Dropping image on canvas causes image to jump.

Question

When I drop an image on a canvas in AIR the image "jumps" a few pixels to several from the current mouse location.
So if the mouse is at location (12, 12) and I drop the image it may appear at (10, 14), or (15, 20), or whatever. It doesn't appear to be a consistent offset like I would expect if this were caused by using global to local mouse position thing (but I'm not ruling that out anyway).
Secondly, when I then drag to move the image on the canvas the drag proxy will again jump many pixels from the mouse cursor.
Here is my mouse down handler:
            private function dragBegin(event:MouseEvent):void
                  var dragInitiator:Image = Image(event.currentTarget);
                var ds:DragSource = new DragSource();
                ds.addData(dragInitiator, "img");   
                var dragProxy:Image = new Image();
                dragProxy.source = event.currentTarget.source;
                DragManager.doDrag(dragInitiator, ds, event, dragProxy);
And the drop handler:
        private function dragDropHandler(event:DragEvent):void
               var image:Image = Image(event.dragSource.dataForFormat("img"));
               image.x = event.localX;
               image.y = event.localY;
               UIComponent(event.currentTarget).addChild(device);
What am I doing wrong that is causing this jumping?
Thanks,
-Mark

Answer 1

Hi,
I think the only way to do this is to use a jsp with a servlet, where the servlet would create the image and send it over as a stream, while the jsp would call on the link of the servlet and display that image using the HTML <IMG> tag.
So, if you have a servlet, lets call it PictureServlet.
This is what you would do in your servet:
// create that image and send it over from the doPost/doGet method of the servlet
public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
response.setContentType("image/jpg"); // set the stream to be a JPEG image
ServletOutputStream sos = response.getOutputStream(); // create the output stream
BufferedImage bImg = createImage(); // this is where you write on your image using canvas and return it as a Bufferedimage
ImageIO.write(bImg,"JPG",sos); // write the image to the stream as JPEG
sos.close(); // close the output stream
public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        doPost(request, response);
    } This is how you would get that image and display it in your JSP.
<img src="../servlet/PictureServlet" name="pic">Note the path might be different, depending on the hierarchy of where jsps and servlets are stored on the server.
I hope this helps,
Val.