Html5 Canvas drawing problem

The trouble is - when I mousedown, then mousemove(about 1-2px), the point, which I draw disappears. It is because I clear context each mousemove, but I dont know how to fix开发者_运维百科 it.

Not quite sure what the problem is, but I think the problem is that rounding is causing your new line to not be a full pixel and thus empty. Could this be the problem? If so the solution is to make the move just a little bigger if it is small.