[Paraview-developers] [EXTERNAL] Re: Color Scale Editor Design

[Scott, W Alan]

Burlen,
There are actually numerous bugs/ feature holes in the implementation of the categorical color tables.  These need to be fixed - categorical color tables is a powerful feature.  I will write up bug reports on known issues this afternoon.

Alan

From: burlen [mailto:burlen.loring at gmail.com]
Sent: Wednesday, July 10, 2013 12:52 PM
To: Utkarsh Ayachit
Cc: ParaView Developers; Scott, W Alan
Subject: [EXTERNAL] Re: [Paraview-developers] Color Scale Editor Design

Hi Utkarsh,

Cool!! Thanks!



3) limit the number of control points used by the widget. The default max number of control points used by the widget would be something reasonable like 16 but the user could increase if desired via a qt spin control. The active control points in the widget would be evenly spaced across the scale and during interaction as the user moves the visible control points the widget would handle linearly re-interpolating the position of the hidden control points automatically.

I'm not sure I follow the need for this. With support for categorical

colors, some of the use-cases with large number of control points may

become unnecessary.

I tried to use it in a few ways just now but this didn't seem to work. Any docs for the new features?  Here's a 256 color LUT attached. How could I use the categorical colors with this?

[cid:image001.png at 01CE7EF4.D8DBB340]

On 07/10/2013 11:23 AM, Utkarsh Ayachit wrote:

Burlen,



1) combine the opacity widget and the color scale widget.



Good idea! Let me see how much effort that's going to be. Hopefully,

it's not too bad to add support for this.



I think it would also be very useful to display a histogram of the active scalar plotted using the LUT colors in the new widget.



We have thought of this in the past. As useful that this is, it's a

bit tedious to implement. I'll put that as a feature request to be

addressed in future for now.



2) add a "mirror scale" option.



Should be too hard to add.





Also, with the current color scale widget it's pretty difficult to interactively manipulate LUT's with many color points (eg when 256 colors are explicitly specified). The control points are too close together to select and they way it's implemented now you'd need to move surrounding control points as well.



Burlen, for such cases you may want to look into using the newly added

"categorical color" support rather than adding 256 control points.





3) limit the number of control points used by the widget. The default max number of control points used by the widget would be something reasonable like 16 but the user could increase if desired via a qt spin control. The active control points in the widget would be evenly spaced across the scale and during interaction as the user moves the visible control points the widget would handle linearly re-interpolating the position of the hidden control points automatically.



I'm not sure I follow the need for this. With support for categorical

colors, some of the use-cases with large number of control points may

become unnecessary.



Utkarsh

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