first comit

venv/lib/python3.10/site-packages/jsignature/utils.py

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+"""
+    Very inspired by zivezab's django-autograph
+    https://github.com/zivezab/django-autograph/blob/master/autograph/utils.py
+"""
+import json
+from itertools import chain
+from PIL import Image, ImageDraw, ImageOps, __version__ as PIL_VERSION
+
+AA = 5  # super sampling for antialiasing
+
+
+def draw_signature(data, as_file=False):
+    """Draw signature based on lines stored in json_string.
+    `data` can be a json object (list in fact) or a json string
+    if `as_file` is True, a temp file is returned instead of Image instance
+    """
+
+    def _remove_empty_pts(pt):
+        return {
+            "x": list(filter(lambda n: n is not None, pt["x"])),
+            "y": list(filter(lambda n: n is not None, pt["y"])),
+        }
+
+    if isinstance(data, str):
+        drawing = json.loads(data, object_hook=_remove_empty_pts)
+    elif isinstance(data, list):
+        drawing = data
+    else:
+        raise ValueError
+
+    # Compute box
+    padding = 10
+    min_width = int(round(min(chain(*[d["x"] for d in drawing])))) - padding
+    max_width = int(round(max(chain(*[d["x"] for d in drawing])))) + padding
+    width = max_width - min_width
+    min_height = int(round(min(chain(*[d["y"] for d in drawing])))) - padding
+    max_height = int(round(max(chain(*[d["y"] for d in drawing])))) + padding
+    height = max_height - min_height
+
+    # Draw image
+    im = Image.new("RGBA", (width * AA, height * AA))
+    draw = ImageDraw.Draw(im)
+    for coords in drawing:
+        line_length = len(coords["x"])
+        if line_length == 1:
+            # This is a single point, convert to a circle of 2x2 AA pixels
+            draw.ellipse(
+                [
+                    (
+                        (coords["x"][0] - min_width) * AA,
+                        (coords["y"][0] - min_height) * AA,
+                    ),
+                    (
+                        (coords["x"][0] - min_width + 2) * AA,
+                        (coords["y"][0] - min_height + 2) * AA,
+                    ),
+                ],
+                fill="#000",
+            )
+        else:
+            points = [
+                ((coords["x"][i] - min_width) * AA, (coords["y"][i] - min_height) * AA)
+                for i in range(0, line_length)
+            ]
+            draw.line(points, fill="#000", width=2 * AA)
+    im = ImageOps.expand(im)
+    # Smart crop
+    bbox = im.getbbox()
+    if bbox:
+        im.crop(bbox)
+
+    im.thumbnail(
+        (width, height),
+        # Image.ANTIALIAS is replaced in PIL 10.0.0
+        Image.ANTIALIAS if int(PIL_VERSION.split(".")[0]) < 10 else Image.LANCZOS,
+    )
+
+    if as_file:
+        ret = im._dump(format="PNG")
+    else:
+        ret = im
+
+    return ret