Fix remaining svg rendering/gerber compositing bugs

gerbonara/gerber/graphic_primitives.py

@@ -177,14 +177,22 @@ def point_line_distance(l1, l2, p):
     return abs((x2-x1)*(y1-y0) - (x1-x0)*(y2-y1)) / length
 
 def svg_arc(old, new, center, clockwise):
-    print(f'{old=} {new=} {center=}')
-    r = point_distance(old, new)
+    r = point_distance(old, center)
     d = point_line_distance(old, new, center)
     # invert sweep flag since the svg y axis is mirrored
     sweep_flag = int(not clockwise)
-    large_arc = int((d > 0) == clockwise) # FIXME check signs
-    print(f'{r=:.3} {d=:.3} {sweep_flag=} {large_arc=} {clockwise=}')
-    return f'A {r:.6} {r:.6} 0 {large_arc} {sweep_flag} {new[0]:.6} {new[1]:.6}'
+    # In the degenerate case where old == new, we always take the long way around. To represent this "full-circle arc"
+    # in SVG, we have to split it into two.
+    if math.isclose(point_distance(old, new), 0):
+        intermediate = center[0] + (center[0] - old[0]), center[1] + (center[1] - old[1])
+        # Note that we have to preserve the sweep flag to avoid causing self-intersections by flipping the direction of
+        # a circular cutin
+        return f'A {r:.6} {r:.6} 0 1 {sweep_flag} {intermediate[0]:.6} {intermediate[1]:.6} ' +\
+               f'A {r:.6} {r:.6} 0 1 {sweep_flag} {new[0]:.6} {new[1]:.6}'
+
+    else: # normal case
+        large_arc = int((d > 0) == clockwise)
+        return f'A {r:.6} {r:.6} 0 {large_arc} {sweep_flag} {new[0]:.6} {new[1]:.6}'
 
 @dataclass
 class ArcPoly(GraphicPrimitive):

gerbonara/gerber/rs274x.py

@@ -91,7 +91,6 @@ class GerberFile(CamFile):
 
         if force_bounds is None:
             (min_x, min_y), (max_x, max_y) = self.bounding_box(svg_unit, default=((0, 0), (0, 0)))
-            print('bounding box:', (min_x, min_y), (max_x, max_y))
         else:
             (min_x, min_y), (max_x, max_y) = force_bounds
             min_x = convert(min_x, arg_unit, svg_unit)
@@ -129,8 +128,9 @@ class GerberFile(CamFile):
         # dedup apertures
         new_apertures = {}
         replace_apertures = {}
+        mock_settings = self.import_settings
         for ap in self.apertures + other.apertures:
-            gbr = ap.to_gerber()
+            gbr = ap.to_gerber(mock_settings)
             if gbr not in new_apertures:
                 new_apertures[gbr] = ap
             else:
@@ -281,13 +281,7 @@ class GerberFile(CamFile):
     def offset(self, dx=0,  dy=0, unit='mm'):
         # TODO round offset to file resolution
     
-        #print(f'offset {dx},{dy} file unit')
-        #for obj in self.objects:
-        #    print('   ', obj)
         self.objects = [ obj.with_offset(dx, dy, unit) for obj in self.objects ]
-        #print('after:')
-        #for obj in self.objects:
-        #    print('   ', obj)
 
     def rotate(self, angle:'radian', center=(0,0), unit='mm'):
         """ Rotate file contents around given point.
@@ -307,17 +301,9 @@ class GerberFile(CamFile):
         for ap in self.apertures:
             ap.rotation += angle
 
-        #print(f'rotate {angle} @ {center}')
-        #for obj in self.objects:
-        #    print('   ', obj)
-
         for obj in self.objects:
             obj.rotate(angle, *center, unit)
 
-        #print('after')
-        #for obj in self.objects:
-        #    print('   ', obj)
-    
     def invert_polarity(self):
         for obj in self.objects:
             obj.polarity_dark = not p.polarity_dark
@@ -459,10 +445,6 @@ class GraphicsState:
 
     def _create_arc(self, old_point, new_point, control_point, aperture=True):
         clockwise = self.interpolation_mode == CircularCWModeStmt
-        print('creating arc')
-        print('  old point', old_point)
-        print('  new point', new_point)
-        print('  control point', self.map_coord(*control_point, relative=True))
         return go.Arc(*old_point, *new_point, *self.map_coord(*control_point, relative=True),
                 clockwise=clockwise, aperture=(self.aperture if aperture else None),
                 polarity_dark=self.polarity_dark, unit=self.file_settings.unit)

gerbonara/gerber/tests/image_support.py

@@ -63,13 +63,14 @@ def run_cargo_cmd(cmd, args, **kwargs):
 def svg_to_png(in_svg, out_png, dpi=100, bg='black'):
     run_cargo_cmd('resvg', ['--background', bg, '--dpi', str(dpi), in_svg, out_png], check=True, stdout=subprocess.DEVNULL)
 
-def gerbv_export(in_gbr, out_svg, format='svg', origin=(0, 0), size=(6, 6), fg='#ffffff'):
+def gerbv_export(in_gbr, out_svg, format='svg', origin=(0, 0), size=(6, 6), fg='#ffffff', bg='#000000'):
     x, y = origin
     w, h = size
     cmd = ['gerbv', '-x', format,
         '--border=0',
         f'--origin={x:.6f}x{y:.6f}', f'--window_inch={w:.6f}x{h:.6f}',
         f'--foreground={fg}',
+        f'--background={bg}',
         '-o', str(out_svg), str(in_gbr)]
     subprocess.run(cmd, check=True, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
 

gerbonara/gerber/tests/test_rs274x.py

@@ -46,7 +46,7 @@ def print_on_error(request):
 
     if request.node.rep_call.failed:
         for msg in messages:
-            print(msg)
+            print(msg, end='')
 
 @pytest.fixture
 def tmpfile(request):
@@ -322,8 +322,14 @@ def test_svg_export(reference, tmpfile):
     with open(out_svg, 'w') as f:
         f.write(str(grb.to_svg(force_bounds=bounds, arg_unit='inch', color='white')))
 
+    # NOTE: Instead of having gerbv directly export a PNG, we ask gerbv to output SVG which we then rasterize using
+    # resvg. We have to do this since gerbv's built-in cairo-based PNG export has severe aliasing issues. In contrast,
+    # using resvg for both allows an apples-to-apples comparison of both results.
+    ref_svg = tmpfile('Reference export', '.svg')
     ref_png = tmpfile('Reference render', '.png')
-    gerbv_export(reference, ref_png, origin=bounds[0], size=bounds[1], format='png', fg='#000000')
+    gerbv_export(reference, ref_svg, origin=bounds[0], size=bounds[1])
+    svg_to_png(ref_svg, ref_png, dpi=72) # make dpi match Cairo's default
+
     out_png = tmpfile('Output render', '.png')
     svg_to_png(out_svg, out_png, dpi=72) # make dpi match Cairo's default
 
@@ -363,11 +369,8 @@ def test_bounding_box(reference, tmpfile):
     assert (img > 0).any() # there must be some content, none of the test gerbers are completely empty.
     cols = img.sum(axis=1)
     rows = img.sum(axis=0)
-    print('shape:', img.shape)
     col_prefix, col_suffix = np.argmax(cols > 0), np.argmax(cols[::-1] > 0)
     row_prefix, row_suffix = np.argmax(rows > 0), np.argmax(rows[::-1] > 0)
-    print('cols', 'prefix:', row_prefix, 'suffix:', row_suffix)
-    print('rows', 'prefix:', row_prefix, 'suffix:', row_suffix)
 
     # Check that all margins are completely black and that the content touches the margins. Allow for some tolerance to
     # allow for antialiasing artifacts.