Cross browser canvas using nodeJS for signature not found function

Question

I am trying to create a canvas on a page that updates itself whenever a user draws something on it. However, it looks like the following code fragment (from index.html) is causing an error

  socket.on("drawn_complete",function(data){
    ctx.putImageData(data.image,0,0);
    console.log("Everthing worked technically");
});

Here is the error that appears on my console:

Uncaught TypeError: Failed to execute 'putImageData' on 'CanvasRenderingContext2D': No function was found that matched the signature provided

my data.image is what is returned from the following code:

ctx.getImageData(0,0,200,100); // ctx is canvas.getContext("2d")

Here is my canvas in my html:

 <canvas id="myCanvas" width="200" height="100"
style="border:1px solid #000000;">
</canvas>

Here is the complete JS node:

    var http = require("http")
var server = http.createServer(handler).listen(1337);
console.log("Server created at 127.0.0.1:1337");
var io = require("socket.io").listen(server);


function handler(req,res)
{
    console.log("Client Connected");
    res.writeHead(200,{"Content-type": "text/plain"});
    res.end("Hello World");
}


io.sockets.on("connection",function(socket){
    socket.on("drawing",function(data){
        var image = data["image"];
        io.sockets.emit("drawn_complete",image);
    });
});

Drawing is done when the user holds and moves the mouse inside my canvas:

Here is the code:

  c.onmousedown = function(evt){
moving = true
};
c.onmousemove = function(evt){
    if(moving == true)
    {
        console.log("holding and moving");

        var x = evt.clientX - rect.left;
        var y = evt.clientY - rect.top;
        console.log("X: " + x + " Y: " + y);
        ctx.fillRect(x,y,1,1);
        socket.emit("drawing",{"image": ctx.getImageData(0,0,200,100)});

    }
};
c.onmouseup = function(evt){
    moving = false;
};

UPDATE

Here is the enitre script:

<script>

window.onload = function(){
var socket = io.connect("http://localhost:1337");
socket.on("drawn_complete",function(data){
    ctx.putImageData(data.image,0,0);
    console.log("Everthing worked technically");
});


var c = document.getElementById("myCanvas");
var moving = false;
console.log(c);
 var ctx = c.getContext("2d");
 var rect = c.getBoundingClientRect();
c.onmousedown = function(evt){
moving = true
};
c.onmousemove = function(evt){
    if(moving == true)
    {
        console.log("holding and moving");

        var x = evt.clientX - rect.left;
        var y = evt.clientY - rect.top;
        console.log("X: " + x + " Y: " + y);
        ctx.fillRect(x,y,1,1);
        socket.emit("drawing",{"image": ctx.getImageData(0,0,200,100)});

    }
};
c.onmouseup = function(evt){
    moving = false;
};
};



</script>

UPDATE As Palahniuk suggested, I tried serializing the image before fixing it:

 var stringfy = JSON.stringify(ctx.getImageData(0,0,200,100));
        socket.emit("drawing",{"image": stringfy});

It looks like the console is throwing the same error anyway

(2) @Palanik, . , , , - :

:

var stringfy = ctx.getImageData(0,0,200,100);
        console.log(stringfy)
        var sent = JSON.stringify(stringfy);
        socket.emit("drawing",{"image": sent});

socket.on("drawn_complete",function(data){
imageData = JSON.parse(data.image);
console.log(imageData);
ctx.putImageData(imageData,0,0);
console.log("Everthing worked technically");

});

, console.log of imageData Oject , ImageData. , . :

{"height":100,"width":200,"data":{"0":0,"1":0,"2":0,"3":0,"4":0,"5 etc... }

, , . java, ,

ImageData object = (ImageData) imageData // Is there a way to do this?

Answer 1

- canvas.toDataURL();.

Base64 ( MIME- ​​).

var canvas = getMyCanvas(),
    ctx = canvas.getContext("2d"),
    encodedImageData = canvas.toDataURL(),
    image = new Image();

image.src = encodedImageData;
ctx.drawImage(image, x, y, w, h...);

, .
HTML <img src="data:image/png;base64,...">.

, toDataURL :

 canvas.toDataURL("image/jpeg", 0.5);`

, - ( 0 1).

, - , , .png (, , , , ,).

, Android 2.2 , IE9, , Mobile Safari 5.1 ( iPad) .toDataURL.
, iPads, API- HTML5, .

Answer 2

ImageData . imagedata .

=== ===

- :

canvasData = ctx.getImageData(0,0,200,100)}
myData = {
        height : canvasData.height,
        width : canvasData.width,
        raw : canvasData.data
};
socket.emit("drawing",{"image": myData});

Receiver

imgData = ctx.getImageData(myData.width, myData.height);
for (var i = 0; i < myData.raw.length) {
        imgData.data[i] = myData.raw[i];
}
ctx.putImageData(imgData, 0, 0);

. .