Talk:Lookup Table Editing

User Requests for TF Like Editor

It's not in the current document as one of the user requests, but I have gotten requests for a lookup table editor that looks like the transfer function editor for volumes. It's usually from someone who we just have shown volume rendering to. Once they see the power of editing colors with the transfer function, it seems strange (and in fact is strange) that the same cannot be done for lookup tables.

--Ken 10:34, 6 Jun 2006 (EDT)

As a long term goal, we could use the line chart to edit/create the transfer function. Prism was going to do that but never got to it. It will take some more work to get the ability to edit the line chart.

--Mark Richardson 11:22, 6 Jun 2006 (EDT)

Lookup Table Wizard

I've always wanted ParaView to support a set of predefined lookup tables. Although the default hue change is common and should be supported, in reality it is one of the worst choices. Having a transfer function like editor for the lookup table is a step in the right direction, it can still be a pain to set up the lookup table.

So, my recommendation is to have a transfer function like editor for the colors AND a helpful wizard to set up the lookup table. The first dialog box would set up the type of table (vary luminance, vary saturation, vary hue, gradient between two colors), the second box could establish whether the user wants luminance, saturation, hue, or color to be interpolated (continuous or in fixed steps) and whether to insert contour lines into the texture. Subsequent boxes would have table type specific options (for example the color to use when varying luminance or saturation).

Because the wizard is probably easier to implement than the transfer function like editing, we could implement that first. That way, we could modify the lookup tables in ParaView III sooner rather than later.

--Ken 11:01, 6 Jun 2006 (EDT)

Contrasting Colors

Expanding on the predefined lookup tables concept, I have a request from the support team for a lookup table where adjacent values are contrasting colors, to emphasize the boundaries between blocks in a dataset. To support datasets with more than 255 blocks, we would need one of:

• Lookup tables with more than 255 entries.
• A mapping from block ID to table entry that repeats, e.g: lut_index = block_id % lut_size.

Tshead 17:44, 3 Jul 2006 (EDT)

Alternate Lookup Table Editing

Another request from the support team: an ability to easily "highlight" an individual block under user control. This could be implemented through a combination of interactive selection and modification of the lookup table. An implied requirement would be lookup tables of arbitrary size, since this could not be used with the "repeating" lookup tables, above.

Tshead 17:44, 3 Jul 2006 (EDT)