From b01c4822b6da6b7be37becb73c58f60621f6366f Mon Sep 17 00:00:00 2001
From: Garret Fick <garret@ficksworkshop.com>
Date: Sat, 25 Jun 2016 12:27:28 +0800
Subject: Render aperture macros with clear regions

---
 gerber/am_statements.py        | 18 ++++++++++++------
 gerber/render/cairo_backend.py |  3 +++
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/gerber/am_statements.py b/gerber/am_statements.py
index c3229ba..f5330a5 100644
--- a/gerber/am_statements.py
+++ b/gerber/am_statements.py
@@ -76,6 +76,12 @@ class AMPrimitive(object):
         Convert to a primitive, as defines the primitives module (for drawing)
         """
         raise NotImplementedError('Subclass must implement `to-primitive`')
+    
+    @property
+    def _level_polarity(self):
+        if self.exposure == 'off':
+            return 'clear'
+        return 'dark'
 
     def __eq__(self, other):
         return self.__dict__ == other.__dict__
@@ -209,7 +215,7 @@ class AMCirclePrimitive(AMPrimitive):
         return '{code},{exposure},{diameter},{x},{y}*'.format(**data)
 
     def to_primitive(self, units):
-        return Circle((self.position), self.diameter, units=units)
+        return Circle((self.position), self.diameter, units=units, level_polarity=self._level_polarity)
 
 
 class AMVectorLinePrimitive(AMPrimitive):
@@ -302,7 +308,7 @@ class AMVectorLinePrimitive(AMPrimitive):
         return fmtstr.format(**data)
     
     def to_primitive(self, units):
-        return Line(self.start, self.end, Rectangle(None, self.width, self.width), units=units)
+        return Line(self.start, self.end, Rectangle(None, self.width, self.width), units=units, level_polarity=self._level_polarity)
 
 
 class AMOutlinePrimitive(AMPrimitive):
@@ -419,7 +425,7 @@ class AMOutlinePrimitive(AMPrimitive):
         if lines[0].start != lines[-1].end:
             raise ValueError('Outline must be closed')
         
-        return Outline(lines, units=units)
+        return Outline(lines, units=units, level_polarity=self._level_polarity)
 
 
 class AMPolygonPrimitive(AMPrimitive):
@@ -517,7 +523,7 @@ class AMPolygonPrimitive(AMPrimitive):
         return fmt.format(**data)
     
     def to_primitive(self, units):
-        return Polygon(self.position, self.vertices, self.diameter / 2.0, rotation=math.radians(self.rotation), units=units)
+        return Polygon(self.position, self.vertices, self.diameter / 2.0, rotation=math.radians(self.rotation), units=units, level_polarity=self._level_polarity)
 
 
 class AMMoirePrimitive(AMPrimitive):
@@ -795,7 +801,7 @@ class AMThermalPrimitive(AMPrimitive):
             
             prev_point = cur_point
             
-            outlines.append(Outline(lines, units=units))
+            outlines.append(Outline(lines, units=units, level_polarity=self._level_polarity))
 
         return outlines
 
@@ -891,7 +897,7 @@ class AMCenterLinePrimitive(AMPrimitive):
         return fmt.format(**data)
 
     def to_primitive(self, units):
-        return Rectangle(self.center, self.width, self.height, rotation=math.radians(self.rotation), units=units)
+        return Rectangle(self.center, self.width, self.height, rotation=math.radians(self.rotation), units=units, level_polarity=self._level_polarity)
 
 
 class AMLowerLeftLinePrimitive(AMPrimitive):
diff --git a/gerber/render/cairo_backend.py b/gerber/render/cairo_backend.py
index 1d168ca..c1bd60c 100644
--- a/gerber/render/cairo_backend.py
+++ b/gerber/render/cairo_backend.py
@@ -191,8 +191,11 @@ class GerberCairoContext(GerberContext):
         self.ctx.stroke()
         
     def _render_amgroup(self, amgroup, color):
+        self.ctx.push_group()
         for primitive in amgroup.primitives:
             self.render(primitive)
+        self.ctx.pop_group_to_source()
+        self.ctx.paint_with_alpha(1)
 
     def _render_test_record(self, primitive, color):
         self.ctx.select_font_face('monospace', cairo.FONT_SLANT_NORMAL, cairo.FONT_WEIGHT_NORMAL)
-- 
cgit