Treat stroke symbols like other symbols

doc/rst/source/explain_symbols.rst_

@@ -83,10 +83,15 @@
     **-Sy**\ *size*
         y-dash (\|). *size* is the length of a short vertical (y-dir) line segment.
 
-    **Note**: The uppercase symbols **A**, **C**, **D**, **G**, **H**, **I**, **N**,
+    **Notes**: (1) The uppercase symbols **A**, **C**, **D**, **G**, **H**, **I**, **N**,
     **S**, **T** are normalized to have the same *area* as a circle with
     diameter *size*, while the *size* of the corresponding lowercase symbols
-    refers to the diameter of a circumscribed circle.
+    refers to the diameter of a circumscribed circle. (2) The stroke-only symbols
+    **x**, **y**, **+** and **-** will derive their pen widths from the symbol size
+    and their pen color from |-G| or |-C|. In that sense they behave as the other
+    symbols (but no outline).  You can override this behavior by specifying |-W|,
+    modify it by adjusting :term:`MAP_STROKE_WIDTH` [15%], or set it to zero to
+    rely on pen defaults (and |-W|).
 
     The next collection shows five symbols that require two or more parameters, and
     some have optional modifiers to enhance the symbol appearance.

doc/rst/source/gmt.conf.rst

@@ -868,6 +868,13 @@ MAP Parameters
         cap is reversed, i.e., *85/90* will draw a r = 5 radius circle at the
         center of the map with less frequent radial lines there.
 
+    **MAP_STROKE_WIDTH**
+        Used to convert non-fillable (**x**, **y**, **+** and **-**) symbol sizes
+        to the width of the pen used to stroke these symbols. Give a factor in the
+        0-1 range (e.g., 0.18) or specify a percentage (e.g., 10%) [15%]. **Note**:
+        If set to 0 then no such conversion takes place and pen settings must rely on
+        **-W** or module defaults.
+
     **MAP_SCALE_HEIGHT**
         Sets the height (> 0) on the map of the map scale bars drawn by
         various programs [default is **5p**].

src/gmt_constants.h

@@ -257,6 +257,9 @@ enum GMT_time_period {
 #define GMT_TEXT_CLEARANCE	15	/* Clearance around text in textboxes, in percent */
 #define GMT_TEXT_OFFSET		20	/* Offset of text from refpoint, in percent */
 
+/* Conversion from symbol size to pen width for stroke-only symbols x,y,+, - */
+#define GMT_SYMBOL_SIZE_TO_PEN_WIDTH	15	/* 15% */
+
 #define GMT_N_MAX_MODEL	20	/* No more than 20 basis functions in a trend model */
 
 #define GMT_PAIR_COORD		0	/* Tell gmt_get_pair to get both x and y as coordinates */

src/gmt_defaults.h

@@ -154,6 +154,8 @@ struct GMT_DEFAULTS {
 	double map_graph_extension;		/* If map_frame_type is graph, how must longer to make axis length. [7.5%] */
 	double map_graph_origin[2];		/* x- and y-origin of graph axis if graph-origin is in use [data 0/0] */
 	double map_graph_shift;			/* Extra offset for title to avoid overwriting the centered y-axis */
+	double map_stroke_width;		/* Conversion factor from symbol size to stroke pen width (non-fillable symbols only) */
+	char map_stroke_width_unit;		/* Either % or not */
 	unsigned int map_annot_oblique;	/* Controls annotations and tick angles etc. [GMT_OBL_ANNOT_ANYWHERE] */
 	unsigned int map_grid_cross_type[2];	/* 0 = normal cross, 1 = symmetric tick, 2 = asymmetric tick */
 	unsigned int map_logo_justify;		/* Justification of the GMT timestamp box [1 (BL)] */

src/gmt_init.c

@@ -208,7 +208,7 @@ struct GMT_parameter {
 	const char *name;
 };
 
-/* These are the active GMT5+ keywords, containing no backwards-compatible variants.
+/* These are the active >= GMT5 keywords, containing no backwards-compatible variants.
  * Also, some grouped keywords such as FONT and FONT_ANNOT are also not listed since they are not in gmt.conf.
  * If new keywords are added they need to be added here as well as to gmt_keywords.txt, plus
  * specific entries in both gmtlib_setparameter and gmtlib_getparameter, and gmt.conf.rst */
@@ -314,6 +314,7 @@ static struct GMT_parameter GMT_keyword_active[]= {
 	{ 0, "MAP_ORIGIN_Y"},
 	{ 0, "MAP_POLAR_CAP"},
 	{ 0, "MAP_SCALE_HEIGHT"},
+	{ 0, "MAP_STROKE_WIDTH"},
 	{ 0, "MAP_TICK_LENGTH_PRIMARY"},
 	{ 0, "MAP_TICK_LENGTH_SECONDARY"},
 	{ 0, "MAP_TICK_PEN_PRIMARY"},
@@ -6616,6 +6617,9 @@ GMT_LOCAL void gmtinit_conf_classic (struct GMT_CTRL *GMT) {
 	/* MAP_POLAR_CAP */
 	GMT->current.setting.map_polar_cap[0] = 85;
 	GMT->current.setting.map_polar_cap[1] = 90;
+	/* MAP_STROKE_WIDTH */
+	GMT->current.setting.map_stroke_width = GMT_SYMBOL_SIZE_TO_PEN_WIDTH / 100.0;	/* Given as percentage */
+	GMT->current.setting.map_stroke_width_unit = '%';
 	/* MAP_SCALE_HEIGHT */
 	GMT->current.setting.map_scale_height = 5 * pt;	/* 5p */
 	GMT->current.setting.given_unit[GMTCASE_MAP_SCALE_HEIGHT] = 'p';
@@ -11237,6 +11241,19 @@ unsigned int gmtlib_setparameter (struct GMT_CTRL *GMT, const char *keyword, cha
 				GMT->current.setting.map_polar_cap[1] = inc[GMT_X];
 			}
 			break;
+		case GMTCASE_MAP_STROKE_WIDTH:
+			dval = atof (value);
+			if (value[len] == '%') {
+				dval /= 100.0;	/* Got factor as a percentage */
+				GMT->current.setting.map_stroke_width_unit = '%';
+			}
+			else	/* Got a fraction */
+				GMT->current.setting.map_stroke_width_unit = '\0';
+			if (dval < 0.0)
+				error = true;
+			else
+				GMT->current.setting.map_stroke_width = dval;
+			break;
 		case GMTCASE_MAP_SCALE_HEIGHT:
 			dval = gmt_M_to_inch (GMT, value);
 			if (dval <= 0.0)
@@ -12798,6 +12815,12 @@ char *gmtlib_getparameter (struct GMT_CTRL *GMT, const char *keyword) {
 			else
 				snprintf (value, GMT_LEN256, "%g/%g", GMT->current.setting.map_polar_cap[0], GMT->current.setting.map_polar_cap[1]);
 			break;
+		case GMTCASE_MAP_STROKE_WIDTH:
+			if (GMT->current.setting.map_stroke_width_unit == '%')	/* Report as percentage */
+				snprintf (value, GMT_LEN256, "%g%%", GMT->current.setting.map_stroke_width * 100.0);
+			else	/* Just a factor */
+				snprintf (value, GMT_LEN256, "%g", GMT->current.setting.map_stroke_width);
+			break;
 		case GMTCASE_MAP_SCALE_HEIGHT:
 			snprintf (value, GMT_LEN256, "%g%c", GMT->current.setting.map_scale_height * gmt_M_def_scale(GMTCASE_MAP_SCALE_HEIGHT), gmt_M_def_unit(GMTCASE_MAP_SCALE_HEIGHT));
 			break;

src/gmt_keywords.txt

@@ -127,6 +127,7 @@ MAP_ORIGIN_X			# x-value of lower-left corner of map relative to page [1i]
 MAP_ORIGIN_Y			# y-value of lower-left corner of map relative to page [1i]
 MAP_POLAR_CAP			# Modify gridline spacing for polar caps
 MAP_SCALE_HEIGHT		# Height of scale bar on maps
+MAP_STROKE_WIDTH		# Percent of strokable-only symbol size for stroke pen width [15%]
 MAP_TICK_LENGTH			# Length of major and minor frame axes ticks [does not go in gmt.conf]
 MAP_TICK_LENGTH_PRIMARY		# Length of major and minor primary frame axes ticks
 MAP_TICK_LENGTH_SECONDARY	# Length of major and minor secondary frame axes ticks

src/psxy.c

@@ -501,6 +501,15 @@ GMT_LOCAL void psxy_plot_end_vectors (struct GMT_CTRL *GMT, double *x, double *y
 	PSL_command (GMT->PSL, "U\n");
 }
 
+GMT_LOCAL bool psxy_is_stroke_symbol (int symbol) {
+	/* Return true if cross, x, y, - symbols */
+	if (symbol == PSL_CROSS) return true;
+	if (symbol == PSL_XDASH) return true;
+	if (symbol == PSL_YDASH) return true;
+	if (symbol == PSL_PLUS)  return true;
+	return false;
+}
+
 static int usage (struct GMTAPI_CTRL *API, int level) {
 	/* This displays the psxy synopsis and optionally full usage information */
 
@@ -1706,6 +1715,13 @@ EXTERN_MSC int GMT_psxy (void *V_API, int mode, void *args) {
 					PSL_command (PSL, "/QR_outline false def\n");
 			}
 
+			if (psxy_is_stroke_symbol (S.symbol)) {	/* These are only stroked, not filled */
+				/* Unless -W was set, compute pen width from symbol size and get pen color from G or z->CPT */
+				if (!Ctrl->W.active)	/* No pen width given, compute from symbol size unless conversion factor is 0 */
+					current_pen.width = (gmt_M_is_zero (GMT->current.setting.map_stroke_width)) ? GMT->current.setting.map_default_pen.width : GMT->current.setting.map_stroke_width * S.size_x * PSL_POINTS_PER_INCH;
+				if (current_fill.rgb[0] > -0.5)	/* Color given, use it for the stroke */
+					gmt_M_rgb_copy (current_pen.rgb, current_fill.rgb);
+			}
 			if (gmt_geo_to_xy (GMT, in[GMT_X], in[GMT_Y], &plot_x, &plot_y)) continue;	/* NaNs on input */
 
 			if (gmt_M_is_dnan (plot_x)) {	/* Transformation of x yielded a NaN (e.g. log (-ve)) */
@@ -2065,9 +2081,11 @@ EXTERN_MSC int GMT_psxy (void *V_API, int mode, void *args) {
 						}
 						break;
 					case GMT_SYMBOL_TEXT:
-						if (Ctrl->G.active && !outline_active)
+						if (fill_active && !outline_active)
 							PSL_setcolor (PSL, current_fill.rgb, PSL_IS_FILL);
-						else if (!Ctrl->G.active)
+						else if (fill_active)
+							PSL_setcolor (PSL, current_fill.rgb, outline_setting);
+						else
 							PSL_setfill (PSL, GMT->session.no_rgb, outline_setting);
 						(void) gmt_setfont (GMT, &S.font);
 						direction = (S.azim) ? gmt_azim_to_angle (GMT, in[GMT_X], in[GMT_Y], 0.1, S.angle) : S.angle;

src/psxyz.c

@@ -136,6 +136,15 @@ struct PSXYZ_DATA {
 	struct GMT_CUSTOM_SYMBOL *custom;
 };
 
+GMT_LOCAL bool psxyz_is_stroke_symbol (int symbol) {
+	/* Return true if cross, x, y, - symbols */
+	if (symbol == PSL_CROSS) return true;
+	if (symbol == PSL_XDASH) return true;
+	if (symbol == PSL_YDASH) return true;
+	if (symbol == PSL_PLUS)  return true;
+	return false;
+}
+
 static void *New_Ctrl (struct GMT_CTRL *GMT) {	/* Allocate and initialize a new control structure */
 	struct PSXYZ_CTRL *C;
 
@@ -1352,6 +1361,14 @@ EXTERN_MSC int GMT_psxyz (void *V_API, int mode, void *args) {
 
 			if (S.base_set & GMT_BASE_ORIGIN) data[n].flag |= 32;	/* Flag that base needs to be added to height(s) */
 
+			if (psxyz_is_stroke_symbol (S.symbol)) {	/* These are only stroked, not filled */
+				/* Unless -W was set, compute pen width from symbol size and get pen color from G or z->CPT */
+				if (!Ctrl->W.active)	/* No pen width given, compute from symbol size */
+					current_pen.width = (gmt_M_is_zero (GMT->current.setting.map_stroke_width)) ? GMT->current.setting.map_default_pen.width : GMT->current.setting.map_stroke_width * S.size_x * PSL_POINTS_PER_INCH;
+				if (current_fill.rgb[0] > -0.5)	/* Color given, use it for the stroke */
+					gmt_M_rgb_copy (current_pen.rgb, current_fill.rgb);
+			}
+
 			if (Ctrl->W.cpt_effect) {
 				if (Ctrl->W.pen.cptmode & 1) {	/* Change pen color via CPT */
 					gmt_M_rgb_copy (Ctrl->W.pen.rgb, current_fill.rgb);

test/psxy/all_psxy_symbols.txt

@@ -1,5 +1,5 @@
 # All the basic psxy symbols + two customs to fill the table
-# ALl dimensions hardwired to be in inches
+# All dimensions hardwired to be in inches
 0.5	0.5	1i	-
 1.5	0.5	1i	+
 2.5	0.5	1i	a

test/psxy/plot_symbols.sh

@@ -4,7 +4,7 @@
 
 ps=plot_symbols.ps
 
-gmt psxy -R0/4/1/6 -Jx1i -P -Bg1 -Gred -W0.25p -S1i -X2i -Y2i << EOF > $ps
+gmt psxy -R0/4/1/6 -Jx1i -P -Bg1 -W0.25p -S1i -X2i -Y2i << EOF > $ps
 > Fat pen -W2p
 0.5	5.5	-
 > Plain red symbols -W- -Gred
@@ -29,7 +29,7 @@ gmt psxy -R0/4/1/6 -Jx1i -P -Bg1 -Gred -W0.25p -S1i -X2i -Y2i << EOF > $ps
 > Blue wedges -Gblue
 3.5	2.5	80	30	w
 0.5	1.5	30	80	w
-> Fat red pen -W2p,red
+> Fat red pen -W2p,red -G-
 1.5	1.5	x
 > Fat pen -W2p
 1.5	1.5	+