I have to draw 3 images on the canvas and need to rotate 2 of the images.
The images are like
1. circular with a vertical straight line
2. just an horizontal line
3. Big circular image
I need to rotate the 1st 2 images in the center of the canvas.
var canvas = document.getElementById('NewImage');
var context = canvas.getContext('2d');
context.canvas.width = window.innerWidth;
context.canvas.height = window.innerHeight*0.7;
var imageObj = new Image();
var imageObj2 = new Image();
var imageObj3 = new Image();
imageObj.onload = function() {
context.save();
context.translate(imageObj.width/2,imageObj.height/2);
context.rotate(-10*Math.PI/180);
//context.translate(-imageObj.width/2,-imageObj.height/2);
context.drawImage(imageObj,-(imageObj.width/2),-(imageObj.height/2),context.canvas.width,context.canvas.height*0.85);
context.restore();
context.save();
context.globalCompositeOperation="source-over";
context.translate(imageObj2.width/2,imageObj2.height/2);
context.rotate(-10*Math.PI/180);
context.translate(-imageObj2.width/2,-imageObj2.height/2);
context.drawImage(imageObj2, x, y,context.canvas.width,6);
context.restore();
//context.rotate(10*Math.PI/180);
context.drawImage(imageObj3, 0, 0,context.canvas.width,context.canvas.height*0.9);
};
imageObj.src = 'canvas/inner_circle_blackline_vertical.png';
imageObj2.src = 'canvas/horizontal.png';
imageObj3.src = 'canvas/outer_circle.png';
When i try to rotate, the images are not rotating in center. when 1st 2 images rotates it has to look like "X" symbol.
How will i rotate in center of the canvas.
Thanks:)
As designed, your imageObj2 and imageObj3 will never load.
Here is a generic image loader that will load all your images and store them in an array called imgs[].
When all your images have fully loaded, the render() function will be called. That’s where you start drawing.
// This is an image loader
// When render() is called, all your images are fully loaded
var imgURLs = [
"https://dl.dropboxusercontent.com/u/139992952/stackoverflow/line.png",
"https://dl.dropboxusercontent.com/u/139992952/stackoverflow/line.png",
"https://dl.dropboxusercontent.com/u/139992952/stackoverflow/line.png"];
var imgs=[];
var imgCount=0;
pre_load();
function pre_load(){
for(var i=0;i<imgURLs.length;i++){
var img=new Image();
imgs.push(img);
img.onload=function(){
if(++imgCount>=imgs.length){
// images are now fully loaded
render();
}
}
img.src=imgURLs[i];
}
}
In render(), you just draw your images.
Since the same action (rotating an image) is done repeatedly, you can create a helper function to do the rotated drawing. Here the helper function is drawImageAtAngle.
// draw the rotated lines on the canvas
function render(){
var x=canvas.width/2;
var y=canvas.height/2;
drawImageAtAngle(imgs[0],x,y,-45);
drawImageAtAngle(imgs[2],x,y,45);
drawImageAtAngle(imgs[1],x,y,0);
}
Here the helper function that rotates a supplied image to a supplied angle:
function drawImageAtAngle(image,X,Y,degrees){
var radians=degrees*Math.PI/180;
var halfWidth=image.width/2;
var halfHeight=image.height/2;
ctx.beginPath();
ctx.save();
ctx.translate(X,Y);
ctx.rotate(radians);
ctx.drawImage(image,-halfWidth,-halfHeight);
ctx.restore();
}
Here is code and a Fiddle: http://jsfiddle.net/m1erickson/ZShWW/
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<style>
body{ background-color: ivory; padding:10px;}
canvas{border:1px solid red;}
</style>
<script>
$(function(){
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
// This is an image loader
// When render() is called, all your images are fully loaded
var imgURLs = [
"https://dl.dropboxusercontent.com/u/139992952/stackoverflow/line.png",
"https://dl.dropboxusercontent.com/u/139992952/stackoverflow/line.png",
"https://dl.dropboxusercontent.com/u/139992952/stackoverflow/line.png"];
var imgs=[];
var imgCount=0;
pre_load();
function pre_load(){
for(var i=0;i<imgURLs.length;i++){
var img=new Image();
imgs.push(img);
img.onload=function(){
if(++imgCount>=imgs.length){
// images are now fully loaded
render();
}
}
img.src=imgURLs[i];
}
}
// draw the rotated lines on the canvas
function render(){
var x=canvas.width/2;
var y=canvas.height/2;
drawImageAtAngle(imgs[0],x,y,-45);
drawImageAtAngle(imgs[2],x,y,45);
drawImageAtAngle(imgs[1],x,y,0);
}
function drawImageAtAngle(image,X,Y,degrees){
var radians=degrees*Math.PI/180;
var halfWidth=image.width/2;
var halfHeight=image.height/2;
ctx.beginPath();
ctx.save();
ctx.translate(X,Y);
ctx.rotate(radians);
ctx.drawImage(image,-halfWidth,-halfHeight);
ctx.restore();
}
}); // end $(function(){});
</script>
</head>
<body>
<p>This is the line image</p>
<img src="https://dl.dropboxusercontent.com/u/139992952/stackoverflow/line.png">
<p>The line image rotated at center of canvas</p>
<canvas id="canvas" width=300 height=300></canvas>
</body>
</html>
To find the center of the canvas you have to use the dimensions of the canvas. In your code you are using the dimensions of the image. That is, this line:
context.translate(imageObj.width/2,imageObj.height/2);
should probably be:
context.translate(canvas.width/2,canvas.height/2);
That moves you to the center of the canvas. The rotation then occurs around that center. You are then drawing the image centered on the origin. That part looks correct.
You will then reverse the rotation and then the translation.
Related
This question already has an answer here:
HTML Canvas: Drawing grid below a plot
(1 answer)
Closed 6 years ago.
I have a canvas, and I want to use drawImage to draw an image behind the current content on the canvas.
Due to the fact that there is content already on the canvas (I'm using Literally Canvas to create a canvas containing an image, so I can't really draw the image first), I cannot use drawImage before I render the rest of my content.
Is it possible to drawImage behind all other content on a canvas?
Yes you can just use globalCompositeOperation destination-over, but note that your first image needs some transparency, otherwise, you will obviously not see anything :
var img1 = new Image();
var img2 = new Image();
var loaded = 0;
var imageLoad = function(){
if(++loaded == 2){
draw();
}
};
img1.onload = img2.onload = imageLoad;
var draw = function(){
var ctx = c.getContext('2d');
ctx.drawImage(img1, 100,100);
// wait a little bit before drawing the background image
setTimeout(function(){
ctx.globalCompositeOperation = 'destination-over';
ctx.drawImage(img2, 0,0);
}, 500);
}
img1.src = "https://dl.dropboxusercontent.com/s/4e90e48s5vtmfbd/aaa.png";
img2.src = "https://picsum.photos/200/200";
<canvas id="c" width="200" height="200"></canvas>
Sorry about the previous post, I didn't properly read your post
Perhaps you could save the canvas, draw your image, and then reload the old content on top of your drawn image? Here's some JS psuedocode:
var imgData=ctx.getImageData(0,0,canvas.width,canvas.height);
ctx.drawImage('Your Image Watermark Stuff');
ctx.putImageData(imgData,0,0);
You can use KonvaJS. And then use layers for it.
<!DOCTYPE html>
<html>
<head>
<script src="https://cdn.rawgit.com/konvajs/konva/0.13.0/konva.min.js"></script>
<meta charset="utf-8">
<title>Konva Rect 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();
var imageObj = new Image();
imageObj.onload = function() {
var baseImage = new Konva.Image({
x: 50,
y: 50,
width: width,
height: height,
image: image
});
// add the shape to the layer
layer.add(rect);
// add the layer to the stage
stage.add(layer);
};
imageObj.src = 'url to your image'
</script>
</body>
</html>
A simple solution would be to use another canvas behind the first one.
Normally canvas pixels are initialized to transparent black and therefore are perfectly see-through.
If your first canvas is created opaque instead the only other option I can think to is
create a temporary canvas of the same size
draw your image in this temporary canvas
get the ImageData object of both the temporary canvas and of the original canvas
copy from the temporary canvas to the original canvas only where the original canvas is not set at the background color
In code:
var tmpcanvas = document.createElement("canvas");
tmpcanvas.width = canvas.width;
tmpcanvas.height = canvas.height;
var temp_ctx = tmpcanvas.getContext("2d");
// ... draw your image into temporary context ...
var temp_idata = temp_ctx.getImageData(0, 0, canvas.width, canvas.height);
var temp_data = temp_idata.data;
// Access the original canvas pixels
var ctx = canvas.getContext("2d");
var idata = ctx.getImageData(0, 0, canvas.width, canvas.height);
var data = idata.data;
// Find the background color (here I'll use first top-left pixel)
var br_r = data[0], bg_g = data[1], bg_b = data[2];
// Replace all background pixels with pixels from temp image
for (var i=0,n=canvas.width*canvas.height*4; i<n; i+=4) {
if (data[i] == bg_r && data[i+1] == bg_g && data[i+2] == bg_b) {
data[i] = tmp_data[i];
data[i+1] = tmp_data[i+1];
data[i+2] = tmp_data[i+2];
data[i+3] = tmp_data[i+3];
}
}
// Update the canvas
ctx.putImageData(idata, 0, 0);
this approach however will have a lower quality if the original canvas graphics has been drawn with antialiasing or if pixels of the background color are also used in the image (e.g. an object on #FFF white background where object highlights are also #FFF). Another problem is if the background color is not a perfectly uniform RGB value (this will happen if the image has been compressed with a lossy algorithm like jpeg).
All these problems could be mitigated with more sophisticated algorithms like range matching, morphological adjustments and color-to-alpha conversions (basically the same machinery used for chroma-keying).
Guess the title of the post may need editing, but for now I don't know where the problems are. I have read pages and answers to similar questions, here and elsewhere. One Stack Overflow answer is especially close, but I don't understand it.
I want a function, to draw polygons on canvas at desired coordinates and to fill them with some background image loaded from a file (large enough that no tiling is needed). Triangles would be fine for a test. Apparently I should use drawImage and clip, and to give the polygon a border, I can resuse the same path for the clip and the stroke. Also apparently I should keep the order of
- define path
- save
- clip
- drawImage
- restore
- stroke.
Also read somewhere that it is enough to load the image once. (If uou want me to quote sources for all these assumptions, I will look for where I saw them. Most of them on Stack Overflow)
The HTML is an otherwise empty
<body onload = "main ();"></body>
First approach, pretending that the browser will wait for the picture to load:
var ctx, img;
var image_path = 'bg.jpg';
function main () {
var CANVAS_SIZE = 600;
var view_field_cnv = document.createElement ('canvas');
view_field_cnv.width = CANVAS_SIZE;
view_field_cnv.height = CANVAS_SIZE;
view_field_cnv.style.border = "1px solid";
document.body.appendChild (view_field_cnv);
ctx = view_field_cnv.getContext ('2d');
img = document.createElement ('img');
img.src = image_path;
place_triangle (0, 0);
place_triangle (300, 300);
place_triangle (500, 500);
place_triangle (0, 0);
}
function place_triangle (x, y) {
console.log (x, y);
ctx.beginPath ();
ctx.moveTo (x + 10, y);
ctx.lineTo (x + 110, y);
ctx.lineTo (x + 60, y + 40);
ctx.closePath ();
img = document.createElement ('img');
img.src = image_path;
ctx.save ();
ctx.clip ();
ctx.drawImage (img, x, y);
ctx.restore ();
ctx.stroke ();
}
That draws all three triangles but no clipped images.
Second try, with drawImage inside image.onload:
var ctx;
var image_path = 'bg.jpg';
function main () {
var CANVAS_SIZE = 600;
var view_field_cnv = document.createElement ('canvas');
view_field_cnv.width = CANVAS_SIZE;
view_field_cnv.height = CANVAS_SIZE;
view_field_cnv.style.border = "1px solid";
document.body.appendChild (view_field_cnv);
ctx = view_field_cnv.getContext ('2d');
place_triangle (0, 0);
place_triangle (300, 300);
place_triangle (500, 500);
place_triangle (0, 0);
}
function place_triangle (x, y) {
console.log (x, y);
var img;
ctx.beginPath ();
ctx.moveTo (x + 10, y);
ctx.lineTo (x + 110, y);
ctx.lineTo (x + 60, y + 40);
ctx.closePath ();
img = document.createElement ('img');
img.src = image_path;
img.onload = function () {
ctx.save ();
ctx.clip ();
ctx.drawImage (img, x, y);
ctx.restore ();
ctx.stroke ();
}
}
This one does draw the clipped image, but only one triangle, the last one. Just commenting out save and restore doesn't help.
So, I don't understand loading images, saving, restoring and probably a million other things. Where be the bugs?
I see you already understand the basics of clipping:
save context, define path, clip, drawImage, restore context.
you can stroke after restore if you want the stroke to slightly overlap the clipped image.
you can stroke before clipping if you don't want the stroke to overlap the clipped image.
Here's example code and a Demo: http://jsfiddle.net/m1erickson/p0fup425/
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<style>
body{ background-color: ivory; }
canvas{border:1px solid red;}
</style>
<script>
$(function(){
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
// image loader
// put the paths to your images in imageURLs[]
var imageURLs=[];
// push all your image urls!
imageURLs.push("https://dl.dropboxusercontent.com/u/139992952/multple/norwayFlag.jpg");
imageURLs.push("https://dl.dropboxusercontent.com/u/139992952/multple/swedishFlag.jpg");
// the loaded images will be placed in images[]
var imgs=[];
var imagesOK=0;
loadAllImages(start);
function loadAllImages(callback){
for (var i=0; i<imageURLs.length; i++) {
var img = new Image();
imgs.push(img);
img.onload = function(){
imagesOK++;
if (imagesOK>=imageURLs.length ) {
callback();
}
};
img.onerror=function(){alert("image load failed");}
img.crossOrigin="anonymous";
img.src = imageURLs[i];
}
}
function start(){
// the imgs[] array now holds fully loaded images
// the imgs[] are in the same order as imageURLs[]
// clip image#1
clippingPath([10,70,50,10,90,70],imgs[0],10,10);
// clip image#2
clippingPath([10,170,50,110,90,170],imgs[1],10,110);
// append the original images for demo purposes
document.body.appendChild(imgs[0]);
document.body.appendChild(imgs[1]);
}
function clippingPath(pathPoints,img,x,y){
// save the unclipped context
ctx.save();
// define the path that will be clipped to
ctx.beginPath();
ctx.moveTo(pathPoints[0],pathPoints[1]);
// this demo has a known number of polygon points
// but include a loop of "lineTo's" if you have a variable number of points
ctx.lineTo(pathPoints[2],pathPoints[3]);
ctx.lineTo(pathPoints[4],pathPoints[5]);
ctx.closePath();
// stroke the path
// half of the stroke is outside the path
// the outside part of the stroke will survive the clipping that follows
ctx.lineWidth=2;
ctx.stroke();
// make the current path a clipping path
ctx.clip();
// draw the image which will be clipped except in the clipping path
ctx.drawImage(img,x,y);
// restore the unclipped context (==undo the clipping path)
ctx.restore();
}
}); // end $(function(){});
</script>
</head>
<body>
<p>Images clipped inside triangular canvas paths</p>
<canvas id="canvas" width=150 height=200></canvas>
<p>Original Images</p>
</body>
</html>
#markE
Images in example are gone.
I cut them from screenshot above and uploaded to our own site and clones/updated the fiddle: http://jsfiddle.net/6gawtudc/
I can't comment on previous answer because of lack of reputation points.
please someone update the answer or reupload the images
imageURLs.push("https://images.v3.webhome.nl/flags_for_polygon/norway.png");
imageURLs.push("https://images.v3.webhome.nl/flags_for_polygon/sweden.png");
I have this canvas I'm drawing onto. And I want to make image to be placed in the left lower corner.
var canvasWidth = 800;
var canvasHeight = 600;
$("#gameCanvas").attr("width", canvasWidth);
$("#gameCanvas").attr("height", canvasHeight);
var canvas = $("#gameCanvas")[0].getContext("2d");
var image = new Image();
image.src="you.png";
var player1X =0;
var imageHeight=image.height;
var player1Y = canvasHeight - imageHeight;
canvas.rect(0, 0, canvasWidth, canvasHeight);
canvas.fillStyle="#5c7792";
canvas.fill();
$(image).load(function(){
canvas.drawImage(image, player1X , player1Y);
});
but the problem is that when I use variable player1Y, it results in image being displayed at coordinates (0, canvasHeight). Actually, it results in image not being shown. But when I write canvas.drawImage(image, player1X, canvasHeight - image.height) it works perfectly.
How do I make the variable to control the posiotion of image?
Here is JSfiddle: http://jsfiddle.net/u9Ehs/10/
The problem is that the image hasn't fully loaded when you are setting imageHeight & player1Y.
Refactor your code to set all image related variables inside image.onload:
Example code and a Demo: http://jsfiddle.net/m1erickson/CSQGh/
<!doctype html>
<html>
<head>
<style>
body{ background-color: ivory; }
canvas{border:1px solid red;}
</style>
<script>
window.onload = function() {
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var player1X=0;
var player1Y;
var img=new Image();
img.onload=start;
img.src="https://dl.dropboxusercontent.com/u/139992952/stackoverflow/ship.png";
function start(){
player1Y=canvas.height-img.height;
ctx.drawImage(img,player1X,player1Y);
}
}; // end $(function(){});
</script>
</head>
<body>
<canvas id="canvas" width=300 height=300></canvas>
</body>
</html>
I want to write code that can filter the source of an image and return the data that it can be used as source for an image tag in the DOM. Therfore I created a virtual canvas. At the moment it only works with a real canvas within the DOM, even though the dimension is wrong. I only want the converted image source and no canvas in the DOM.
this is how I need it but it doesn't work: js fiddle
this one works with wrong img dimension and unwanted canvas in the DOM: js fiddle2
js:
var image = new Image();
image.onload = function () {
var helperCanvas = document.createElement('canvas');
var ctx = helperCanvas.getContext('2d');
ctx.width = image.width;
ctx.height = image.height;
ctx.drawImage(image, 0, 0, helperCanvas.width, helperCanvas.height);
var imageData = ctx.getImageData(0, 0, helperCanvas.width, helperCanvas.height);
filter(imageData);
data_as_source = ctx.putImageData(imageData, 0, 0 ).toURL();
var img = new Image();
img.src = data_as_source;
context.drawImage(img,0,0);
}
image.src = ....
In your demo code, you should be changing the temporary canvas width/height, not the context’s.
helperCanvas.width = image.width;
helperCanvas.height = image.height;
Here is code with a test filter that just turns all non-transparent pixels red.
It also renders the filtered canvas image to an image on the page.
BTW, when creating an image object, there is a new Chrome bug that can be avoided if you create like this:
var img=document.createElement("img");
Fiddle that must be viewed in Chrome or FF (IE==CORS failure): http://jsfiddle.net/m1erickson/LeGD5/
Here is code:
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<style>
body{ background-color: ivory; }
canvas{border:1px solid red;}
</style>
<script>
$(function(){
var canvas=document.createElement("canvas");
var ctx=canvas.getContext("2d");
var img=document.createElement("img");
img.onload=function(){
canvas.width=img.width;
canvas.height=img.height;
ctx.drawImage(img,0,0,img.width,img.height);
// test -- turn every non-transparent pixel red
var imgData = ctx.getImageData(0, 0, canvas.width, canvas.height);
var pixels = imgData.data; // get pixel data
for (var i = 0; i < pixels.length; i +=4)
{
// if this pixel is not transparent,
// mask it in pure red
if(pixels[i+3]>0){
pixels[i]=255; // this is the red component of the pixel
pixels[i+1]=0; // this is the green component of the pixel
pixels[i+2]=0; // this is the blue component of the pixel
pixels[i+3]=255; // this is the alpha component of the pixel
}
}
ctx.putImageData(imgData, 0, 0);
var theImage=document.getElementById("theImage");
theImage.src=canvas.toDataURL();
}
img.crossOrigin="anonymous";
img.src="https://dl.dropboxusercontent.com/u/139992952/stackoverflow/KoolAidMan.png";
}); // end $(function(){});
</script>
</head>
<body>
<img id="theImage" width=300 height=300>
</body>
</html>
you had a couple bugs in your dataURL part, but this seems to work:
var image = new Image();
image.onload = function () {
var helperCanvas = document.createElement('canvas');
var ctx = helperCanvas.getContext('2d');
ctx.width = image.width;
ctx.height = image.height;
ctx.drawImage(image, 0, 0, helperCanvas.width, helperCanvas.height);
var imageData = ctx.getImageData(0, 0, helperCanvas.width, helperCanvas.height);
filter(imageData);
ctx.putImageData(imageData, 0, 0 );
//context.drawImage(img,0,0);
data_as_source = helperCanvas.toDataURL();
var img = new Image();
img.src = data_as_source;
img.style.border="3px solid red";// for demo sake
document.body.appendChild(img); // for demo sake
}
There are plenty of questions about how to move objects around in the first place, but this is different: suppose that I (obviously) want my object to go "in front" of the background, and that my background is being changed/generated all the time. Therefore, when I move the object from one place to another, I want what would have been generated if the object wasn't blocking it to appear where it was before. How should I handle this? Should I keep a record of "what would have been generated" where the object is and plop it on when it moves, or is there a less annoying way to get around this?
Canvas has a drawing setting to do exactly what you want !
You can use the canvas context's globalCompositeOperation.
This allows you to move your "front" image on top of your "background-changing" image.
Here is some code and a Fiddle: http://jsfiddle.net/m1erickson/TrXB4/
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
<style>
body{ background-color: ivory; background-color:black; }
canvas{border:1px solid red;}
</style>
<script>
$(function(){
var canvas=document.getElementById("canvas");
var ctx=canvas.getContext("2d");
var sun = new Image();
var moon = new Image();
var earth = new Image();
function init(){
sun.src = 'http://cdn-img.easyicon.cn/png/36/3642.png';
moon.src = 'http://openclipart.org/people/purzen/purzen_A_cartoon_moon_rocket.svg';
earth.src = 'http://iconbug.com/data/26/256/e5b23e861bc9979da6c3d03b75862b7e.png';
setInterval(draw,100);
}
function draw() {
var ctx = document.getElementById('canvas').getContext('2d');
ctx.globalCompositeOperation = 'destination-over';
ctx.clearRect(0,0,350,350); // clear canvas
ctx.fillStyle = 'rgba(0,0,0,0.4)';
ctx.strokeStyle = 'rgba(0,153,255,0.4)';
ctx.save();
ctx.translate(150,150);
// Earth
var time = new Date();
ctx.rotate( ((2*Math.PI)/60)*time.getSeconds() + ((2*Math.PI)/60000)*time.getMilliseconds() );
ctx.translate(105,0);
ctx.fillRect(0,-12,50,24); // Shadow
ctx.drawImage(earth,-12,-12,48,48);
// Moon
ctx.save();
ctx.rotate( ((2*Math.PI)/6)*time.getSeconds() + ((2*Math.PI)/6000)*time.getMilliseconds() );
ctx.translate(0,28.5);
ctx.drawImage(moon,-3.5,-3.5,16,32);
ctx.restore();
ctx.restore();
ctx.beginPath();
ctx.arc(150,150,105,0,Math.PI*2,false); // Earth orbit
ctx.stroke();
ctx.drawImage(sun,100,100,96,96);
}
init();
}); // end $(function(){});
</script>
</head>
<body>
<canvas id="canvas" width=350 height=350></canvas>
</body>
</html>