<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> </head> <body> <div class="moz-cite-prefix">On 11/10/20 1:43 AM, Sam Varshavchik wrote: </div> <blockquote type="cite" cite="mid:CAMO9ifvf9dyVvjOq2xHTz6GhRMF6j_LmKFHSvxq74go20b6y8w@mail.gmail.com"> <pre class="moz-quote-pre" wrap="">libxcb has no involvement with actual drawing or rendering. It's sole function is to transmit requests, and all their parameters, to the X server which then executes them. libxcb is really just a very thin mapping layer between a functional API and X protocol messages.</pre> </blockquote> Great, then we can rule out any XCB issues. <blockquote type="cite" cite="mid:CAMO9ifvf9dyVvjOq2xHTz6GhRMF6j_LmKFHSvxq74go20b6y8w@mail.gmail.com"> <blockquote type="cite"> <pre class="moz-quote-pre" wrap=""> xcb_poly_line (connection, XCB_COORD_MODE_ORIGIN, window, foreground, 5, diamond); </pre> </blockquote> <pre class="moz-quote-pre" wrap=""> This would be the PolyLine request: <a class="moz-txt-link-freetext" href="https://www.x.org/releases/X11R7.7/doc/xproto/x11protocol.html#requests:PolyLine">https://www.x.org/releases/X11R7.7/doc/xproto/x11protocol.html#requests:PolyLine</a> </pre> </blockquote> Thanks, I've now read the polyline section thoroughly, some other sections not as thoroughly, and skimmed the rest of the document. <blockquote type="cite" cite="mid:CAMO9ifvf9dyVvjOq2xHTz6GhRMF6j_LmKFHSvxq74go20b6y8w@mail.gmail.com"> <pre class="moz-quote-pre" wrap="">Note the nuanced detail of how various coordinates get interpreted and the meticulous detail in defining the actual drawn pixels. </pre> </blockquote> Yes, the documentation is pretty exact in many aspects. <blockquote type="cite" cite="mid:CAMO9ifvf9dyVvjOq2xHTz6GhRMF6j_LmKFHSvxq74go20b6y8w@mail.gmail.com"> <pre class="moz-quote-pre" wrap="">You're going to have to sift through the specification, to get the details of what happens. That's just one example (whose answer I don't recall off the top of my head), you'll have to decipher what's happening in your case similarly. </pre> </blockquote> I can't find anything that reasonably will account for the behaviour I see, although I have not yet fully comprehended the protocol. From the polyline section: "The lines join correctly at all intermediate points, and if the first and last points coincide, the first and last lines also join correctly." - Even without defining "join correctly" my example on my machine joins the lines differently. My diamonds are looking like this (missing right corner pixel): <pre> X X X X X X X </pre> Except when starting and ending at the right corner, in which case my diamonds look like this: <pre> X X X X X X X X</pre> My reasoning is: Entire shape is within clipping/bounding (as far as I can see at least), the line joins should "join correctly", the polylines consist of the same points (another test I made) but still the diamond is only rendered correctly if the rightmost corner is first/last. To me this seems inconsistent. How does it render on your machine? </body> </html>