Function gmt_init_vector_param

src/gmt_init.c:16719–16741

! Update vector head length and width parameters based on size_z and v_angle, and deal with pen/fill settings */

/*! Update vector head length and width parameters based on size_z and v_angle, and deal with pen/fill settings */
int gmt_init_vector_param (struct GMT_CTRL *GMT, struct GMT_SYMBOL *S, bool set, bool outline, struct GMT_PEN *pen, bool do_fill, struct GMT_FILL *fill) {
	bool no_outline = false, no_fill = false;
	if (S == NULL) return 0;	/* Nothing to do */
	if (set) {	/* Determine proper settings for head fill or outline */
		if (outline && (S->v.status & PSL_VEC_OUTLINE2) == 0 && pen) S->v.pen = *pen;	/* If no +p<pen> but -W<pen> was used, use same pen for vector heads */
		else if (!outline && S->v.status & PSL_VEC_OUTLINE2 && pen) *pen = S->v.pen;	/* If no -W<pen> was set but +p<pen> given, use same pen for vector tails */
		else if (!outline && (S->v.status & PSL_VEC_OUTLINE2) == 0) no_outline = true;
		if (do_fill && (S->v.status & PSL_VEC_FILL2) == 0 && fill) S->v.fill = *fill;	/* If no +g<fill> but -G<fill> was used, use same fill for vector heads */
		else if (!do_fill && S->v.status & PSL_VEC_FILL2) no_fill = false;		/* If no -G<fill> was set but +g<fill> given, we do nothing here */
		else if (!do_fill && (S->v.status & PSL_VEC_FILL2) == 0) no_fill = true;	/* Neither -G<fill> nor +g<fill> were set */
		if (no_outline && no_fill && (S->v.status & PSL_VEC_HEADS)) {
			GMT_Report (GMT->parent, GMT_MSG_ERROR, "Cannot draw vector heads without specifying at least one of head outline or head fill.\n");
			return 1;
		}
	}
	if (gmt_M_is_zero (S->v.comp_scale)) S->v.comp_scale = 1.0;	/* Safety valve for GMT4 vectors */
	if (gmt_M_is_zero (S->size_x)) return 0;	/* Not set yet */
	if (!(S->symbol == GMT_SYMBOL_VECTOR_V4 || S->v.parsed_v4)) {
		S->v.h_length = (float)S->size_x;
		S->v.h_width = (float)(2.0 * S->v.h_length * tand (0.5 * S->v.v_angle));
	}
	return 0;
}

GMT_LOCAL unsigned int gmtinit_get_length (struct GMT_CTRL *GMT, char symbol, char *string, bool norm, bool is_grdvector, float *value, bool *user_unit) {
	/* Used by gmt_parse_vector to set length scales or limits related to vectors.