[PyX-devel] Dash length relative to line width

[Otto T. <zz...@ma...>]

Hi,

I just recently discovered PyX and I must say that it looks really
promising. Especially you got one really important thing right that
most (if any) other packages fail with, namely you use (La)TeX for
typesetting the text. And that is number one reason for me to try out
PyX.

However, I have found one thing that I miss. The length of dashes and
space in dashed, dotted, and dashdotted is absolute and not relative
to line width. So if I draw a THICK dotted line I get a semi solid
line instead. Therefore, I propose to add the possibility to define
the dashes in terms of the current line width, something like the
attached patch. 

It does the following: 

1: The init function of dashes takes an additional argument
normdist. If it is set to true it emitts code like
[0 currentlinewidth mul 3 currentlinewidth mul ] 0 setdash
instead of
[0 3 ] 0 setdash
BTW: What version of python do you require? Is it ok to use True and
False instead?

2: However, for this to work the linewidth must be set before we set
the dash so I introduced a class member in PathStyle named prio
(default 0) and I set this prio to 1 in linewidth. Then in
decoratedpath::_writestyles I do a reverse sort on prio before we
write the styles to file.

3: I wasn't sure if it should be default behavior so I
introduced dottedn, dashedn, and dashdottedn for now.


I don't know if this takes care of all cases for dashed lines (can I
draw a dashed line without decoratedpath?) However, it works for the
attached test case (dotted-test.py) so it is at least a proof of concept.

What do you think, is this a wanted feature?


/Otto