User283571144 posted
Hi sweetSteal,
According to your description, I suggest you could firstly use jquery toDataURL to convert the canvas to image/png format.
Then we could use ajax to send this image to web method in code-behind.
At last we could save the image in the web method.
Aspx:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="GetCanvasFromClientToServer.aspx.cs" Inherits="AspNetNormalIssue.Webform.GetCanvasFromClientToServer" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.2.min.js" type="text/javascript"></script>
<script>
function drawShapes() {
var canvas = document.getElementById("SigCnv");
var context = canvas.getContext("2d");
context.fillStyle = "Blue";
context.fillRect(0, 0, 200, 200);
context.beginPath();
context.lineWidth = "4";
context.strokeStyle = "Green";
context.fillStyle = "Yellow";
context.arc(150, 100, 50, 20, Math.PI * 2, false);
context.stroke();
context.fill();
}
</script>
</head>
<body onload="drawShapes()">
<form id="form1" runat="server">
<div>
<canvas id="SigCnv" name="SigCnv" width="250" height="50" style="border: solid;"></canvas>
<input type="button" id="btnSave" name="btnSave" value="Save the canvas to server" />
<script type="text/javascript">
// Send the canvas image to the server.
$(function () {
$("#btnSave").click(function () {
var image = document.getElementById("SigCnv").toDataURL("image/png");
image = image.replace('data:image/png;base64,', '');
$.ajax({
type: 'POST',
url: 'GetCanvasFromClientToServer.aspx/UploadImage',
data: '{ "imageData" : "' + image + '" }',
contentType: 'application/json; charset=utf-8',
dataType: 'json',
success: function (msg) {
alert('Image saved successfully !');
}
});
});
});
</script>
</div>
</form>
</body>
</html>
Webmethod:
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace AspNetNormalIssue.Webform
{
public partial class GetCanvasFromClientToServer : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
[WebMethod()]
public static void UploadImage(string imageData)
{
string fileNameWitPath = @"D:\" + DateTime.Now.ToString().Replace("/", "-").Replace(" ", "- ").Replace(":", "") + ".png";
using (FileStream fs = new FileStream(fileNameWitPath, FileMode.Create))
{
using (BinaryWriter bw = new BinaryWriter(fs))
{
byte[] data = Convert.FromBase64String(imageData);
bw.Write(data);
bw.Close();
}
}
}
}
}
Best Regards,
Brando
