composeApp/src/commonMain/kotlin/mg/dot/feufaro/solfa/Transpose.kt

@@ -61,12 +61,10 @@ class Transpose {
                         val remaining = token.drop(separators.length)
 
                         val totalAlter = interval + currentModulationInterval
-                        val rawIndex = (0 + totalAlter) % 12
-                        val targetKeyIndex = if (rawIndex < 0) rawIndex + 12 else rawIndex
-                        val calculatedToKey = keyToNumber[targetKeyIndex]
+
                         val transposedBody = NOTE_UNIT_REGEX.replace(remaining) { matchResult ->
                             val fullNote = matchResult.value
-                            transpose(note = fullNote, fromKey = "C", toKey = calculatedToKey)
+                            transpose(note = fullNote, fromKey = "C", toKey = "C", alter = totalAlter)
                         }
 
                         val result = separators + transposedBody

composeApp/src/commonMain/kotlin/mg/dot/feufaro/ui/DrawerUI.kt

@@ -248,8 +248,7 @@ fun MainScreenWithDrawer(
                     var isEyeVisible by remember { mutableStateOf(false) }
                     val keysOrder = Transpose.keyToNumber
                     val songKeyIndex = keysOrder.indexOf(songKey).takeIf { it != -1 } ?: 0
-                    val rawKeyIndex = (songKeyIndex + tempInterval) % 12
-                    val tempUiKey = keysOrder[if (rawKeyIndex < 0) rawKeyIndex + 12 else rawKeyIndex]
+                    val tempUiKey = keysOrder[(songKeyIndex + tempInterval + 24) % 12]
                     val appliedInterval by sharedScreenModel.transpositionInterval.collectAsState()
                     val isPendingChange = tempInterval != appliedInterval
                     val isCurrentlyTransposed = appliedInterval != 0