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IDProjectCategoryView StatusDate SubmittedLast Update
0014284ParaView(No Category)public2013-09-17 14:212015-01-11 08:23
ReporterAlan Scott 
Assigned ToUtkarsh Ayachit 
PriorityhighSeverityminorReproducibilityhave not tried
StatusclosedResolutionfixed 
PlatformOSOS Version
Product Versiongit-master 
Target Version4.1Fixed in Version4.1 
Summary0014284: Creating mid range buttons in the mapping data, color editor is wrong.
DescriptionMaster, Linux, local server.
Wavelet. Apply. Color by RTData.
Color Editor. Enable opacity mapping for surfaces.
Update.

Now, on the horizontal bar in the Mapping data, click about 1/4 from the right side. Without moving this button, nothing should happen. But, the colors all shift! Update. The image changes.

This is a bug.
TagsNo tags attached.
ProjectSandia
Topic Name0014284_fix_color_map
Typeincorrect functionality
Attached Files

 Relationships

  Notes
(0031616)
Ken Moreland (manager)
2013-09-24 13:53

First, I want to clarify that as far as I can tell, this bug really has nothing to do with the "Enable opacity mapping for surfaces" option. I get the described behavior regardless of whether that is enabled when clicking in the color bar, and I see no problem when adding a control point to the transparency area.

Now, the problem, as properly diagnosed by Utkarsh in a previous email, is that the diverging color map will place a white point between any two control points of sufficiently different hue and strong enough saturation. Thus, when you add the control point at the 75% mark, the white point shifts from the 50% mark (between 0% and 100%) to about the 37% mark (between 0% and 75%).

I don't think it is a good idea to change the behavior of the diverging interpolation. However, there is a trick that I think will basically solve the problem. If a control point has a sufficiently low saturation, it will be treated as the white point. Thus, if you add a control point at the 50% mark, it will hold the white point there when you add control points to its left or right.

Incidentally, the white point should not be totally white (that will cause problems with the interpolation of the colors). The appropriate color to add to the 50% mark is [0.865,0.865,0.865] (or [221,221,221] if defined in unsigned char), not [1.0,1.0,1.0].
(0031617)
Alan Scott (manager)
2013-09-24 15:07

Adding a note from Ken, explaining why to go to 221, 221, 221.

The interpolation happens in polar coordinates with the axis of singularity along the black-grey-white axis. The point is to create a smooth arc at the white point rather than a point. The problem is that the color gamut of RGB space is a point there, so the curve leaves the color gamut if you go all the way to pure white.
(0031640)
Utkarsh Ayachit (administrator)
2013-09-26 16:28

commit 4276a9822d85847bf40a7f8b5a930d4c5a7b135e
Author: Utkarsh Ayachit <utkarsh.ayachit@kitware.com>
Date: Thu Sep 26 13:59:26 2013 -0400

    BUG 0014284: Fixing LUT with white point in middle.
    
    As discussed on the bug report, adding a white-point in the middle of the
    default lookup table to overcome the shifting whitepoint problem as user added
    new control points.
    
    Change-Id: I49525d55a497d2b499d7cac63eee9911a9aa8793
(0031661)
Utkarsh Ayachit (administrator)
2013-09-30 09:21

SUMMARY
---------------------------------------------
Topics merged into master:
        0014284_fix_color_map
        13797_fix_chart_sizes
        14287_fix_proxy_delete
        14289_fix_extent_issues
        14299_fix_contour_panel
        14309-chart-selection-buggy
        fix_python_windows_coprocessing
(VTK) forward-to-vtk-master
(VTK) parallel-surface-lic-pv
        sqtk-fix-some-issues

(0031793)
Alan Scott (manager)
2013-10-30 22:35

Tested local server, Linux, using CAM data.

 Issue History
Date Modified Username Field Change
2013-09-17 14:21 Alan Scott New Issue
2013-09-17 16:52 Utkarsh Ayachit Assigned To => Utkarsh Ayachit
2013-09-17 16:53 Utkarsh Ayachit Target Version => 4.1
2013-09-24 13:53 Ken Moreland Note Added: 0031616
2013-09-24 15:07 Alan Scott Note Added: 0031617
2013-09-26 13:59 Utkarsh Ayachit Topic Name => 0014284_fix_color_map
2013-09-26 16:28 Utkarsh Ayachit Note Added: 0031640
2013-09-26 16:28 Utkarsh Ayachit Status backlog => gatekeeper review
2013-09-26 16:28 Utkarsh Ayachit Fixed in Version => git-next
2013-09-26 16:28 Utkarsh Ayachit Resolution open => fixed
2013-09-30 09:21 Utkarsh Ayachit Status gatekeeper review => customer review
2013-09-30 09:21 Utkarsh Ayachit Note Added: 0031661
2013-10-21 08:16 Utkarsh Ayachit Fixed in Version git-next => git-master
2013-10-30 22:35 Alan Scott Note Added: 0031793
2013-10-30 22:35 Alan Scott Status customer review => closed
2013-11-01 13:17 Utkarsh Ayachit Fixed in Version git-master => 4.1
2015-01-11 08:23 Utkarsh Ayachit Source_changeset_attached => ParaView master b3b25d0a
2015-01-11 08:23 Utkarsh Ayachit Source_changeset_attached => ParaView master 4276a982


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