WIP. Fix jump detection in gmtmap_jump_x and re-enable psxy/nojump

src/gmt_map.c

@@ -1161,11 +1161,16 @@ GMT_LOCAL int gmtmap_jump_x (struct GMT_CTRL *GMT, double x0, double y0, double
 	dx = x1 - x0;
 	if (fabs (dx) > map_half_size) {	/* Possible jump; let's see how far apart those longitudes really are */
 		/* This test on longitudes was added to deal with issue #672, also see test/psxy/nojump.sh */
-		double last_lon = 0.0, this_lon = 0.0, dummy = 0.0, dlon;
+		double last_lon = 0.0, this_lon = 0.0, dummy = 0.0, dlon, d0, d1, mid_lon;
 		gmt_xy_to_geo (GMT, &last_lon, &dummy, x0, y0);
 		gmt_xy_to_geo (GMT, &this_lon, &dummy, x1, y1);
 		gmt_M_set_delta_lon (last_lon, this_lon, dlon);	/* Beware of jumps due to sign differences */
-		if (fabs (dlon) < half_lon_range) /* Not going the long way so we judge this to be no jump */
+		if (fabs (dlon) < half_lon_range) /* Gap is less than half the region width so we judge this to be no jump */
+			return (0);
+		mid_lon = 0.5 * (GMT->common.R.wesn[XLO] + GMT->common.R.wesn[XHI]);
+		gmt_M_set_delta_lon (mid_lon, last_lon, d0);	/* Longitudes relative to the middle of the region */
+		gmt_M_set_delta_lon (mid_lon, this_lon, d1);
+		if (fabs (d1 - d0) < 180.0)	/* The straight path is the short way, so no jump */
 			return (0);
 		/* Jump it is */
 		if (dx > map_half_size)	return (-1);	/* Cross left/west boundary */

test/baseline/psxy.dvc

@@ -1,5 +1,6 @@
 outs:
-- md5: fd04135cb8226c86f8f109e5dca463fe.dir
+- md5: 6dbbc75aa2f8752b1450e4f22b7656f2.dir
   nfiles: 147
   path: psxy
   hash: md5
+  size: 9555170

test/psxy/nojump.sh

@@ -1,8 +1,6 @@
 #!/usr/bin/env bash
-# GMT_KNOWN_FAILURE
 # Added after issue #672 which exposed a map jump that should not happen
 # Fixed in r14052 but we keep this test in case it resurfaces
-# Well, bottom panel plots the wrong closed polygon
 ps=nojump.ps
 cat << EOF > t.txt
 115 -20