<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type"> <title></title> </head> <body bgcolor="#ffffff" text="#000000"> this isnt a cario specific solution but if you only have a few different, but very complex primitives that you need to hit test, could render them as opaque to a separate surface each with their own color, then sample the color to determine which primitive you hit.   if you need:  you can scale up / down your drawing to increase / decrease the amount of precision you need in your clicks.  -- you do have to worry about antialiasing at the edges of polys tho you may ( i'm still new to using cairo ) be able to turn that off.  <br> <br> Kalle Vahlman wrote: <blockquote cite="mid:177e83dd0708272340p67e9ddc3gbe6107a97721ada9@mail.gmail.com" type="cite"> <pre wrap="">2007/8/28, Deepankar Sharma <a class="moz-txt-link-rfc2396E" href="mailto:deepankar.sharma@gmail.com"><deepankar.sharma@gmail.com></a>: </pre> <blockquote type="cite"> <pre wrap="">I am just beginning to play with cairo and am currently battling with this problem. I have a few cairo curves (drawn with cairo_curve_to) on the screen. I am storing the begin, end, thickness and control points for the curves. When I detect a click, I want to check if I just clicked over a curve. In essence, I want to check if an x,y co-ordinate lies on a curve. Any ideas / hints / approaches ? </pre> </blockquote> <pre wrap=""> Maybe you could keep the resulting paths around and use cairo_in_stroke()? <a class="moz-txt-link-freetext" href="http://cairographics.org/manual/cairo-cairo-t.html#cairo-in-stroke">http://cairographics.org/manual/cairo-cairo-t.html#cairo-in-stroke</a> Not sure how efficient it is though, nor if you really want that level of precision (usually within user interfaces you'll want to allow the user to miss a little to prevent frustration of pixel-perfect clicking if the targets are small). </pre> </blockquote> </body> </html>