inkscape 20sec on unselect with node tool a long nodes path

Based on tests with archived builds (on OS X 10.7.5):
- not reproduced with Inkscape 0.91,
- not reproduced with lp:inkscape rev <= 14527,
- reproduced with lp:inkscape rev >= 14537,
- reproduced with Inkscape 0.92pre4;
the slow tool switch / deselection of nodes in the node tool context possibly was exposed by changed between 14527 and 14537:
https://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/changes/14537

I've located the change that is most likely the culprit:

https://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/14529#src/display/sp-canvas.cpp

Look at lines 1036 in the diff. Commenting out 'items->remove(item);' increases the speed of trunk an awful lot. It brings the de-selection time down to the selection time, which is about right.

From LiamW: well you can't just comment out the line, you'll get hilarious dangling pointer errors later on.

So we'll probably have to pick through the problem some more.

Mc and I figured out why the commit mentioned in #3 regressed performance.

I just committed a fix in
  https://gitlab.com/inkscape/inkscape/commit/8052d8eadcfa0201ee0ec7a1230bbf91c470da79
which should restore previous performance.

As this shows the data structure used here is not ideal some further optimizations in this code might be possible in future.

Oh my god, thank you! Much much better! with 14,347 nodes it now only
takes 4.5 seconds to come out of node editing mode. That's quite an
improvement!

Thanks everyone for taking a look at this.
-C

On Mon, Mar 12, 2018 at 6:43 PM, Eduard Braun <email address hidden> wrote:
> Mc and I figured out why the commit mentioned in #3 regressed
> performance.
>
> I just committed a fix in
> https://gitlab.com/inkscape/inkscape/commit/8052d8eadcfa0201ee0ec7a1230bbf91c470da79
> which should restore previous performance.
>
> As this shows the data structure used here is not ideal some further
> optimizations in this code might be possible in future.
>
> ** Changed in: inkscape
> Status: Confirmed => Fix Committed
>
> ** Changed in: inkscape
> Assignee: (unassigned) => Eduard Braun (eduard-braun2)
>
> ** Changed in: inkscape
> Milestone: None => 0.93
>
> ** Tags added: backport-proposed
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1652100
>
> Title:
> inkscape 20sec on unselect with node tool a long nodes path
>
> Status in Inkscape:
> Fix Committed
>
> Bug description:
> Hi inkscape frezze on node tool unselect, select is about 1/2 sec in
> my machine, unselect moe than twenty. Hapends in trunk r.15348 and in
> 0.92.x. r.15276
>
> Original reported by CR with the link to the test file. I try today to
> fix and no look, seems deleting __mmap std::map<ShapeRecord,
> boost::shared_ptr<PathManipulator> > is too slow in this case. I try
> to fix but no lucky :(.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/inkscape/+bug/1652100/+subscriptions

Backported to 0.92.x in
  https://gitlab.com/inkscape/inkscape/commit/8052d8eadcfa0201ee0ec7a1230bbf91c470da79