<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Bezier curve with matching start/end and control points is not rendered correctly" href="https://bugs.freedesktop.org/show_bug.cgi?id=101763#c4">Comment # 4</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Bezier curve with matching start/end and control points is not rendered correctly" href="https://bugs.freedesktop.org/show_bug.cgi?id=101763">bug 101763</a> from <a class="email" href="mailto:psychon@znc.in" title="Uli Schlachter <psychon@znc.in>"> Uli Schlachter</a> <pre>What happens is: _cairo_path_fixed_stroke_to_polygon is called and in its curve_to() callback it calls _cairo_spline_decompose() on this curve. The original curve is (100,100)->(200,200)->(200,200)->(100,100) (these are its four control points) and it is decomposed into the following two curves: (100,100)->(150,150)->(175,175)->(175,175) (175,175)->(175,175)->(150,150)->(100,100) The error now is 0 so points are added. The add_point callback of the spline is spline_to() and it gets the following arguments: spline to (175,175) with tangent (0,0) spline to (100,100) with tangent (-100,-100) The problem is the tangent (0,0), which means that spline_to() just calls add_fan(). At this point I am lost on what is going on. This code ignores the point argument and only uses the passed-in point. Thus, only "things around (100,100)" happen. With the following patch, things work as expected. Since I have no clue about the algorithm, I'm not sure how incorrect this is. I guess that the thought here was "tangent (0,0) can only happen if the points are all the same", which this example shows is wrong. However, since this is just a guess, I'll hope that someone with more of a clue looks at this. Oh and: The test suite should be checked for regressions. Chris? Andrea? Anyone with some clue about this?</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>