1 files changed, 63 insertions, 0 deletions
diff --git a/gerbonara/gerber/tests/image_support.py b/gerbonara/gerber/tests/image_support.py
new file mode 100644
index 0000000..ee8e6b9
--- /dev/null
+++ b/gerbonara/gerber/tests/image_support.py
@@ -0,0 +1,63 @@
+import subprocess
+from pathlib import Path
+import tempfile
+
+import numpy as np
+
+class ImageDifference(float):
+    def __init__(self, value, ref_path, out_path):
+        super().__init__(value)
+        self.ref_path, self.out_path = ref_path, out_path
+
+def run_cargo_cmd(cmd, args, **kwargs):
+    if cmd.upper() in os.environ:
+        return subprocess.run([os.environ[cmd.upper()], *args], **kwargs)
+
+    try:
+        return subprocess.run([cmd, *args], **kwargs)
+
+    except FileNotFoundError:
+        return subprocess.run([str(Path.home() / '.cargo' / 'bin' / cmd), *args], **kwargs)
+
+def svg_to_png(in_svg, out_png):
+    run_cargo_cmd('resvg', [in_svg, out_png], check=True, stdout=subprocess.DEVNULL)
+
+def gbr_to_svg(in_gbr, out_svg):
+    cmd = ['gerbv', '-x', 'svg',
+        '--border=0',
+        #f'--origin={origin_x:.6f}x{origin_y:.6f}', f'--window_inch={width:.6f}x{height:.6f}',
+        '--foreground=#ffffff',
+        '-o', str(out_svg), str(in_gbr)]
+    subprocess.run(cmd, check=True, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+
+def gerber_difference(reference, actual):
+    with tempfile.NamedTemporaryFile(suffix='.svg') as out_svg,\
+        tempfile.NamedTemporaryFile(suffix='.svg') as ref_svg:
+
+        gbr_to_svg(reference, ref_svg.name)
+        gbr_to_svg(actual, act_svg.name)
+
+        diff = svg_difference(ref_svg.name, act_svg.name)
+        diff.ref_path, diff.act_path = reference, actual
+        return diff
+
+def svg_difference(reference, actual):
+    with tempfile.NamedTemporaryFile(suffix='.png') as ref_png,\
+        tempfile.NamedTemporaryFile(suffix='.png') as act_png:
+
+        svg_to_png(reference, ref_png.name)
+        svg_to_png(actual, act_png.name)
+
+        diff = image_difference(ref_png.name, act_png.name)
+        diff.ref_path, diff.act_path = reference, actual
+        return diff
+
+def image_difference(reference, actual):
+    ref = np.array(Image.open(reference)).astype(float)
+    out = np.array(Image.open(actual)).astype(float)
+
+    ref, out = ref.mean(axis=2), out.mean(axis=2) # convert to grayscale
+    delta = np.abs(out - ref).astype(float) / 255
+    return ImageDifference(delta.mean(), ref, out)
+
+