Graft pcb-tools upstream onto gerbonara tree

6 files changed, 1703 insertions, 0 deletions

diff --git a/gerber/render/__init__.py b/gerber/render/__init__.py
new file mode 100644
index 0000000..c7dbdd5
--- /dev/null
+++ b/gerber/render/__init__.py
@@ -0,0 +1,31 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# copyright 2014 Hamilton Kibbe <ham@hamiltonkib.be>
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+gerber.render
+============
+**Gerber Renderers**
+
+This module provides contexts for rendering images of gerber layers. Currently
+SVG is the only supported format.
+"""
+
+from .render import RenderSettings
+from .cairo_backend import GerberCairoContext
+
+available_renderers = {
+    'cairo': GerberCairoContext,
+}
diff --git a/gerber/render/cairo_backend.py b/gerber/render/cairo_backend.py
new file mode 100644
index 0000000..e1d1408
--- /dev/null
+++ b/gerber/render/cairo_backend.py
@@ -0,0 +1,616 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright 2014 Hamilton Kibbe <ham@hamiltonkib.be>
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+try:
+    import cairo
+except ImportError:
+    import cairocffi as cairo
+
+from operator import mul
+import tempfile
+import copy
+import os
+
+from .render import GerberContext, RenderSettings
+from .theme import THEMES
+from ..primitives import *
+from ..utils import rotate_point
+
+from io import BytesIO
+
+
+class GerberCairoContext(GerberContext):
+
+    def __init__(self, scale=300):
+        super(GerberCairoContext, self).__init__()
+        self.scale = (scale, scale)
+        self.surface = None
+        self.surface_buffer = None
+        self.ctx = None
+        self.active_layer = None
+        self.active_matrix = None
+        self.output_ctx = None
+        self.has_bg = False
+        self.origin_in_inch = None
+        self.size_in_inch = None
+        self._xform_matrix = None
+        self._render_count = 0
+
+    @property
+    def origin_in_pixels(self):
+        return (self.scale_point(self.origin_in_inch)
+                if self.origin_in_inch is not None else (0.0, 0.0))
+
+    @property
+    def size_in_pixels(self):
+        return (self.scale_point(self.size_in_inch)
+                if self.size_in_inch is not None else (0.0, 0.0))
+
+    def set_bounds(self, bounds, new_surface=False):
+        origin_in_inch = (bounds[0][0], bounds[1][0])
+        size_in_inch = (abs(bounds[0][1] - bounds[0][0]),
+                        abs(bounds[1][1] - bounds[1][0]))
+        size_in_pixels = self.scale_point(size_in_inch)
+        self.origin_in_inch = origin_in_inch if self.origin_in_inch is None else self.origin_in_inch
+        self.size_in_inch = size_in_inch if self.size_in_inch is None else self.size_in_inch
+        self._xform_matrix = cairo.Matrix(xx=1.0, yy=-1.0,
+                                          x0=-self.origin_in_pixels[0],
+                                          y0=self.size_in_pixels[1])
+        if (self.surface is None) or new_surface:
+            self.surface_buffer = tempfile.NamedTemporaryFile()
+            self.surface = cairo.SVGSurface(self.surface_buffer, size_in_pixels[0], size_in_pixels[1])
+            self.output_ctx = cairo.Context(self.surface)
+
+    def render_layer(self, layer, filename=None, settings=None, bgsettings=None,
+                     verbose=False, bounds=None):
+        if settings is None:
+            settings = THEMES['default'].get(layer.layer_class, RenderSettings())
+        if bgsettings is None:
+            bgsettings = THEMES['default'].get('background', RenderSettings())
+
+        if self._render_count == 0:
+            if verbose:
+                print('[Render]: Rendering Background.')
+            self.clear()
+            if bounds is not None:
+                self.set_bounds(bounds)
+            else:
+                self.set_bounds(layer.bounds)
+            self.paint_background(bgsettings)
+        if verbose:
+            print('[Render]: Rendering {} Layer.'.format(layer.layer_class))
+        self._render_count += 1
+        self._render_layer(layer, settings)
+        if filename is not None:
+            self.dump(filename, verbose)
+
+    def render_layers(self, layers, filename, theme=THEMES['default'],
+                      verbose=False, max_width=800, max_height=600):
+        """ Render a set of layers
+        """
+        # Calculate scale parameter
+        x_range = [10000, -10000]
+        y_range = [10000, -10000]
+        for layer in layers:
+            bounds = layer.bounds
+            if bounds is not None:
+                layer_x, layer_y = bounds
+                x_range[0] = min(x_range[0], layer_x[0])
+                x_range[1] = max(x_range[1], layer_x[1])
+                y_range[0] = min(y_range[0], layer_y[0])
+                y_range[1] = max(y_range[1], layer_y[1])
+        width = x_range[1] - x_range[0]
+        height = y_range[1] - y_range[0]
+
+        scale = math.floor(min(float(max_width)/width, float(max_height)/height))
+        self.scale = (scale, scale)
+
+        self.clear()
+
+        # Render layers
+        bgsettings = theme['background']
+        for layer in layers:
+            settings = theme.get(layer.layer_class, RenderSettings())
+            self.render_layer(layer, settings=settings, bgsettings=bgsettings,
+                              verbose=verbose)
+        self.dump(filename, verbose)
+
+    def dump(self, filename=None, verbose=False):
+        """ Save image as `filename`
+        """
+        try:
+            is_svg = os.path.splitext(filename.lower())[1] == '.svg'
+        except:
+            is_svg = False
+        if verbose:
+            print('[Render]: Writing image to {}'.format(filename))
+        if is_svg:
+            self.surface.finish()
+            self.surface_buffer.flush()
+            with open(filename, "wb") as f:
+                self.surface_buffer.seek(0)
+                f.write(self.surface_buffer.read())
+                f.flush()
+        else:
+            return self.surface.write_to_png(filename)
+
+    def dump_str(self):
+        """ Return a byte-string containing the rendered image.
+        """
+        fobj = BytesIO()
+        self.surface.write_to_png(fobj)
+        return fobj.getvalue()
+
+    def dump_svg_str(self):
+        """ Return a string containg the rendered SVG.
+        """
+        self.surface.finish()
+        self.surface_buffer.flush()
+        return self.surface_buffer.read()
+
+    def clear(self):
+        self.surface = None
+        self.output_ctx = None
+        self.has_bg = False
+        self.origin_in_inch = None
+        self.size_in_inch = None
+        self._xform_matrix = None
+        self._render_count = 0
+        self.surface_buffer = None
+
+    def _new_mask(self):
+        class Mask:
+            def __enter__(msk):
+                size_in_pixels = self.size_in_pixels
+                msk.surface = cairo.SVGSurface(None, size_in_pixels[0],
+                                               size_in_pixels[1])
+                msk.ctx = cairo.Context(msk.surface)
+                msk.ctx.translate(-self.origin_in_pixels[0], -self.origin_in_pixels[1])
+                return msk
+
+
+            def __exit__(msk, exc_type, exc_val, traceback):
+                if hasattr(msk.surface, 'finish'):
+                    msk.surface.finish()
+
+        return Mask()
+
+    def _render_layer(self, layer, settings):
+        self.invert = settings.invert
+        # Get a new clean layer to render on
+        self.new_render_layer(mirror=settings.mirror)
+        for prim in layer.primitives:
+            self.render(prim)
+        # Add layer to image
+        self.flatten(settings.color, settings.alpha)
+
+    def _render_line(self, line, color):
+        start = self.scale_point(line.start)
+        end = self.scale_point(line.end)
+        self.ctx.set_operator(cairo.OPERATOR_OVER
+                              if (not self.invert)
+                                 and line.level_polarity == 'dark'
+                              else cairo.OPERATOR_CLEAR)
+
+        with self._clip_primitive(line):
+            with self._new_mask() as mask:
+                if isinstance(line.aperture, Circle):
+                    width = line.aperture.diameter
+                    mask.ctx.set_line_width(width * self.scale[0])
+                    mask.ctx.set_line_cap(cairo.LINE_CAP_ROUND)
+                    mask.ctx.move_to(*start)
+                    mask.ctx.line_to(*end)
+                    mask.ctx.stroke()
+
+                elif hasattr(line, 'vertices') and line.vertices is not None:
+                    points = [self.scale_point(x) for x in line.vertices]
+                    mask.ctx.set_line_width(0)
+                    mask.ctx.move_to(*points[-1])
+                    for point in points:
+                        mask.ctx.line_to(*point)
+                    mask.ctx.fill()
+                self.ctx.mask_surface(mask.surface, self.origin_in_pixels[0])
+
+    def _render_arc(self, arc, color):
+        center = self.scale_point(arc.center)
+        start = self.scale_point(arc.start)
+        end = self.scale_point(arc.end)
+        radius = self.scale[0] * arc.radius
+        two_pi = 2 * math.pi
+        angle1 = (arc.start_angle + two_pi) % two_pi
+        angle2 = (arc.end_angle + two_pi) % two_pi
+        if angle1 == angle2 and arc.quadrant_mode != 'single-quadrant':
+            # Make the angles slightly different otherwise Cario will draw nothing
+            angle2 -= 0.000000001
+        if isinstance(arc.aperture, Circle):
+            width = arc.aperture.diameter if arc.aperture.diameter != 0 else 0.001
+        else:
+            width = max(arc.aperture.width, arc.aperture.height, 0.001)
+
+        self.ctx.set_operator(cairo.OPERATOR_OVER
+                              if (not self.invert)
+                                 and arc.level_polarity == 'dark'
+                              else cairo.OPERATOR_CLEAR)
+        with self._clip_primitive(arc):
+            with self._new_mask() as mask:
+                mask.ctx.set_line_width(width * self.scale[0])
+                mask.ctx.set_line_cap(cairo.LINE_CAP_ROUND if isinstance(arc.aperture, Circle) else cairo.LINE_CAP_SQUARE)
+                mask.ctx.move_to(*start)  # You actually have to do this...
+                if arc.direction == 'counterclockwise':
+                    mask.ctx.arc(center[0], center[1], radius, angle1, angle2)
+                else:
+                    mask.ctx.arc_negative(center[0], center[1], radius,
+                                          angle1, angle2)
+                mask.ctx.move_to(*end)  # ...lame
+                mask.ctx.stroke()
+
+                #if isinstance(arc.aperture, Rectangle):
+                #    print("Flash Rectangle Ends")
+                #    print(arc.aperture.rotation * 180/math.pi)
+                #    rect = arc.aperture
+                #    width = self.scale[0] * rect.width
+                #    height = self.scale[1] * rect.height
+                #    for point, angle in zip((start, end), (angle1, angle2)):
+                #        print("{} w {} h{}".format(point, rect.width, rect.height))
+                #        mask.ctx.rectangle(point[0] - width/2.0,
+                #                           point[1] - height/2.0, width, height)
+                #        mask.ctx.fill()
+
+                self.ctx.mask_surface(mask.surface, self.origin_in_pixels[0])
+
+    def _render_region(self, region, color):
+        self.ctx.set_operator(cairo.OPERATOR_OVER
+                              if (not self.invert) and region.level_polarity == 'dark'
+                              else cairo.OPERATOR_CLEAR)
+        with self._clip_primitive(region):
+            with self._new_mask() as mask:
+                mask.ctx.set_line_width(0)
+                mask.ctx.set_line_cap(cairo.LINE_CAP_ROUND)
+                mask.ctx.move_to(*self.scale_point(region.primitives[0].start))
+                for prim in region.primitives:
+                    if isinstance(prim, Line):
+                        mask.ctx.line_to(*self.scale_point(prim.end))
+                    else:
+                        center = self.scale_point(prim.center)
+                        radius = self.scale[0] * prim.radius
+                        angle1 = prim.start_angle
+                        angle2 = prim.end_angle
+                        if prim.direction == 'counterclockwise':
+                            mask.ctx.arc(center[0], center[1], radius,
+                                         angle1, angle2)
+                        else:
+                            mask.ctx.arc_negative(center[0], center[1], radius,
+                                                  angle1, angle2)
+                mask.ctx.fill()
+                self.ctx.mask_surface(mask.surface, self.origin_in_pixels[0])
+
+    def _render_circle(self, circle, color):
+        center = self.scale_point(circle.position)
+        self.ctx.set_operator(cairo.OPERATOR_OVER
+                              if (not self.invert)
+                                 and circle.level_polarity == 'dark'
+                              else cairo.OPERATOR_CLEAR)
+        with self._clip_primitive(circle):
+            with self._new_mask() as mask:
+                mask.ctx.set_line_width(0)
+                mask.ctx.arc(center[0], center[1], (circle.radius * self.scale[0]), 0, (2 * math.pi))
+                mask.ctx.fill()
+
+                if hasattr(circle, 'hole_diameter') and circle.hole_diameter is not None and circle.hole_diameter > 0:
+                    mask.ctx.set_operator(cairo.OPERATOR_CLEAR)
+                    mask.ctx.arc(center[0], center[1], circle.hole_radius * self.scale[0], 0, 2 * math.pi)
+                    mask.ctx.fill()
+
+                if (hasattr(circle, 'hole_width') and hasattr(circle, 'hole_height')
+                        and circle.hole_width is not None and circle.hole_height is not None
+                        and circle.hole_width > 0 and circle.hole_height > 0):
+                    mask.ctx.set_operator(cairo.OPERATOR_CLEAR
+                                          if circle.level_polarity == 'dark'
+                                             and (not self.invert)
+                                          else cairo.OPERATOR_OVER)
+                    width, height = self.scale_point((circle.hole_width, circle.hole_height))
+                    lower_left = rotate_point(
+                        (center[0] - width / 2.0, center[1] - height / 2.0),
+                                              circle.rotation, center)
+                    lower_right = rotate_point((center[0] + width / 2.0, center[1] - height / 2.0),
+                                               circle.rotation, center)
+                    upper_left = rotate_point((center[0] - width / 2.0, center[1] + height / 2.0),
+                                              circle.rotation, center)
+                    upper_right = rotate_point((center[0] + width / 2.0, center[1] + height / 2.0),
+                                               circle.rotation, center)
+                    points = (lower_left, lower_right, upper_right, upper_left)
+                    mask.ctx.move_to(*points[-1])
+                    for point in points:
+                        mask.ctx.line_to(*point)
+                    mask.ctx.fill()
+                self.ctx.mask_surface(mask.surface, self.origin_in_pixels[0])
+
+    def _render_rectangle(self, rectangle, color):
+        lower_left = self.scale_point(rectangle.lower_left)
+        width, height = tuple([abs(coord) for coord in
+                               self.scale_point((rectangle.width,
+                                                 rectangle.height))])
+        self.ctx.set_operator(cairo.OPERATOR_OVER
+                              if (not self.invert)
+                                 and rectangle.level_polarity == 'dark'
+                              else cairo.OPERATOR_CLEAR)
+        with self._clip_primitive(rectangle):
+            with self._new_mask() as mask:
+                mask.ctx.set_line_width(0)
+                mask.ctx.rectangle(lower_left[0], lower_left[1], width, height)
+                mask.ctx.fill()
+
+                center = self.scale_point(rectangle.position)
+                if rectangle.hole_diameter > 0:
+                    # Render the center clear
+                    mask.ctx.set_operator(cairo.OPERATOR_CLEAR
+                                          if rectangle.level_polarity == 'dark'
+                                             and (not self.invert)
+                                          else cairo.OPERATOR_OVER)
+
+                    mask.ctx.arc(center[0], center[1], rectangle.hole_radius * self.scale[0], 0, 2 * math.pi)
+                    mask.ctx.fill()
+
+                if rectangle.hole_width > 0 and rectangle.hole_height > 0:
+                    mask.ctx.set_operator(cairo.OPERATOR_CLEAR
+                                          if rectangle.level_polarity == 'dark'
+                                             and (not self.invert)
+                                          else cairo.OPERATOR_OVER)
+                    width, height = self.scale_point((rectangle.hole_width, rectangle.hole_height))
+                    lower_left = rotate_point((center[0] - width/2.0, center[1] - height/2.0), rectangle.rotation, center)
+                    lower_right = rotate_point((center[0] + width/2.0, center[1] - height/2.0), rectangle.rotation, center)
+                    upper_left = rotate_point((center[0] - width / 2.0, center[1] + height / 2.0), rectangle.rotation, center)
+                    upper_right = rotate_point((center[0] + width / 2.0, center[1] + height / 2.0), rectangle.rotation, center)
+                    points = (lower_left, lower_right, upper_right, upper_left)
+                    mask.ctx.move_to(*points[-1])
+                    for point in points:
+                        mask.ctx.line_to(*point)
+                    mask.ctx.fill()
+                self.ctx.mask_surface(mask.surface, self.origin_in_pixels[0])
+
+    def _render_obround(self, obround, color):
+        self.ctx.set_operator(cairo.OPERATOR_OVER
+                              if (not self.invert)
+                                 and obround.level_polarity == 'dark'
+                              else cairo.OPERATOR_CLEAR)
+        with self._clip_primitive(obround):
+            with self._new_mask() as mask:
+                mask.ctx.set_line_width(0)
+
+                # Render circles
+                for circle in (obround.subshapes['circle1'], obround.subshapes['circle2']):
+                    center = self.scale_point(circle.position)
+                    mask.ctx.arc(center[0], center[1], (circle.radius * self.scale[0]), 0, (2 * math.pi))
+                    mask.ctx.fill()
+
+                # Render Rectangle
+                rectangle = obround.subshapes['rectangle']
+                lower_left = self.scale_point(rectangle.lower_left)
+                width, height = tuple([abs(coord) for coord in
+                                       self.scale_point((rectangle.width,
+                                                         rectangle.height))])
+                mask.ctx.rectangle(lower_left[0], lower_left[1], width, height)
+                mask.ctx.fill()
+
+                center = self.scale_point(obround.position)
+                if obround.hole_diameter > 0:
+                    # Render the center clear
+                    mask.ctx.set_operator(cairo.OPERATOR_CLEAR)
+                    mask.ctx.arc(center[0], center[1], obround.hole_radius * self.scale[0], 0, 2 * math.pi)
+                    mask.ctx.fill()
+
+                if obround.hole_width > 0 and obround.hole_height > 0:
+                    mask.ctx.set_operator(cairo.OPERATOR_CLEAR
+                                          if rectangle.level_polarity == 'dark'
+                                             and (not self.invert)
+                                          else cairo.OPERATOR_OVER)
+                    width, height =self.scale_point((obround.hole_width, obround.hole_height))
+                    lower_left = rotate_point((center[0] - width / 2.0, center[1] - height / 2.0),
+                                              obround.rotation, center)
+                    lower_right = rotate_point((center[0] + width / 2.0, center[1] - height / 2.0),
+                                               obround.rotation, center)
+                    upper_left = rotate_point((center[0] - width / 2.0, center[1] + height / 2.0),
+                                              obround.rotation, center)
+                    upper_right = rotate_point((center[0] + width / 2.0, center[1] + height / 2.0),
+                                               obround.rotation, center)
+                    points = (lower_left, lower_right, upper_right, upper_left)
+                    mask.ctx.move_to(*points[-1])
+                    for point in points:
+                        mask.ctx.line_to(*point)
+                    mask.ctx.fill()
+
+                self.ctx.mask_surface(mask.surface, self.origin_in_pixels[0])
+
+    def _render_polygon(self, polygon, color):
+        self.ctx.set_operator(cairo.OPERATOR_OVER
+                              if (not self.invert)
+                                 and polygon.level_polarity == 'dark'
+                              else cairo.OPERATOR_CLEAR)
+        with self._clip_primitive(polygon):
+            with self._new_mask() as mask:
+
+                vertices = polygon.vertices
+                mask.ctx.set_line_width(0)
+                mask.ctx.set_line_cap(cairo.LINE_CAP_ROUND)
+                # Start from before the end so it is easy to iterate and make sure
+                # it is closed
+                mask.ctx.move_to(*self.scale_point(vertices[-1]))
+                for v in vertices:
+                    mask.ctx.line_to(*self.scale_point(v))
+                mask.ctx.fill()
+
+                center = self.scale_point(polygon.position)
+                if polygon.hole_radius > 0:
+                    # Render the center clear
+                    mask.ctx.set_operator(cairo.OPERATOR_CLEAR
+                                          if polygon.level_polarity == 'dark'
+                                             and (not self.invert)
+                                          else cairo.OPERATOR_OVER)
+                    mask.ctx.set_line_width(0)
+                    mask.ctx.arc(center[0],
+                                 center[1],
+                                 polygon.hole_radius * self.scale[0], 0, 2 * math.pi)
+                    mask.ctx.fill()
+
+                if polygon.hole_width > 0 and polygon.hole_height > 0:
+                    mask.ctx.set_operator(cairo.OPERATOR_CLEAR
+                                          if polygon.level_polarity == 'dark'
+                                             and (not self.invert)
+                                          else cairo.OPERATOR_OVER)
+                    width, height = self.scale_point((polygon.hole_width, polygon.hole_height))
+                    lower_left = rotate_point((center[0] - width / 2.0, center[1] - height / 2.0),
+                                              polygon.rotation, center)
+                    lower_right = rotate_point((center[0] + width / 2.0, center[1] - height / 2.0),
+                                               polygon.rotation, center)
+                    upper_left = rotate_point((center[0] - width / 2.0, center[1] + height / 2.0),
+                                              polygon.rotation, center)
+                    upper_right = rotate_point((center[0] + width / 2.0, center[1] + height / 2.0),
+                                               polygon.rotation, center)
+                    points = (lower_left, lower_right, upper_right, upper_left)
+                    mask.ctx.move_to(*points[-1])
+                    for point in points:
+                        mask.ctx.line_to(*point)
+                    mask.ctx.fill()
+
+                self.ctx.mask_surface(mask.surface, self.origin_in_pixels[0])
+
+    def _render_drill(self, circle, color=None):
+        color = color if color is not None else self.drill_color
+        self._render_circle(circle, color)
+
+    def _render_slot(self, slot, color):
+        start = map(mul, slot.start, self.scale)
+        end = map(mul, slot.end, self.scale)
+
+        width = slot.diameter
+
+        self.ctx.set_operator(cairo.OPERATOR_OVER
+                              if slot.level_polarity == 'dark' and
+                                 (not self.invert) else cairo.OPERATOR_CLEAR)
+        with self._clip_primitive(slot):
+            with self._new_mask() as mask:
+                mask.ctx.set_line_width(width * self.scale[0])
+                mask.ctx.set_line_cap(cairo.LINE_CAP_ROUND)
+                mask.ctx.move_to(*start)
+                mask.ctx.line_to(*end)
+                mask.ctx.stroke()
+                self.ctx.mask_surface(mask.surface, self.origin_in_pixels[0])
+
+    def _render_amgroup(self, amgroup, color):
+        for primitive in amgroup.primitives:
+            self.render(primitive)
+
+    def _render_test_record(self, primitive, color):
+        position = [pos + origin for pos, origin in
+                    zip(primitive.position, self.origin_in_inch)]
+        self.ctx.select_font_face(
+            'monospace', cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_BOLD)
+        self.ctx.set_font_size(13)
+        self._render_circle(Circle(position, 0.015), color)
+        self.ctx.set_operator(cairo.OPERATOR_OVER
+                              if primitive.level_polarity == 'dark' and
+                              (not self.invert) else cairo.OPERATOR_CLEAR)
+        self.ctx.move_to(*[self.scale[0] * (coord + 0.015) for coord in position])
+        self.ctx.scale(1, -1)
+        self.ctx.show_text(primitive.net_name)
+        self.ctx.scale(1, -1)
+
+    def new_render_layer(self, color=None, mirror=False):
+        size_in_pixels = self.scale_point(self.size_in_inch)
+        matrix = copy.copy(self._xform_matrix)
+        layer = cairo.SVGSurface(None, size_in_pixels[0], size_in_pixels[1])
+        ctx = cairo.Context(layer)
+
+        if self.invert:
+            ctx.set_source_rgba(0.0, 0.0, 0.0, 1.0)
+            ctx.set_operator(cairo.OPERATOR_OVER)
+            ctx.paint()
+        if mirror:
+            matrix.xx = -1.0
+            matrix.x0 = self.origin_in_pixels[0] + self.size_in_pixels[0]
+        self.ctx = ctx
+        self.ctx.set_matrix(matrix)
+        self.active_layer = layer
+        self.active_matrix = matrix
+
+    def flatten(self, color=None, alpha=None):
+        color = color if color is not None else self.color
+        alpha = alpha if alpha is not None else self.alpha
+        self.output_ctx.set_source_rgba(color[0], color[1], color[2], alpha)
+        self.output_ctx.mask_surface(self.active_layer)
+        self.ctx = None
+        self.active_layer = None
+        self.active_matrix = None
+
+    def paint_background(self, settings=None):
+        color = settings.color if settings is not None else self.background_color
+        alpha = settings.alpha if settings is not None else 1.0
+        if not self.has_bg:
+            self.has_bg = True
+            self.output_ctx.set_source_rgba(color[0], color[1], color[2], alpha)
+            self.output_ctx.paint()
+
+    def _clip_primitive(self, primitive):
+        """ Clip rendering context to pixel-aligned bounding box
+
+        Calculates pixel- and axis- aligned bounding box, and clips current
+        context to that region. Improves rendering speed significantly. This
+        returns a context manager, use as follows:
+
+            with self._clip_primitive(some_primitive):
+                do_rendering_stuff()
+                do_more_rendering stuff(with, arguments)
+
+        The context manager will reset the context's clipping region when it
+        goes out of scope.
+
+        """
+        class Clip:
+            def __init__(clp, primitive):
+                x_range, y_range = primitive.bounding_box
+                xmin, xmax = x_range
+                ymin, ymax = y_range
+
+                # Round bounds to the nearest pixel outside of the primitive
+                clp.xmin = math.floor(self.scale[0] * xmin)
+                clp.xmax = math.ceil(self.scale[0] * xmax)
+
+                # We need to offset Y to take care of the difference in y-pos
+                # caused by flipping the axis.
+                clp.ymin = math.floor(
+                    (self.scale[1] * ymin) - math.ceil(self.origin_in_pixels[1]))
+                clp.ymax = math.floor(
+                    (self.scale[1] * ymax) - math.floor(self.origin_in_pixels[1]))
+
+                # Calculate width and height, rounded to the nearest pixel
+                clp.width = abs(clp.xmax - clp.xmin)
+                clp.height = abs(clp.ymax - clp.ymin)
+
+            def __enter__(clp):
+                # Clip current context to primitive's bounding box
+                self.ctx.rectangle(clp.xmin, clp.ymin, clp.width, clp.height)
+                self.ctx.clip()
+
+            def __exit__(clp, exc_type, exc_val, traceback):
+                # Reset context clip region
+                self.ctx.reset_clip()
+
+        return Clip(primitive)
+
+    def scale_point(self, point):
+        return tuple([coord * scale for coord, scale in zip(point, self.scale)])
diff --git a/gerber/render/excellon_backend.py b/gerber/render/excellon_backend.py
new file mode 100644
index 0000000..765d68c
--- /dev/null
+++ b/gerber/render/excellon_backend.py
@@ -0,0 +1,188 @@
+
+from .render import GerberContext
+from ..excellon import DrillSlot
+from ..excellon_statements import *
+
+class ExcellonContext(GerberContext):
+
+    MODE_DRILL = 1
+    MODE_SLOT =2
+
+    def __init__(self, settings):
+        GerberContext.__init__(self)
+
+        # Statements that we write
+        self.comments = []
+        self.header = []
+        self.tool_def = []
+        self.body_start = [RewindStopStmt()]
+        self.body = []
+        self.start = [HeaderBeginStmt()]
+
+        # Current tool and position
+        self.handled_tools = set()
+        self.cur_tool = None
+        self.drill_mode = ExcellonContext.MODE_DRILL
+        self.drill_down = False
+        self._pos = (None, None)
+
+        self.settings = settings
+
+        self._start_header()
+        self._start_comments()
+
+    def _start_header(self):
+        """Create the header from the settings"""
+
+        self.header.append(UnitStmt.from_settings(self.settings))
+
+        if self.settings.notation == 'incremental':
+            raise NotImplementedError('Incremental mode is not implemented')
+        else:
+            self.body.append(AbsoluteModeStmt())
+
+    def _start_comments(self):
+
+        # Write the digits used - this isn't valid Excellon statement, so we write as a comment
+        self.comments.append(CommentStmt('FILE_FORMAT=%d:%d' % (self.settings.format[0], self.settings.format[1])))
+
+    def _get_end(self):
+        """How we end depends on our mode"""
+
+        end = []
+
+        if self.drill_down:
+            end.append(RetractWithClampingStmt())
+            end.append(RetractWithoutClampingStmt())
+
+        end.append(EndOfProgramStmt())
+
+        return end
+
+    @property
+    def statements(self):
+        return self.start + self.comments + self.header + self.body_start + self.body + self._get_end()
+
+    def set_bounds(self, bounds, *args, **kwargs):
+        pass
+
+    def paint_background(self):
+        pass
+
+    def _render_line(self, line, color):
+        raise ValueError('Invalid Excellon object')
+    def _render_arc(self, arc, color):
+        raise ValueError('Invalid Excellon object')
+
+    def _render_region(self, region, color):
+        raise ValueError('Invalid Excellon object')
+
+    def _render_level_polarity(self, region):
+        raise ValueError('Invalid Excellon object')
+
+    def _render_circle(self, circle, color):
+        raise ValueError('Invalid Excellon object')
+
+    def _render_rectangle(self, rectangle, color):
+        raise ValueError('Invalid Excellon object')
+
+    def _render_obround(self, obround, color):
+        raise ValueError('Invalid Excellon object')
+
+    def _render_polygon(self, polygon, color):
+        raise ValueError('Invalid Excellon object')
+
+    def _simplify_point(self, point):
+        return (point[0] if point[0] != self._pos[0] else None, point[1] if point[1] != self._pos[1] else None)
+
+    def _render_drill(self, drill, color):
+
+        if self.drill_mode != ExcellonContext.MODE_DRILL:
+            self._start_drill_mode()
+
+        tool = drill.hit.tool
+        if not tool in self.handled_tools:
+            self.handled_tools.add(tool)
+            self.header.append(ExcellonTool.from_tool(tool))
+
+        if tool != self.cur_tool:
+            self.body.append(ToolSelectionStmt(tool.number))
+            self.cur_tool = tool
+
+        point = self._simplify_point(drill.position)
+        self._pos = drill.position
+        self.body.append(CoordinateStmt.from_point(point))
+
+    def _start_drill_mode(self):
+        """
+        If we are not in drill mode, then end the ROUT so we can do basic drilling
+        """
+
+        if self.drill_mode == ExcellonContext.MODE_SLOT:
+
+            # Make sure we are retracted before changing modes
+            last_cmd = self.body[-1]
+            if self.drill_down:
+                self.body.append(RetractWithClampingStmt())
+                self.body.append(RetractWithoutClampingStmt())
+                self.drill_down = False
+
+            # Switch to drill mode
+            self.body.append(DrillModeStmt())
+            self.drill_mode = ExcellonContext.MODE_DRILL
+
+        else:
+            raise ValueError('Should be in slot mode')
+
+    def _render_slot(self, slot, color):
+
+        # Set the tool first, before we might go into drill mode
+        tool = slot.hit.tool
+        if not tool in self.handled_tools:
+            self.handled_tools.add(tool)
+            self.header.append(ExcellonTool.from_tool(tool))
+
+        if tool != self.cur_tool:
+            self.body.append(ToolSelectionStmt(tool.number))
+            self.cur_tool = tool
+
+        # Two types of drilling - normal drill and slots
+        if slot.hit.slot_type == DrillSlot.TYPE_ROUT:
+
+            # For ROUT, setting the mode is part of the actual command.
+
+            # Are we in the right position?
+            if slot.start != self._pos:
+                if self.drill_down:
+                    # We need to move into the right position, so retract
+                    self.body.append(RetractWithClampingStmt())
+                    self.drill_down = False
+
+                # Move to the right spot
+                point = self._simplify_point(slot.start)
+                self._pos = slot.start
+                self.body.append(CoordinateStmt.from_point(point, mode="ROUT"))
+
+            # Now we are in the right spot, so drill down
+            if not self.drill_down:
+                self.body.append(ZAxisRoutPositionStmt())
+                self.drill_down = True
+
+            # Do a linear move from our current position to the end position
+            point = self._simplify_point(slot.end)
+            self._pos = slot.end
+            self.body.append(CoordinateStmt.from_point(point, mode="LINEAR"))
+
+            self.drill_mode = ExcellonContext.MODE_SLOT
+
+        else:
+            # This is a G85 slot, so do this in normally drilling mode
+            if self.drill_mode != ExcellonContext.MODE_DRILL:
+                self._start_drill_mode()
+
+            # Slots don't use simplified points
+            self._pos = slot.end
+            self.body.append(SlotStmt.from_points(slot.start, slot.end))
+
+    def _render_inverted_layer(self):
+        pass
diff --git a/gerber/render/render.py b/gerber/render/render.py
new file mode 100644
index 0000000..580a7ea
--- /dev/null
+++ b/gerber/render/render.py
@@ -0,0 +1,246 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# copyright 2014 Hamilton Kibbe <ham@hamiltonkib.be>
+# Modified from code by Paulo Henrique Silva <ph.silva@gmail.com>
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""
+Rendering
+============
+**Gerber (RS-274X) and Excellon file rendering**
+
+Render Gerber and Excellon files to a variety of formats. The render module
+currently supports SVG rendering using the `svgwrite` library.
+"""
+
+
+from ..primitives import *
+from ..gerber_statements import (CommentStmt, UnknownStmt, EofStmt, ParamStmt,
+                                 CoordStmt, ApertureStmt, RegionModeStmt,
+                                 QuadrantModeStmt,)
+
+
+class GerberContext(object):
+    """ Gerber rendering context base class
+
+    Provides basic functionality and API for rendering gerber files.  Medium-
+    specific renderers should subclass GerberContext and implement the drawing
+    functions. Colors are stored internally as 32-bit RGB and may need to be
+    converted to a native format in the rendering subclass.
+
+    Attributes
+    ----------
+    units : string
+        Measurement units. 'inch' or 'metric'
+
+    color : tuple (<float>, <float>, <float>)
+        Color used for rendering as a tuple of normalized (red, green, blue)
+        values.
+
+    drill_color : tuple (<float>, <float>, <float>)
+        Color used for rendering drill hits. Format is the same as for `color`.
+
+    background_color : tuple (<float>, <float>, <float>)
+        Color of the background. Used when exposing areas in 'clear' level
+        polarity mode. Format is the same as for `color`.
+
+    alpha : float
+        Rendering opacity. Between 0.0 (transparent) and 1.0 (opaque.)
+    """
+
+    def __init__(self, units='inch'):
+        self._units = units
+        self._color = (0.7215, 0.451, 0.200)
+        self._background_color = (0.0, 0.0, 0.0)
+        self._drill_color = (0.0, 0.0, 0.0)
+        self._alpha = 1.0
+        self._invert = False
+        self.ctx = None
+
+    @property
+    def units(self):
+        return self._units
+
+    @units.setter
+    def units(self, units):
+        if units not in ('inch', 'metric'):
+            raise ValueError('Units may be "inch" or "metric"')
+        self._units = units
+
+    @property
+    def color(self):
+        return self._color
+
+    @color.setter
+    def color(self, color):
+        if len(color) != 3:
+            raise TypeError('Color must be a tuple of R, G, and B values')
+        for c in color:
+            if c < 0 or c > 1:
+                raise ValueError('Channel values must be between 0.0 and 1.0')
+        self._color = color
+
+    @property
+    def drill_color(self):
+        return self._drill_color
+
+    @drill_color.setter
+    def drill_color(self, color):
+        if len(color) != 3:
+            raise TypeError('Drill color must be a tuple of R, G, and B values')
+        for c in color:
+            if c < 0 or c > 1:
+                raise ValueError('Channel values must be between 0.0 and 1.0')
+        self._drill_color = color
+
+    @property
+    def background_color(self):
+        return self._background_color
+
+    @background_color.setter
+    def background_color(self, color):
+        if len(color) != 3:
+            raise TypeError('Background color must be a tuple of R, G, and B values')
+        for c in color:
+            if c < 0 or c > 1:
+                raise ValueError('Channel values must be between 0.0 and 1.0')
+        self._background_color = color
+
+    @property
+    def alpha(self):
+        return self._alpha
+
+    @alpha.setter
+    def alpha(self, alpha):
+        if alpha < 0 or alpha > 1:
+            raise ValueError('Alpha must be between 0.0 and 1.0')
+        self._alpha = alpha
+
+    @property
+    def invert(self):
+        return self._invert
+
+    @invert.setter
+    def invert(self, invert):
+        self._invert = invert
+
+    def render(self, primitive):
+        if not primitive:
+            return
+
+        self.pre_render_primitive(primitive)
+
+        color = self.color
+        if isinstance(primitive, Line):
+            self._render_line(primitive, color)
+        elif isinstance(primitive, Arc):
+            self._render_arc(primitive, color)
+        elif isinstance(primitive, Region):
+            self._render_region(primitive, color)
+        elif isinstance(primitive, Circle):
+            self._render_circle(primitive, color)
+        elif isinstance(primitive, Rectangle):
+            self._render_rectangle(primitive, color)
+        elif isinstance(primitive, Obround):
+            self._render_obround(primitive, color)
+        elif isinstance(primitive, Polygon):
+            self._render_polygon(primitive, color)
+        elif isinstance(primitive, Drill):
+            self._render_drill(primitive, self.color)
+        elif isinstance(primitive, Slot):
+            self._render_slot(primitive, self.color)
+        elif isinstance(primitive, AMGroup):
+            self._render_amgroup(primitive, color)
+        elif isinstance(primitive, Outline):
+            self._render_region(primitive, color)
+        elif isinstance(primitive, TestRecord):
+            self._render_test_record(primitive, color)
+
+        self.post_render_primitive(primitive)
+
+    def set_bounds(self, bounds, *args, **kwargs):
+        """Called by the renderer to set the extents of the file to render.
+
+        Parameters
+        ----------
+        bounds: Tuple[Tuple[float, float], Tuple[float, float]]
+            ( (x_min, x_max), (y_min, y_max)
+        """
+        pass
+
+    def paint_background(self):
+        pass
+
+    def new_render_layer(self):
+        pass
+
+    def flatten(self):
+        pass
+
+    def pre_render_primitive(self, primitive):
+        """
+        Called before rendering a primitive. Use the callback to perform some action before rendering
+        a primitive, for example adding a comment.
+        """
+        return
+
+    def post_render_primitive(self, primitive):
+        """
+        Called after rendering a primitive. Use the callback to perform some action after rendering
+        a primitive
+        """
+        return
+
+
+    def _render_line(self, primitive, color):
+        pass
+
+    def _render_arc(self, primitive, color):
+        pass
+
+    def _render_region(self, primitive, color):
+        pass
+
+    def _render_circle(self, primitive, color):
+        pass
+
+    def _render_rectangle(self, primitive, color):
+        pass
+
+    def _render_obround(self, primitive, color):
+        pass
+
+    def _render_polygon(self, primitive, color):
+        pass
+
+    def _render_drill(self, primitive, color):
+        pass
+
+    def _render_slot(self, primitive, color):
+        pass
+
+    def _render_amgroup(self, primitive, color):
+        pass
+
+    def _render_test_record(self, primitive, color):
+        pass
+
+
+class RenderSettings(object):
+    def __init__(self, color=(0.0, 0.0, 0.0), alpha=1.0, invert=False,
+                 mirror=False):
+        self.color = color
+        self.alpha = alpha
+        self.invert = invert
+        self.mirror = mirror
diff --git a/gerber/render/rs274x_backend.py b/gerber/render/rs274x_backend.py
new file mode 100644
index 0000000..c7af2ea
--- /dev/null
+++ b/gerber/render/rs274x_backend.py
@@ -0,0 +1,510 @@
+"""Renders an in-memory Gerber file to statements which can be written to a string
+"""
+from copy import deepcopy
+
+try:
+    from cStringIO import StringIO
+except(ImportError):
+    from io import StringIO
+
+from .render import GerberContext
+from ..am_statements import *
+from ..gerber_statements import *
+from ..primitives import AMGroup, Arc, Circle, Line, Obround, Outline, Polygon, Rectangle
+
+
+class AMGroupContext(object):
+    '''A special renderer to generate aperature macros from an AMGroup'''
+
+    def __init__(self):
+        self.statements = []
+
+    def render(self, amgroup, name):
+
+        if amgroup.stmt:
+            # We know the statement it was generated from, so use that to create the AMParamStmt
+            # It will give a much better result
+
+            stmt = deepcopy(amgroup.stmt)
+            stmt.name = name
+
+            return stmt
+
+        else:
+            # Clone ourselves, then offset by the psotion so that
+            # our render doesn't have to consider offset. Just makes things simpler
+            nooffset_group = deepcopy(amgroup)
+            nooffset_group.position = (0, 0)
+
+            # Now draw the shapes
+            for primitive in nooffset_group.primitives:
+                if isinstance(primitive, Outline):
+                    self._render_outline(primitive)
+                elif isinstance(primitive, Circle):
+                    self._render_circle(primitive)
+                elif isinstance(primitive, Rectangle):
+                    self._render_rectangle(primitive)
+                elif isinstance(primitive, Line):
+                    self._render_line(primitive)
+                elif isinstance(primitive, Polygon):
+                    self._render_polygon(primitive)
+                else:
+                    raise ValueError('amgroup')
+
+            statement = AMParamStmt('AM', name, self._statements_to_string())
+            return statement
+
+    def _statements_to_string(self):
+        macro = ''
+
+        for statement in self.statements:
+            macro += statement.to_gerber()
+
+        return macro
+
+    def _render_circle(self, circle):
+        self.statements.append(AMCirclePrimitive.from_primitive(circle))
+
+    def _render_rectangle(self, rectangle):
+        self.statements.append(AMCenterLinePrimitive.from_primitive(rectangle))
+
+    def _render_line(self, line):
+        self.statements.append(AMVectorLinePrimitive.from_primitive(line))
+
+    def _render_outline(self, outline):
+        self.statements.append(AMOutlinePrimitive.from_primitive(outline))
+
+    def _render_polygon(self, polygon):
+        self.statements.append(AMPolygonPrimitive.from_primitive(polygon))
+
+    def _render_thermal(self, thermal):
+        pass
+
+
+class Rs274xContext(GerberContext):
+
+    def __init__(self, settings):
+        GerberContext.__init__(self)
+        self.comments = []
+        self.header = []
+        self.body = []
+        self.end = [EofStmt()]
+
+        # Current values so we know if we have to execute
+        # moves, levey changes before anything else
+        self._level_polarity = None
+        self._pos = (None, None)
+        self._func = None
+        self._quadrant_mode = None
+        self._dcode = None
+
+        # Primarily for testing and comarison to files, should we write
+        # flashes as a single statement or a move plus flash? Set to true
+        # to do in a single statement. Normally this can be false
+        self.condensed_flash = True
+
+        # When closing a region, force a D02 staement to close a region.
+        # This is normally not necessary because regions are closed with a G37
+        # staement, but this will add an extra statement for doubly close
+        # the region
+        self.explicit_region_move_end = False
+
+        self._next_dcode = 10
+        self._rects = {}
+        self._circles = {}
+        self._obrounds = {}
+        self._polygons = {}
+        self._macros = {}
+
+        self._i_none = 0
+        self._j_none = 0
+
+        self.settings = settings
+
+        self._start_header(settings)
+
+    def _start_header(self, settings):
+        self.header.append(FSParamStmt.from_settings(settings))
+        self.header.append(MOParamStmt.from_units(settings.units))
+
+    def _simplify_point(self, point):
+        return (point[0] if point[0] != self._pos[0] else None, point[1] if point[1] != self._pos[1] else None)
+
+    def _simplify_offset(self, point, offset):
+
+        if point[0] != offset[0]:
+            xoffset = point[0] - offset[0]
+        else:
+            xoffset = self._i_none
+
+        if point[1] != offset[1]:
+            yoffset = point[1] - offset[1]
+        else:
+            yoffset = self._j_none
+
+        return (xoffset, yoffset)
+
+    @property
+    def statements(self):
+        return self.comments + self.header + self.body + self.end
+
+    def set_bounds(self, bounds, *args, **kwargs):
+        pass
+
+    def paint_background(self):
+        pass
+
+    def _select_aperture(self, aperture):
+
+        # Select the right aperture if not already selected
+        if aperture:
+            if isinstance(aperture, Circle):
+                aper = self._get_circle(aperture.diameter, aperture.hole_diameter, aperture.hole_width, aperture.hole_height)
+            elif isinstance(aperture, Rectangle):
+                aper = self._get_rectangle(aperture.width, aperture.height)
+            elif isinstance(aperture, Obround):
+                aper = self._get_obround(aperture.width, aperture.height)
+            elif isinstance(aperture, AMGroup):
+                aper = self._get_amacro(aperture)
+            else:
+                raise NotImplementedError('Line with invalid aperture type')
+
+            if aper.d != self._dcode:
+                self.body.append(ApertureStmt(aper.d))
+                self._dcode = aper.d
+
+    def pre_render_primitive(self, primitive):
+
+        if hasattr(primitive, 'comment'):
+            self.body.append(CommentStmt(primitive.comment))
+
+    def _render_line(self, line, color, default_polarity='dark'):
+
+        self._select_aperture(line.aperture)
+
+        self._render_level_polarity(line, default_polarity)
+
+        # Get the right function
+        if self._func != CoordStmt.FUNC_LINEAR:
+            func = CoordStmt.FUNC_LINEAR
+        else:
+            func = None
+        self._func = CoordStmt.FUNC_LINEAR
+
+        if self._pos != line.start:
+            self.body.append(CoordStmt.move(func, self._simplify_point(line.start)))
+            self._pos = line.start
+            # We already set the function, so the next command doesn't require that
+            func = None
+
+        point = self._simplify_point(line.end)
+
+        # In some files, we see a lot of duplicated ponts, so omit those
+        if point[0] != None or point[1] != None:
+            self.body.append(CoordStmt.line(func, self._simplify_point(line.end)))
+            self._pos = line.end
+        elif func:
+            self.body.append(CoordStmt.mode(func))
+
+    def _render_arc(self, arc, color, default_polarity='dark'):
+
+        # Optionally set the quadrant mode if it has changed:
+        if arc.quadrant_mode != self._quadrant_mode:
+
+            if arc.quadrant_mode != 'multi-quadrant':
+                self.body.append(QuadrantModeStmt.single())
+            else:
+                self.body.append(QuadrantModeStmt.multi())
+
+            self._quadrant_mode = arc.quadrant_mode
+
+        # Select the right aperture if not already selected
+        self._select_aperture(arc.aperture)
+
+        self._render_level_polarity(arc, default_polarity)
+
+        # Find the right movement mode. Always set to be sure it is really right
+        dir = arc.direction
+        if dir == 'clockwise':
+            func = CoordStmt.FUNC_ARC_CW
+            self._func = CoordStmt.FUNC_ARC_CW
+        elif dir == 'counterclockwise':
+            func = CoordStmt.FUNC_ARC_CCW
+            self._func = CoordStmt.FUNC_ARC_CCW
+        else:
+            raise ValueError('Invalid circular interpolation mode')
+
+        if self._pos != arc.start:
+            # TODO I'm not sure if this is right
+            self.body.append(CoordStmt.move(CoordStmt.FUNC_LINEAR, self._simplify_point(arc.start)))
+            self._pos = arc.start
+
+        center = self._simplify_offset(arc.center, arc.start)
+        end = self._simplify_point(arc.end)
+        self.body.append(CoordStmt.arc(func, end, center))
+        self._pos = arc.end
+
+    def _render_region(self, region, color):
+
+        self._render_level_polarity(region)
+
+        self.body.append(RegionModeStmt.on())
+
+        for p in region.primitives:
+
+            # Make programmatically generated primitives within a region with
+            # unset level polarity inherit the region's level polarity
+            if isinstance(p, Line):
+                self._render_line(p, color, default_polarity=region.level_polarity)
+            else:
+                self._render_arc(p, color, default_polarity=region.level_polarity)
+
+        if self.explicit_region_move_end:
+            self.body.append(CoordStmt.move(None, None))
+
+        self.body.append(RegionModeStmt.off())
+
+    def _render_level_polarity(self, obj, default='dark'):
+        obj_polarity = obj.level_polarity if obj.level_polarity is not None else default
+        if obj_polarity != self._level_polarity:
+            self._level_polarity = obj_polarity
+            self.body.append(LPParamStmt('LP', obj_polarity))
+
+    def _render_flash(self, primitive, aperture):
+
+        self._render_level_polarity(primitive)
+
+        if aperture.d != self._dcode:
+            self.body.append(ApertureStmt(aperture.d))
+            self._dcode = aperture.d
+
+        if self.condensed_flash:
+            self.body.append(CoordStmt.flash(self._simplify_point(primitive.position)))
+        else:
+            self.body.append(CoordStmt.move(None, self._simplify_point(primitive.position)))
+            self.body.append(CoordStmt.flash(None))
+
+        self._pos = primitive.position
+
+    def _get_circle(self, diameter, hole_diameter=None, hole_width=None,
+                    hole_height=None, dcode = None):
+        '''Define a circlar aperture'''
+
+        key = (diameter, hole_diameter, hole_width, hole_height)
+        aper = self._circles.get(key, None)
+
+        if not aper:
+            if not dcode:
+                dcode = self._next_dcode
+                self._next_dcode += 1
+            else:
+                self._next_dcode = max(dcode + 1, self._next_dcode)
+
+            aper = ADParamStmt.circle(dcode, diameter, hole_diameter, hole_width, hole_height)
+            self._circles[(diameter, hole_diameter, hole_width, hole_height)] = aper
+            self.header.append(aper)
+
+        return aper
+
+    def _render_circle(self, circle, color):
+
+        aper = self._get_circle(circle.diameter, circle.hole_diameter, circle.hole_width, circle.hole_height)
+        self._render_flash(circle, aper)
+
+    def _get_rectangle(self, width, height, hole_diameter=None, hole_width=None,
+                       hole_height=None, dcode = None):
+        '''Get a rectanglar aperture. If it isn't defined, create it'''
+
+        key = (width, height, hole_diameter, hole_width, hole_height)
+        aper = self._rects.get(key, None)
+
+        if not aper:
+            if not dcode:
+                dcode = self._next_dcode
+                self._next_dcode += 1
+            else:
+                self._next_dcode = max(dcode + 1, self._next_dcode)
+
+            aper = ADParamStmt.rect(dcode, width, height, hole_diameter, hole_width, hole_height)
+            self._rects[(width, height, hole_diameter, hole_width, hole_height)] = aper
+            self.header.append(aper)
+
+        return aper
+
+    def _render_rectangle(self, rectangle, color):
+
+        aper = self._get_rectangle(rectangle.width, rectangle.height,
+                                   rectangle.hole_diameter,
+                                   rectangle.hole_width, rectangle.hole_height)
+        self._render_flash(rectangle, aper)
+
+    def _get_obround(self, width, height, hole_diameter=None, hole_width=None,
+                     hole_height=None, dcode = None):
+
+        key = (width, height, hole_diameter, hole_width, hole_height)
+        aper = self._obrounds.get(key, None)
+
+        if not aper:
+            if not dcode:
+                dcode = self._next_dcode
+                self._next_dcode += 1
+            else:
+                self._next_dcode = max(dcode + 1, self._next_dcode)
+
+            aper = ADParamStmt.obround(dcode, width, height, hole_diameter, hole_width, hole_height)
+            self._obrounds[key] = aper
+            self.header.append(aper)
+
+        return aper
+
+    def _render_obround(self, obround, color):
+
+        aper = self._get_obround(obround.width, obround.height,
+                                 obround.hole_diameter, obround.hole_width,
+                                 obround.hole_height)
+        self._render_flash(obround, aper)
+
+    def _render_polygon(self, polygon, color):
+
+        aper = self._get_polygon(polygon.radius, polygon.sides,
+                                 polygon.rotation, polygon.hole_diameter,
+                                 polygon.hole_width, polygon.hole_height)
+        self._render_flash(polygon, aper)
+
+    def _get_polygon(self, radius, num_vertices, rotation, hole_diameter=None,
+                     hole_width=None, hole_height=None, dcode = None):
+
+        key = (radius, num_vertices, rotation, hole_diameter, hole_width, hole_height)
+        aper = self._polygons.get(key, None)
+
+        if not aper:
+            if not dcode:
+                dcode = self._next_dcode
+                self._next_dcode += 1
+            else:
+                self._next_dcode = max(dcode + 1, self._next_dcode)
+
+            aper = ADParamStmt.polygon(dcode, radius * 2, num_vertices,
+                                       rotation, hole_diameter, hole_width,
+                                       hole_height)
+            self._polygons[key] = aper
+            self.header.append(aper)
+
+        return aper
+
+    def _render_drill(self, drill, color):
+        raise ValueError('Drills are not valid in RS274X files')
+
+    def _hash_amacro(self, amgroup):
+        '''Calculate a very quick hash code for deciding if we should even check AM groups for comparision'''
+
+        # We always start with an X because this forms part of the name
+        # Basically, in some cases, the name might start with a C, R, etc. That can appear
+        # to conflict with normal aperture definitions. Technically, it shouldn't because normal
+        # aperture definitions should have a comma, but in some cases the commit is omitted
+        hash = 'X'
+        for primitive in amgroup.primitives:
+
+            hash += primitive.__class__.__name__[0]
+
+            bbox = primitive.bounding_box
+            hash += str((bbox[0][1] - bbox[0][0]) * 100000)[0:2]
+            hash += str((bbox[1][1] - bbox[1][0]) * 100000)[0:2]
+
+            if hasattr(primitive, 'primitives'):
+                hash += str(len(primitive.primitives))
+
+            if isinstance(primitive, Rectangle):
+                hash += str(primitive.width * 1000000)[0:2]
+                hash += str(primitive.height * 1000000)[0:2]
+            elif isinstance(primitive, Circle):
+                hash += str(primitive.diameter * 1000000)[0:2]
+
+            if len(hash) > 20:
+                # The hash might actually get quite complex, so stop before
+                # it gets too long
+                break
+
+        return hash
+
+    def _get_amacro(self, amgroup, dcode = None):
+        # Macros are a little special since we don't have a good way to compare them quickly
+        # but in most cases, this should work
+
+        hash = self._hash_amacro(amgroup)
+        macro = None
+        macroinfo = self._macros.get(hash, None)
+
+        if macroinfo:
+
+            # We have a definition, but check that the groups actually are the same
+            for macro in macroinfo:
+
+                # Macros should have positions, right? But if the macro is selected for non-flashes
+                # then it won't have a position. This is of course a bad gerber, but they do exist
+                if amgroup.position:
+                    position = amgroup.position
+                else:
+                    position = (0, 0)
+
+                offset = (position[0] - macro[1].position[0], position[1] - macro[1].position[1])
+                if amgroup.equivalent(macro[1], offset):
+                    break
+                macro = None
+
+        # Did we find one in the group0
+        if not macro:
+            # This is a new macro, so define it
+            if not dcode:
+                dcode = self._next_dcode
+                self._next_dcode += 1
+            else:
+                self._next_dcode = max(dcode + 1, self._next_dcode)
+
+            # Create the statements
+            # TODO
+            amrenderer = AMGroupContext()
+            statement = amrenderer.render(amgroup, hash)
+
+            self.header.append(statement)
+
+            aperdef = ADParamStmt.macro(dcode, hash)
+            self.header.append(aperdef)
+
+            # Store the dcode and the original so we can check if it really is the same
+            # If it didn't have a postition, set it to 0, 0
+            if amgroup.position == None:
+                amgroup.position = (0, 0)
+            macro = (aperdef, amgroup)
+
+            if macroinfo:
+                macroinfo.append(macro)
+            else:
+                self._macros[hash] = [macro]
+
+        return macro[0]
+
+    def _render_amgroup(self, amgroup, color):
+
+        aper = self._get_amacro(amgroup)
+        self._render_flash(amgroup, aper)
+
+    def _render_inverted_layer(self):
+        pass
+
+    def new_render_layer(self):
+        # TODO Might need to implement this
+        pass
+
+    def flatten(self):
+        # TODO Might need to implement this
+        pass
+
+    def dump(self):
+        """Write the rendered file to a StringIO steam"""
+        statements = map(lambda stmt: stmt.to_gerber(self.settings), self.statements)
+        stream = StringIO()
+        for statement in statements:
+            stream.write(statement + '\n')
+
+        return stream
diff --git a/gerber/render/theme.py b/gerber/render/theme.py
new file mode 100644
index 0000000..2f558a1
--- /dev/null
+++ b/gerber/render/theme.py
@@ -0,0 +1,112 @@
+#! /usr/bin/env python
+# -*- coding: utf-8 -*-
+
+# Copyright 2013-2014 Paulo Henrique Silva <ph.silva@gmail.com>
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+from .render import RenderSettings
+
+COLORS = {
+    'black': (0.0, 0.0, 0.0),
+    'white': (1.0, 1.0, 1.0),
+    'red': (1.0, 0.0, 0.0),
+    'green': (0.0, 1.0, 0.0),
+    'yellow': (1.0, 1.0, 0),
+    'blue': (0.0, 0.0, 1.0),
+    'fr-4': (0.290, 0.345, 0.0),
+    'green soldermask': (0.0, 0.412, 0.278),
+    'blue soldermask': (0.059, 0.478, 0.651),
+    'red soldermask': (0.968, 0.169, 0.165),
+    'black soldermask': (0.298, 0.275, 0.282),
+    'purple soldermask': (0.2, 0.0, 0.334),
+    'enig copper': (0.694, 0.533, 0.514),
+    'hasl copper': (0.871, 0.851, 0.839)
+}
+
+
+SPECTRUM = [
+    (0.804, 0.216, 0),
+    (0.78, 0.776, 0.251),
+    (0.545, 0.451, 0.333),
+    (0.545, 0.137, 0.137),
+    (0.329, 0.545, 0.329),
+    (0.133, 0.545, 0.133),
+    (0, 0.525, 0.545),
+    (0.227, 0.373, 0.804),
+]
+
+
+class Theme(object):
+
+    def __init__(self, name=None, **kwargs):
+        self.name = 'Default' if name is None else name
+        self.background = kwargs.get('background', RenderSettings(COLORS['fr-4']))
+        self.topsilk = kwargs.get('topsilk', RenderSettings(COLORS['white']))
+        self.bottomsilk = kwargs.get('bottomsilk', RenderSettings(COLORS['white'], mirror=True))
+        self.topmask = kwargs.get('topmask', RenderSettings(COLORS['green soldermask'], alpha=0.85, invert=True))
+        self.bottommask = kwargs.get('bottommask', RenderSettings(COLORS['green soldermask'], alpha=0.85, invert=True, mirror=True))
+        self.top = kwargs.get('top', RenderSettings(COLORS['hasl copper']))
+        self.bottom = kwargs.get('bottom', RenderSettings(COLORS['hasl copper'], mirror=True))
+        self.drill = kwargs.get('drill', RenderSettings(COLORS['black']))
+        self.ipc_netlist = kwargs.get('ipc_netlist', RenderSettings(COLORS['red']))
+        self._internal = kwargs.get('internal', [RenderSettings(x) for x in SPECTRUM])
+        self._internal_gen = None
+
+    def __getitem__(self, key):
+        return getattr(self, key)
+
+    @property
+    def internal(self):
+        if not self._internal_gen:
+            self._internal_gen = self._internal_gen_func()
+        return next(self._internal_gen)
+
+    def _internal_gen_func(self):
+        for setting in self._internal:
+            yield setting
+
+    def get(self, key, noneval=None):
+        val = getattr(self, key, None)
+        return val if val is not None else noneval
+
+
+THEMES = {
+    'default': Theme(),
+    'OSH Park': Theme(name='OSH Park',
+                      background=RenderSettings(COLORS['purple soldermask']),
+                      top=RenderSettings(COLORS['enig copper']),
+                      bottom=RenderSettings(COLORS['enig copper'], mirror=True),
+                      topmask=RenderSettings(COLORS['purple soldermask'], alpha=0.85, invert=True),
+                      bottommask=RenderSettings(COLORS['purple soldermask'], alpha=0.85, invert=True, mirror=True),
+                      topsilk=RenderSettings(COLORS['white'], alpha=0.8),
+                      bottomsilk=RenderSettings(COLORS['white'], alpha=0.8, mirror=True)),
+
+    'Blue': Theme(name='Blue',
+                  topmask=RenderSettings(COLORS['blue soldermask'], alpha=0.8, invert=True),
+                  bottommask=RenderSettings(COLORS['blue soldermask'], alpha=0.8, invert=True)),
+
+    'Transparent Copper': Theme(name='Transparent',
+                                background=RenderSettings((0.9, 0.9, 0.9)),
+                                top=RenderSettings(COLORS['red'], alpha=0.5),
+                                bottom=RenderSettings(COLORS['blue'], alpha=0.5),
+                                drill=RenderSettings((0.3, 0.3, 0.3))),
+
+    'Transparent Multilayer': Theme(name='Transparent Multilayer',
+                                    background=RenderSettings((0, 0, 0)),
+                                    top=RenderSettings(SPECTRUM[0], alpha=0.8),
+                                    bottom=RenderSettings(SPECTRUM[-1], alpha=0.8),
+                                    drill=RenderSettings((0.3, 0.3, 0.3)),
+                                    internal=[RenderSettings(x, alpha=0.5) for x in SPECTRUM[1:-1]]),
+}