From 5d7ab083a3c2c623ad162c6f05f8911996d52388 Mon Sep 17 00:00:00 2001
From: werner <werner@99fdad57-331a-0410-800a-d7fa5415bdb3>
Date: Tue, 4 Aug 2009 21:45:33 +0000
Subject: [PATCH] - README: described use of semicolons - README: added that
 loops can also execute zero times - accept labels only at the beginning of a
 line - rectangles and lines no longer use the bounding box for drawing
 (caused   offset problems since we now correct for the line width) -
 dist_rect and inside_rect no longer require their input pre-sorted - pad
 instances now have their own structure and no longer abuse the bounding   box
 to know the pad coordinates - Makefile: use $(GEN) for fig2dev, to reduce
 chattiness - when dragging a point, the symbol is now adjusted accordingly -
 added moving of rects, pads, circles, and arcs - added creation of pads -
 moved rotate_r from gui_inst.c to coord.c - new function "theta" that
 combines most of the angle calculations - save_pix_buf: y < 0 clipping
 changed width, not height

git-svn-id: http://svn.openmoko.org/trunk/eda/fped@5386 99fdad57-331a-0410-800a-d7fa5415bdb3
---
 Makefile    |   2 +-
 README      |   8 ++-
 TODO        |   1 +
 coord.c     |  65 +++++++++++++++---
 coord.h     |  10 ++-
 fpd.l       |   2 +-
 gui_inst.c  |  43 +++++-------
 gui_tools.c | 189 +++++++++++++++++++++++++++++++++++++++++++++++-----
 gui_tools.h |  11 +++
 gui_util.c  |   2 +-
 inst.c      |  50 +++++++++-----
 inst.h      |   7 ++
 12 files changed, 315 insertions(+), 75 deletions(-)

diff --git a/Makefile b/Makefile
index 59e3d03..c3ae0d7 100644
--- a/Makefile
+++ b/Makefile
@@ -74,7 +74,7 @@ endif
 # sed '/2 2 0 1 /{s//2 2 0 15 /;s/ 0 7 / 22 7 /;}' $< | \
 
 .fig.xpm:
-		fig2dev -L xpm -Z 0.32 -S 4 $< | \
+		$(GEN) fig2dev -L xpm -Z 0.32 -S 4 $< | \
 		  convert -crop 24x24+1+1 - - | \
 		  sed "s/*.*\[]/*xpm_`basename $@ .xpm`[]/" >$@
 
diff --git a/README b/README
index 9b379d0..b2c4987 100644
--- a/README
+++ b/README
@@ -50,7 +50,8 @@ with existing designs when introduction future language features.
 
 fped uses the C preprocessor for comments, conditional compilation,
 and - to a limited extent - also macros. Long lines can be split by
-ending them with a backslash.
+ending them with a backslash. If multiple items need to be placed in a
+single line, e.g., in a macro, they can be separated with semicolons.
 
 
 Geometry model
@@ -279,7 +280,10 @@ and
 
 loop n = 1, 3.5
 
-both assign the values 1, 2, and 3 to the variable "n".
+both assign the values 1, 2, and 3 to the variable "n". The
+following loop would not execute at all:
+
+loop n = 1, 0
 
 When a loop is executed, the objects contained in the body of the
 enclosing frame are generated for each value of the variable. If
diff --git a/TODO b/TODO
index 074b8a6..4edddba 100644
--- a/TODO
+++ b/TODO
@@ -18,6 +18,7 @@ Style:
 
 Bugs:
 - default silk width has no business being hard-coded in obj.c
+- after moving, arc sometimes wrap the wrong way
 
 Code cleanup:
 - merge edit_unique with edit_name
diff --git a/coord.c b/coord.c
index ca9c2fd..c191051 100644
--- a/coord.c
+++ b/coord.c
@@ -79,6 +79,54 @@ struct coord neg_vec(struct coord v)
 }
 
 
+/* ----- point on circle --------------------------------------------------- */
+
+
+struct coord rotate_r(struct coord c, unit_type r, double angle)
+{
+	struct coord p;
+
+	angle = angle/180.0*M_PI;
+	p.x = c.x+r*cos(angle);
+	p.y = c.y+r*sin(angle);
+	return p;
+}
+
+
+double theta(struct coord c, struct coord p)
+{
+	double a;
+
+	a = atan2(p.y-c.y, p.x-c.x)/M_PI*180.0;
+	if (a < 0)
+		a += 360.0;
+	return a;
+}
+
+
+/* ----- sorting coordinates ----------------------------------------------- */
+
+
+void swap_coord(unit_type *a, unit_type *b)
+{
+	unit_type tmp;
+
+	tmp = *a;
+	*a = *b;
+	*b = tmp;
+}
+
+
+void sort_coord(struct coord *min, struct coord *max)
+{
+	if (min->x > max->x)
+		swap_coord(&min->x, &max->x);
+	if (min->y > max->y)
+		swap_coord(&min->y, &max->y);
+
+}
+
+
 /* ----- distance calculations --------------------------------------------- */
 
 
@@ -127,29 +175,30 @@ unit_type dist_line(struct coord p, struct coord a, struct coord b)
 }
 
 
-unit_type dist_rect(struct coord p, struct coord min, struct coord max)
+unit_type dist_rect(struct coord p, struct coord a, struct coord b)
 {
 	unit_type d_min, d;
 
-	d_min = dist_line_xy(p.x, p.y, min.x, min.y, max.x, min.y);
-	d = dist_line_xy(p.x, p.y, min.x, min.y, min.x, max.y);
+	d_min = dist_line_xy(p.x, p.y, a.x, a.y, b.x, a.y);
+	d = dist_line_xy(p.x, p.y, a.x, a.y, a.x, b.y);
 	if (d < d_min)
 		d_min = d;
-	d = dist_line_xy(p.x, p.y, min.x, max.y, max.x, max.y);
+	d = dist_line_xy(p.x, p.y, a.x, b.y, b.x, b.y);
 	if (d < d_min)
 		d_min = d;
-	d = dist_line_xy(p.x, p.y, max.x, min.y, max.x, max.y);
+	d = dist_line_xy(p.x, p.y, b.x, a.y, b.x, b.y);
 	if (d < d_min)
 		d_min = d;
 	return d_min;
 }
 
 
-int inside_rect(struct coord p, struct coord min, struct coord max)
+int inside_rect(struct coord p, struct coord a, struct coord b)
 {
-	if (p.x < min.x || p.x > max.x)
+	sort_coord(&a, &b);
+	if (p.x < a.x || p.x > b.x)
 		return 0;
-	if (p.y < min.y || p.y > max.y)
+	if (p.y < a.y || p.y > b.y)
 		return 0;
 	return 1;
 }
diff --git a/coord.h b/coord.h
index e9a9df8..01dbe3b 100644
--- a/coord.h
+++ b/coord.h
@@ -69,10 +69,16 @@ struct coord add_vec(struct coord a, struct coord b);
 struct coord sub_vec(struct coord a, struct coord b);
 struct coord neg_vec(struct coord v);
 
+struct coord rotate_r(struct coord c, unit_type r, double angle);
+double theta(struct coord c, struct coord p);
+
+void swap_coord(unit_type *a, unit_type *b);
+void sort_coord(struct coord *min, struct coord *max);
+
 unit_type dist_point(struct coord a, struct coord b);
 unit_type dist_line(struct coord p, struct coord a, struct coord b);
-unit_type dist_rect(struct coord p, struct coord min, struct coord max);
-int inside_rect(struct coord p, struct coord min, struct coord max);
+unit_type dist_rect(struct coord p, struct coord a, struct coord b);
+int inside_rect(struct coord p, struct coord a, struct coord b);
 unit_type dist_circle(struct coord p, struct coord c, unit_type r);
 
 #endif /* !COORD_H */
diff --git a/fpd.l b/fpd.l
index 8f68992..bb29165 100644
--- a/fpd.l
+++ b/fpd.l
@@ -93,7 +93,7 @@ SP	[\t ]*
 <INITIAL>"meas"			{ BEGIN(NOKEYWORD);
 				  return TOK_MEAS; }
 
-[a-zA-Z_][a-zA-Z_0-9]*:		{ *strchr(yytext, ':') = 0;
+<INITIAL>[a-zA-Z_][a-zA-Z_0-9]*: { *strchr(yytext, ':') = 0;
 				  yylval.id = unique(yytext);
 				  return LABEL; }
 [a-zA-Z_][a-zA-Z_0-9]*		{ yylval.id = unique(yytext);
diff --git a/gui_inst.c b/gui_inst.c
index 67843e6..d4fa4fd 100644
--- a/gui_inst.c
+++ b/gui_inst.c
@@ -176,7 +176,7 @@ unit_type gui_dist_line(struct inst *self, struct coord pos, unit_type scale)
 	r = self->u.rect.width/scale/2;
 	if (r < SELECT_R)
 		r = SELECT_R;
-	d = dist_line(pos, self->bbox.min, self->bbox.max)/scale;
+	d = dist_line(pos, self->base, self->u.rect.end)/scale;
 	return d > r ? -1 : d;
 }
 
@@ -203,21 +203,22 @@ unit_type gui_dist_rect(struct inst *self, struct coord pos, unit_type scale)
 	r = self->u.rect.width/scale/2;
 	if (r < SELECT_R)
 		r = SELECT_R;
-	d = dist_rect(pos, self->bbox.min, self->bbox.max)/scale;
+	d = dist_rect(pos, self->base, self->u.rect.end)/scale;
 	return d > r ? -1 : d;
 }
 
 
 void gui_draw_rect(struct inst *self, struct draw_ctx *ctx)
 {
-	struct coord min = translate(ctx, self->bbox.min);
-	struct coord max = translate(ctx, self->bbox.max);
+	struct coord min = translate(ctx, self->base);
+	struct coord max = translate(ctx, self->u.rect.end);
 	GdkGC *gc;
 
+	sort_coord(&min, &max);
 	gc = gc_obj[get_mode(self)];
 	set_width(gc, self->u.rect.width/ctx->scale);
 	gdk_draw_rectangle(DA, gc, FALSE,
-	    min.x, max.y, max.x-min.x, min.y-max.y);
+	    min.x, min.y, max.x-min.x, max.y-min.y);
 }
 
 
@@ -228,31 +229,32 @@ unit_type gui_dist_pad(struct inst *self, struct coord pos, unit_type scale)
 {
 	unit_type d;
 
-	if (inside_rect(pos, self->bbox.min, self->bbox.max))
+	if (inside_rect(pos, self->base, self->u.pad.other))
 		return SELECT_R;
-	d = dist_rect(pos, self->bbox.min, self->bbox.max)/scale;
+	d = dist_rect(pos, self->base, self->u.pad.other)/scale;
 	return d > SELECT_R ? -1 : d;
 }
 
 
 void gui_draw_pad(struct inst *self, struct draw_ctx *ctx)
 {
-	struct coord min = translate(ctx, self->bbox.min);
-	struct coord max = translate(ctx, self->bbox.max);
+	struct coord min = translate(ctx, self->base);
+	struct coord max = translate(ctx, self->u.pad.other);
 	GdkGC *gc;
 	struct coord c;
 	unit_type h, w;
 
 	gc = gc_pad[get_mode(self)];
+	sort_coord(&min, &max);
 	gdk_draw_rectangle(DA, gc, TRUE,
-	    min.x, max.y, max.x-min.x, min.y-max.y);
+	    min.x, min.y, max.x-min.x, max.y-min.y);
 
 	gc = gc_ptext[get_mode(self)];
 	c = add_vec(min, max);
-	h = min.y-max.y;
+	h = max.y-min.y;
 	w = max.x-min.x;
-	render_text(DA, gc, c.x/2, c.y/2, w <= h*1.1 ? 0 : 90, self->u.name,
-	    PAD_FONT, 0.5, 0.5,
+	render_text(DA, gc, c.x/2, c.y/2, w <= h*1.1 ? 0 : 90,
+	    self->u.pad.name, PAD_FONT, 0.5, 0.5,
 	    w-2*PAD_BORDER, h-2*PAD_BORDER);
 }
 
@@ -260,17 +262,6 @@ void gui_draw_pad(struct inst *self, struct draw_ctx *ctx)
 /* ----- arc --------------------------------------------------------------- */
 
 
-static struct coord rotate_r(struct coord center, unit_type r, double angle)
-{
-	struct coord res;
-
-	angle = angle/180.0*M_PI;
-	res.x = center.x+r*cos(angle);
-	res.y = center.y+r*sin(angle);
-	return res;
-}
-
-
 unit_type gui_dist_arc(struct inst *self, struct coord pos, unit_type scale)
 {
 	struct coord c = self->base;
@@ -305,9 +296,7 @@ unit_type gui_dist_arc(struct inst *self, struct coord pos, unit_type scale)
 
 	/* see if we're close to the part that's actually drawn */
 
-	angle = atan2(pos.y-c.y, pos.x-c.x)/M_PI*180.0;
-	if (angle < 0)
-		angle += 180;
+	angle = theta(c, pos);
 	a2 = self->u.arc.a2;
 	if (a2 < self->u.arc.a1)
 		a2 += 180;
diff --git a/gui_tools.c b/gui_tools.c
index 77d1b94..312afb4 100644
--- a/gui_tools.c
+++ b/gui_tools.c
@@ -65,7 +65,6 @@ static struct pix_buf *pix_buf;
 static struct tool_ops vec_ops;
 static struct tool_ops frame_ops;
 static struct tool_ops pad_ops;
-static struct tool_ops circ_ops;
 static struct tool_ops meas_ops;
 
 
@@ -101,6 +100,31 @@ static struct pix_buf *drag_new_line(struct draw_ctx *ctx,
 }
 
 
+struct pix_buf *draw_move_line(struct inst *inst, struct draw_ctx *ctx,
+    struct coord pos, int i)
+{
+	struct coord from, to;
+	struct pix_buf *buf;
+
+	from = translate(ctx, inst->base);
+	to = translate(ctx, inst->u.rect.end);
+	pos = translate(ctx, pos);
+	switch (i) {
+	case 0:
+		from = pos;
+		break;
+	case 1:
+		to = pos;
+		break;
+	default:
+		abort();
+	}
+	buf = save_pix_buf(DA, from.x, from.y, to.x, to.y, 1);
+	gdk_draw_line(DA, gc_drag, from.x, from.y, to.x, to.y);
+	return buf;
+}
+
+
 static int end_new_line(struct draw_ctx *ctx,
     struct inst *from, struct inst *to)
 {
@@ -124,16 +148,6 @@ static struct tool_ops line_ops = {
 /* ----- rect -------------------------------------------------------------- */
 
 
-static void swap_coord(unit_type *a, unit_type *b)
-{
-	unit_type tmp;
-
-	tmp = *a;
-	*a = *b;
-	*b = tmp;
-}
-
-
 static struct pix_buf *drag_new_rect(struct draw_ctx *ctx,
     struct inst *from, struct coord to)
 {
@@ -142,10 +156,7 @@ static struct pix_buf *drag_new_rect(struct draw_ctx *ctx,
 
 	pos = translate(ctx, inst_get_point(from));
 	to = translate(ctx, to);
-	if (pos.x > to.x)
-		swap_coord(&pos.x, &to.x);
-	if (pos.y > to.y)
-		swap_coord(&pos.y, &to.y);
+	sort_coord(&pos, &to);
 	buf = save_pix_buf(DA, pos.x, pos.y, to.x, to.y, 1);
 	gdk_draw_rectangle(DA, gc_drag, FALSE,
 	    pos.x, pos.y, to.x-pos.x, to.y-pos.y);
@@ -153,6 +164,40 @@ static struct pix_buf *drag_new_rect(struct draw_ctx *ctx,
 }
 
 
+static struct pix_buf *draw_move_rect_common(struct inst *inst,
+    struct coord other, struct draw_ctx *ctx, struct coord pos, int i)
+{
+	struct coord min, max;
+	struct pix_buf *buf;
+
+	min = translate(ctx, inst->base);
+	max = translate(ctx, other);
+	pos = translate(ctx, pos);
+	switch (i) {
+	case 0:
+		min = pos;
+		break;
+	case 1:
+		max = pos;
+		break;
+	default:
+		abort();
+	}
+	sort_coord(&min, &max);
+	buf = save_pix_buf(DA, min.x, min.y, max.x, max.y, 1);
+	gdk_draw_rectangle(DA, gc_drag, FALSE,
+	    min.x, min.y, max.x-min.x, max.y-min.y);
+	return buf;
+}
+
+
+struct pix_buf *draw_move_rect(struct inst *inst, struct draw_ctx *ctx,
+    struct coord pos, int i)
+{
+	return draw_move_rect_common(inst, inst->u.rect.end, ctx, pos, i);
+}
+
+
 static int end_new_rect(struct draw_ctx *ctx,
     struct inst *from, struct inst *to)
 {
@@ -173,6 +218,36 @@ static struct tool_ops rect_ops = {
 };
 
 
+/* ----- pad --------------------------------------------------------------- */
+
+
+static int end_new_pad(struct draw_ctx *ctx,
+    struct inst *from, struct inst *to)
+{
+	struct obj *obj;
+
+	if (from == to)
+		return 0;
+	obj = new_obj(ot_pad, from);
+	obj->u.pad.other = inst_get_ref(to);
+	obj->u.pad.name = stralloc("?");
+	return 1;
+}
+
+
+struct pix_buf *draw_move_pad(struct inst *inst, struct draw_ctx *ctx,
+    struct coord pos, int i)
+{
+	return draw_move_rect_common(inst, inst->u.pad.other, ctx, pos, i);
+}
+
+
+static struct tool_ops pad_ops = {
+	.drag_new	= drag_new_rect,
+	.end_new	= end_new_pad,
+};
+
+
 /* ----- circ -------------------------------------------------------------- */
 
 
@@ -207,6 +282,83 @@ static int end_new_circ(struct draw_ctx *ctx,
 }
 
 
+struct pix_buf *draw_move_arc(struct inst *inst, struct draw_ctx *ctx,
+    struct coord pos, int i)
+{
+	struct coord c, from, to;
+	double r, a1, a2;
+	struct pix_buf *buf;
+
+	c = translate(ctx, inst->base);
+	from =
+	    translate(ctx, rotate_r(inst->base, inst->u.arc.r, inst->u.arc.a1));
+	to =
+	    translate(ctx, rotate_r(inst->base, inst->u.arc.r, inst->u.arc.a2));
+	pos = translate(ctx, pos);
+	switch (i) {
+	case 0:
+		c = pos;
+		break;
+	case 1:
+		from = pos;
+		if (inst->obj->u.arc.start != inst->obj->u.arc.end)
+			break;
+		/* fall through */
+	case 2:
+		to = pos;
+		break;
+	default:
+		abort();
+	}
+	r = hypot(from.x-c.x, from.y-c.y);
+	/*
+	 * the screen coordinate system is reversed with y growing downward,
+	 * so we have to negate the angles.
+	 */
+	a1 = -theta(c, from);
+	a2 = -theta(c, to);
+	if (a2 < a1)
+		a2 += 360.0;
+	buf = save_pix_buf(DA, c.x-r, c.y-r, c.x+r, c.y+r, 1);
+	draw_arc(DA, gc_drag, FALSE, c.x, c.y, r, a1, a2);
+	return buf;
+}
+
+
+static void replace(struct vec **anchor, struct vec *new)
+{
+	if (*anchor)
+		(*anchor)->n_refs--;
+	*anchor = new;
+	if (new)
+		new->n_refs++;
+}
+
+
+void do_move_to_arc(struct inst *inst, struct vec *vec, int i)
+{
+	struct obj *obj = inst->obj;
+	int is_circle;
+
+	is_circle = obj->u.arc.start == obj->u.arc.end;
+	switch (i) {
+	case 0:
+		replace(&obj->base, vec);
+		break;
+	case 1:
+		replace(&obj->u.arc.start, vec);
+		if (!is_circle)
+			break;
+		/* fall through */
+	case 2:
+		replace(&obj->u.arc.end, vec);
+		break;
+	default:
+		abort();
+	}
+}
+
+
 static struct tool_ops circ_ops = {
 	.drag_new	= drag_new_circ,
 	.end_new	= end_new_circ,
@@ -274,7 +426,6 @@ static void do_move_to(struct drag_state *state, struct inst *curr)
 	if (old)
 		old->n_refs--;
 	*state->anchors[state->anchor_i] = inst_get_ref(curr);
-	state->anchors_n = 0;
 }
 
 
@@ -339,7 +490,8 @@ void tool_drag(struct draw_ctx *ctx, struct coord to)
 	if (pix_buf)
 		restore_pix_buf(pix_buf);
 	tool_hover(ctx, to);
-	pix_buf = drag.new ? active_ops->drag_new(ctx, drag.new, to) : NULL;
+	pix_buf = drag.new ? active_ops->drag_new(ctx, drag.new, to) :
+	    inst_draw_move(selected_inst, ctx, to, drag.anchor_i);
 }
 
 
@@ -369,7 +521,8 @@ int tool_end_drag(struct draw_ctx *ctx, struct coord to)
 		return ops->end_new(ctx, state.new, end);
 	if (!may_move_to(&state, end))
 		return 0;
-	do_move_to(&state, end);
+	if (!inst_do_move_to(selected_inst, inst_get_vec(end), state.anchor_i))
+		do_move_to(&state, end);
 	return 1;
 }
 
diff --git a/gui_tools.h b/gui_tools.h
index 300c393..946424f 100644
--- a/gui_tools.h
+++ b/gui_tools.h
@@ -19,6 +19,17 @@
 #include "inst.h"
 
 
+struct pix_buf *draw_move_line(struct inst *inst, struct draw_ctx *ctx,
+    struct coord pos, int i);
+struct pix_buf *draw_move_rect(struct inst *inst, struct draw_ctx *ctx,
+    struct coord pos, int i);
+struct pix_buf *draw_move_pad(struct inst *inst, struct draw_ctx *ctx,
+    struct coord pos, int i);
+struct pix_buf *draw_move_arc(struct inst *inst, struct draw_ctx *ctx,
+    struct coord pos, int i);
+
+void do_move_to_arc(struct inst *inst, struct vec *vec, int i);
+
 void tool_dehover(struct draw_ctx *ctx);
 void tool_hover(struct draw_ctx *ctx, struct coord pos);
 int tool_consider_drag(struct draw_ctx *ctx, struct coord pos);
diff --git a/gui_util.c b/gui_util.c
index 2fe0fb8..7d34c2b 100644
--- a/gui_util.c
+++ b/gui_util.c
@@ -79,7 +79,7 @@ struct pix_buf *save_pix_buf(GdkDrawable *da, int xa, int ya, int xb, int yb,
 		buf->x = 0;
 	}
 	if (buf->y < 0) {
-		w += buf->y;
+		h += buf->y;
 		buf->y = 0;
 	}
 	buf->buf = gdk_pixbuf_get_from_drawable(NULL, da, NULL,
diff --git a/inst.c b/inst.c
index 742aa5c..10bfd2a 100644
--- a/inst.c
+++ b/inst.c
@@ -20,7 +20,7 @@
 #include "expr.h"
 #include "obj.h"
 #include "gui_status.h"
-#include "gui_status.h"
+#include "gui_tools.h"
 #include "gui_inst.h"
 #include "inst.h"
 
@@ -34,6 +34,10 @@ struct inst_ops {
 	    unit_type scale);
 	void (*select)(struct inst *self);
 	int (*anchors)(struct inst *self, struct vec ***anchors);
+	struct pix_buf *(*draw_move)(struct inst *inst, struct draw_ctx *ctx,
+	    struct coord pos, int i);
+	/* arcs need this special override */
+	void (*do_move_to)(struct inst *inst, struct vec *vec, int i);
 };
 
 enum inst_prio {
@@ -269,9 +273,7 @@ static void rect_status(struct coord a, struct coord b, unit_type width)
 	if (!d.x && !d.y)
 		status_set_angle("a = 0 deg");
 	else {
-		angle = atan2(d.y, d.x)/M_PI*180.0;
-		if (angle < 0)
-			angle += 360;
+		angle = theta(a, b);
 		status_set_angle("a = %3.1f deg", angle);
 	}
 	status_set_r("r = %5.2f mm", hypot(units_to_mm(d.x), units_to_mm(d.y)));
@@ -432,6 +434,7 @@ static struct inst_ops line_ops = {
 	.distance	= gui_dist_line,
 	.select		= line_op_select,
 	.anchors	= line_op_anchors,
+	.draw_move	= draw_move_line,
 };
 
 
@@ -474,6 +477,7 @@ static struct inst_ops rect_ops = {
 	.distance	= gui_dist_rect,
 	.select		= rect_op_select,
 	.anchors	= line_op_anchors,
+	.draw_move	= draw_move_rect,
 };
 
 
@@ -498,8 +502,8 @@ int inst_rect(struct obj *obj, struct coord a, struct coord b, unit_type width)
 static void pad_op_debug(struct inst *self)
 {
 	printf("pad \"%s\" %lg, %lg / %lg, %lg\n", self->u.name,
-	    units_to_mm(self->bbox.min.x), units_to_mm(self->bbox.min.y),
-	    units_to_mm(self->bbox.max.x), units_to_mm(self->bbox.max.y));
+	    units_to_mm(self->base.x), units_to_mm(self->base.y),
+	    units_to_mm(self->u.pad.other.x), units_to_mm(self->u.pad.other.y));
 }
 
 
@@ -518,8 +522,8 @@ static int validate_pad_name(const char *s, void *ctx)
 static void pad_op_select(struct inst *self)
 {
 	status_set_type_entry("label =");
-	status_set_name("%s", self->u.name);
-	rect_status(self->bbox.min, self->bbox.max, -1);
+	status_set_name("%s", self->u.pad.name);
+	rect_status(self->base, self->u.pad.other, -1);
 	edit_name(&self->obj->u.pad.name, validate_pad_name, NULL);
 }
 
@@ -540,6 +544,7 @@ static struct inst_ops pad_ops = {
 	.distance	= gui_dist_pad,
 	.select		= pad_op_select,
 	.anchors	= pad_op_anchors,
+	.draw_move	= draw_move_pad,
 };
 
 
@@ -549,7 +554,8 @@ int inst_pad(struct obj *obj, const char *name, struct coord a, struct coord b)
 
 	inst = add_inst(&pad_ops, ip_pad, a);
 	inst->obj = obj;
-	inst->u.name = stralloc(name);
+	inst->u.pad.name = stralloc(name);
+	inst->u.pad.other = b;
 	update_bbox(&inst->bbox, b);
 	propagate_bbox(inst);
 	return 1;
@@ -597,6 +603,8 @@ static struct inst_ops arc_ops = {
 	.distance	= gui_dist_arc,
 	.select		= arc_op_select,
 	.anchors	= arc_op_anchors,
+	.draw_move	= draw_move_arc,
+	.do_move_to	= do_move_to_arc,
 };
 
 
@@ -609,13 +617,9 @@ int inst_arc(struct obj *obj, struct coord center, struct coord start,
 	inst = add_inst(&arc_ops, ip_arc, center);
 	inst->obj = obj;
 	r = hypot(start.x-center.x, start.y-center.y);
-	a1 = atan2(start.y-center.y, start.x-center.x)/M_PI*180.0;
-	a2 = atan2(end.y-center.y, end.x-center.x)/M_PI*180.0;
-	if (a1 < 0)
-		a1 += 360.0;
-	if (a2 < 0)
-		a2 += 360.0;
 	inst->u.arc.r = r;
+	a1 = theta(center, start);
+	a2 = theta(center, end);
 	inst->u.arc.a1 = a1;
 	inst->u.arc.a2 = a2;
 	inst->u.arc.width = width;
@@ -834,6 +838,22 @@ void inst_draw(struct draw_ctx *ctx)
 }
 
 
+struct pix_buf *inst_draw_move(struct inst *inst, struct draw_ctx *ctx,
+    struct coord pos, int i)
+{
+	return inst->ops->draw_move(inst, ctx, pos, i);
+}
+
+
+int inst_do_move_to(struct inst *inst, struct vec *vec, int i)
+{
+	if (!inst->ops->do_move_to)
+		return 0;
+	inst->ops->do_move_to(inst, vec, i);
+	return 1;
+}
+
+
 void inst_hover(struct inst *inst, struct draw_ctx *ctx, int on)
 {
 	if (!inst->ops->hover)
diff --git a/inst.h b/inst.h
index 5a834c4..4b98077 100644
--- a/inst.h
+++ b/inst.h
@@ -58,6 +58,10 @@ struct inst {
 			struct coord end;
 			unit_type width;
 		} rect;
+		struct {
+			const char *name;
+			struct coord other;
+		} pad;
 		struct {
 			unit_type r;
 			double a1, a2;
@@ -109,6 +113,9 @@ void inst_commit(void);
 void inst_revert(void);
 
 void inst_draw(struct draw_ctx *ctx);
+struct pix_buf *inst_draw_move(struct inst *inst, struct draw_ctx *ctx,
+    struct coord pos, int i);
+int inst_do_move_to(struct inst *inst, struct vec *vec, int i);
 void inst_hover(struct inst *inst, struct draw_ctx *ctx, int on);
 void inst_debug(void);