Add arc rendering and tests

1 files changed, 19 insertions, 1 deletions

diff --git a/gerber/render/cairo_backend.py b/gerber/render/cairo_backend.py
index 1c69725..125a125 100644
--- a/gerber/render/cairo_backend.py
+++ b/gerber/render/cairo_backend.py
@@ -56,13 +56,31 @@ class GerberCairoContext(GerberContext):
         self.ctx.line_to(*end)

         self.ctx.stroke()

 

+    def _render_arc(self, arc, color):

+        center = map(mul, arc.center, self.scale)

+        start = map(mul, arc.start, self.scale)

+        end = map(mul, arc.end, self.scale)

+        radius = SCALE * arc.radius

+        angle1 = arc.start_angle

+        angle2 = arc.end_angle

+        width = arc.width if arc.width != 0 else 0.001

+        self.ctx.set_source_rgba(*color, alpha=self.alpha)

+        self.ctx.set_line_width(width * SCALE)

+        self.ctx.set_line_cap(cairo.LINE_CAP_ROUND)

+        self.ctx.move_to(*start)  # You actually have to do this...

+        if arc.direction == 'counterclockwise':

+            self.ctx.arc(*center, radius=radius, angle1=angle1, angle2=angle2)

+        else:

+            self.ctx.arc_negative(*center, radius=radius, angle1=angle1, angle2=angle2)

+        self.ctx.move_to(*end)  # ...lame

+

     def _render_region(self, region, color):

         points = [tuple(map(mul, point, self.scale)) for point in region.points]

         self.ctx.set_source_rgba(*color, alpha=self.alpha)

         self.ctx.set_line_width(0)

         self.ctx.move_to(*points[0])

         for point in points[1:]:

-            self.ctx.move_to(*point)

+            self.ctx.line_to(*point)

         self.ctx.fill()

 

     def _render_circle(self, circle, color):