorY = 2.6;
var growthFactorP = 3;
var planeRotation = 30;
// dashed line
var trail = new Kinetic.Line({
points: [{x: xPos,y: yPos}],
stroke: 'white',
strokeWidth: 2,
lineJoin: 'round',
dashArray: [6, 5]
});
var imageObj = new Image();
imageObj.src = '/assets/img/plane.png';
var plane = new Kinetic.Image({
x: xPos,
y: yPos - 15,
width: 54,
height: 30
});
imageObj.onload = function() {
plane.setImage(imageObj);
layer.add(plane);
stage.add(layer);
};
plane.rotateDeg( planeRotation );
layer.add(trail);
stage.add(layer);
var anim = new Kinetic.Animation(function(frame) {
if( xPos < 500 ) {
xPos = growthFactorX + xPos; // adds 3 to xPos on each loop
if( xPos > 400 ) {
yPos = yPos - growthFactorY;
if( plane.getRotationDeg() > 0 )
plane.rotateDeg( (-growthFactorP) ) ;
}
var curPoints = trail.getPoints();
var newPoints = [{x: xPos, y: yPos}];
trail.setPoints(curPoints.concat(newPoints));
plane.setX(xPos + 10);
plane.setY(yPos - 35);
}
else {
anim.stop();
}
}, layer);
anim.start();
</script>

I have created a fiddle for you,
and have changed this factors, al thought it looks smooth to me, please let me know if any specification
var xPos = 0;
var yPos = 126;
var growthFactorX = 5;
var growthFactorY = 2;
var growthFactorP = 1;
var planeRotation = 30;
The fiddle link
I hope this will do :)

Fabric.js - Free draw a rectangle

I have the following which doesn't work correctly:
var canvas = new fabric.Canvas('canvas');
canvas.observe('mouse:down', function(e) { mousedown(e); });
canvas.observe('mouse:move', function(e) { mousemove(e); });
canvas.observe('mouse:up', function(e) { mouseup(e); });
var started = false;
var x = 0;
var y = 0;
/* Mousedown */
function mousedown(e) {
var mouse = canvas.getPointer(e.memo.e);
started = true;
x = mouse.x;
y = mouse.y;
var square = new fabric.Rect({
width: 1,
height: 1,
left: mouse.x,
top: mouse.y,
fill: '#000'
});
canvas.add(square);
canvas.renderAll();
canvas.setActiveObject(square);
}
/* Mousemove */
function mousemove(e) {
if(!started) {
return false;
}
var mouse = canvas.getPointer(e.memo.e);
var x = Math.min(mouse.x, x),
y = Math.min(mouse.y, y),
w = Math.abs(mouse.x - x),
h = Math.abs(mouse.y - y);
if (!w || !h) {
return false;
}
var square = canvas.getActiveObject();
square.set('top', y).set('left', x).set('width', w).set('height', h);
canvas.renderAll();
}
/* Mouseup */
function mouseup(e) {
if(started) {
started = false;
}
}
The above logic is from a simple rectangle drawing system I used without fabric.js so I know it works, just not with fabric.js.
It seems the maths is off or I'm setting the incorrect params with the width/height/x/y values, as when you draw the rectangle does not follow the cursor correctly.
Any help is much appreciated, thanks in advance :)

I have written an example for you. Please follow the link below:
http://jsfiddle.net/a7mad24/aPLq5/
var canvas = new fabric.Canvas('canvas', { selection: false });
var rect, isDown, origX, origY;
canvas.on('mouse:down', function(o){
isDown = true;
var pointer = canvas.getPointer(o.e);
origX = pointer.x;
origY = pointer.y;
var pointer = canvas.getPointer(o.e);
rect = new fabric.Rect({
left: origX,
top: origY,
originX: 'left',
originY: 'top',
width: pointer.x-origX,
height: pointer.y-origY,
angle: 0,
fill: 'rgba(255,0,0,0.5)',
transparentCorners: false
});
canvas.add(rect);
});
canvas.on('mouse:move', function(o){
if (!isDown) return;
var pointer = canvas.getPointer(o.e);
if(origX>pointer.x){
rect.set({ left: Math.abs(pointer.x) });
}
if(origY>pointer.y){
rect.set({ top: Math.abs(pointer.y) });
}
rect.set({ width: Math.abs(origX - pointer.x) });
rect.set({ height: Math.abs(origY - pointer.y) });
canvas.renderAll();
});
canvas.on('mouse:up', function(o){
isDown = false;
});

Looks like Fabric.js calculates everything from the origin. So, 'Top' and 'Left' are a bit misleading. Check the following link: Canvas Coordinates Have Offset. Also, I've changed a bit of your code:
var canvas = new fabric.Canvas('canvas');
canvas.observe('mouse:down', function(e) { mousedown(e); });
canvas.observe('mouse:move', function(e) { mousemove(e); });
canvas.observe('mouse:up', function(e) { mouseup(e); });
var started = false;
var x = 0;
var y = 0;
/* Mousedown */
function mousedown(e) {
var mouse = canvas.getPointer(e.memo.e);
started = true;
x = mouse.x;
y = mouse.y;
var square = new fabric.Rect({
width: 0,
height: 0,
left: x,
top: y,
fill: '#000'
});
canvas.add(square);
canvas.renderAll();
canvas.setActiveObject(square);
}
/* Mousemove */
function mousemove(e) {
if(!started) {
return false;
}
var mouse = canvas.getPointer(e.memo.e);
var w = Math.abs(mouse.x - x),
h = Math.abs(mouse.y - y);
if (!w || !h) {
return false;
}
var square = canvas.getActiveObject();
square.set('width', w).set('height', h);
canvas.renderAll();
}
/* Mouseup */
function mouseup(e) {
if(started) {
started = false;
}
var square = canvas.getActiveObject();
canvas.add(square);
canvas.renderAll();
}

Here is the detail blog with jsfiddle - https://blog.thirdrocktechkno.com/drawing-a-square-or-rectangle-over-html5-canvas-using-fabricjs-f48beeedb4d3
var Rectangle = (function () {
function Rectangle(canvas) {
var inst=this;
this.canvas = canvas;
this.className= 'Rectangle';
this.isDrawing = false;
this.bindEvents();
}
Rectangle.prototype.bindEvents = function() {
var inst = this;
inst.canvas.on('mouse:down', function(o) {
inst.onMouseDown(o);
});
inst.canvas.on('mouse:move', function(o) {
inst.onMouseMove(o);
});
inst.canvas.on('mouse:up', function(o) {
inst.onMouseUp(o);
});
inst.canvas.on('object:moving', function(o) {
inst.disable();
})
}
Rectangle.prototype.onMouseUp = function (o) {
var inst = this;
inst.disable();
};
Rectangle.prototype.onMouseMove = function (o) {
var inst = this;
if(!inst.isEnable()){ return; }
var pointer = inst.canvas.getPointer(o.e);
var activeObj = inst.canvas.getActiveObject();
activeObj.stroke= 'red',
activeObj.strokeWidth= 5;
activeObj.fill = 'transparent';
if(origX > pointer.x){
activeObj.set({ left: Math.abs(pointer.x) });
}
if(origY > pointer.y){
activeObj.set({ top: Math.abs(pointer.y) });
}
activeObj.set({ width: Math.abs(origX - pointer.x) });
activeObj.set({ height: Math.abs(origY - pointer.y) });
activeObj.setCoords();
inst.canvas.renderAll();
};
Rectangle.prototype.onMouseDown = function (o) {
var inst = this;
inst.enable();
var pointer = inst.canvas.getPointer(o.e);
origX = pointer.x;
origY = pointer.y;
var rect = new fabric.Rect({
left: origX,
top: origY,
originX: 'left',
originY: 'top',
width: pointer.x-origX,
height: pointer.y-origY,
angle: 0,
transparentCorners: false,
hasBorders: false,
hasControls: false
});
inst.canvas.add(rect).setActiveObject(rect);
};
Rectangle.prototype.isEnable = function(){
return this.isDrawing;
}
Rectangle.prototype.enable = function(){
this.isDrawing = true;
}
Rectangle.prototype.disable = function(){
this.isDrawing = false;
}
return Rectangle;
}());
var canvas = new fabric.Canvas('canvas');
var rect = new Rectangle(canvas);
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.7.17/fabric.min.js"></script>
Please draw rectangle here
<div id="canvasContainer">
<canvas id="canvas" width="400" height="400" style="border: solid 1px"></canvas>
</div>

The answer above seems to be deprecated. I changed some things on the code below to fix that. And on the mousedown function I add the if to detect the active object to avoid creating a new rectangle when the user's move a selected object.
var canvas = new fabric.Canvas('canvas');
canvas.on('mouse:down', function(options) {
if(canvas.getActiveObject()){
return false;
}
started = true;
x = options.e.clientX;
y = options.e.clientY;
var square = new fabric.Rect({
width: 0,
height: 0,
left: x,
top: y,
fill: '#000'
});
canvas.add(square);
canvas.setActiveObject(square);
});
canvas.on('mouse:move', function(options) {
if(!started) {
return false;
}
var w = Math.abs(options.e.clientX - x),
h = Math.abs(options.e.clientY - y);
if (!w || !h) {
return false;
}
var square = canvas.getActiveObject();
square.set('width', w).set('height', h);
});
canvas.on('mouse:up', function(options) {
if(started) {
started = false;
}
var square = canvas.getActiveObject();
canvas.add(square);
});

Slight modification on the mouse up event to allow the object to be selectable and moveable.
Note: adding the object to canvas again on the mouse:up even will add it twice to the canvase and it is the wrong thing to do.
canvas.on('mouse:up', function(o){
isDown = false;
var square = canvas.getActiveObject();
square.setCoords(); //allows object to be selectable and moveable
});

you can use this simple code
canvas.add(new fabric.Rect({ left: 110, top: 110, fill: '#f0f', width: 50, height: 50 }));