[bug #65910] [pic] some dashed ellipse sizes produce irregular dashes

[Deri James]

Follow-up Comment #9, bug #65910 (group groff):

In some cases pic can't draw an arc of the desired length in one go, it has to
break it down into multiple pieces.

If you imagine a very flat ellipse and a dash length which wraps around the
foci there is no one circlar arc which can draw the line, you probably need to
draw this as three joined lines the middle one will be tightest curve with the
smallest radius to the foci, then two other arcs to complete the dash. Pic has
some code to do multiple arcs to stroke one dash, which I don't understand,
but in the attached files I have numbered the actual arcs emitted by pic. The
"good" ellipse does have 20 dashes, but this equates to 34 arcs.

I felt better when I found out that inkscape can get a dashed ellipse wrong
when you select the longest dash length and fiddle with the offset!



(file #56258, file #56259)

    _______________________________________________________

Additional Item Attachment:

File name: 4x1.5-debug-numbered.pdf       Size: 7KiB
   
<https://file.savannah.gnu.org/file/4x1.5-debug-numbered.pdf?file_id=56258>

File name: 8x3-debug-numbered.pdf         Size: 9KiB
    <https://file.savannah.gnu.org/file/8x3-debug-numbered.pdf?file_id=56259>


    AGPL NOTICE

These attachments are served by Savane. You can download the corresponding
source code of Savane at
https://git.savannah.nongnu.org/cgit/administration/savane.git/snapshot/savane-05e690add83a426b3815318aa602289c02cdb981.tar.gz


    _______________________________________________________

Reply to this item at:

  <https://savannah.gnu.org/bugs/?65910>

_______________________________________________
Message sent via Savannah
https://savannah.gnu.org/

signature.asc
Description: PGP signature