Guides flicker under the mouse after changing the label of any guide

[Pedro de Carvalho]

Hi everyone!

Steps:
1 - open document, add guides and add a label to one of them,
2 - hover past any guide.
3 - see that some of them flicker.

If I reopen the document, the guides don't flicker any more and all the labels are present.

Arch Linux, 4.1.6 x86_64
Inkscape 0.91 r13725
RV710/M92 [Mobility Radeon HD 4530/4570/545v]

Thanks for your hard work!
p.

[jazzynico (jazzynico)]

Not reproduced on Xubuntu 15.04 with Inkscape 0.91 and trunk rev. 14380 (tested with 10 horizontal guides and 10 vertical guides -all with a label- on a simple rectangle drawing).

Could you please attach a test document we could use to try to reproduce the bug?

[Pedro de Carvalho (p.c)]

Hi jazzynico, thanks for your help.

i've built from bzr the latest inkscape and now i have Inkscape 0.91+devel r14381, with gtk3. ( hey, coloured guides!! )

The problem persists.

i've included the same file from the screencast.

i'm using the open source driver for amd, tonight i'll change to the proprietary one and check if the issue remains.

thanks again,
p.

[su_v (suv-lp)]

Flickering not reproduced with GTK2-based Inkscape 0.91+devel r14381 on OS X 10.7.5
(both available GTK+ backends tested: X11, Quartz)

[su_v (suv-lp)]

JFTR (likely unrelated to the flickering reported here) - a known issue with guide labels which still persists in latest trunk:
* Bug #1469514 “Crash when renaming a guideline label in a new session”
  https://bugs.launchpad.net/inkscape/+bug/1469514

[jazzynico (jazzynico)]

Flickering confirmed on Xubuntu 15.04, Inkscape trunk rev. 14380.
Steps:
1. Open the document attached comment #3.
2. Change a label (tested with the guide named "asdasd2", label replaced with "test").
3. Hover the guides.
4. Some of them flicker.

Note sure it's directly related, but when double-clicking the changed guide, the label field shows "P\Uffffffff", as if there were something wrong with the label encoding or a memory management problem (and it strongly reminds me a of bug I already ran into in the past...)

[jazzynico (jazzynico)]

And the following message shows on the console when opening the guides dialog on a changed guide:
----
Pango-WARNING **: Invalid UTF-8 string passed to pango_layout_set_text()

[Pedro de Carvalho (p.c)]

i just found that opening any file with guides and renaming one, reproduces the flickering.

here's a simpler file:

[su_v (suv-lp)]

On 2015-09-22 18:02 (+0200), jazzynico wrote:
> Note sure it's directly related, but when double-clicking the
> changed guide, the label field shows "P\Uffffffff", as if there were
> something wrong with the label encoding or a memory management
> problem (and it strongly reminds me a of bug I already ran into in
> the past...)

Since these steps on my system trigger a crash, it seems related to bug #1469514 after all (maybe depending on compiler or other local differences in the build env).

Other earlier related reports: Bug #1299185, Bug #1029033

[jazzynico (jazzynico)]

Thanks ~suv!

Yes, I was referring to Bug #1029033 (see comment #4...). But there are chances the flickering, invalid encoding and crash are all linked.

[jazzynico (jazzynico)]

It seems the label value is double-freed in sp-guide.cpp (http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/view/14380/src/sp-guide.cpp#L106) and in display/guideline.cpp (http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/view/14380/src/display/guideline.cpp#L231). Removing sp-guide.cpp:106 seems to fix the issue (and related crashes and encoding issues).

[jazzynico (jazzynico)]

@Martin - Could you please take a look and confirm the memory issue?

[su_v (suv-lp)]

Attaching fix proposed in the comment 11 as diff (based on trunk r14415).

[Pedro de Carvalho (p.c)]

you guys are amazing! looking forward to the next version!

[jazzynico (jazzynico)]

Patch applied to the trunk rev. 14426.

Feel free to revert if there's a more elegant or efficient fix.

[su_v (suv-lp)]

Fix backported to 0.91.x in rev 13846.