Linesort breaking straight lines

[abey79]

Linesort breaking straight lines

[abey79]

I just pushed b1b4ab7 to better visualise what happens.

[abey79]

The root cause is the fact that your SVG paths are made of (straight) curves instead of lines:

(Notice the "c" in the d attribute.)

vpype converts everything to poly lines on input, and will quantise curves based on the --quantization parameter. Apparently, the implicit linesimplify of the read command is not able to completely cope with it It does, to some extend, eg. compare:

vpype read blockhouse.svg show -d
vpype read -s blockhouse.svg show -d

(You'll need to update vpype before, I just added -d.)

I suggest you look at whatever generated the file to see if you can have it generate lines instead of curves. It may very well be that the situation will improve when #31 is fixed too.

[ithinkido]

That - d is very useful. I can not use the -s , I am getting an "not valid integer' error, but still i get the idea, the lines are not lines, but curves and that is not great for optimization.

[abey79]

Sorry the -s was meant to be after the read, not before. I fixed it up there.

[abey79]

Hey @ithinkido, I revisited this following the resolution of #34, and although the implicit simplify in read still has issues (#31), an explicit linesimplify now cleans your example file nicely:

[ithinkido]

Super clean !! Thanks

[haschdl]

sorry to open and old topic, but since my issue is identical to the one initially reported here by @ithinkido , I decided writing a comment instead of opening a new issue. I read @abey79 comment and while I understand that "vpype converts everything to poly lines on input" I still would like to know if there is a way to prevent that, when my primary goal is to use only linemerge.

In other words, I would like to use the power of linemerge and leave the rest intact. The reason for that is what the initial post mentioned, it affects the plot results.

Here is an example, on the right the result after linemerge

The SVG is created using Processing and its arc() command (using bezier() has the same effect).
I am using vpype 1.9.0, the entire command is:

vpype read --single-layer 20220329174853.svg linemerge write out.svg

For reference purposes only, Adobe Illustrator's simplify command "recreates" the curves, while vpype's linesimplify would, as described, reduce the number of line segments.

[abey79]

Hello @haschdl. No, there is currently no way around the linearisation at all. I'm kind of thinking of getting there, but it'll take an entire rewrite of pretty much everything, so it could be years until that happens (if at all).

As a side note, a "line-merge-only" Python script could conceivably be hacked without much hassle using svgelements to extract path elements and using the same merging algorithm as vpype, since it only considers end points. But that would be just a script. There is currently no way to fit this into vpype.

[ithinkido]

@haschdl take a look at this. It should do what you are looking for. https://github.com/fablabnbg/inkscape-chain-paths

[haschdl]

@abey79 thank you, I understand it now. I will check the alternatives.
@ithinkido thanks for the tip! inkscape-chain-paths looks like the right solution, but unfortunately it didn't work in Inskcape 1.1 with my drawing. It could be a good starting point to get hands-on, as it is just one script. Are you using the extension?

[ithinkido]

Yes, I used it an hour ago in 1.1. Still seems to work for me.