feat(visualize): add option to not trust the box

signwriting/visualizer/test_visualize.py

@@ -38,6 +38,22 @@ def test_image_invalid_fsw(self):
 
         assert_array_equal(np.array(image), np.array(reference_image))
 
+    def test_image_small_box(self):
+        fsw = "M500x500S2ff00407x501S1ce20436x535S2e300413x552S22b04418x565S36520420x523"
+
+        with self.assertRaises(ValueError):
+            signwriting_to_image(fsw)
+
+    def test_image_small_box_is_corrected(self):
+        fsw = "M500x500S2ff00407x501S1ce20436x535S2e300413x552S22b04418x565S36520420x523"
+
+        image = signwriting_to_image(fsw, trust_box=False)
+
+        assets_path = Path(__file__).parent / "test_assets" / f"{fsw}.png"
+        reference_image = Image.open(assets_path)
+
+        assert_array_equal(np.array(image), np.array(reference_image))
+
 
 if __name__ == '__main__':
     unittest.main()

signwriting/visualizer/visualize.py

@@ -8,21 +8,38 @@
 
 
 @lru_cache(maxsize=None)
-def get_font(font_name: str):
+def get_font(font_name: str) -> ImageFont.FreeTypeFont:
     font_path = Path(__file__).parent / f'{font_name}.ttf'
     return ImageFont.truetype(str(font_path), 30)
 
 
+def get_symbol_size(symbol: str):
+    font = get_font('SuttonSignWritingLine')
+    line_id = symbol_line(key2id(symbol))
+    left, top, right, bottom = font.getbbox(line_id)
+    return right - left, bottom - top
+
+
 # pylint: disable=too-many-locals
-def signwriting_to_image(fsw: str, antialiasing=True) -> Image:
+def signwriting_to_image(fsw: str, antialiasing=True, trust_box=True) -> Image:
     sign = fsw_to_sign(fsw)
     if len(sign['symbols']) == 0:
         return Image.new('RGBA', (1, 1), (0, 0, 0, 0))
 
     positions = [s["position"] for s in sign['symbols']]
     min_x = min(positions, key=lambda p: p[0])[0]
     min_y = min(positions, key=lambda p: p[1])[1]
+
     max_x, max_y, = sign["box"]["position"]
+
+    if not trust_box:
+        max_x, max_y = 0, 0
+        for symbol in sign['symbols']:
+            symbol_x, symbol_y = symbol["position"]
+            symbol_width, symbol_height = get_symbol_size(symbol["symbol"])
+            max_x = max(max_x, symbol_x + symbol_width)
+            max_y = max(max_y, symbol_y + symbol_height)
+
     img = Image.new('RGBA', (max_x - min_x, max_y - min_y), (255, 255, 255, 0))
     draw = ImageDraw.Draw(img)
     if not antialiasing: