diff --git a/src/groovylight/geom.py b/src/groovylight/geom.py
index d80d6ac..51e4e42 100644
--- a/src/groovylight/geom.py
+++ b/src/groovylight/geom.py
@@ -110,17 +110,17 @@ class DisplayRotation(Enum):
     Generally, prefer LEFTRIGHT/UPDOWN over other rotations.
     """
 
-    LEFTRIGHT = 0
-    UPDOWN = 1
-    DOWNUP = 2
-    RIGHTLEFT = 3  # why are you like this.
+    R0 = 0
+    R90 = 1
+    R180 = 2
+    R270 = 3  # why are you like this.
 
 
 @dataclass(frozen=True)
 class DisplayString:
     """Internal class to represent a string of HUB75 displays.
 
-    position: (X,Y) coordinates of the local top-left of the display
+    position: (X,Y) screen coordinates of the top-left of the display.
 
     dimensions: (length, height) local-coordinate dimensions of the display.
 
@@ -129,8 +129,7 @@ class DisplayString:
 
     position: Coord
     dimensions: DisplayDimensions
-    rotation: DisplayRotation
-    # TODO: encode muxing
+    rotation: DisplayRotation = DisplayRotation.R0
 
     @property
     def bbox(self) -> BBox:
@@ -140,14 +139,10 @@ class DisplayString:
         l = self.dimensions.length
         h = self.dimensions.height
         match self.rotation:
-            case DisplayRotation.LEFTRIGHT:
+            case DisplayRotation.R0 | DisplayRotation.R270:
                 return BBox(Coord(x, y), Coord(x + l, y + h))
-            case DisplayRotation.UPDOWN:
-                return BBox(Coord(x - h, y), Coord(x, y + l))
-            case DisplayRotation.DOWNUP:
-                return BBox(Coord(x, y + l), Coord(x + h, y))
-            case DisplayRotation.RIGHTLEFT:
-                return BBox(Coord(x - l, y - h), Coord(x, y))
+            case DisplayRotation.R90 | DisplayRotation.R180:
+                return BBox(Coord(x, y), Coord(x + h, y + l))
 
     def contains_pix(self, coord: Coord) -> bool:
         """Checks if the given coordinate is inside this display."""
@@ -157,6 +152,38 @@ class DisplayString:
         """Checks if the given BBox intersects with this display"""
         return self.bbox.intersects(box)
 
+    def translate_coord(self, pixnum, addr, mux):
+        """Helper function to translate string coordinates to screen coordinates"""
+
+        assert mux < self.dimensions.mux, "Mux must be within the mux of the display"
+
+        x = self.position.x
+        y = self.position.y
+
+        addrshift = addr + (self.dimensions.height // self.dimensions.mux) * mux
+        #
+        match self.rotation:
+            case DisplayRotation.R0:
+                # x is linear
+                return {
+                    "x": x + pixnum,
+                    "y": y + addrshift,
+                }
+            case DisplayRotation.R90:
+                # x is height - addrshift
+                return {
+                    "x": x + self.dimensions.height - addrshift - 1,
+                    "y": y + pixnum,
+                }
+            case DisplayRotation.R180:
+                pass
+            case DisplayRotation.R270:
+                # x and y are both length - pixnum
+                return {
+                    "x": x + self.dimensions.length - 1 - pixnum,
+                    "y": y + addrshift,
+                }
+
 
 class DisplayGeometry:
     """Represents a display based on several strings in different positions."""
@@ -185,7 +212,7 @@ class DisplayGeometry:
         return sum
 
     def add_string(self, s: DisplayString):
-        """Add a new string to the display. 
+        """Add a new string to the display.
         When in strict mode, this method will throw an exception if this new string
         will overlap with an existing string.
         """
diff --git a/src/groovylight/tests/test_geom.py b/src/groovylight/tests/test_geom.py
index fdba69c..9e7453f 100644
--- a/src/groovylight/tests/test_geom.py
+++ b/src/groovylight/tests/test_geom.py
@@ -1,4 +1,4 @@
-from ..geom import Coord, BBox
+from ..geom import Coord, BBox, DisplayString, DisplayDimensions, DisplayRotation
 
 import pytest
 
@@ -37,3 +37,21 @@ def test_bbox():
         BBox(Coord(0, 0), Coord(1, 0))
     with pytest.raises(RuntimeError):
         BBox(Coord(1, 1), Coord(0, 0))
+
+
+ds_testdata = [
+    (DisplayRotation.R0, (0, 0, 0), {"x": 3, "y": 0}),
+    (DisplayRotation.R0, (40, 2, 0), {"x": 43, "y": 2}),
+    (DisplayRotation.R0, (40, 2, 1), {"x": 43, "y": 34}),
+    (DisplayRotation.R90, (40, 0, 0), {"x": 66, "y": 40}),
+    (DisplayRotation.R90, (120, 2, 0), {"x": 64, "y": 120}),
+]
+
+
+@pytest.mark.parametrize("rot, inp, expected", ds_testdata)
+def test_displaystring(rot, inp, expected):
+    ds = DisplayString(Coord(3, 0), DisplayDimensions(128, 64), rot)
+
+    res = ds.translate_coord(*inp)
+
+    assert res == expected