36e24af8e99c9fc7317933d69beb0455f531d268
braney
  Thu Feb 23 14:02:10 2017 -0800
don't crash on bigMaf's when the summary hasn't been set and the track
is dense or in a >1Mb view

diff --git src/hg/hgTracks/wigMafTrack.c src/hg/hgTracks/wigMafTrack.c
index ae79ef4..1308a98 100644
--- src/hg/hgTracks/wigMafTrack.c
+++ src/hg/hgTracks/wigMafTrack.c
@@ -971,30 +971,32 @@
 }
 
 static void drawScoreOverviewBig( struct track *track,  int height,
                                int seqStart, int seqEnd,
                                struct hvGfx *hvg, int xOff, int yOff,
                                int width, MgFont *font,
                                Color color, Color altColor,
                                enum trackVisibility vis)
 /* Draw density plot or graph for overall maf scores rather than computing
  * by sections, for speed.  Don't actually load the mafs -- just
  * the scored refs from the table.
  */
 {
 struct lm *lm = lmInit(0);
 char *fileName = trackDbSetting(track->tdb, "summary");
+if (fileName == NULL)
+    return;
 struct bbiFile *bbi =  bigBedFileOpen(fileName);
 struct bigBedInterval *bb, *bbList =  bigBedIntervalQuery(bbi, chromName, seqStart, seqEnd, 0, lm);
 char *bedRow[7];
 char startBuf[16], endBuf[16];
 double scale = scaleForPixels(width);
 
 for (bb = bbList; bb != NULL; bb = bb->next)
     {
     bigBedIntervalToRow(bb, chromName, startBuf, endBuf, bedRow, ArraySize(bedRow));
     struct mafSummary *ms;
     ms = mafSummaryLoad(bedRow);
     drawScore(ms->score, ms->chromStart, ms->chromEnd, seqStart, scale,
                     hvg, xOff, yOff, height, color, vis);
 
     }