620a5662ff280f5ef66a061748b68e88c2824dfb
braney
  Mon Feb 19 12:07:33 2024 -0800
make sure coverage graphs always include zero

diff --git src/hg/hgTracks/simpleTracks.c src/hg/hgTracks/simpleTracks.c
index 33ba9df..c83190c 100644
--- src/hg/hgTracks/simpleTracks.c
+++ src/hg/hgTracks/simpleTracks.c
@@ -4976,30 +4976,31 @@
                                        struct hvGfx *hvg, int xOff, int yOff, int width,
                                        MgFont *font, Color color, enum trackVisibility vis)
 /* Draw a list of linked features into a wiggle. */
 {
 struct wigCartOptions *wigCart = tg->wigCartData;
 struct preDrawContainer *pre = tg->preDrawContainer = initPreDrawContainer(insideWidth);
 struct trackDb *tdb = tg->tdb;
 boolean parentLevel = isNameAtParentLevel(tdb,tdb->track);
 
 char *autoScale = cartOptionalStringClosestToHome(cart, tdb, parentLevel, AUTOSCALE);
 if (autoScale == NULL)
     wigCart->autoScale =  wiggleScaleAuto;
 char *windowingFunction = cartOptionalStringClosestToHome(cart, tdb, parentLevel, WINDOWINGFUNCTION);
 if (windowingFunction == NULL)
     wigCart->windowingFunction = wiggleWindowingMean;
+wigCart->alwaysZero = TRUE;
 
 if (tg->summary)
     summaryToPixels(tg->summary, pre);
 else
     {
     unsigned *counts = countOverlaps(tg);
     countsToPixels(counts, pre);
     freez(&counts);
     }
 
 tg->colorShades = shadesOfGray;
 hvGfxSetClip(hvg, insideX, yOff, insideWidth, tg->height);
 tg->mapsSelf = FALSE; // some magic to turn off the link out
 wigPreDrawPredraw(tg, seqStart, seqEnd, hvg, xOff, yOff, width, font, color, vis,
 	       tg->preDrawContainer, tg->preDrawContainer->preDrawZero, tg->preDrawContainer->preDrawSize, &tg->graphUpperLimit, &tg->graphLowerLimit);