change the color of the Pen helper path

[Bug Importer]

When I'm creating straight lines with the Bezier tool,
sometimes i have to trace over black lines. The current
Bezier tool drag line is 'red'. There isn't a way to change the default
color of the drag line to white or some other color.
-Christopher

[prkos (prkos)]

Yes, while drawing a Bezier path the active part between the last drawn node and the mouse pointer is always red (while the path between completed nodes is always green). So if you're trying to draw a Bezier path on a red background its very hard to see it (impossible if the background color matches the help red path color). This means you're trying to draw but can't see what youre doing exactly.

It would maybe be useful to make the Bezier path change its color automatically according to the background over which its drawn. Its equivalent to the way the Selector arrows work (resize and rotate); if they're over blue bg - theyre yellow, if over red bg - theyre blue, if over green bg - theyre purple etc...

[Erik Johnson (ekriirke)]

Inverting the line would be a good option as well (XOR the pixels underneath)

[prkos (prkos)]

The same goes for node handles.

[su_v (suv-lp)]

Lowering importance to 'Medium' in accordance with <http://wiki.inkscape.org/wiki/index.php/Bug_management>

[Jabiertxof (jabiertxof)]

This patch improve a bit the situation.
It use the same way as the line handles, also make handles contrast on dark places a bit lower. Is too agersive in my point of view. The handles of the line handles not be tweaked :(.

Please confirm is a good idea add to current trunk, or if not maybe is time to hide the handles line color workaround.

[Jabiertxof (jabiertxof)]

My work over XOR. Coulden't get it working

[Jabiertxof (jabiertxof)]

With this patch also handles pencil.

[Jabiertxof (jabiertxof)]

A helper to XOR code: http://zetcode.com/gfx/cairo/compositing/

[Jabiertxof (jabiertxof)]

I do two diferent XOR attemps. Is just base code for BPaths (pen, pencil helper lines and more).
I attach here with a test SVG I made.
No one of both is perfect, but I spend a lot of time finetuning it, I think is dificult get too much better display.
The bad thing: It slow the dreawing process and seems dificult to fix because it render the down drawing in each movement. Maybe we finaly need to say goodby to XOR or Difference BPaths because his slowest, and going to previous patch well implemented in each canvas item.

[Jabiertxof (jabiertxof)]

XOR colored version proposal

[Jabiertxof (jabiertxof)]

XOR "White" version

[Jabiertxof (jabiertxof)]

@jazzynico: About the change of milestone, I want to ask if is better remove the first patch based code applied to handles a long time ago to 0.91+devel. Not look much well, too much contrast and is a incomplete work.

Thanks in advance, Jabier.

[jazzynico (jazzynico)]

@Javier: no problem for the milestone (I just felt it was an enhancement more than a bug fix).
As for the patch, I can't say for now. I'll try to test later today or tomorrow.

[jazzynico (jazzynico)]

Thanks for your patches!
Tested on Xubuntu 16.04, Inkscape trunk rev. 15009.

As you wrote each patch has its culprits:
- Both show temporary artifacts when moving the mouse just after snapping to a point (see 172063-ColorPatchTest.png).
- The color one is difficult to use on a green background.
- The white one is difficult to use on a white background (see 172063-WhitePatchTest.png).
Apparently not an easy issue to solve.

The good point is that I see no performance regression, even with a quite big file.

[Jabiertxof (jabiertxof)]

@jazzynico, thanks!

Just for try to clarify:
There is 3 patch:
1 patch use the actual workaround for handles with the color a bit retouched for better display,
2 and 3 is a rewrite to use XOR, with the problems I describe.
2 and 3 need a deep evaluation and implementation, Its just test case.
1 could be implemented easy, if in 0.92 ping me, or if think is better on 0.93 I think is better remove the similar code for pen handles, to give better consistence.

To answer:
Patch 1 0.92 or 0.93?
If 0.93, remove handles code for 0.92? Is only remove or comment a few lines.
If 0.92, I could do a new patch to cover better. Also for 0.93 :)

Cheers, Jabier.

[Jabiertxof (jabiertxof)]

I forget say 2 and 3 are working currently with pen/pencil tool for UX review.

[jazzynico (jazzynico)]

@Jabier - I suggest you ask the list. I really don't know what's the best option for 0.92. I feel the current behavior is not that bad and that the additional patch can be postponed to 0.93, but if you think it can be improved for 0.92, why not.

[Jabiertxof (jabiertxof)]

@jazzynico, thanks for testing.
About the performance regression, it happens in long red curves -pen tool- moving fast trought the window. Anyway I work now throught VNC and maybe this is the problem -I think no, because the cursor update his position but...
To me the best scenario is:
x0.92 make a patch for helper lines like the handles one -over blue to view well- but with a bit more transparent the white line. (patch 1)
x0.93 evaluate improve the XOR code, if we can discard performance regression
x0.93 allow configure in preferences dialog the color/transparency of the helper lines on the whole aplication.

I put it on the mailing list. But previously I complete the patch 1 to well test it in all Canvas Items.

Cheers, Jabier.

[Jabiertxof (jabiertxof)]

Here are the Patch 1 filled to manage handles and other tools using BPaths.
This patch is non compositing patch, only add a translucen white line to helper paths.

[Jabiertxof (jabiertxof)]

I just commit 0.92.x and trunk with #20 patch a bit modified. About the other patch. I think similar XOR methods introduce confussion instead clarify. Realy think this last option give the better result to the user.

[Jabiertxof (jabiertxof)]

In my TODO list to 0.93 I want to have a 3 color inkscape widgets in preferences to set the colors for helper paths

[Jabiertxof (jabiertxof)]

colors and opacity

[mray (mrayyyy)]

Hi - thanks for reporting this bug, I've manually migrated it to Inkscape's new bug tracker on GitLab, and closed it here.

Please feel free to file new bugs about the issues you're seeing at http://inkscape.org/report.

Moved to: https://gitlab.com/inkscape/inbox/issues/350
Closed by: https://gitlab.com/mray