Add a bunch of 2d to_poly / bounding_box functions (untested)

4 files changed, 384 insertions, 132 deletions

diff --git a/gerbonara/gerber/apertures.py b/gerbonara/gerber/apertures.py
index 7c98775..104b021 100644
--- a/gerbonara/gerber/apertures.py
+++ b/gerbonara/gerber/apertures.py
@@ -7,9 +7,12 @@ from .aperture_macros.parse import GenericMacros
 from . import graphic_primitives as gp
 
 
-def _flash_hole(self, x, y):
+def _flash_hole(self, x, y, unit=None):
     if self.hole_rect_h is not None:
-        return self.primitives(x, y), Rectangle((x, y), (self.hole_dia, self.hole_rect_h), rotation=self.rotation, polarity_dark=False)
+        return [*self.primitives(x, y, unit),
+                Rectangle((x, y),
+                    (self.convert(self.hole_dia, unit), self.convert(self.hole_rect_h, unit)),
+                    rotation=self.rotation, polarity_dark=False)]
     else:
         return self.primitives(x, y), Circle((x, y), self.hole_dia, polarity_dark=False)
 
@@ -71,11 +74,10 @@ class Aperture:
 
         return out
 
-    def flash(self, x, y):
-        return self.primitives(x, y)
+    def flash(self, x, y, unit=None):
+        return self.primitives(x, y, unit)
 
-    @property
-    def equivalent_width(self):
+    def equivalent_width(self, unit=None):
         raise ValueError('Non-circular aperture used in interpolation statement, line width is not properly defined.')
 
     def to_gerber(self, settings=None):
@@ -108,17 +110,16 @@ class CircleAperture(Aperture):
     hole_rect_h : Length(float) = None
     rotation : float = 0 # radians; for rectangular hole; see hack in Aperture.to_gerber
 
-    def primitives(self, x, y, rotation):
-        return [ gp.Circle(x, y, self.diameter/2) ]
+    def primitives(self, x, y, unit=None):
+        return [ gp.Circle(x, y, self.convert(self.diameter/2, unit)) ]
 
     def __str__(self):
         return f'<circle aperture d={self.diameter:.3}>'
 
     flash = _flash_hole
 
-    @property
-    def equivalent_width(self):
-        return self.diameter
+    def equivalent_width(self, unit=None):
+        return self.convert(self.diameter, unit)
 
     def dilated(self, offset, unit='mm'):
         offset = self.convert_from(offset, unit)
@@ -150,17 +151,16 @@ class RectangleAperture(Aperture):
     hole_rect_h : Length(float) = None
     rotation : float = 0 # radians
 
-    def primitives(self, x, y):
-        return [ gp.Rectangle(x, y, self.w, self.h, rotation=self.rotation) ]
+    def primitives(self, x, y, unit=None):
+        return [ gp.Rectangle(x, y, self.convert(self.w, unit), self.convert(self.h, unit), rotation=self.rotation) ]
 
     def __str__(self):
         return f'<rect aperture {self.w:.3}x{self.h:.3}>'
 
     flash = _flash_hole
 
-    @property
-    def equivalent_width(self):
-        return math.sqrt(self.w**2 + self.h**2)
+    def equivalent_width(self, unit=None):
+        return self.convert(math.sqrt(self.w**2 + self.h**2), unit)
 
     def dilated(self, offset, unit='mm'):
         offset = self.convert_from(offset, unit)
@@ -200,8 +200,8 @@ class ObroundAperture(Aperture):
     hole_rect_h : Length(float) = None
     rotation : float = 0
 
-    def primitives(self, x, y):
-        return [ gp.Obround(x, y, self.w, self.h, rotation=self.rotation) ]
+    def primitives(self, x, y, unit=None):
+        return [ gp.Obround(x, y, self.convert(self.w, unit), self.convert(self.h, unit), rotation=self.rotation) ]
 
     def __str__(self):
         return f'<obround aperture {self.w:.3}x{self.h:.3}>'
@@ -246,8 +246,8 @@ class PolygonAperture(Aperture):
     rotation : float = 0
     hole_dia : Length(float) = None
 
-    def primitives(self, x, y):
-        return [ gp.RegularPolygon(x, y, diameter, n_vertices, rotation=self.rotation) ]
+    def primitives(self, x, y, unit=None):
+        return [ gp.RegularPolygon(x, y, self.convert(diameter, unit), n_vertices, rotation=self.rotation) ]
 
     def __str__(self):
         return f'<{self.n_vertices}-gon aperture d={self.diameter:.3}'
@@ -279,16 +279,13 @@ class ApertureMacroInstance(Aperture):
     parameters : [float]
     rotation : float = 0
 
-    def __post__init__(self, macro):
-        self._primitives = macro.to_graphic_primitives(parameters)
-
     @property
     def gerber_shape_code(self):
         return self.macro.name
 
-    def primitives(self, x, y):
-        # FIXME return graphical primitives not macro primitives here
-        return [ primitive.with_offset(x, y).rotated(self.rotation, cx=0, cy=0) for primitive in self._primitives ]
+    def primitives(self, x, y, unit=None):
+        return [ primitive.with_offset(x, y).rotated(self.rotation, cx=0, cy=0)
+                for primitive in self.macro.to_graphic_primitives(self.parameters, unit=unit) ]
 
     def dilated(self, offset, unit='mm'):
         return replace(self, macro=self.macro.dilated(offset, unit))
diff --git a/gerbonara/gerber/graphic_objects.py b/gerbonara/gerber/graphic_objects.py
index 5c523d5..d9736cf 100644
--- a/gerbonara/gerber/graphic_objects.py
+++ b/gerbonara/gerber/graphic_objects.py
@@ -5,29 +5,69 @@ from dataclasses import dataclass, KW_ONLY, astuple, replace
 from . import graphic_primitives as gp
 from .gerber_statements import *
 
+
+def convert(value, src, dst):
+        if src == dst or src is None or dst is None or value is None:
+            return value
+        elif dst == 'mm':
+            return value * 25.4
+        else:
+            return value / 25.4
+
+class Length:
+    def __init__(self, obj_type):
+        self.type = obj_type
+
 @dataclass
 class GerberObject:
     _ : KW_ONLY
     polarity_dark : bool = True
     unit : str = None
 
-    def to_primitives(self):
+    def converted(self, unit):
+        return replace(self, 
+                **{
+                    f.name: convert(getattr(self, f.name), self.unit, unit)
+                    for f in fields(self)
+                    })
+
+    def _conv(self, value, unit):
+        return convert(value, src=unit, dst=self.unit)
+
+    def with_offset(self, dx, dy, unit='mm'):
+        dx, dy = self._conv(dx, unit), self._conv(dy, unit)
+        return self._with_offset(dx, dy)
+
+    def rotate(self, rotation, cx=0, cy=0, unit='mm'):
+        cx, cy = self._conv(cx, unit), self._conv(cy, unit)
+        return self._rotate(cx, cy)
+
+    def bounding_box(self, unit=None):
+        bboxes = [ p.bounding_box for p in self.to_primitives(unit) ]
+        min_x = min(min_x for (min_x, _min_y), _ in bboxes)
+        min_y = min(min_y for (_min_x, min_y), _ in bboxes)
+        max_x = max(max_x for _, (max_x, _max_y) in bboxes)
+        max_y = max(max_y for _, (_max_x, max_y) in bboxes)
+        return ((min_x, min_y), (max_x, max_y))
+
+    def to_primitives(self, unit=None):
         raise NotImplementedError()
 
 @dataclass
 class Flash(GerberObject):
-    x : float
-    y : float
+    x : Length(float)
+    y : Length(float)
     aperture : object
 
-    def with_offset(self, dx, dy):
+    def _with_offset(self, dx, dy):
         return replace(self, x=self.x+dx, y=self.y+dy)
 
-    def rotate(self, rotation, cx=0, cy=0):
+    def _rotate(self, rotation, cx=0, cy=0):
         self.x, self.y = gp.rotate_point(self.x, self.y, rotation, cx, cy)
 
-    def to_primitives(self):
-        yield from self.aperture.flash(self.x, self.y)
+    def to_primitives(self, unit=None):
+        conv = self.converted(unit)
+        yield from self.aperture.flash(conv.x, conv.y, unit)
 
     def to_statements(self, gs):
         yield from gs.set_polarity(self.polarity_dark)
@@ -48,31 +88,33 @@ class Region(GerberObject):
     def __bool__(self):
         return bool(self.poly)
 
-    def with_offset(self, dx, dy):
+    def _with_offset(self, dx, dy):
         return Region([ (x+dx, y+dy) for x, y in self.poly.outline ],
                 self.poly.arc_centers,
                 polarity_dark=self.polarity_dark,
                 unit=self.unit)
 
-    def rotate(self, angle, cx=0, cy=0):
+    def _rotate(self, angle, cx=0, cy=0):
         self.poly.outline = [ gp.rotate_point(x, y, angle, cx, cy) for x, y in self.poly.outline ]
         self.poly.arc_centers = [
-                gp.rotate_point(*center, angle, cx, cy) if center else None
-                for center in self.poly.arc_centers ]
+                (arc[0], gp.rotate_point(*arc[1], angle, cx, cy)) if arc else None
+                for arc in self.poly.arc_centers ]
 
     def append(self, obj):
+        if obj.unit != self.unit:
+            raise ValueError('Cannot append Polyline with "{obj.unit}" coords to Region with "{self.unit}" coords.')
         if not self.poly.outline:
             self.poly.outline.append(obj.p1)
         self.poly.outline.append(obj.p2)
 
         if isinstance(obj, Arc):
-            self.poly.arc_centers.append(obj.center)
+            self.poly.arc_centers.append((obj.clockwise, obj.center))
         else:
             self.poly.arc_centers.append(None)
 
-    def to_primitives(self):
+    def to_primitives(self, unit=None):
         self.poly.polarity_dark = polarity_dark
-        yield self.poly
+        yield self.poly.converted(unit)
 
     def to_statements(self, gs):
         yield from gs.set_polarity(self.polarity_dark)
@@ -87,9 +129,9 @@ class Region(GerberObject):
                 gs.update_point(*point, unit=self.unit)
 
             else:
-                cx, cy = arc_center
+                clockwise, (cx, cy) = arc_center
                 x2, y2 = point
-                yield from gs.set_interpolation_mode(CircularCCWModeStmt)
+                yield from gs.set_interpolation_mode(CircularCWModeStmt if clockwise else CircularCCWModeStmt)
                 yield InterpolateStmt(x2, y2, cx-x2, cy-y2, unit=self.unit)
                 gs.update_point(x2, y2, unit=self.unit)
 
@@ -99,16 +141,16 @@ class Region(GerberObject):
 @dataclass
 class Line(GerberObject):
     # Line with *round* end caps.
-    x1 : float
-    y1 : float
-    x2 : float
-    y2 : float
+    x1 : Length(float)
+    y1 : Length(float)
+    x2 : Length(float)
+    y2 : Length(float)
     aperture : object
 
-    def with_offset(self, dx, dy):
+    def _with_offset(self, dx, dy):
         return replace(self, x1=self.x1+dx, y1=self.y1+dy, x2=self.x2+dx, y2=self.y2+dy)
 
-    def rotate(self, rotation, cx=0, cy=0):
+    def _rotate(self, rotation, cx=0, cy=0):
         self.x1, self.y1 = gp.rotate_point(self.x1, self.y1, rotation, cx, cy)
         self.x2, self.y2 = gp.rotate_point(self.x2, self.y2, rotation, cx, cy)
 
@@ -120,8 +162,9 @@ class Line(GerberObject):
     def p2(self):
         return self.x2, self.y2
 
-    def to_primitives(self):
-        yield gp.Line(*self.p1, *self.p2, self.aperture.equivalent_width, polarity_dark=self.polarity_dark)
+    def to_primitives(self, unit=None):
+        conv = self.converted(unit)
+        yield gp.Line(*conv.p1, *conv.p2, self.aperture.equivalent_width(unit), polarity_dark=self.polarity_dark)
 
     def to_statements(self, gs):
         yield from gs.set_polarity(self.polarity_dark)
@@ -134,32 +177,33 @@ class Line(GerberObject):
 
 @dataclass
 class Drill(GerberObject):
-    x : float
-    y : float
-    diameter : float
+    x : Length(float)
+    y : Length(float)
+    diameter : Length(float)
 
-    def with_offset(self, dx, dy):
+    def _with_offset(self, dx, dy):
         return replace(self, x=self.x+dx, y=self.y+dy)
 
-    def rotate(self, angle, cx=0, cy=0):
+    def _rotate(self, angle, cx=0, cy=0):
         self.x, self.y = gp.rotate_point(self.x, self.y, angle, cx, cy)
 
-    def to_primitives(self):
-        yield gp.Circle(self.x, self.y, self.diameter/2)
+    def to_primitives(self, unit=None):
+        conv = self.converted(unit)
+        yield gp.Circle(conv.x, conv.y, conv.diameter/2)
 
 
 @dataclass
 class Slot(GerberObject):
-    x1 : float
-    y1 : float
-    x2 : float
-    y2 : float
-    width : float
+    x1 : Length(float)
+    y1 : Length(float)
+    x2 : Length(float)
+    y2 : Length(float)
+    width : Length(float)
 
-    def with_offset(self, dx, dy):
+    def _with_offset(self, dx, dy):
         return replace(self, x1=self.x1+dx, y1=self.y1+dy, x2=self.x2+dx, y2=self.y2+dy)
 
-    def rotate(self, rotation, cx=0, cy=0):
+    def _rotate(self, rotation, cx=0, cy=0):
         if cx is None:
             cx = (self.x1 + self.x2) / 2
             cy = (self.y1 + self.y2) / 2
@@ -174,22 +218,23 @@ class Slot(GerberObject):
     def p2(self):
         return self.x2, self.y2
 
-    def to_primitives(self):
-        yield gp.Line(*self.p1, *self.p2, self.width, polarity_dark=self.polarity_dark)
+    def to_primitives(self, unit=None):
+        conv = self.converted(unit)
+        yield gp.Line(*conv.p1, *conv.p2, conv.width, polarity_dark=self.polarity_dark)
 
 
 @dataclass
 class Arc(GerberObject):
-    x1 : float
-    y1 : float
-    x2 : float
-    y2 : float
-    cx : float
-    cy : float
-    flipped : bool
+    x1 : Length(float)
+    y1 : Length(float)
+    x2 : Length(float)
+    y2 : Length(float)
+    cx : Length(float)
+    cy : Length(float)
+    clockwise : bool
     aperture : object
 
-    def with_offset(self, dx, dy):
+    def _with_offset(self, dx, dy):
         return replace(self, x1=self.x1+dx, y1=self.y1+dy, x2=self.x2+dx, y2=self.y2+dy)
 
     @property
@@ -204,15 +249,16 @@ class Arc(GerberObject):
     def center(self):
         return self.cx + self.x1, self.cy + self.y1
 
-    def rotate(self, rotation, cx=0, cy=0):
+    def _rotate(self, rotation, cx=0, cy=0):
         # rotate center first since we need old x1, y1 here
         new_cx, new_cy = gp.rotate_point(*self.center, rotation, cx, cy)
         self.x1, self.y1 = gp.rotate_point(self.x1, self.y1, rotation, cx, cy)
         self.x2, self.y2 = gp.rotate_point(self.x2, self.y2, rotation, cx, cy)
         self.cx, self.cy = new_cx - self.x1, new_cy - self.y1
 
-    def to_primitives(self):
-        yield gp.Arc(*astuple(self)[:7], width=self.aperture.equivalent_width, polarity_dark=self.polarity_dark)
+    def to_primitives(self, unit=None):
+        conv = self.converted(unit)
+        yield gp.Arc(*astuple(conv)[:7], width=self.aperture.equivalent_width(unit), polarity_dark=self.polarity_dark)
 
     def to_statements(self, gs):
         yield from gs.set_polarity(self.polarity_dark)
diff --git a/gerbonara/gerber/graphic_primitives.py b/gerbonara/gerber/graphic_primitives.py
index 966cac1..3052322 100644
--- a/gerbonara/gerber/graphic_primitives.py
+++ b/gerbonara/gerber/graphic_primitives.py
@@ -10,7 +10,6 @@ from .gerber_statements import *
 class GraphicPrimitive:
     _ : KW_ONLY
     polarity_dark : bool = True
-    unit : str = None
 
 
 def rotate_point(x, y, angle, cx=0, cy=0):
@@ -19,6 +18,26 @@ def rotate_point(x, y, angle, cx=0, cy=0):
     return (cx + (x - cx) * math.cos(-angle) - (y - cy) * math.sin(-angle),
             cy + (x - cx) * math.sin(-angle) + (y - cy) * math.cos(-angle))
 
+def min_none(a, b):
+    if a is None:
+        return b
+    if b is None:
+        return a
+    return min(a, b)
+
+def max_none(a, b):
+    if a is None:
+        return b
+    if b is None:
+        return a
+    return max(a, b)
+
+def add_bounds(b1, b2):
+    (min_x_1, min_y_1), (max_x_1, max_y_1) = b1
+    (min_x_2, min_y_2), (max_x_2, max_y_2) = b2
+    min_x, min_y = min_none(min_x_1, min_x_2), min_none(min_y_1, min_y_2)
+    max_x, max_y = max_none(max_x_1, max_x_2), max_none(max_y_1, max_y_2)
+    return ((min_x, min_y), (max_x, max_y))
 
 @dataclass
 class Circle(GraphicPrimitive):
@@ -26,9 +45,12 @@ class Circle(GraphicPrimitive):
     y : float
     r : float # Here, we use radius as common in modern computer graphics, not diameter as gerber uses.
 
-    def bounds(self):
+    def bounding_box(self):
         return ((self.x-self.r, self.y-self.r), (self.x+self.r, self.y+self.r))
 
+    def to_svg(self):
+        return 'circle', (), dict(cx=x, cy=y, r=r)
+
 
 @dataclass
 class Obround(GraphicPrimitive):
@@ -38,30 +60,121 @@ class Obround(GraphicPrimitive):
     h : float
     rotation : float # radians!
 
-    def decompose(self):
-        ''' decompose obround to two circles and one rectangle '''
-
-        cx = self.x + self.w/2
-        cy = self.y + self.h/2
-
+    def to_line(self):
         if self.w > self.h:
-            x = self.x + self.h/2
-            yield Circle(x, cy, self.h/2)
-            yield Circle(x + self.w, cy, self.h/2)
-            yield Rectangle(x, self.y, self.w - self.h, self.h)
+            w, a, b = self.h, self.w, 0
+        else:
+            w, a, b = self.w, 0, self.h
+        return Line(
+                *rotate_point(self.x-a/2, self.y-b/2, self.rotation, self.x, self.y),
+                *rotate_point(self.x+a/2, self.y+b/2, self.rotation, self.x, self.y),
+                w)
+
+    def bounding_box(self):
+        return self.to_line().bounding_box()
+
+    def to_svg(self):
+        return self.to_line().to_svg()
+
+
+def arc_bounds(x1, y1, x2, y2, cx, cy, clockwise):
+    # This is one of these problems typical for computer geometry where out of nowhere a seemingly simple task just
+    # happens to be anything but in practice.
+    #
+    # Online there are a number of algorithms to be found solving this problem. Often, they solve the more general
+    # problem for elliptic arcs. We can keep things simple here since we only have circular arcs.
+    # 
+    # This solution manages to handle circular arcs given in gerber format (with explicit center and endpoints, plus
+    # sweep direction instead of a format with e.g. angles and radius) without any trigonometric functions (e.g. atan2).
+
+    # Center arc on cx, cy
+    x1 -= cx
+    x2 -= cx
+    y1 -= cy
+    y2 -= cy
+    clockwise = bool(clockwise) # bool'ify for XOR/XNOR below
+
+    # Calculate radius
+    r = math.sqrt(x1**2 + y1**2)
+
+    # Calculate in which half-planes (north/south, west/east) P1 and P2 lie.
+    # Note that we assume the y axis points upwards, as in Gerber and maths.
+    # SVG has its y axis pointing downwards.
+    p1_west = x1 < 0
+    p1_north = y1 > 0
+    p2_west = x2 < 0
+    p2_north = y2 > 0
+
+    # Calculate bounding box of P1 and P2
+    min_x = min(x1, x2)
+    min_y = min(y1, y2)
+    max_x = max(x1, x2)
+    max_y = max(y1, y2)
+
+    #               North
+    #                 ^
+    #                 |
+    #                 |(0,0)
+    #      West <-----X-----> East
+    #                 |
+    #  +Y             |
+    #   ^             v
+    #   |           South
+    #   |
+    #   +-----> +X
+    #
+    # Check whether the arc sweeps over any coordinate axes. If it does, add the intersection point to the bounding box.
+    # Note that, since this intersection point is at radius r, it has coordinate e.g. (0, r) for the north intersection.
+    # Since we know that the points lie on either side of the coordinate axis, the '0' coordinate of the intersection
+    # point will not change the bounding box in that axis--only its 'r' coordinate matters. We also know that the
+    # absolute value of that coordinate will be greater than or equal to the old coordinate in that direction since the
+    # intersection with the axis is the point where the full circle is tangent to the AABB. Thus, we can blindly set the
+    # corresponding coordinate of the bounding box without min()/max()'ing first.
+
+    # Handle north/south halfplanes
+    if p1_west != p2_west: # arc starts in west half-plane, ends in east half-plane
+        if p1_west == clockwise: # arc is clockwise west -> east or counter-clockwise east -> west
+            max_y = r # add north to bounding box
+        else: # arc is counter-clockwise west -> east or clockwise east -> west
+            min_y = -r # south
+    else: # Arc starts and ends in same halfplane west/east
+        # Since both points are on the arc (at same radius) in one halfplane, we can use the y coord as a proxy for
+        # angle comparisons. 
+        small_arc_is_north_to_south = y1 > y2
+        small_arc_is_clockwise = small_arc_is_north_to_south == p1_west
+        if small_arc_is_clockwise != clockwise:
+            min_y, max_y = -r, r # intersect aabb with both north and south
+
+    # Handle west/east halfplanes
+    if p1_north != p2_north:
+        if p1_north == clockwise:
+            max_x = r # east
+        else:
+            min_x = -r # west
+    else:
+        small_arc_is_west_to_east = x1 < x2
+        small_arc_is_clockwise = small_arc_is_west_to_east == p1_north
+        if small_arc_is_clockwise != clockwise:
+            min_x, max_x = -r, r # intersect aabb with both north and south
 
-        elif self.h > self.w:
-            y = self.y + self.w/2
-            yield Circle(cx, y, self.w/2)
-            yield Circle(cx, y + self.h, self.w/2)
-            yield Rectangle(self.x, y, self.w, self.h - self.w)
+    return (min_x+cx, min_y+cy), (max_x+cx, max_y+cy)
 
-        else:
-            yield Circle(cx, cy, self.w/2)
 
-    def bounds(self):
-        return ((self.x-self.w/2, self.y-self.h/2), (self.x+self.w/2, self.y+self.h/2))
+def point_distance(a, b):
+    return math.sqrt((b[0] - a[0])**2 + (b[1] - a[1])**2)
 
+def point_line_distance(l1, l2, p):
+    x1, y1 = l1
+    x2, y2 = l2
+    x0, y0 = p
+    return abs((x2-x1)*(y1-y0) - (x1-x0)*(y2-y1))/point_distance(l1, l2)
+
+def svg_arc(old, new, center, clockwise):
+    r = point_distance(old, new)
+    d = point_line_distance(old, new, center)
+    sweep_flag = int(clockwise)
+    large_arc = int((d > 0) == clockwise) # FIXME check signs
+    return f'A {r:.6} {r:.6} {large_arc} {sweep_flag} {new[0]:.6} {new[1]:.6}'
 
 @dataclass
 class ArcPoly(GraphicPrimitive):
@@ -72,15 +185,23 @@ class ArcPoly(GraphicPrimitive):
     outline : [(float,)]
     # list of radii of segments, must be either None (all segments are straight lines) or same length as outline.
     # Straight line segments have None entry.
-    arc_centers : [(float,)]
+    arc_centers : [(float,)] = None
 
     @property
     def segments(self):
-        return itertools.zip_longest(self.outline[:-1], self.outline[1:], self.radii or [])
+        ol = self.outline
+        return itertools.zip_longest(ol, ol[1:] + [ol[0]], self.arc_centers)
+
+    def bounding_box(self):
+        bbox = (None, None), (None, None)
+        for (x1, y1), (x2, y2), arc in self.segments:
+            if arc:
+                clockwise, center = arc
+                bbox = add_bounds(bbox, arc_bounds(x1, y1, x2, y2, *center, clockwise))
 
-    def bounds(self):
-        for (x1, y1), (x2, y2), radius in self.segments:
-            return 
+            else:
+                line_bounds = (min(x1, x2), min(y1, y2)), (max(x1, x2), max(y1, y2))
+                bbox = add_bounds(bbox, line_bounds)
 
     def __len__(self):
         return len(self.outline)
@@ -88,6 +209,21 @@ class ArcPoly(GraphicPrimitive):
     def __bool__(self):
         return bool(len(self))
 
+    def _path_d(self):
+        if len(self.outline) == 0:
+            return
+
+        yield f'M {outline[0][0]:.6}, {outline[0][1]:.6}'
+        for old, new, arc in self.segments:
+            if not arc:
+                yield f'L {new[0]:.6} {new[1]:.6}'
+            else:
+                clockwise, center = arc
+                yield svg_arc(old, new, center, clockwise)
+
+    def to_svg(self):
+        return 'path', [], {'d': ' '.join(self._path_d())}
+
 
 @dataclass
 class Line(GraphicPrimitive):
@@ -97,7 +233,14 @@ class Line(GraphicPrimitive):
     y2 : float
     width : float
 
-    # FIXME bounds
+    def bounding_box(self):
+        r = self.width / 2
+        return add_bounds(Circle(self.x1, self.y1, r).bounding_box(), Circle(self.x2, self.y2, r).bounding_box())
+
+    def to_svg(self):
+        return 'path', [], dict(
+                d=f'M {self.x1:.6} {self.y1:.6} L {self.x2:.6} {self.y2:.6}',
+                style=f'stroke-width: {self.width:.6}; stroke-linecap: round')
 
 @dataclass
 class Arc(GraphicPrimitive):
@@ -107,10 +250,36 @@ class Arc(GraphicPrimitive):
     y2 : float
     cx : float
     cy : float
-    flipped : bool
+    clockwise : bool
     width : float
 
-    # FIXME bounds
+    def bounding_box(self):
+        r = self.w/2
+        endpoints = add_bounds(Circle(self.x1, self.y1, r).bounding_box(), Circle(self.x2, self.y2, r).bounding_box())
+
+        arc_r = point_distance((self.cx, self.cy), (self.x1, self.y1))
+
+        # extend C -> P1 line by line width / 2 along radius
+        dx, dy = self.x1 - self.cx, self.y1 - self.cy
+        x1 = self.x1 + dx/arc_r * r
+        y1 = self.y1 + dy/arc_r * r
+
+        # same for C -> P2
+        dx, dy = self.x2 - self.cx, self.y2 - self.cy
+        x2 = self.x2 + dx/arc_r * r
+        y2 = self.y2 + dy/arc_r * r
+
+        arc = arc_bounds(x1, y1, x2, y2, cx, cy, self.clockwise)
+        return add_bounds(endpoints, arc) # FIXME add "include_center" switch
+
+    def to_svg(self):
+        arc = svg_arc((self.x1, self.y1), (self.x2, self.y2), (self.cx, self.cy), self.clockwise)
+        return 'path', [], dict(
+                d=f'M {self.x1:.6} {self.y1:.6} {arc}',
+                style=f'stroke-width: {self.width:.6}; stroke-linecap: round')
+
+def svg_rotation(angle_rad):
+    return f'rotation({angle_rad/math.pi*180:.4})'
 
 @dataclass
 class Rectangle(GraphicPrimitive):
@@ -121,13 +290,29 @@ class Rectangle(GraphicPrimitive):
     h : float
     rotation : float # radians, around center!
 
-    def bounds(self):
-        return ((self.x, self.y), (self.x+self.w, self.y+self.h))
+    def bounding_box(self):
+        return self.to_arc_poly().bounding_box()
+
+    def to_arc_poly(self):
+        sin, cos = math.sin(self.rotation), math.cos(self.rotation)
+        sw, cw = sin*self.w/2, cos*self.w/2
+        sh, ch = sin*self.h/2, cos*self.h/2
+        x, y = self.x, self.y
+        return ArcPoly([
+            (x - (cw+sh), y - (ch+sw)),
+            (x - (cw+sh), y + (ch+sw)),
+            (x + (cw+sh), y + (ch+sw)),
+            (x + (cw+sh), y - (ch+sw)),
+            ])
 
     @property
     def center(self):
         return self.x + self.w/2, self.y + self.h/2
 
+    def to_svg(self):
+        x, y = self.x - self.w/2, self.y - self.h/2
+        return 'rect', [], dict(x=x, y=y, w=self.w, h=self.h, transform=svg_rotation(self.rotation))
+
 
 class RegularPolygon(GraphicPrimitive):
     x : float
@@ -136,13 +321,19 @@ class RegularPolygon(GraphicPrimitive):
     n : int
     rotation : float # radians!
 
-    def decompose(self):
-        ''' convert n-sided gerber polygon to normal Region defined by outline '''
+    def to_arc_poly(self):
+        ''' convert n-sided gerber polygon to normal ArcPoly defined by outline '''
 
         delta = 2*math.pi / self.n
 
-        yield Region([
+        return ArcPoly([
                 (self.x + math.cos(self.rotation + i*delta) * self.r,
                  self.y + math.sin(self.rotation + i*delta) * self.r)
                 for i in range(self.n) ])
 
+    def bounding_box(self):
+        return self.to_arc_poly().bounding_box()
+
+    def to_svg(self):
+        return self.to_arc_poly().to_svg()
+
diff --git a/gerbonara/gerber/rs274x.py b/gerbonara/gerber/rs274x.py
index 38dfe06..f53c78a 100644
--- a/gerbonara/gerber/rs274x.py
+++ b/gerbonara/gerber/rs274x.py
@@ -59,6 +59,18 @@ def points_close(a, b):
     else:
         return math.isclose(a[0], b[0]) and math.isclose(a[1], b[1])
 
+def Tag:
+    def __init__(self, name, children=None, **attrs):
+        self.name, self.children, self.attrs = name, children, attrs
+
+    def __str__(self):
+        opening = ' '.join([self.name] + [f'{key}="{value}"' for key, value in self.attrs.items()])
+        if self.children:
+            children = '\n'.join(textwrap.indent(str(c), '  ') for c in children)
+            return f'<{opening}>\n{children}\n</{self.name}>'
+        else:
+            return f'<{opening}/>'
+
 class GerberFile(CamFile):
     """ A class representing a single gerber file
 
@@ -71,6 +83,27 @@ class GerberFile(CamFile):
         self.comments = []
         self.objects = []
 
+    def to_svg(self, tag=Tag, margin=0, margin_unit='mm', svg_unit='mm'):
+
+        (min_x, min_y), (max_x, max_y) = self.bounding_box(svg_unit)
+
+        if margin:
+            margin = convert(margin, margin_unit, svg_unit)
+            min_x -= margin
+            min_y -= margin
+            max_x += margin
+            max_y += margin
+
+        w, h = max_x - min_x, max_y - min_y
+
+        primitives = [
+                [ tag(*prim.to_svg()) for prim in obj.to_primitives(unit=svg_unit) ]
+                for obj in self.objects ]
+
+        # FIXME setup viewport transform flipping y axis
+
+        return tag('svg', [defs, *primitives], width=w, height=h, viewBox=f'{min_x} {min_y} {w} {h}')
+
     def merge(self, other):
         """ Merge other GerberFile into this one """
         self.comments += other.comments
@@ -158,8 +191,8 @@ class GerberFile(CamFile):
         return (x1 - x0, y1 - y0)
 
     @property
-    def bounding_box(self):
-        bounds = [ p.bounding_box for p in self.pDeprecatedrimitives ]
+    def bounding_box(self, unit='mm'):
+        bounds = [ p.bounding_box(unit) for p in self.objects ]
 
         min_x = min(x0 for (x0, y0), (x1, y1) in bounds)
         min_y = min(y0 for (x0, y0), (x1, y1) in bounds)
@@ -227,27 +260,14 @@ class GerberFile(CamFile):
     def offset(self, dx=0,  dy=0, unit='mm'):
         # TODO round offset to file resolution
     
-        dx, dy = self.convert_length(dx, unit), self.convert_length(dy, unit)
         #print(f'offset {dx},{dy} file unit')
         #for obj in self.objects:
         #    print('   ', obj)
-        self.objects = [ obj.with_offset(dx, dy) for obj in self.objects ]
+        self.objects = [ obj.with_offset(dx, dy, unit) for obj in self.objects ]
         #print('after:')
         #for obj in self.objects:
         #    print('   ', obj)
 
-    def convert_length(self, value, unit='mm'):
-        """ Convert length into file unit """
-
-        if unit == 'mm':
-            if self.unit == 'inch':
-                return value / 25.4
-        elif unit == 'inch':
-            if self.unit == 'mm':
-                return value * 25.4
-
-        return value
-
     def rotate(self, angle:'radian', center=(0,0), unit='mm'):
         """ Rotate file contents around given point.
 
@@ -261,8 +281,6 @@ class GerberFile(CamFile):
         if math.isclose(angle % (2*math.pi), 0):
             return
 
-        center = self.convert_length(center[0], unit), self.convert_length(center[1], unit)
-
         # First, rotate apertures. We do this separately from rotating the individual objects below to rotate each
         # aperture exactly once.
         for ap in self.apertures:
@@ -273,7 +291,7 @@ class GerberFile(CamFile):
         #    print('   ', obj)
 
         for obj in self.objects:
-            obj.rotate(angle, *center)
+            obj.rotate(angle, *center, unit)
 
         #print('after')
         #for obj in self.objects:
@@ -414,9 +432,9 @@ class GraphicsState:
                 polarity_dark=self.polarity_dark, unit=self.file_settings.unit)
 
     def _create_arc(self, old_point, new_point, control_point, aperture=True):
-        direction = 'ccw' if self.interpolation_mode == CircularCCWModeStmt else 'cw'
+        clockwise = self.interpolation_mode == CircularCWModeStmt
         return go.Arc(*old_point, *new_point,* self.map_coord(*control_point, relative=True),
-                flipped=(direction == 'cw'), aperture=(self.aperture if aperture else None),
+                clockwise=clockwise, aperture=(self.aperture if aperture else None),
                 polarity_dark=self.polarity_dark, unit=self.file_settings.unit)
 
     def update_point(self, x, y, unit=None):