On Tue, 12 Aug 2008 22:27:28 +0800 "Lazy Fox" <lazy.fox.wu@xxxxxxxxx> wrote: > I want to draw a loopback-able dynamic curve, just like the following >picture: >http://www.nlm.nih.gov/medlineplus/ency/images/ency/fullsize/18030.jpg > >The curve is keeping going, from left to right. When reach the right border, >it will loopback to the left border, and do this again and again. > >But, when the curve loopback to the left border, the existent drawing will >not >be erased immediately. Instead, the older drawing will be erased step by >step, >where the new curve is drawing. > >Considering the efficiency. In this case, which widget should I draw on? >How can I erase the image step by step, >not erase all of it? Which function should I use? > >-- The Goo::Canvas can make those shapes easily with it's polyline. All you would need to do is write the plot in a group, then when the plot reaches the right side, remove the polyline, or the group, with remove_child(). That would blank it. Then restart drawing the polyline at the left edge. I think if you were on a DrawingArea, just draw a black filled rect over the area to blank it out. I write almost exclusively in Perl, but the c should work the same. zentara -- I'm not really a human, but I play one on earth. http://zentara.net/Remember_How_Lucky_You_Are.html _______________________________________________ gtk-list mailing list gtk-list@xxxxxxxxx http://mail.gnome.org/mailman/listinfo/gtk-list
