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Color Picker Value Bug
Closed, ResolvedPublic

Description

Blender Version
Broken: 0284392c489

Short description of error
When dragging the Value up to the brightest point in the color picker, the value goes beyond the maximum of 1 and instead up to 16.292.
The halfway point of Value on the color picker is also not 0.5 but instead 0.18.
There seems to be some conflict with the color picker graphic and the color correction in the editors.

Event Timeline

Brecht Van Lommel (brecht) triaged this task as Needs Information from User priority.

When dragging the Value up to the brightest point in the color picker, the value goes beyond the maximum of 1 and instead up to 16.292.

I can't reproduce this one. Are you using the default color picker or did you change it in the user preferences? Are you just dragging the vertical value slider with the mouse?

The halfway point of Value on the color picker is also not 0.5 but instead 0.18.

This by design, the middle show 0.5 in display space which is about 0.18 in scene linear space. We could make it 0.5 in scene linear space but then darker colors will only have a little bit of space at the bottom of the slider.

I can reproduce it.

If you set the color picker to HSV, then move the V all the way to 1, and then return to RGB, the values are over 1 (16.2917, 16.2917, 16.2917).

@Julien Kaspar (JulienKaspar), does the issue happen in the daily build from https://builder.blender.org/download for you?

If it doesn't, I think we need to upgrade OpenColorIO in the studio.

@Brecht Van Lommel (brecht) All of the color picker types act out but the default only once you change the HSV sliders to the maximum.
I noticed that it does actually work as it should (mostly) for the HSV sliders but the RGB ones all act wrong.
These three don't match with the HSV values or the graphic color picker.

I for one get the same bug with builds from builder.blender.org

@Brecht Van Lommel (brecht) I am currently working with the latest compiled version of Blender 2.8.

Right, I suspect this is happening due issues with an older version of OpenColorIO, which the Linux studio builds and macOS buildbot are still using. The Linux buildbot on the other hand was upgraded and so would not have the bug, if my theory is right.

@Julien Kaspar (JulienKaspar) did you try with a linux buildbot build? or did you update ocio in the studio already?

@Bastien Montagne (mont29) I just update Blender with the buildbot. How can/should I update the OpenColorIO manually? Are you having the same issue?

@Julien Kaspar (JulienKaspar) you downloaded blender from https://builder.blender.org/download ? Then you have nothing to do but try that blender and see if things work or not (just to be sure, buildbot has nothing to do with the build script you have at the studio ;) ).

Studio OCIO update is job for @Sergey Sharybin (sergey) or @Brecht Van Lommel (brecht)!

And no, here everything seems to work fine.

It seems to work fine now on Mac after the libs were updated.

Brecht Van Lommel (brecht) claimed this task.

We still need to update the libs in the studio, will be done soon. But seems no bug in Blender itself.

Sam Van Hulle (sam_vh) reopened this task as Open.

Just wanted to report that this has been back for a few days. Current build with the problem is e4153946ad1.

This is weird. Studio sues OCIO 1.1.0, which is would guess is an updated version.

@Brecht Van Lommel (brecht), i guess this is due to the for for the default view transform of the display. Guess a view somewhere is to be initialized to IMB_colormanagement_init_default_view_settings.

I think the bug is that the view transform is involved at all in HSV conversion, to me it seems HSV should be remain linear.

@Brecht Van Lommel (brecht) I would expect the same from the RGB values, no? Only involve the view transform in displaying the colours, not the numbers? I just assumed all of the values were always linear, and wherever I'd see an actual colour displayed, that would have been transformed. Or am I seeing things wrong?

The RGB values are linear. I would also expect the view transform to be for displaying the colors only. It apparently was changed to fix T39627: HSL color sliders acting funky, but it seems like the wrong solution.