5 files changed, 35 insertions, 11 deletions
diff --git a/gerber/cam.py b/gerber/cam.py
index cf06ec9..92ce83d 100644
--- a/gerber/cam.py
+++ b/gerber/cam.py
@@ -256,9 +256,10 @@ class CamFile(object):
         """
         ctx.set_bounds(self.bounds)
         ctx._paint_background()
+
         if invert:
             ctx.invert = True
-            ctx._paint_inverted_layer()
+            ctx._clear_mask()
         for p in self.primitives:
             ctx.render(p)
         if invert:
diff --git a/gerber/exceptions.py b/gerber/exceptions.py
index 71defd1..fdd548c 100644
--- a/gerber/exceptions.py
+++ b/gerber/exceptions.py
@@ -18,14 +18,18 @@
 class ParseError(Exception):
     pass
 
+
 class GerberParseError(ParseError):
     pass
 
+
 class ExcellonParseError(ParseError):
     pass
 
+
 class ExcellonFileError(IOError):
     pass
 
+
 class GerberFileError(IOError):
     pass
diff --git a/gerber/render/cairo_backend.py b/gerber/render/cairo_backend.py
index c8f94ff..8283ae0 100644
--- a/gerber/render/cairo_backend.py
+++ b/gerber/render/cairo_backend.py
@@ -15,16 +15,20 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .render import GerberContext
 
 import cairocffi as cairo
-
 from operator import mul
 import math
 import tempfile
 
+from .render import GerberContext
 from ..primitives import *
 
+try:
+    from cStringIO import StringIO
+except(ImportError):
+    from io import StringIO
+
 
 class GerberCairoContext(GerberContext):
     def __init__(self, scale=300):
@@ -184,7 +188,7 @@ class GerberCairoContext(GerberContext):
         self.ctx.show_text(primitive.net_name)
         self.ctx.scale(1, -1)
 
-    def _paint_inverted_layer(self):
+    def _clear_mask(self):
         self.mask_ctx.set_operator(cairo.OPERATOR_OVER)
         self.mask_ctx.set_source_rgba(*self.color, alpha=self.alpha)
         self.mask_ctx.paint()
@@ -214,7 +218,16 @@ class GerberCairoContext(GerberContext):
         else:
             self.surface.write_to_png(filename)
 
+    def dump_str(self):
+        """ Return a string containing the rendered image.
+        """
+        fobj = StringIO()
+        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()
diff --git a/gerber/render/theme.py b/gerber/render/theme.py
index 5d39bb6..eae3735 100644
--- a/gerber/render/theme.py
+++ b/gerber/render/theme.py
@@ -19,12 +19,13 @@
 COLORS = {
     'black': (0.0, 0.0, 0.0),
     'white': (1.0, 1.0, 1.0),
-    'fr-4': (0.702, 0.655, 0.192),
+    'fr-4': (0.290, 0.345, 0.0),
     'green soldermask': (0.0, 0.612, 0.396),
     'blue soldermask': (0.059, 0.478, 0.651),
     'red soldermask': (0.968, 0.169, 0.165),
     'black soldermask': (0.298, 0.275, 0.282),
-    'enig copper': (0.780, 0.588, 0.286),
+    'purple soldermask': (0.2, 0.0, 0.334),
+    'enig copper': (0.686, 0.525, 0.510),
     'hasl copper': (0.871, 0.851, 0.839)
 }
 
@@ -40,11 +41,19 @@ class Theme(object):
     def __init__(self, **kwargs):
         self.background = kwargs.get('background', RenderSettings(COLORS['black'], 0.0))
         self.topsilk = kwargs.get('topsilk', RenderSettings(COLORS['white']))
-        self.topsilk = kwargs.get('bottomsilk', RenderSettings(COLORS['white']))
-        self.topmask = kwargs.get('topmask', RenderSettings(COLORS['green soldermask'], 0.8, True))
+        self.bottomsilk = kwargs.get('bottomsilk', RenderSettings(COLORS['white']))
         self.topmask = kwargs.get('topmask', RenderSettings(COLORS['green soldermask'], 0.8, True))
+        self.bottommask = kwargs.get('bottommask', RenderSettings(COLORS['green soldermask'], 0.8, True))
         self.top = kwargs.get('top', RenderSettings(COLORS['hasl copper']))
         self.bottom = kwargs.get('top', RenderSettings(COLORS['hasl copper']))
         self.drill = kwargs.get('drill', self.background)
 
 
+THEMES = {
+    'Default': Theme(),
+    'Osh Park': Theme(top=COLORS['enig copper'],
+                      bottom=COLORS['enig copper'],
+                      topmask=COLORS['purple soldermask'],
+                      bottommask=COLORS['purple soldermask']),
+}
+
diff --git a/gerber/rs274x.py b/gerber/rs274x.py
index d9fd317..319d58f 100644
--- a/gerber/rs274x.py
+++ b/gerber/rs274x.py
@@ -110,16 +110,13 @@ class GerberFile(CamFile):
     def bounds(self):
         min_x = min_y = 1000000
         max_x = max_y = -1000000
-
         for stmt in [stmt for stmt in self.statements if isinstance(stmt, CoordStmt)]:
             if stmt.x is not None:
                 min_x = min(stmt.x, min_x)
                 max_x = max(stmt.x, max_x)
-
             if stmt.y is not None:
                 min_y = min(stmt.y, min_y)
                 max_y = max(stmt.y, max_y)
-
         return ((min_x, max_x), (min_y, max_y))
 
     def write(self, filename, settings=None):