diff --git a/Makefile b/Makefile
index f109b04..ab62898 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,7 @@ OBJS = fped.o expr.o coord.o obj.o delete.o inst.o util.o error.o \
        unparse.o dump.o meas.o \
        cpp.o lex.yy.o y.tab.o \
        gui.o gui_util.o gui_style.o gui_inst.o gui_status.o gui_canvas.o \
-       gui_tools.o gui_over.o
+       gui_tools.o gui_over.o gui_meas.o
 
 XPMS = point.xpm delete.xpm vec.xpm frame.xpm frame_locked.xpm frame_ready.xpm \
        line.xpm rect.xpm pad.xpm circ.xpm meas.xpm meas_x.xpm meas_y.xpm
diff --git a/README b/README
index dd356d5..0723aa4 100644
--- a/README
+++ b/README
@@ -445,7 +445,7 @@ Known issues:
 
 Syntax:
 
-<type> [<label>] <from> <op> <to> <offset>
+<type> [<label>] <from> <op> <to> [<offset>]
 
 Types:
 - measxy: measure diagonally
diff --git a/coord.h b/coord.h
index 01dbe3b..44199b9 100644
--- a/coord.h
+++ b/coord.h
@@ -60,6 +60,12 @@ static inline double units_to_kicad(unit_type u)
 }
 
 
+static inline int coord_eq(struct coord a, struct coord b)
+{
+	return a.x == b.x && a.y == b.y;
+}
+
+
 double mm_to_mil(double mm, int exponent);
 double mil_to_mm(double mil, int exponent);
 
diff --git a/fpd.y b/fpd.y
index b336628..f83852b 100644
--- a/fpd.y
+++ b/fpd.y
@@ -493,7 +493,7 @@ measurements:
 	;
 
 meas:
-	meas_type opt_string qbase meas_op qbase expr
+	meas_type opt_string qbase meas_op qbase opt_expr
 		{
 			$$ = alloc_type(struct meas);
 			$$->type = $4.max ? $1+3 : $1;
diff --git a/gui_meas.c b/gui_meas.c
new file mode 100644
index 0000000..a6ad2c5
--- /dev/null
+++ b/gui_meas.c
@@ -0,0 +1,337 @@
+/*
+ * gui_meas.c - GUI, canvas overlays
+ *
+ * Written 2009 by Werner Almesberger
+ * Copyright 2009 by Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#include "util.h"
+#include "meas.h"
+#include "gui_canvas.h"
+#include "gui_tools.h"
+#include "gui_meas.h"
+
+
+static struct inst *meas_inst; /* point from which we're dragging */
+
+static enum {
+	min_to_next_or_max,
+	max_to_min,
+	next_to_min,
+} mode;
+
+
+/* ----- measurement type characteristics ---------------------------------- */
+
+
+static struct meas_dsc {
+	lt_op_type lt;
+	enum meas_type type;
+} *meas_dsc;
+
+
+static struct meas_dsc meas_dsc_xy = {
+	.lt	= lt_xy,
+	.type	= mt_xy_next,
+};
+
+
+static struct meas_dsc meas_dsc_x = {
+	.lt	= lt_x,
+	.type	= mt_x_next,
+};
+
+
+static struct meas_dsc meas_dsc_y = {
+	.lt	= lt_y,
+	.type	= mt_y_next,
+};
+
+
+/* ----- min/next/max tester ----------------------------------------------- */
+
+
+static int is_min(lt_op_type lt, const struct inst *inst)
+{
+	struct coord min;
+
+	min = meas_find_min(lt, inst->vec->samples);
+	return coord_eq(inst->u.rect.end, min);
+}
+
+
+static int is_next(lt_op_type lt,
+    const struct inst *inst, const struct inst *ref)
+{
+	struct coord next;
+
+	next = meas_find_next(lt, inst->vec->samples, ref->u.rect.end);
+	return coord_eq(inst->u.rect.end, next);
+}
+
+
+static int is_max(lt_op_type lt, const struct inst *inst)
+{
+	struct coord max;
+
+	max = meas_find_max(lt, inst->vec->samples);
+	return coord_eq(inst->u.rect.end, max);
+}
+
+
+static int is_a_next(lt_op_type lt, struct inst *inst)
+{
+	struct inst *a;
+	struct coord min, next;
+
+	for (a = insts_ip_vec(); a; a = a->next) {
+		min = meas_find_min(lt, a->vec->samples);
+		next = meas_find_next(lt, inst->vec->samples, min);
+		if (coord_eq(next, inst->u.rect.end))
+			return 1;
+	}
+	return 0;
+}
+
+
+static int is_min_of_next(lt_op_type lt,
+    const struct inst *inst, const struct inst *ref)
+{
+	struct coord min, next;
+
+	min = meas_find_min(lt, inst->vec->samples);
+	next = meas_find_next(lt, ref->vec->samples, min);
+	return coord_eq(next, ref->u.rect.end);
+}
+
+
+/* ----- picker functions -------------------------------------------------- */
+
+
+static int meas_pick_vec_a(struct inst *inst, void *ctx)
+{
+	struct vec *vec = inst->vec;
+
+	if (!vec->samples)
+		return 0;
+	if (is_min(meas_dsc->lt, inst)) {
+		mode = min_to_next_or_max;
+		return 1;
+	}
+	if (is_max(meas_dsc->lt, inst)) {
+		mode = max_to_min;
+		return 1;
+	}
+	if (is_a_next(meas_dsc->lt, inst)) {
+		mode = next_to_min;
+		return 1;
+	}
+	return 0;
+}
+
+
+static int meas_pick_vec_b(struct inst *inst, void *ctx)
+{
+	struct vec *vec = inst->vec;
+	struct inst *a = ctx;
+
+	if (!vec->samples)
+		return 0;
+	switch (mode) {
+	case min_to_next_or_max:
+		if (is_max(meas_dsc->lt, inst))
+			return 1;
+		if (is_next(meas_dsc->lt, inst, a))
+			return 1;
+		return 0;
+	case max_to_min:
+		return is_min(meas_dsc->lt, inst);
+	case next_to_min:
+		return is_min_of_next(meas_dsc->lt, inst, a);
+	default:
+		abort();
+	}
+}
+
+
+/* ----- highlighting ------------------------------------------------------ */
+
+
+static void meas_highlight_a(void)
+{
+	inst_highlight_vecs(meas_pick_vec_a, NULL);
+}
+
+
+static void meas_highlight_b(void)
+{
+	inst_highlight_vecs(meas_pick_vec_b, meas_inst);
+}
+
+
+/* ----- meas -------------------------------------------------------------- */
+
+
+struct pix_buf *draw_move_meas(struct inst *inst, struct coord pos, int i)
+{
+	return draw_move_line_common(inst, inst->u.meas.end, pos, i);
+}
+
+
+/* ----- tool selection ---------------------------------------------------- */
+
+
+static void tool_selected_meas(void)
+{
+	highlight = meas_highlight_a;
+	redraw();
+}
+
+
+static void tool_selected_meas_xy(void)
+{
+	meas_dsc = &meas_dsc_xy;
+	tool_selected_meas();
+}
+
+
+static void tool_selected_meas_x(void)
+{
+	meas_dsc = &meas_dsc_x;
+	tool_selected_meas();
+}
+
+
+static void tool_selected_meas_y(void)
+{
+	meas_dsc = &meas_dsc_y;
+	tool_selected_meas();
+}
+
+
+static void tool_deselected_meas(void)
+{
+	highlight = NULL;
+	redraw();
+}
+
+
+/* ----- find point ------------------------------------------------------- */
+
+
+static struct inst *find_point_meas(struct coord pos)
+{
+	if (meas_inst)
+		return inst_find_vec(pos, meas_pick_vec_b, meas_inst);
+	else
+		return inst_find_vec(pos, meas_pick_vec_a, NULL);
+}
+
+
+/* ----- begin dragging new measurement ------------------------------------ */
+
+
+static void begin_drag_new_meas(struct inst *inst)
+{
+	highlight = meas_highlight_b;
+	meas_inst = inst;
+	if (is_min(meas_dsc->lt, inst))
+		mode = min_to_next_or_max;
+	else if (is_max(meas_dsc->lt, inst))
+		mode = max_to_min;
+	else
+		mode = next_to_min;
+	redraw();
+}
+
+
+/* ----- end dragging new measurement -------------------------------------- */
+
+
+static int end_new_meas(struct inst *from, struct inst *to)
+{
+	struct meas *meas;
+
+	meas_inst = NULL;
+	if (from == to)
+		return 0;
+	meas = alloc_type(struct meas);
+	meas->label = NULL;
+	switch (mode) {
+	case min_to_next_or_max:
+		if (!is_max(meas_dsc->lt, to)) {
+			meas->type = meas_dsc->type;
+		} else {
+			meas->type = meas_dsc->type+3;
+		}
+		meas->low = from->vec;
+		meas->high = to->vec;
+		break;
+	case next_to_min:
+		meas->type = meas_dsc->type;
+		meas->low = to->vec;
+		meas->high = from->vec;
+		break;
+	case max_to_min:
+		meas->type = meas_dsc->type+3;
+		meas->low = to->vec;
+		meas->high = from->vec;
+		break;
+	default:
+		abort();
+	}
+	meas->inverted = meas_dsc->lt(from->u.rect.end, to->u.rect.end) !=
+	    (mode == min_to_next_or_max);
+{
+char *sm[] = { "min_to", "max_to", "next_to" };
+char *st[] = { "nxy", "nx", "ny", "mxy", "mx", "my" };
+fprintf(stderr, "mode %s type %s, inverted %d\n",
+sm[mode], st[meas->type], meas->inverted);
+}
+	meas->offset = parse_expr("0mm");
+	meas->next = measurements;
+	measurements = meas;
+	meas_dsc = NULL;
+	return 1;
+}
+
+
+/* ----- begin dragging existing measurement ------------------------------- */
+
+
+/* ----- operations ------------------------------------------------------- */
+
+
+struct tool_ops meas_ops = {
+	.tool_selected	= tool_selected_meas_xy,
+	.tool_deselected= tool_deselected_meas,
+	.find_point	= find_point_meas,
+	.begin_drag_new	= begin_drag_new_meas,
+	.drag_new	= drag_new_line,
+	.end_new	= end_new_meas,
+};
+
+struct tool_ops meas_ops_x = {
+	.tool_selected	= tool_selected_meas_x,
+	.tool_deselected= tool_deselected_meas,
+	.find_point	= find_point_meas,
+	.begin_drag_new	= begin_drag_new_meas,
+	.drag_new	= drag_new_line,
+	.end_new	= end_new_meas,
+};
+
+
+struct tool_ops meas_ops_y = {
+	.tool_selected	= tool_selected_meas_y,
+	.tool_deselected= tool_deselected_meas,
+	.find_point	= find_point_meas,
+	.begin_drag_new	= begin_drag_new_meas,
+	.drag_new	= drag_new_line,
+	.end_new	= end_new_meas,
+};
diff --git a/gui_meas.h b/gui_meas.h
new file mode 100644
index 0000000..f9b33bb
--- /dev/null
+++ b/gui_meas.h
@@ -0,0 +1,22 @@
+/*
+ * gui_meas.c - GUI, canvas overlays
+ *
+ * Written 2009 by Werner Almesberger
+ * Copyright 2009 by Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#ifndef GUI_MEAS_H
+#define GUI_MEAS_H
+
+
+struct tool_ops meas_ops;
+struct tool_ops meas_ops_x;
+struct tool_ops meas_ops_y;
+
+#endif /* !GUI_MEAS_H */
diff --git a/gui_tools.c b/gui_tools.c
index 0285c1b..f7e5ad4 100644
--- a/gui_tools.c
+++ b/gui_tools.c
@@ -26,6 +26,7 @@
 #include "gui_canvas.h"
 #include "gui_status.h"
 #include "gui.h"
+#include "gui_meas.h"
 #include "gui_tools.h"
 
 
@@ -44,16 +45,6 @@
 #include "icons/vec.xpm"
 
 
-struct tool_ops {
-	void (*tool_selected)(void);
-	void (*tool_deselected)(void);
-	void (*click)(struct coord pos);
-	struct pix_buf *(*drag_new)(struct inst *from, struct coord to);
-	int (*end_new_raw)(struct inst *from, struct coord to);
-	int (*end_new)(struct inst *from, struct inst *to);
-};
-
-
 static GtkWidget *ev_point, *ev_frame;
 static GtkWidget *active_tool;
 static struct tool_ops *active_ops = NULL;
@@ -109,7 +100,7 @@ static struct obj *new_obj(enum obj_type type, struct inst *base)
 /* ----- shared functions -------------------------------------------------- */
 
 
-static struct pix_buf *draw_move_line_common(struct inst *inst,
+struct pix_buf *draw_move_line_common(struct inst *inst,
     struct coord end, struct coord pos, int i)
 {
 	struct coord from, to;
@@ -270,7 +261,7 @@ static struct tool_ops vec_ops = {
 /* ----- line -------------------------------------------------------------- */
 
 
-static struct pix_buf *drag_new_line(struct inst *from, struct coord to)
+struct pix_buf *drag_new_line(struct inst *from, struct coord to)
 {
 	struct coord pos;
 	struct pix_buf *buf;
@@ -496,86 +487,6 @@ static struct tool_ops circ_ops = {
 };
 
 
-/* ----- meas -------------------------------------------------------------- */
-
-
-struct pix_buf *draw_move_meas(struct inst *inst, struct coord pos, int i)
-{
-	return draw_move_line_common(inst, inst->u.meas.end, pos, i);
-}
-
-
-static int end_new_meas(struct inst *from, struct inst *to)
-{
-	struct obj *obj;
-
-	if (from == to)
-		return 0;
-	obj = new_obj(ot_meas, from);
-	obj->u.meas.other = inst_get_vec(to);
-	obj->u.meas.offset = parse_expr("0mm");
-	return 1;
-}
-
-
-static int meas_x_pick_vec(struct inst *inst, void *ctx)
-{
-	struct vec *vec = inst->vec;
-	struct coord min;
-
-	if (!vec->samples)
-		return 0;
-	min = meas_find_min(lt_xy, vec->samples);
-	return inst->u.rect.end.x == min.x && inst->u.rect.end.y == min.y;
-}
-
-
-static void highlight_vecs(void)
-{
-	inst_highlight_vecs(meas_x_pick_vec, NULL);
-}
-
-
-static void tool_selected_meas_x(void)
-{
-	highlight = highlight_vecs;
-	redraw();
-}
-
-
-static void tool_selected_meas_y(void)
-{
-	highlight = NULL;
-	redraw();
-}
-
-
-static void tool_deselected_meas(void)
-{
-	highlight = NULL;
-	redraw();
-}
-
-
-static struct tool_ops meas_ops = {
-	.drag_new	= drag_new_line,
-	.end_new	= end_new_meas,
-};
-
-static struct tool_ops meas_ops_x = {
-	.tool_selected	= tool_selected_meas_x,
-	.tool_deselected= tool_deselected_meas,
-	.drag_new	= drag_new_line,
-	.end_new	= end_new_meas,
-};
-static struct tool_ops meas_ops_y = {
-	.tool_selected	= tool_selected_meas_y,
-	.tool_deselected= tool_deselected_meas,
-	.drag_new	= drag_new_line,
-	.end_new	= end_new_meas,
-};
-
-
 /* ----- frame helper ------------------------------------------------------ */
 
 
@@ -766,7 +677,10 @@ void tool_hover(struct coord pos)
 {
 	struct inst *curr;
 
-	curr = inst_find_point(pos);
+	if (active_ops && active_ops->find_point)
+		curr = active_ops->find_point(pos);
+	else
+		curr = inst_find_point(pos);
 	if ((drag.new && curr == drag.new) || (drag.inst && curr == drag.inst))
 		return;
 	if (curr && !active_ops) {
@@ -817,12 +731,17 @@ int tool_consider_drag(struct coord pos)
 		active_ops->click(pos);
 		return 0;
 	}
-	curr = inst_find_point(pos);
+	if (active_ops && active_ops->find_point)
+		curr = active_ops->find_point(pos);
+	else
+		curr = inst_find_point(pos);
 	if (!curr)
 		return 0;
 	tool_dehover();
 	if (active_ops) {
 		if (active_ops->drag_new) {
+			if (active_ops->begin_drag_new)
+				active_ops->begin_drag_new(curr);
 			drag.inst = NULL;
 			drag.new = curr;
 			over_begin(drag_save_and_draw, NULL, pos);
@@ -872,7 +791,10 @@ int tool_end_drag(struct coord to)
 	tool_cancel_drag();
 	if (state.new && ops->end_new_raw)
 		return ops->end_new_raw(state.new, to);
-	end = inst_find_point(to);
+	if (ops->find_point)
+		end = ops->find_point(to);
+	else
+		end = inst_find_point(to);
 	if (!end)
 		return 0;
 	if (state.new)
diff --git a/gui_tools.h b/gui_tools.h
index b4f6ae1..b65f5ad 100644
--- a/gui_tools.h
+++ b/gui_tools.h
@@ -19,6 +19,20 @@
 #include "inst.h"
 
 
+struct tool_ops {
+	void (*tool_selected)(void);
+	void (*tool_deselected)(void);
+	struct inst *(*find_point)(struct coord pos);
+	void (*click)(struct coord pos);
+	void (*begin_drag_new)(struct inst *from);
+// in inst
+//	void (*begin_drag_move)struct inst *from, int anchor_i);
+	struct pix_buf *(*drag_new)(struct inst *from, struct coord to);
+	int (*end_new_raw)(struct inst *from, struct coord to);
+	int (*end_new)(struct inst *from, struct inst *to);
+};
+
+
 struct pix_buf *draw_move_vec(struct inst *inst, struct coord pos, int i);
 struct pix_buf *draw_move_line(struct inst *inst, struct coord pos, int i);
 struct pix_buf *draw_move_rect(struct inst *inst, struct coord pos, int i);
@@ -40,7 +54,15 @@ void tool_cancel_drag(void);
 int tool_end_drag(struct coord to);
 void tool_redraw(void);
 
-struct pix_buf *tool_drag_new(struct inst *inst, struct coord pos);
+/*
+ * The following functions are for measurements which are now in a separate
+ * compilation unit.
+ */
+
+struct pix_buf *draw_move_line_common(struct inst *inst,
+    struct coord end, struct coord pos, int i);
+struct pix_buf *drag_new_line(struct inst *from, struct coord to);
+
 
 /*
  * Cache the frame and track it.
diff --git a/inst.c b/inst.c
index d90b411..455510c 100644
--- a/inst.c
+++ b/inst.c
@@ -852,6 +852,35 @@ void inst_highlight_vecs(int (*pick)(struct inst *inst, void *user), void *user)
 }
 
 
+struct inst *inst_find_vec(struct coord pos,
+    int (*pick)(struct inst *inst, void *user), void *user)
+{
+	struct inst *inst, *found;
+	int best_dist = 0; /* keep gcc happy */
+	int dist;
+
+	found = NULL;
+	for (inst = insts[ip_vec]; inst; inst = inst->next) {
+		if (!inst->ops->distance)
+			continue;
+		dist = inst->ops->distance(inst, pos, draw_ctx.scale);
+		if (dist < 0 || (found && best_dist <= dist))
+			continue;
+		if (!pick(inst, user))
+			continue;
+		found = inst;
+		best_dist = dist;
+	}
+	return found;
+}
+
+
+struct inst *insts_ip_vec(void)
+{
+	return insts[ip_vec];
+}
+
+
 struct pix_buf *inst_draw_move(struct inst *inst, struct coord pos, int i)
 {
 	return inst->ops->draw_move(inst, pos, i);
diff --git a/inst.h b/inst.h
index 4f27381..a7224a3 100644
--- a/inst.h
+++ b/inst.h
@@ -115,6 +115,10 @@ void inst_revert(void);
 void inst_draw(void);
 void inst_highlight_vecs(int (*pick)(struct inst *inst, void *user),
      void *user);
+struct inst *inst_find_vec(struct coord pos, 
+    int (*pick)(struct inst *inst, void *user), void *user);
+struct inst *insts_ip_vec(void);
+
 struct pix_buf *inst_draw_move(struct inst *inst, struct coord pos, int i);
 int inst_do_move_to(struct inst *inst, struct vec *vec, int i);
 struct pix_buf *inst_hover(struct inst *inst);
diff --git a/meas.c b/meas.c
index c8e5061..790662b 100644
--- a/meas.c
+++ b/meas.c
@@ -75,6 +75,9 @@ void meas_post(struct vec *vec, struct coord pos)
 }
 
 
+/* ----- lt operators ------------------------------------------------------ */
+
+
 int lt_x(struct coord a, struct coord b)
 {
 	return a.x < b.x;
@@ -93,6 +96,9 @@ int lt_xy(struct coord a, struct coord b)
 }
 
 
+/* ----- measurement type map ---------------------------------------------- */
+
+
 static lt_op_type lt_op[mt_n] = {
 	lt_xy,
 	lt_x,
@@ -109,8 +115,11 @@ static int is_next[mt_n] = {
 };
 
 
+/* ----- search functions -------------------------------------------------- */
+
+
 static int better_next(lt_op_type lt,
-    struct coord a0, struct coord b0, struct coord b)
+    struct coord a0, struct coord b0, struct coord b, int recursing)
 {
 	/* if we don't have any suitable point A0 < B0 yet, use this one */
 	if (!lt(a0, b0))
@@ -133,12 +142,12 @@ static int better_next(lt_op_type lt,
 	 * coordinate a chance. This gives us a stable sort order and it
 	 * makes meas/measx/measy usually select the same point.
 	 */
-	if (lt == lt_xy)
+	if (lt == lt_xy || recursing)
 		return 0;
 	if (lt == lt_x)
-		return better_next(lt_y, a0, b0, b);
+		return better_next(lt_y, a0, b0, b, 1);
 	if (lt == lt_y)
-		return better_next(lt_x, a0, b0, b);
+		return better_next(lt_x, a0, b0, b, 1);
 	abort();
 }
 
@@ -173,7 +182,7 @@ struct coord meas_find_next(lt_op_type lt, const struct sample *s,
 
 	next = s->pos;
 	while (s) {
-		if (better_next(lt, ref, next, s->pos))
+		if (better_next(lt, ref, next, s->pos, 0))
 			next = s->pos;
 		s = s->next;
 	}
@@ -196,6 +205,9 @@ struct coord meas_find_max(lt_op_type lt, const struct sample *s)
 }
 
 
+/* ----- instantiation ----------------------------------------------------- */
+
+
 int instantiate_meas(void)
 {
 	struct meas *meas;
@@ -214,9 +226,13 @@ int instantiate_meas(void)
 		else
 			b0 = meas_find_max(lt, meas->high->samples);
 
-		offset = eval_unit(meas->offset, root_frame);
-		if (is_undef(offset))
-			return 0;
+		if (!meas->offset)
+			offset.n = 0;
+		else {
+			offset = eval_unit(meas->offset, root_frame);
+			if (is_undef(offset))
+				return 0;
+		}
 		inst_meas(NULL, meas,
 		    meas->inverted ? b0 : a0, meas->inverted ? a0 : b0,
 		    offset.n);