Thank you, Julian. This was a very helpful observation. In our actual application there is an underlying JPEG image, and we wanted the image data to show through the drawn lines, so GXcopy doesn't do what I want, but GXand does, and it renders instantly!
That was driving me crazy. Also, sorry to respond in this non-standard way, but I started this thread with a work email but now work is blocking mail from xorg, so I had to switch to personal mail. Thanks again, - Paul *Julian Bradfield* jcb+fdt at julianbradfield.org <xorg%40lists.x.org?Subject=Re%3A%20Slow%20rendering%20when%20GC.line_style%20%3D%20LineOnOffDash&In-Reply-To=%3C25483.8043.752740.986387%40high.jcbradfield.org%3E> *Sat Dec 3 10:05:31 UTC 2022* - Previous message (by thread): Slow rendering when GC.line_style = LineOnOffDash <https://lists.x.org/archives/xorg/2022-December/061187.html> - Next message (by thread): [ANNOUNCE] transset 1.0.3 <https://lists.x.org/archives/xorg/2022-December/061189.html> - *Messages sorted by:* [ date ] <https://lists.x.org/archives/xorg/2022-December/date.html#61188> [ thread ] <https://lists.x.org/archives/xorg/2022-December/thread.html#61188> [ subject ] <https://lists.x.org/archives/xorg/2022-December/subject.html#61188> [ author ] <https://lists.x.org/archives/xorg/2022-December/author.html#61188> ------------------------------ On 2022-12-03, Farrington, Paul <Paul.Farrington at fisglobal.com <https://lists.x.org/mailman/listinfo/xorg>> wrote: >* We’ve noticed that XDrawRectangle where the GC.line_style is LineOnOffDash >has *>* gotten slower in recent X Server releases. We’ve observed this on both Linux *>* RH8 and FBSD 11.4 and above. There are two sample programs pasted below, one *>* which draws 5 rectangles with LineSolid and one which draws 5 rectangles with *>* LineOnOffDash. There is also a makefile for RH8. Running the two programs with *>* an X Server version 1.18.4, both programs render the rectangles instantly. But *>* in X Server version 1.20.8 or more obviously 1.20.14, rendering the dashed *>* line rectangles is much slower. You can watch them being drawn on the screen, *>* whereas the solid line version still renders instantly. * Interesting. It's still a bug, but your sample programs use an odd way to draw lines - setting the GC function to Clear, leaving foreground and background at default, and using the plane_mask to specify the color. If you draw dashed lines the normal way (with GC function Copy and the color specified in foreground), it's fine - it's the non-trivial plane_mask that appears to be triggering the problem. Quite how Xorg can take human-noticeable time to do masked dashed line draw, I can't imagine! -- Paul Farrington p...@eastshore.com linkedin.com/in/paulfarrington1 <http://www.linkedin.com/in/paulfarrington1> 510-914-0088 (cell)
