Konvajs - relative zoom in to pointer, but non-relative zoom out - javascript

I am using Konva canvas framework and I want to implement zoom in and zoom out with mouse wheel.
The zoom in should be relative to my cursor pointer, but zoom out should always zoom out to the initial state.
<!DOCTYPE html>
<html>
<head>
<script src="https://unpkg.com/konva#7.2.2/konva.min.js"></script>
<meta charset="utf-8" />
<title>Konva Zoom Relative to Stage Demo</title>
<style>
body {
margin: 0;
padding: 0;
overflow: hidden;
background-color: #f0f0f0;
}
</style>
</head>
<body>
<div id="container"></div>
<script>
var width = window.innerWidth;
var height = window.innerHeight;
var stage = new Konva.Stage({
container: 'container',
width: width,
height: height,
});
var layer = new Konva.Layer();
stage.add(layer);
var circle = new Konva.Circle({
x: stage.width() / 2,
y: stage.height() / 2,
radius: 50,
fill: 'green',
});
layer.add(circle);
layer.draw();
var scaleBy = 0.95;
stage.on('wheel', (e) => {
e.evt.preventDefault();
var oldScale = stage.scaleX();
var pointer = stage.getPointerPosition();
var mousePointTo = {
x: (pointer.x - stage.x()) / oldScale,
y: (pointer.y - stage.y()) / oldScale,
};
var newScale =
e.evt.deltaY > 0 ? oldScale * scaleBy : oldScale / scaleBy;
stage.scale({ x: newScale, y: newScale });
var newPos = {
x: pointer.x - mousePointTo.x * newScale,
y: pointer.y - mousePointTo.y * newScale,
};
stage.position(newPos);
stage.batchDraw();
});
</script>
</body>
</html>
So, in the example you can see there is circle green in the center. When client zoom in, I want the zoom to be relative to pointer. But, when zooming out, the zoom won't be relative to pointer, but simply goes back to the initial state (green circle in the center).

So I changed some things, only for demo purpose - but the concept is the same:
<!DOCTYPE html>
<html>
<head>
<script src="https://unpkg.com/konva#7.2.2/konva.min.js"></script>
<meta charset="utf-8" />
<title>Konva Zoom Relative to Stage Demo</title>
<style>
body {
margin: 0;
padding: 0;
overflow: hidden;
background-color: #f0f0f0;
}
</style>
</head>
<body>
<div id="container"></div>
<script>
var width = window.innerWidth;
var height = window.innerHeight;
var stage = new Konva.Stage({
container: 'container',
width: width,
height: height,
});
var layer = new Konva.Layer();
stage.add(layer);
var circle = new Konva.Rect({
x: stage.width()/2,
y:stage.height()/2,
width: 50,
height: 50,
fill: 'green',
});
layer.add(circle);
layer.draw();
var scaleBy = 0.99;
stage.on('wheel', (e) => {
e.evt.preventDefault();
var oldScale = stage.scaleX();
var mousePointTo = {
x: stage.getPointerPosition().x / oldScale - stage.x() / oldScale,
y: stage.getPointerPosition().y / oldScale - stage.y() / oldScale
};
var newScale =
e.evt.deltaY > 0 ? oldScale * scaleBy : oldScale / scaleBy;
newScale = Math.max( newScale, 1 );
stage.scale({ x: newScale, y: newScale });
var newPos = {
x:
-(mousePointTo.x - stage.getPointerPosition().x / newScale) *
newScale,
y:
-(mousePointTo.y - stage.getPointerPosition().y / newScale) *
newScale
};
newPos.x = Math.min( newPos.x, 0 );
newPos.x = Math.max( newPos.x, width * ( 1 - newScale ) );
newPos.y = Math.min( newPos.y, 0 );
newPos.y = Math.max( newPos.y, height * ( 1 - newScale ) );
stage.position(newPos);
stage.batchDraw();
});
</script>
</body>
</html>

Related

clickable object or shape inside a canvas viewbox window

<!DOCTYPE html>
<html>
<head>
<title>Page Title</title>
<style>
body {
font-family: "Lato", sans-serif;
}
.sidenav {
height: 100%;
width: 0;
position: fixed;
z-index: 1;
top: 0;
left: 0;
background-color: #111;
overflow-x: hidden;
transition: 0.5s;
padding-top: 60px;
}
.sidenav a {
padding: 8px 8px 8px 32px;
text-decoration: none;
font-size: 25px;
color: #818181;
display: block;
transition: 0.3s;
}
.sidenav a:hover {
color: #f1f1f1;
}
.sidenav .closebtn {
position: absolute;
top: 0;
right: 25px;
font-size: 36px;
margin-left: 50px;
}
#main {
transition: margin-left .5s;
padding: 16px;
}
#media screen and (max-height: 450px) {
.sidenav {padding-top: 15px;}
.sidenav a {font-size: 18px;}
}
</style>
</head>
<body>
<div id="mySidenav" class="sidenav">
×
About
Services
Clients
Contact
</div>
<div id="main">
<span style="font-size:30px;cursor:pointer" onclick="openNav()">☰ Menu</span>
<canvas id="canvas" width="600" height="350" style="border:2px solid #d3d3d3;">></canvas>
</div>
<script>
var zoomIntensity = 0.1;
var canvas = document.getElementById("canvas");
var context = canvas.getContext("2d");
var width = 90;
var height = 50;
var scale = 1;
var originx = 0;
var originy = 0;
var visibleWidth = width;
var visibleHeight = height;
var c = document.getElementById("canvas");
var ctx = c.getContext("2d");
function draw(){
context.fillStyle = "white";
context.fillRect(originx,originy,1000/scale,800/scale);
context.fillStyle = "blue";
context.fillRect(170,50,50,50);
context.fillStyle = "white";
context.fillText('click here',175,70);
}
setInterval(draw, 1000/60);
canvas.onwheel = function (event){
event.preventDefault();
var mousex = event.clientX - canvas.offsetLeft;
var mousey = event.clientY - canvas.offsetTop;
var wheel = event.deltaY < 0 ? 1 : -1;
var zoom = Math.exp(wheel*zoomIntensity);
context.translate(originx, originy);
originx -= mousex/(scale*zoom) - mousex/scale;
originy -= mousey/(scale*zoom) - mousey/scale;
context.scale(zoom, zoom);
context.translate(-originx, -originy);
scale *= zoom;
visibleWidth = width / scale;
visibleHeight = height / scale;
}
function openNav() {
document.getElementById("mySidenav").style.width = "200px";
document.getElementById("main").style.marginLeft = "200px";
}
function closeNav() {
document.getElementById("mySidenav").style.width = "0";
document.getElementById("main").style.marginLeft= "0";
}
</script>
</body>
</html>
is there away to make a shape or object clickable on canvas frame or viewbox, even when i zoom in or out, cause all the examples i saw was just a fixed clickable location. for instance google map locations when i zoom in i can click more objects.
is there away to make a shape or object clickable on canvas frame or viewbox, even when i zoom in or out, cause all the examples i saw was just a fixed clickable location. for instance google map locations when i zoom in i can click more objects.
There are two spaces you have to account for, the actual canvas space and the translated space. This means you need to translate the mouse coordinates in order to know where in the space the object is actually located and map it back to the canvas coordinates so you can know if you are clicking on it. This is achieved by keeping track of the offset value you provided in the var originx, but the problem is that there is no way based on my trails at least for you to translate the mouse click location if you use the context.translate(originx, originy) if you both scale and pan the object space.
I have rewritten the code without the use of the translate function by making my own translate function that enables you to translate between the canvas space and object space in order to register a click event on the object regardless of the panned or zoomed in location.
This function also has a click to pan feature so you can click and drag the object screen to where ever you want to object to be positioned.
/*jshint esversion: 8 */
(function() {
const canvas = document.querySelector("canvas");
const context = canvas.getContext("2d");
let canvasWidth = 600;
let canvasHeight = 600;
let offset = {
x: 0,
y: 0
};
let pan = {
x: 0,
y: 0
};
var zoomIntensity = 0.1;
let scale = 1;
let mouse = {
x: 0,
y: 0
};
let dragging = false;
let square;
let shapes = [{
x: 170,
y: 50,
w: 50,
h: 50,
color: "blue"
},
{
x: 85,
y: 25,
w: 50,
h: 50,
color: "red"
},
{
x: 50,
y: 100,
w: 50,
h: 50,
color: "green"
},
];
function init() {
canvas.width = canvasWidth;
canvas.height = canvasHeight;
renderCanvas();
}
function drawSquare(x, y, width, height, color) {
context.fillStyle = color;
context.fillRect(x, y, width, height);
}
function objectsToCanvasScreen(x, y) {
const canvasScreenX = Math.floor((x - offset.x) * scale);
const canvasScreenY = Math.floor((y - offset.y) * scale);
return {
x: canvasScreenX,
y: canvasScreenY
};
}
function canvasToObjectsScreen(x, y) {
return {
x: x / scale + offset.x,
y: y / scale + offset.y
};
}
function renderCanvas() {
context.clearRect(0, 0, canvas.width, canvas.height);
shapes.forEach(({
x,
y,
w,
h,
color
}, index) => {
const {
x: csx,
y: csy
} = objectsToCanvasScreen(x, y);
shapes[index]._x = csx;
shapes[index]._y = csy;
shapes[index]._w = w * scale;
shapes[index]._h = h * scale;
drawSquare(csx, csy, w * scale, h * scale, color);
});
}
canvas.onwheel = function(e) {
const zoom = Math.exp((e.deltaY < 0 ? 1 : -1) * zoomIntensity);
const beforeZoom = canvasToObjectsScreen(mouse.x, mouse.y);
scale *= zoom;
const afterZoom = canvasToObjectsScreen(mouse.x, mouse.y);
offset.x += beforeZoom.x - afterZoom.x;
offset.y += beforeZoom.y - afterZoom.y;
renderCanvas();
};
canvas.onmousedown = function(e) {
if (e.button === 0) {
pan.x = mouse.x;
pan.y = mouse.y;
dragging = true;
}
};
canvas.onmouseup = (e) => (dragging = false);
canvas.onmousemove = function(e) {
mouse.x = e.offsetX;
mouse.y = e.offsetY;
if (dragging) {
offset.x -= (mouse.x - pan.x) / scale;
offset.y -= (mouse.y - pan.y) / scale;
pan.x = mouse.x;
pan.y = mouse.y;
renderCanvas();
}
};
canvas.onclick = function(e) {
shapes.forEach(({
_x,
_y,
_w,
_h,
color
}) => {
const {
x: mousex,
y: mousey
} = canvasToObjectsScreen(mouse.x, mouse.y);
const {
x: squarex,
y: squarey
} = canvasToObjectsScreen(_x, _y);
if (
mousex >= squarex &&
mousex <= _w / scale + squarex &&
mousey >= squarey &&
mousey <= _h / scale + squarey
) {
alert(`${color} clicked!`);
}
});
};
init();
})();
body {
font-family: "Lato", sans-serif;
}
#canvas {
background: #E1BC8B;
}
<body>
<div id="main">
<canvas id="canvas" width="300" height="350"></canvas>
</div>
</body>

Solid torus with nontransparent edge - THREE.js

I need to draw few toruses and balls (spheres) going through them. Problem is: edge of torus should be solid and stop balls, but they are alowing balls to go through them
I tried to use BoxMesh, but its not allowing balls to go throught hoops. i want to made torus: so ball is going throught inside of it, but edge of torus is solid and ball is not going through the edge
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
<link rel="stylesheet" href="styles.css" />
<style>
#display { position: fixed; left: 0px; top: 0px;
width: 100%; height: 100%; z-index: -1 }
.manipulate { text-align: center }
.view { width: 5in; height: 5in; margin: auto }
button { width: .75in }
</style>
</head>
<body>
<div class="viewport"></div>
<canvas id="display"> </div>
<script src="three.min.js"></script>
<script src="physi.js"></script>
<script src="http://cdn.jsdelivr.net/gh/mrdoob/three.js#r73/examples/js/controls/OrbitControls.js"></script>
<script>
plane = new Physijs.BoxMesh(
new THREE.CubeGeometry(100, 100, 2, 10, 10),
Physijs.createMaterial(
new THREE.MeshLambertMaterial({
color: 0xeeeeee
}),
.4,
.99
),
0
);
for (var i=0;i<50;i++) {
torus = new Physijs.Mesh(
new THREE.TorusGeometry(18, 0.2, 16,100),
Physijs.createMaterial(
new THREE.MeshNormalMaterial({
color: 0x00FFFF,
transparent:false
})
),
0
);
torus.translateY(i)
torus.collisions=0;
torus.rotation.y=Math.PI/24
torus.rotation.x=-Math.PI/2
scene.add(torus);
}
setInterval(function() {
ball = new Physijs.SphereMesh(
new THREE.SphereGeometry(
Math.random() * (4 - 1) + 1,
16,
16
),
Physijs.createMaterial(
new THREE.MeshLambertMaterial({
color: 0xff0000,
reflectivity: .8
}),
.4,
.99
),
1
);
var r = {
x: Math.random() * (Math.PI - Math.PI / 12) + Math.PI / 12,
y: Math.random() * (Math.PI - Math.PI / 12) + Math.PI / 12,
z: Math.random() * (Math.PI - Math.PI / 12) + Math.PI / 12
};
ball.rotation.set(r.x, r.y, r.z);
ball.position.y = 40;
ball.castShadow = true;
ball.receiveShadow = true;
scene.add(ball);
}, 600);
window.onload=init
function init() {
render();
}
scene.simulate()
function render() {
for (var i = 5; i < scene.children.length - 5; i++) {
var obj = scene.children[i];
//if (obj.position.y <= -50) {
// scene.remove(obj);
//}
}
</script>
</body>
</html>
Plane is solid : Its made of BoxMesh and is preventing all balls to falling through. I want to do same with torrus. I want balls to go through it, but bounce of the edges of torus

Mouse Wheel Zooming

so i'm working on a canvas that you can only drag a image from side to side and use the mouse wheel to re size the image by zooming in and out on it here is the code i have so far please feel free to ask any more details. I'm trying to find a way that's compact to do this and require minimum code.
<!DOCTYPE HTML>
<html>
<head>
<style>
body {
margin: 0px;
padding: 0px;
}
</style>
<script src="kinetic-v5.1.0.min.js" type="text/javascript"></script>
</head>
<body>
<div id="container"></div>
<script type="text/javascript">
function drawImage(imageObj) {
var stage = new Kinetic.Stage({
container: "container",
width: 1800,
height: 800
});
var layer = new Kinetic.Layer();
// image
var image1 = new Kinetic.Image({
image: imageObj,
x: stage.getWidth() / 2 - 896 / 1,
y: stage.getHeight() / 2 - 255 / 2,
width: 200,
height: 157,
draggable: true,
dragBoundFunc: function (pos) {
if (pos.x < this.minX) { }
this.minX = pos.x;
return {
x: pos.x,
y: this.getAbsolutePosition().y
}
}
});
// add cursor styling
image1.on('mouseover', function() {
document.body.style.cursor = 'pointer';
});
image1.on('mouseout', function() {
document.body.style.cursor = 'default';
});
layer.add(image1);
stage.add(layer);
}
var imageObj = new Image();
imageObj.onload = function() {
drawImage(this);
};
imageObj.src = 'image1.png';
</script>
</body>
</html>
One way would be to use a zoom helper. For example:
var zoomHelper = {
stage: null,
scale: 1,
zoomFactor: 1.1,
origin: {
x: 0,
y: 0
},
zoom: function(event) {
event.preventDefault();
var delta;
if (navigator.userAgent.toLowerCase().indexOf('firefox') > -1) {
if (event.originalEvent.detail > 0) {
//scroll down
delta = 0.2;
} else {
//scroll up
delta = 0;
}
} else {
if (event.originalEvent.wheelDelta < 0) {
//scroll down
delta = 0.2;
} else {
//scroll up
delta = 0;
}
}
var evt = event.originalEvent,
mx = evt.clientX - zoomHelper.stage.getX(),
my = evt.clientY - zoomHelper.stage.getY(),
zoom = (zoomHelper.zoomFactor - delta),
newscale = zoomHelper.scale * zoom;
zoomHelper.origin.x = mx / zoomHelper.scale + zoomHelper.origin
.x - mx / newscale;
zoomHelper.origin.y = my / zoomHelper.scale + zoomHelper.origin
.y - my / newscale;
zoomHelper.stage.setOffset({
x: zoomHelper.origin.x,
y: zoomHelper.origin.y
});
zoomHelper.stage.setScale({
x: newscale,
y: newscale
});
zoomHelper.stage.draw();
zoomHelper.scale *= zoom;
}
};
Here is a demo with code you provided in as an example slightly changed.
Try using this full javascript library.

Draw arc on mousemove event using Kineticjs

I have to draw an arc on the layer on mousemove event as per requirement. How can be the parameters in the function context.arc(x,y,startAngel,endAngle,Counterclockwise) fixed according to current mouseposition? My code is as following :
var newarc;
ui.stage.on("mousedown", function () {
var arc = new Kinetic.Shape({
drawFunc: function (canvas) {
var context = canvas.getContext();
var pos = ui.stage.getMousePosition();
var sx = Math.floor(pos.x / ui.scale - ui.stage.getAbsolutePosition().x / ui.scale + ui.stage.getOffset().x);
var sy = Math.floor(pos.y / ui.scale - ui.stage.getAbsolutePosition().y / ui.scale + ui.stage.getOffset().y);
var x = sx;
var y = sy;
var radius = 100;
var startAngle = 1 * Math.PI;
var endAngle = 0.5 * Math.PI;
var context = canvas.getContext('2d');
context.beginPath();
context.arc(x, y, radius, startAngle, endAngle, false);
canvas.stroke(this);
},
fill: '#00D2FF',
stroke: 'red',
strokeWidth: 2,
// draggable: false
});
newarc = arc;
moving = true;
ui.myLayer.add(newarc );
});
ui.stage.on("mouseup", function () {
moving = false;
})
ui.stage.on("mousemove", function () {
if (!moving) {
return;
}
var dx = x - startX;
var dy = y - startY
var aradius = Math.sqrt(dx * dx + dy * dy)
newarc.radius = aradius;
ui.myLayer.drawScene();
ui.myLayer.add(newarc);
ui.stage.add(ui.myLayer);
});
Here is how to create a circle by dragging the mouse.
Mousedown:
Create a new circle with its center at the mouse position.
Mousemove:
Change the radius of the circle to the distance between center-circle and the mouse.
Mouseup:
End resizing the circle
Here is code and a Fiddle: http://jsfiddle.net/m1erickson/NQDdE/
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Prototype</title>
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<script src="http://d3lp1msu2r81bx.cloudfront.net/kjs/js/lib/kinetic-v4.7.2.min.js"></script>
<style>
body{padding:20px;}
#container{
border:solid 1px #ccc;
margin-top: 10px;
width:350px;
height:350px;
}
</style>
<script>
$(function(){
var stage = new Kinetic.Stage({
container: 'container',
width: 350,
height: 350
});
var layer = new Kinetic.Layer();
stage.add(layer);
var newArc;
var isDown=false;
stage.on("contentMousedown",function(){
var mouse=stage.getMousePosition();
newArc=new Kinetic.Circle({
x:mouse.x,
y:mouse.y,
radius:.25,
fill:randomColor(),
stroke:"lightgray",
strokeWidth:3
});
layer.add(newArc);
layer.draw();
isDown=true;
});
stage.on("contentMousemove",function(){
if(!isDown){return;}
var mouse=stage.getMousePosition();
var dx=mouse.x-newArc.getX();
var dy=mouse.y-newArc.getY();
var radius=Math.sqrt(dx*dx+dy*dy);
newArc.setRadius(radius);
layer.draw();
});
$(stage.getContent()).on('mouseup', function () {
isDown=false;
newArc=null;
});
function randomColor(){
return('#'+Math.floor(Math.random()*16777215).toString(16));
}
layer.draw();
}); // end $(function(){});
</script>
</head>
<body>
<div id="container"></div>
</body>
</html>

Scaling to a fixed point in KineticJS

I'm having some problems with scaling a container to a fixed point.
In my case I'm trying to scale (zoom) a stage to the mouse cursor.
Here is a way to do with pure canvas:
http://phrogz.net/tmp/canvas_zoom_to_cursor.html (as discussed at Zoom Canvas to Mouse Cursor)
I just can't get figure out how to apply the same logic while using the KineticJS API.
Sample code:
var position = this.stage.getUserPosition();
var scale = Math.max(this.stage.getScale().x + (0.05 * (scaleUp ? 1 : -1)), 0);
this.stage.setScale(scale);
// Adjust scale to position...?
this.stage.draw();
After a lot of struggling and searching and trying, using the tip provided by #Eric Rowell and the code posted in the SO question Zoom in on a point (using scale and translate) I finally got the zooming in and out of a fixed point working using KineticJS.
Here's a working DEMO.
And here's the code:
var ui = {
stage: null,
scale: 1,
zoomFactor: 1.1,
origin: {
x: 0,
y: 0
},
zoom: function(event) {
event.preventDefault();
var evt = event.originalEvent,
mx = evt.clientX /* - canvas.offsetLeft */,
my = evt.clientY /* - canvas.offsetTop */,
wheel = evt.wheelDelta / 120;
var zoom = (ui.zoomFactor - (evt.wheelDelta < 0 ? 0.2 : 0));
var newscale = ui.scale * zoom;
ui.origin.x = mx / ui.scale + ui.origin.x - mx / newscale;
ui.origin.y = my / ui.scale + ui.origin.y - my / newscale;
ui.stage.setOffset(ui.origin.x, ui.origin.y);
ui.stage.setScale(newscale);
ui.stage.draw();
ui.scale *= zoom;
}
};
$(function() {
var width = $(document).width() - 2,
height = $(document).height() - 5;
var stage = ui.stage = new Kinetic.Stage({
container: 'container',
width: width,
height: height
});
var layer = new Kinetic.Layer({
draggable: true
});
var rectX = stage.getWidth() / 2 - 50;
var rectY = stage.getHeight() / 2 - 25;
var box = new Kinetic.Circle({
x: 100,
y: 100,
radius: 50,
fill: '#00D200',
stroke: 'black',
strokeWidth: 2,
});
// add cursor styling
box.on('mouseover', function() {
document.body.style.cursor = 'pointer';
});
box.on('mouseout', function() {
document.body.style.cursor = 'default';
});
layer.add(box);
stage.add(layer);
$(stage.content).on('mousewheel', ui.zoom);
});​
You need to offset the stage such that it's center point is positioned at the fixed point. Here's an example, because the center point of the stage is defaulted to the upper left corner of the canvas. Let's say that your stage is 600px wide and 400px tall, and you want the stage to zoom from the center. You would need to do this:
var stage = new Kinetic.Stage({
container: 'container',
width: 600,
height: 400,
offset: [300, 200]
};
updated #juan.facorro's demo to scale shape instead of stage
jsFiddle
var ui = {
stage: null,
box: null,
scale: 1,
zoomFactor: 1.1,
zoom: function(event) {
event.preventDefault();
var evt = event.originalEvent,
mx = evt.offsetX,
my = evt.offsetY,
wheel = evt.wheelDelta / 120; //n or -n
var zoom = (ui.zoomFactor - (evt.wheelDelta < 0 ? 0.2 : 0));
var newscale = ui.scale * zoom;
var origin = ui.box.getPosition();
origin.x = mx - (mx - origin.x) * zoom;
origin.y = my - (my - origin.y) * zoom;
ui.box.setPosition(origin.x, origin.y);
ui.box.setScale(newscale);
ui.stage.draw();
ui.scale *= zoom;
}
};
$(function() {
var width = $(document).width() - 2,
height = $(document).height() - 5;
var stage = ui.stage = new Kinetic.Stage({
container: 'container',
width: width,
height: height
});
var layer = new Kinetic.Layer();
var rectX = stage.getWidth() / 2 - 50;
var rectY = stage.getHeight() / 2 - 25;
var box = ui.box = new Kinetic.Circle({
x: 100,
y: 100,
radius: 50,
fill: '#00D200',
stroke: 'black',
strokeWidth: 2,
draggable: true
});
// add cursor styling
box.on('mouseover', function() {
document.body.style.cursor = 'pointer';
});
box.on('mouseout', function() {
document.body.style.cursor = 'default';
});
layer.add(box);
stage.add(layer);
$(stage.content).on('mousewheel', ui.zoom);
});
The demo above only works if the x and y coordinates of the stage are 0. If e.g. the stage is draggable it will change these coordinates while dragging so they need to be included in the offset calculation. This can be achieved by subtracting them from the canvas offsets:
jsfiddle
zoom: function(event) {
event.preventDefault();
var evt = event.originalEvent,
mx = evt.offsetX - ui.scale.getX(),
my = evt.offsetY - ui.scale.getY(),
var zoom = (ui.zoomFactor - (evt.wheelDelta < 0 ? 0.2 : 0));
var newscale = ui.scale * zoom;
var origin = ui.box.getPosition();
origin.x = mx - (mx - origin.x) * zoom;
origin.y = my - (my - origin.y) * zoom;
ui.box.setPosition(origin.x, origin.y);
ui.box.setScale(newscale);
ui.stage.draw();
ui.scale *= zoom;
}

Categories