Question

I load an image in my web application using the following code :

    Bitmap oCanvas = (Bitmap)Bitmap.FromFile(Server.MapPath("Images\\2.jpg"));
    Graphics g = Graphics.FromImage(oCanvas);
    Response.ContentType = "image/jpeg";
    oCanvas.Save(Response.OutputStream, ImageFormat.Jpeg);
    Response.End();
    g.Dispose();
    oCanvas.Dispose();

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Now how to write on this image by mouse and save the result as an image ?

Answer 1

In order to let the end user write on the image using his mouse, you need a client-side ActiveX control on your page. That will only work on Windows PCs and it can get pretty complicated quickly.

Another option would be to host the image in a Flash application, which could run on all platforms (except iOS 🙂 You can find an example of that here: http://active.tutsplus.com/tutorials/games/create-a-basic-drawing-application-in-flash/

And yet a third option would be to use an HTML5 Canvas + client-side JavaScript. Not all browsers support the HTML5 (pre-)standard yet. A good example you can find here: http://www.williammalone.com/articles/create-html5-canvas-javascript-drawing-app/#demo-complete, and another one here: http://www.codicode.com/art/how_to_draw_on_a_html5_canvas_with_a_mouse.aspx

Good luck!