5dc1d6e658ab009f27314e192340275a6bb70237
max
  Tue Jun 2 16:20:48 2026 -0700
Add colorFields trackDb setting for bigBed/bigGenePred color scheme switching

Adds a new trackDb statement `colorFields` that renders a "Color by:" dropdown
in the track controls page, letting users switch among multiple pre-computed
color schemes stored as extra bigBed fields containing R,G,B strings.

The `default="label"` key renames the standard itemRgb option in the dropdown.
Other entries name extra bigBed fields whose R,G,B values override itemRgb when
selected. When a non-default scheme is active, a "(Coloring by: label)" suffix
appears in the track long label.

Changes:
- hui.c/hui.h: new colorFieldsCfgUi() rendered inside bedScoreCfgUi() for bigBed
- bigBedTrack.c: colorFieldIdx lookup + per-item filterColor override + longLabel suffix
- tagTypes.tab: register colorFields for bigBed and bigGenePred
- trackDbLibrary.shtml, trackDbDoc.html, trackDbHub.v3.html, changes.html: documentation

refs #26253

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

diff --git src/hg/htdocs/goldenPath/help/trackDb/trackDbHub.v3.html src/hg/htdocs/goldenPath/help/trackDb/trackDbHub.v3.html
index 6f9ed1d915c..4742c1f32b4 100755
--- src/hg/htdocs/goldenPath/help/trackDb/trackDbHub.v3.html
+++ src/hg/htdocs/goldenPath/help/trackDb/trackDbHub.v3.html
@@ -613,30 +613,37 @@
 <TABLE class="settingsTable" id="bigBed_-_Item_or_Region_Track_Settings">
 <THEAD><TR><TD><DIV ID="bigBed_intro" class="intro"></DIV></TD></TR></THEAD>
     <TR VALIGN=TOP><TH><IMG class='toggle oneSection'>
         &nbsp;bigBed - Item or region track settings
     </TH></TR>
     <TR VALIGN=TOP><TD class="bigBed"><IMG class='toggle detail'>
         <div class="format">
             <code>type bigBed &lt;3-12&gt; [+/.]</code></div>
     </TD></TR>
     <TR VALIGN=TOP><TD class="bigDataUrl"><IMG class='toggle detail'>
         <div class="format"><code class="level-required">bigDataUrl &lt;url/relativePath&gt;</code></div>
     </TD></TR>
     <TR VALIGN=TOP><TD class="itemRgb"><A name="itemRgb"></A><IMG class='toggle detail'>
         <div class="format"><code class="level-base">itemRgb on</code></div>
     </TD></TR>
+
+    <TR VALIGN=TOP><TD class="colorFields"><A name="colorFields"></A><IMG class='toggle detail'>
+        <div class="format">
+            <code class="level-new">colorFields default="&lt;label&gt;" &lt;fieldName&gt;="&lt;label&gt;" ...</code>
+        </div>
+    </TD></TR>
+
     <TR VALIGN=TOP><TD class="colorByStrand"><A name="colorByStrand"></A><IMG class='toggle detail'>
         <div class="format"><code class="level-base">colorByStrand &lt;red,green,blue&gt;
                                             &lt;red,green,blue&gt;</code></div>
     </TD></TR>
     <TR VALIGN=TOP><TD class="denseCoverage"><A name="denseCoverage"></A><IMG class='toggle detail'>
         <div class="format"><code class="level-full">denseCoverage &lt;maxVal&gt;</code></div>
     </TD></TR>
     <TR VALIGN=TOP><TD class="labelOnFeature"><A name="labelOnFeature"></A><IMG class='toggle detail'>
         <div class="format"><code class="level-full">labelOnFeature &lt;on/off&gt;</code></div>
     </TD></TR>
     <tr valign=top><td class="extraDetailsTable"><a name="extraDetailsTable"></a><img alt="" class='toggle detail'>
         <div class="format"><code class="level-deprecated">extraDetailsTable &lt;url/relativePath&gt;</code>
         </div>
     </td></tr>
     <tr valign=top><td class="extraTableFields"><a name="extraTableFields"></a><img alt="" class='toggle detail'>