Fix hard requirement of cairo per #83, and add stubs for required subclass methods to GerberContext per #84

examples/cairo_example.py

@@ -25,7 +25,8 @@ a .png file.
 
 import os
 from gerber import load_layer
-from gerber.render import GerberCairoContext, RenderSettings, theme
+from gerber.render import RenderSettings, theme
+from gerber.render.cairo_backend import GerberCairoContext
 
 GERBER_FOLDER = os.path.abspath(os.path.join(os.path.dirname(__file__), 'gerbers'))
 

examples/pcb_example.py

@@ -22,7 +22,8 @@ images using the PCB interface
 
 import os
 from gerber import PCB
-from gerber.render import GerberCairoContext, theme
+from gerber.render import theme
+from gerber.render.cairo_backend import GerberCairoContext
 
 
 GERBER_FOLDER = os.path.abspath(os.path.join(os.path.dirname(__file__), 'gerbers'))

gerber/cam.py

@@ -250,6 +250,10 @@ class CamFile(object):
         """
         pass
 
+    @property
+    def bounding_box(self):
+        pass
+
     def to_inch(self):
         pass
 
@@ -271,12 +275,12 @@ class CamFile(object):
             from .render import GerberCairoContext
             ctx = GerberCairoContext()
         ctx.set_bounds(self.bounding_box)
-        ctx._paint_background()
+        ctx.paint_background()
         ctx.invert = invert
-        ctx._new_render_layer()
+        ctx.new_render_layer()
         for p in self.primitives:
             ctx.render(p)
-        ctx._flatten()
+        ctx.flatten()
 
         if filename is not None:
             ctx.dump(filename)

gerber/render/__init__.py

@@ -23,6 +23,4 @@ This module provides contexts for rendering images of gerber layers. Currently
 SVG is the only supported format.
 """
 
-
-from .cairo_backend import GerberCairoContext
 from .render import RenderSettings

gerber/render/cairo_backend.py

@@ -91,7 +91,7 @@ class GerberCairoContext(GerberContext):
                 self.set_bounds(bounds)
             else:
                 self.set_bounds(layer.bounds)
-            self._paint_background(bgsettings)
+            self.paint_background(bgsettings)
         if verbose:
             print('[Render]: Rendering {} Layer.'.format(layer.layer_class))
         self._render_count += 1
@@ -193,11 +193,11 @@ class GerberCairoContext(GerberContext):
     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)
+        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)
+        self.flatten(settings.color, settings.alpha)
 
     def _render_line(self, line, color):
         start = self.scale_point(line.start)
@@ -530,7 +530,7 @@ class GerberCairoContext(GerberContext):
         self.ctx.show_text(primitive.net_name)
         self.ctx.scale(1, -1)
 
-    def _new_render_layer(self, color=None, mirror=False):
+    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])
@@ -548,8 +548,7 @@ class GerberCairoContext(GerberContext):
         self.active_layer = layer
         self.active_matrix = matrix
 
-
-    def _flatten(self, color=None, alpha=None):
+    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)
@@ -558,7 +557,7 @@ class GerberCairoContext(GerberContext):
         self.active_layer = None
         self.active_matrix = None
 
-    def _paint_background(self, settings=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:

gerber/render/excellon_backend.py

@@ -63,10 +63,10 @@ class ExcellonContext(GerberContext):
     def statements(self):
         return self.start + self.comments + self.header + self.body_start + self.body + self._get_end()
 
-    def set_bounds(self, bounds):
+    def set_bounds(self, bounds, *args, **kwargs):
         pass
 
-    def _paint_background(self):
+    def paint_background(self):
         pass
 
     def _render_line(self, line, color):
@@ -186,4 +186,3 @@ class ExcellonContext(GerberContext):
 
     def _render_inverted_layer(self):
         pass
-        

gerber/render/render.py

@@ -139,7 +139,7 @@ class GerberContext(object):
         if not primitive:
             return
 
-        self._pre_render_primitive(primitive)
+        self.pre_render_primitive(primitive)
 
         color = self.color
         if isinstance(primitive, Line):
@@ -167,16 +167,35 @@ class GerberContext(object):
         elif isinstance(primitive, TestRecord):
             self._render_test_record(primitive, color)
 
-        self._post_render_primitive(primitive)
+        self.post_render_primitive(primitive)
 
-    def _pre_render_primitive(self, 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):
+    def post_render_primitive(self, primitive):
         """
         Called after rendering a primitive. Use the callback to perform some action after rendering
         a primitive

gerber/render/rs274x_backend.py

@@ -148,10 +148,10 @@ class Rs274xContext(GerberContext):
     def statements(self):
         return self.comments + self.header + self.body + self.end
 
-    def set_bounds(self, bounds):
+    def set_bounds(self, bounds, *args, **kwargs):
         pass
 
-    def _paint_background(self):
+    def paint_background(self):
         pass
 
     def _select_aperture(self, aperture):
@@ -173,7 +173,7 @@ class Rs274xContext(GerberContext):
                 self.body.append(ApertureStmt(aper.d))
                 self._dcode = aper.d
 
-    def _pre_render_primitive(self, primitive):
+    def pre_render_primitive(self, primitive):
 
         if hasattr(primitive, 'comment'):
             self.body.append(CommentStmt(primitive.comment))
@@ -489,11 +489,11 @@ class Rs274xContext(GerberContext):
     def _render_inverted_layer(self):
         pass
 
-    def _new_render_layer(self):
+    def new_render_layer(self):
         # TODO Might need to implement this
         pass
 
-    def _flatten(self):
+    def flatten(self):
         # TODO Might need to implement this
         pass