From 5c506faef25e3a0d90635463602b938a6f20811b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=A0imon=20Bo=C5=99il?= <519192@mail.muni.cz>
Date: Wed, 25 Mar 2026 13:51:13 +0000
Subject: [PATCH 1/3] chore: JSONMultiClassMask

---
 ratiopath/parsers/json_multi_class_mask.py | 45 ++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 ratiopath/parsers/json_multi_class_mask.py

diff --git a/ratiopath/parsers/json_multi_class_mask.py b/ratiopath/parsers/json_multi_class_mask.py
new file mode 100644
index 0000000..9eb07ff
--- /dev/null
+++ b/ratiopath/parsers/json_multi_class_mask.py
@@ -0,0 +1,45 @@
+import json
+from pathlib import Path
+
+import numpy as np
+from PIL import Image, ImageDraw
+
+
+class JSONMultiClassMask:
+    """Parses JSON annotations and renders them into a multi-class mask array.
+    
+    Expects class to value mapping on input.
+    """
+
+    def __init__(
+        self,
+        json_path: Path,
+        mask_size: tuple[int, int],
+        scale_factor: float,
+        target_groups: dict[str, int],
+    ):
+        self.json_path = json_path
+        self.mask_size = mask_size  # (width, height)
+        self.scale = scale_factor
+        self.target_groups = target_groups
+
+    def __call__(self) -> np.ndarray:
+        mask_img = Image.new("L", self.mask_size, 0)
+        draw = ImageDraw.Draw(mask_img)
+
+        with open(self.json_path) as f:
+            data = json.load(f)
+
+        for item in data.get("items", []):
+            class_name = item.get("name")
+
+            if class_name in self.target_groups:
+                coords = item.get("coordinates", [])
+                if not coords:
+                    continue
+
+                fill_value = self.target_groups[class_name]
+                scaled_coords = [(c[0] * self.scale, c[1] * self.scale) for c in coords]
+                draw.polygon(scaled_coords, fill=fill_value)
+
+        return np.array(mask_img)

From b1b0ef28ffc3b8c16b68cdd6eb52778adaa67e9e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=A0imon=20Bo=C5=99il?= <519192@mail.muni.cz>
Date: Wed, 25 Mar 2026 13:53:33 +0000
Subject: [PATCH 2/3] fix: fix init

---
 ratiopath/parsers/__init__.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ratiopath/parsers/__init__.py b/ratiopath/parsers/__init__.py
index 9aa5761..99ff7e0 100644
--- a/ratiopath/parsers/__init__.py
+++ b/ratiopath/parsers/__init__.py
@@ -1,6 +1,7 @@
 from ratiopath.parsers.asap_parser import ASAPParser
 from ratiopath.parsers.darwin7_json_parser import Darwin7JSONParser
 from ratiopath.parsers.geojson_parser import GeoJSONParser
+from ratiopath.parsers.json_multi_class_mask import JSONMultiClassMask
 
 
-__all__ = ["ASAPParser", "Darwin7JSONParser", "GeoJSONParser"]
+__all__ = ["ASAPParser", "Darwin7JSONParser", "GeoJSONParser", "JSONMultiClassMask"]

From f888896027f1e7609d55dc7f553801b3f31f1889 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=A0imon=20Bo=C5=99il?= <519192@mail.muni.cz>
Date: Wed, 25 Mar 2026 13:55:23 +0000
Subject: [PATCH 3/3] fix: mypy

---
 ratiopath/parsers/json_multi_class_mask.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ratiopath/parsers/json_multi_class_mask.py b/ratiopath/parsers/json_multi_class_mask.py
index 9eb07ff..86dc484 100644
--- a/ratiopath/parsers/json_multi_class_mask.py
+++ b/ratiopath/parsers/json_multi_class_mask.py
@@ -7,7 +7,7 @@
 
 class JSONMultiClassMask:
     """Parses JSON annotations and renders them into a multi-class mask array.
-    
+
     Expects class to value mapping on input.
     """