[XRender] Howto draw a hairline-trapezoid?

[Clemens Eisserer]

Hi,

I have some troubles replacing XDrawLine with XRender code.

XDrawLine seems to take care that the line "appears" 1px wide, whereas
XRender does (mathematically correct) draw overlapping line segments,
which looks like the 1px line has not a constant width.

I created two demos which show the difference:
http://picasaweb.google.com/linuxhippy/Cairo/photo#5207262578956837426

The first circle was done using XDrawLine, the second with plain
XRender (Cairo showed the same problems).

Any idea how I could mimic the "old" XDrawLine behaviour with XRender?

Thank you in advance, lg Clemens