[Xcb] xcb, xrender and thin lines

[Vincent Torri]

hello,

i'm writing the xcb-based xrender engine for evas. Its interface requires
a function that draws thin lines, like what the Bresenham algorithm would
draw.

For the xlib engine, raster uses XRenderCompositeDoublePoly for drawaing
thin lines (and thin polygons too). That function is quite complicated and
maybe there is a better idea. Does someone as an idea about how to do that
with xcb, which maybe can be simpler ?

Apart that line stuff, i'll also need to write a similar function to
XRenderFindVisualFormat. Maybe this one can fit in xcb_aux. What do you
think ?

thank you

Vincent