Add cutom color support to rendering

src/robofish/io/app.py

@@ -241,6 +241,16 @@ def render(args: argparse.Namespace = None) -> None:
         help="Last frame to render. Render until the end if set to 0.",
     )
 
+    parser.add_argument(
+        "--custom-colors",
+        type=str,
+        nargs="+",
+        default=[],
+        help="Custom colors to use for guppies. Use spaces as delimiter. "
+        "To set all guppies to the same color, pass only one color. "
+        "Hexadecimal values, color names and matplotlib abbreviations are supported (\"#000000\", black, k)"
+    )
+
     default_options = {
         "linewidth": 2,
         "speedup": 1,

src/robofish/io/file.py

@@ -1004,6 +1004,7 @@ class File(h5py.File):
         render_zones: bool = False,
         render_swarm_center: bool = False,
         highlight_switches: bool = False,
+        custom_colors: bool = None,
         dpi: int = 200,
         figsize: int = 10,
     ) -> None:
@@ -1058,7 +1059,17 @@ class File(h5py.File):
         categories = [entity.attrs.get("category", None) for entity in self.entities]
         n_fish = len([c for c in categories if c == "organism"])
 
-        lines = [plt.plot([], [], lw=linewidth, zorder=0)[0] for _ in range(n_entities)]
+
+        lines = [
+            plt.plot(
+                [],
+                [],
+                lw=linewidth,
+                color=custom_colors[i%len(custom_colors)-1] if custom_colors else None,
+                zorder=0,
+            )[0]
+            for i in range(n_entities)
+        ]
         entity_colors = [lines[entity].get_color() for entity in range(n_entities)]
         fish_colors = [
             color