diff --git a/api/advent22_api/routers/_image.py b/api/advent22_api/routers/_image.py
index 99498e3..4637e66 100644
--- a/api/advent22_api/routers/_image.py
+++ b/api/advent22_api/routers/_image.py
@@ -1,3 +1,4 @@
+import colorsys
 from dataclasses import dataclass
 
 import numpy as np
@@ -81,3 +82,49 @@ class AdventImage:
         mean_color: np.ndarray = np.mean(pixel_data, axis=0)
 
         return tuple(mean_color.astype(int).tolist())
+
+    async def hide_text(
+        self,
+        xy: tuple[float, float],
+        text: str | bytes,
+        font: "ImageFont._Font",
+        anchor: str | None = "mm",
+        **text_kwargs,
+    ) -> None:
+        # betroffenen Bildbereich bestimmen
+        text_box = await self.get_text_box(
+            xy=xy,
+            text=text,
+            font=font,
+            anchor=anchor,
+            **text_kwargs
+        )
+
+        if text_box is not None:
+            # Durchschnittsfarbe bestimmen
+            text_color = await self.get_average_color(
+                box=text_box,
+            )
+
+            # etwas heller/dunkler machen
+            tc_h, tc_s, tc_v = colorsys.rgb_to_hsv(*text_color)
+            tc_v = int((tc_v - 127) * 0.97) + 127
+
+            if tc_v < 127:
+                tc_v += 3
+
+            else:
+                tc_v -= 3
+
+            text_color = colorsys.hsv_to_rgb(tc_h, tc_s, tc_v)
+            text_color = tuple(int(val) for val in text_color)
+
+            # Buchstaben verstecken
+            ImageDraw.Draw(self.img).text(
+                xy=xy,
+                text=text,
+                font=font,
+                fill=text_color,
+                anchor=anchor,
+                **text_kwargs
+            )
diff --git a/api/advent22_api/routers/days.py b/api/advent22_api/routers/days.py
index 3d5c838..5a27efc 100644
--- a/api/advent22_api/routers/days.py
+++ b/api/advent22_api/routers/days.py
@@ -1,11 +1,10 @@
-import colorsys
 import re
 # from datetime import date
 from io import BytesIO
 
 from fastapi import APIRouter, Depends
 from fastapi.responses import StreamingResponse
-from PIL import ImageDraw, ImageFont
+from PIL import ImageFont
 
 from ..dav_common import dav_get_file, dav_list_files
 from ._image import AdventImage
@@ -102,40 +101,12 @@ async def get_picture_for_day(
     xy = tuple(rnd.choices(range(30, 470), k=2))
 
     # betroffenen Bildbereich bestimmen
-    text_box = await adv_img.get_text_box(
+    await adv_img.hide_text(
         xy=xy,
         text=letter,
         font=font,
     )
 
-    if text_box is not None:
-        # Durchschnittsfarbe bestimmen
-        text_color = await adv_img.get_average_color(
-            box=text_box,
-        )
-
-        # etwas heller/dunkler machen
-        tc_h, tc_s, tc_v = colorsys.rgb_to_hsv(*text_color)
-        tc_v = int((tc_v - 127) * 0.97) + 127
-
-        if tc_v < 127:
-            tc_v += 3
-
-        else:
-            tc_v -= 3
-
-        text_color = colorsys.hsv_to_rgb(tc_h, tc_s, tc_v)
-        text_color = tuple(int(val) for val in text_color)
-
-        # Buchstaben verstecken
-        ImageDraw.Draw(adv_img.img).text(
-            xy=xy,
-            text=letter,
-            font=font,
-            anchor="mm",
-            fill=text_color,
-        )
-
     # Bilddaten in Puffer laden
     img_buffer = BytesIO()
     adv_img.img.save(img_buffer, format="JPEG", quality=85)