easiest way to clear a canvas is to use the context clearRect function and pass the canvas co-ordinate space width & height. This would clear the entire canvas. And you can redraw the shapes you want to remain on screen.
You can also clear portion of a screen, using the above function by passing the position and size of the ellipse you draw but if there are multiple shapes in that position then they would also get erased, you will have to manage redrawing them. check out the canvas sample in gwt-examples, it gives a very good demo of how to use front and back canvas for complex rendering. Using this technique gives you smooth graphics and also better performance. On Mon, Jan 21, 2013 at 1:31 AM, membersound <[email protected]> wrote: > Hi, > > I draw ellipses on a canvas on click, and want to remove them on > doubleclick. > Therefor I track them in a list with coordinates tracked, and iterate if > on mouseclick. I'm already detecting if an element is under mouseclick or > not. > > BUT: how do I remove that element from the canvas? Would I have to remove > it from my list, then clear and redraw the whole canvas? > Can't I just somehow "clear" the ellipse selected? > > -- > You received this message because you are subscribed to the Google Groups > "Google Web Toolkit" group. > To view this discussion on the web visit > https://groups.google.com/d/msg/google-web-toolkit/-/kAQ-dtNuGz4J. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/google-web-toolkit?hl=en. > -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
