Fix #8993 "-Ba5f1g1+0.5, grid offset affects grid, minor and major/annotated tick positions"

doc/rst/source/explain_-B.rst_

@@ -162,8 +162,10 @@ direction of increasing coordinates (i.e., to make the y-axis positive down).
    [**a**\|\ **f**\|\ **g**]\ [*stride*][*phase*][*unit*].
 
 The choice of **a**\|\ **f**\|\ **g** sets the axis item of interest, which are detailed in the Table
-:ref:`interval types <tbl-inttype>`. Optionally, append *phase* to shift the annotations by that amount (positive or
-negative with the sign being required). Optionally, append *unit* to specify the units of *stride*, where *unit* is one
+:ref:`interval types <tbl-inttype>`. Optionally, append *phase* to shift that item by that amount (positive or
+negative with the sign being required); the shift only affects the item it is appended to, so
+**-Ba5f1g1+0.5** offsets the grid lines only while **-Ba5+0.5f1+0.5g1+0.5** offsets annotations, ticks and grid
+lines alike. Optionally, append *unit* to specify the units of *stride*, where *unit* is one
 of the 18 supported :ref:`unit codes <tbl-units>`. For custom annotations and intervals, *intervals* can be given as
 **c**\ *intfile*, where *intfile* contains any number of records with *coord* *type* [*label*]. See the section
 :ref:`Custom axes <custom_axes>` for more details.

src/gmt_init.c

@@ -4275,7 +4275,6 @@ GMT_LOCAL int gmtinit_set_titem (struct GMT_CTRL *GMT, struct GMT_PLOT_AXIS *A,
 			break;
 	}
 
-	if (phase != 0.0) A->phase = phase;	/* phase must apply to entire axis */
 	if (I->active) {
 		GMT_Report (GMT->parent, GMT_MSG_INFORMATION, "Axis sub-item %c set more than once (typo?)\n", flag);
 		return (GMT_NOERROR);
@@ -4293,6 +4292,7 @@ GMT_LOCAL int gmtinit_set_titem (struct GMT_CTRL *GMT, struct GMT_PLOT_AXIS *A,
 	I->type = flag;
 	I->unit = unit;
 	I->interval = val;
+	I->phase = phase;	/* Phase shift only applies to this axis item [0] */
 	I->flavor = 0;
 	I->active = true;
 	if (!custom && in[0] && val == 0.0) I->active = false;
@@ -7752,7 +7752,7 @@ void gmtlib_explain_options (struct GMT_CTRL *GMT, char *options) {
 				"more substrings of the form [a|f|g][<stride>[+-<phase>]], where the (optional) a "
 				"indicates annotation and major tick interval, f minor tick interval, and g grid interval. "
 				"Here, <stride> is the spacing between ticks or annotations, the (optional, and with required sign)"
-				"<phase> specifies phase-shifted annotations/ticks by that amount, and the (optional) "
+				"<phase> shifts that item (only) by that amount, and the (optional) "
 				"<unit> specifies the <stride> unit [Default is the unit implied in -R]. There can be "
 				"no spaces between the substrings; just append items to make one very long string. "
 				"For custom annotations or intervals, let <intervals> be c<intfile>; see documentation for details. "

src/gmt_internals.h

@@ -157,7 +157,7 @@ EXTERN_MSC unsigned int gmtlib_unit_lookup (struct GMT_CTRL *GMT, int c, unsigne
 EXTERN_MSC void gmtlib_get_annot_label (struct GMT_CTRL *GMT, double val, char *label, bool do_minutes, bool do_seconds, bool do_hemi, unsigned int lonlat, bool worldmap);
 EXTERN_MSC unsigned int gmtlib_coordinate_array (struct GMT_CTRL *GMT, double min, double max, struct GMT_PLOT_AXIS_ITEM *T, double **array, char ***labels);
 EXTERN_MSC unsigned int gmtlib_linear_array (struct GMT_CTRL *GMT, double min, double max, double delta, double phase, double **array);
-EXTERN_MSC unsigned int gmtlib_pow_array (struct GMT_CTRL *GMT, double min, double max, double delta, unsigned int x_or_y_or_z, double **array);
+EXTERN_MSC unsigned int gmtlib_pow_array (struct GMT_CTRL *GMT, double min, double max, double delta, double phase, unsigned int x_or_y_or_z, double **array);
 EXTERN_MSC int gmtlib_prepare_label (struct GMT_CTRL *GMT, double angle, unsigned int side, double x, double y, unsigned int type, double *line_angle, double *text_angle, unsigned int *justify);
 EXTERN_MSC unsigned int gmtlib_time_array (struct GMT_CTRL *GMT, double min, double max, struct GMT_PLOT_AXIS_ITEM *T, double **array);
 EXTERN_MSC void gmtlib_get_lon_minmax (struct GMT_CTRL *GMT, double *lon, uint64_t n, double *min, double *max);

src/gmt_project.h

@@ -486,6 +486,7 @@ enum GMT_enum_tick {GMT_ANNOT_UPPER = 0,	/* Tick annotations closest to the axis
 
 struct GMT_PLOT_AXIS_ITEM {		/* Information for one type of tick/annotation */
 	double interval;		/* Distance between ticks in user units */
+	double phase;			/* Phase offset for this item's stride: (knot-phase)%interval = 0  */
 	unsigned int parent;		/* Id of axis this item belongs to (0,1,2) */
 	bool active;			/* true if we want to use this item */
 	bool generated;			/* true if this is an auto-generated interval */
@@ -505,7 +506,6 @@ struct GMT_PLOT_AXIS {		/* Information for one time axis */
 	bool use_angle[2];		/* True if we got +a<angle>|n|p for this axis, for [GMT_PRIMARY] and [GMT_SECONDARY] annotations */
 	bool skip[2];			/* Determines if we skip annotations at the lower or upper bounds of an axis [false/false] */
 	struct GMT_PLOT_AXIS_ITEM item[8];	/* see above defines for which is which */
-	double phase;			/* Phase offset for strides: (knot-phase)%interval = 0  */
 	double angle[2];		/* Annotations angle set by user, for [GMT_PRIMARY] and [GMT_SECONDARY] annotations (issue #7036) */
 	char label[GMT_LEN256];		/* Label of the axis */
 	char secondary_label[GMT_LEN256];	/* Optionally use this label when axis is right or top */

src/gmt_prototypes.h

@@ -282,7 +282,7 @@ EXTERN_MSC double gmt_inch_to_degree_scale (struct GMT_CTRL *GMT, double lon0, d
 EXTERN_MSC bool gmt_text_is_latex (struct GMT_CTRL *GMT, const char *string);
 EXTERN_MSC void gmt_map_text (struct GMT_CTRL *GMT, double x, double y, struct GMT_FONT *font, char *label, double angle, int just, unsigned int form);
 EXTERN_MSC void gmt_map_title (struct GMT_CTRL *GMT, double x, double y);
-EXTERN_MSC void gmt_linearx_grid (struct GMT_CTRL *GMT, struct PSL_CTRL *P, double w, double e, double s, double n, double dval);
+EXTERN_MSC void gmt_linearx_grid (struct GMT_CTRL *GMT, struct PSL_CTRL *P, double w, double e, double s, double n, double dval, double phase);
 EXTERN_MSC int gmt_ps_append (struct GMT_CTRL *GMT, char *source, unsigned int mode, FILE *dest);
 EXTERN_MSC char *gmt_export2proj4 (struct GMT_CTRL *GMT);
 EXTERN_MSC char *gmt_importproj4 (struct GMT_CTRL *GMT, char *szProj4, int *scale_pos, char *epsg2proj);

src/gmt_support.c

@@ -15729,9 +15729,9 @@ unsigned int gmtlib_log2_array (struct GMT_CTRL *GMT, double min, double max, do
 }
 
 /*! . */
-unsigned int gmtlib_pow_array(struct GMT_CTRL *GMT, double min, double max, double delta, unsigned int x_or_y_or_z, double **array) {
+unsigned int gmtlib_pow_array(struct GMT_CTRL *GMT, double min, double max, double delta, double phase, unsigned int x_or_y_or_z, double **array) {
 	int i, n = 0;
-	double *val = NULL, v0, v1, phase = GMT->current.map.frame.axis[x_or_y_or_z].phase;
+	double *val = NULL, v0, v1;
 
 	if (delta <= 0.0) return (0);
 
@@ -15917,13 +15917,13 @@ unsigned int gmtlib_coordinate_array(struct GMT_CTRL *GMT, double min, double ma
 
 	switch (GMT->current.proj.xyz_projection[T->parent]) {
 		case GMT_LINEAR:
-			n = gmtlib_linear_array (GMT, min, max, gmtlib_get_map_interval (GMT, GMT_LINEAR, T), GMT->current.map.frame.axis[T->parent].phase, array);
+			n = gmtlib_linear_array (GMT, min, max, gmtlib_get_map_interval (GMT, GMT_LINEAR, T), T->phase, array);
 			break;
 		case GMT_LOG10:
 			n = gmtlib_log_array (GMT, min, max, gmtlib_get_map_interval (GMT, GMT_LOG10, T), array);
 			break;
 		case GMT_POW:
-			n = gmtlib_pow_array (GMT, min, max, gmtlib_get_map_interval (GMT, GMT_POW, T), T->parent, array);
+			n = gmtlib_pow_array (GMT, min, max, gmtlib_get_map_interval (GMT, GMT_POW, T), T->phase, T->parent, array);
 			break;
 		case GMT_TIME:
 			n = gmtlib_time_array (GMT, min, max, T, array);

src/psscale.c

@@ -1428,7 +1428,7 @@ GMT_LOCAL void psscale_draw_colorbar (struct GMT_CTRL *GMT, struct PSSCALE_CTRL
 				if (A->type == GMT_TIME)
 					gmt_plot_timex_grid(GMT, PSL, P->data[0].z_low, P->data[P->n_colors-1].z_high, 0.0, width, GMT_GRID_UPPER);
 				else
-					gmt_linearx_grid(GMT, PSL, P->data[0].z_low, P->data[P->n_colors-1].z_high, 0.0, width, dx);
+					gmt_linearx_grid(GMT, PSL, P->data[0].z_low, P->data[P->n_colors-1].z_high, 0.0, width, dx, A->item[GMT_GRID_UPPER].phase);
 			}
 		}
 		else if (!GMT->current.map.frame.no_frame) {	/* When no -B we annotate every CPT bound which may be non-equidistant, hence this code (i.e., we cannot fake a call to -B) */
@@ -1812,7 +1812,7 @@ GMT_LOCAL void psscale_draw_colorbar (struct GMT_CTRL *GMT, struct PSSCALE_CTRL
 				if (A->type == GMT_TIME)
 					gmt_plot_timex_grid (GMT, PSL, P->data[0].z_low, P->data[P->n_colors-1].z_high, 0.0, width, GMT_GRID_UPPER);
 				else
-					gmt_linearx_grid (GMT, PSL, P->data[0].z_low, P->data[P->n_colors-1].z_high, 0.0, width, dx);
+					gmt_linearx_grid (GMT, PSL, P->data[0].z_low, P->data[P->n_colors-1].z_high, 0.0, width, dx, A->item[GMT_GRID_UPPER].phase);
 			}
 			PSL_setorigin (PSL, 0.0, 0.0, -90.0, PSL_FWD);	/* Rotate back so we can plot y-axis */
 			/* Copy x-axis annotation and scale info to y-axis.  We don't need to undo this since gmt_end_module will restore it for us */

test/psbasemap/axis_phase.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+#
+# Test that a phase shift appended to a -B interval only shifts the item it belongs to.
+# See https://github.com/GenericMappingTools/gmt/issues/8993
+#
+# No baseline PostScript is needed: we compare the plot records from a single -B call
+# with those from the two-call sequence that has always placed the items correctly.
+
+# Keep the moveto/lineto records and the annotation strings of the plot itself.  The
+# two-call reference draws the frame twice, hence the sort -u.
+extract () {
+	sed -n '/BeginObject/,/EndObject/p' "$1" | grep -E '^(N )?-?[0-9]+ -?[0-9]+ (M|D)|^\(.*\) (mr|bc) Z' | sort -u
+}
+
+# 1. Phase on the grid interval only: annotations and ticks must stay put
+gmt psbasemap -R0/10/0/10 -JX5c -Ba5f1g1+0.5 -P > one.ps
+gmt psbasemap -R0/10/0/10 -JX5c -Ba5f1 -P -K > two.ps
+gmt psbasemap -R -J -Bg1+0.5 -O >> two.ps
+extract one.ps > one.txt
+extract two.ps > two.txt
+diff one.txt two.txt > fail
+
+# 2. Repeating the phase on every item still shifts everything alike
+gmt psbasemap -R0/10/0/10 -JX5c -Ba5+0.5f1+0.5g1+0.5 -P > all.ps
+gmt psbasemap -R0/10/0/10 -JX5c -Ba5+0.5f1+0.5 -P -K > allref.ps
+gmt psbasemap -R -J -Bg1+0.5 -O >> allref.ps
+extract all.ps > all.txt
+extract allref.ps > allref.txt
+diff all.txt allref.txt >> fail
+
+# 3. The annotations of case 1 are the unshifted 0, 5 and 10
+cat << EOF > annot_answer.txt
+0
+5
+10
+EOF
+grep -E '^\(.*\) bc Z' one.ps | tr -d '()' | awk '{print $1}' | sort -n -u > annot.txt
+diff annot.txt annot_answer.txt >> fail

test/pscoast/pscoast_180.sh

@@ -3,5 +3,5 @@
 
 ps=pscoast_180.ps
 
-gmt pscoast -R-10/180/20/50 -JM6i -Bxa20g20 -Bya20g20+10 -Dc -G221/204/170 -A0/0/1 -P -Xc -K > $ps
-gmt pscoast -R0/180/20/50 -JM6i -Bxa20g20 -Bya20g20+10 -Dc -G221/204/170 -A0/0/1 -O -Y2.5i >> $ps
+gmt pscoast -R-10/180/20/50 -JM6i -Bxa20g20 -Bya20+10g20+10 -Dc -G221/204/170 -A0/0/1 -P -Xc -K > $ps
+gmt pscoast -R0/180/20/50 -JM6i -Bxa20g20 -Bya20+10g20+10 -Dc -G221/204/170 -A0/0/1 -O -Y2.5i >> $ps

test/psxy/units.sh

@@ -2,7 +2,7 @@
 # Test that symbol units is picked up from datafile, symbol option, and GMT default, in that order
 ps=units.ps
 # No unit in data, PROJ_LENGTH_UNIT decides the size
-echo "-2 2 1" | gmt psxy -JX6i -R-3/3/-3/3 -Ba1g1+0.5 -BWeSn -P -Sc -Ggray --PROJ_LENGTH_UNIT=inch -Xc -K > $ps
+echo "-2 2 1" | gmt psxy -JX6i -R-3/3/-3/3 -Ba1+0.5g1+0.5 -BWeSn -P -Sc -Ggray --PROJ_LENGTH_UNIT=inch -Xc -K > $ps
 # Unit in data, whatever PROJ_LENGTH_UNIT says should be ignored
 echo "2 2 1i" | gmt psxy -J -R -O -K -Sc -Ggray --PROJ_LENGTH_UNIT=point >> $ps
 # No unit in data, PROJ_LENGTH_UNIT decides the size