Javascript Canvas in ASP.net
Question
I'm trying to draw an image on a canvas in a Visual Studio application and then have that image get displayed on a PDF file after clicking a button. I'm using javascript and C#. So far I created a Web Page called “A” and in the .aspx page I created a canvas and button, but I'm unsure how I can get this image in the .aspx.cs page (where it says “ Image Here ”) so it can write to the PDF file. I'm pretty sure my code currently puts my canvas image in base 64. Any help is greatly appreciated. Thanks!
//A.aspx:
//Create canvas and save as base 64
<head>
<script type="text/javascript">
$(document).ready(function() {
$('#saveButton').click(saveDrawing);
});
</script>
</head>
<canvas id ="canvas1" class="pad" width="198" height="55"></canvas>
<input type="button" name="saveButton" id="saveButton" value="Save Drawing">
<script type="text/javascript">
function saveDrawing() {
var canvas = document.getElementById("canvas1");
var context = canvas.getContext("2d");
var imgData = canvas.toDataURL();
//window.open(imgData); //Not sure if I need this or not
}
//A.aspx.cs: Code Behind
public void Method(string A)
{
PdfStamper pdfStamper = new PdfStamper(
pdfReader,
new FileStream(newFile, FileMode.Create)
);
AcroFields pdfForm = pdfStamper.AcroFields;
//This is where I need to get the image from A.aspx
pdfForm.SetField("Picture is", (**Image Here**));
}
1 answers
solution1
0 2012-11-06 18:23:25
I made a jsFiddle with the basics of what you need to do. Since you are using Asp.Net, your whole page is in a form. When you click the submit button it should post the data from the canvas in a hidden field and you can grab the data from imageData in the page load.
I am not sure if you will have to do any conversion of the data before you try to save it to the PDF but this should give you a good start.
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