Add random scale note selection feature

- Add "Random" button option to scale note section that selects different random scale notes each pattern loop
- Update arpeggiator engine to support "random" as scale_note_start value alongside integers
- Add helper method _get_actual_scale_note_start() to handle random selection on each pattern generation
- Update GUI to properly style and handle "Random" button selection with orange coloring
- Support both immediate and armed state changes for random scale note selection

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

core/arpeggiator_engine.py

@@ -8,7 +8,8 @@ Generates arpeggio patterns, handles timing, and integrates with routing and vol
 import time
 import math
 import threading
-from typing import Dict, List, Optional, Tuple, Set
+import random
+from typing import Dict, List, Optional, Tuple, Set, Union
 from PyQt5.QtCore import QObject, pyqtSignal, QTimer
 
 from .midi_channel_manager import MIDIChannelManager
@@ -237,13 +238,19 @@ class ArpeggiatorEngine(QObject):
         """Set base velocity 0-127"""
         self.velocity = max(0, min(127, velocity))
     
-    def set_scale_note_start(self, scale_note_index: int):
-        """Set which scale note to start the arpeggio from"""
+    def set_scale_note_start(self, scale_note_index: Union[int, str]):
+        """Set which scale note to start the arpeggio from (integer index or 'random')"""
+        if scale_note_index == "random":
+            self.scale_note_start = "random"
+        else:
             self.scale_note_start = max(0, scale_note_index)
         self.regenerate_pattern()
     
-    def arm_scale_note_start(self, scale_note_index: int):
+    def arm_scale_note_start(self, scale_note_index: Union[int, str]):
         """Arm a scale note start position to change at pattern end"""
+        if scale_note_index == "random":
+            self.armed_scale_note_start = "random"
+        else:
             self.armed_scale_note_start = max(0, scale_note_index)
         self.armed_state_changed.emit()
     
@@ -618,7 +625,8 @@ class ArpeggiatorEngine(QObject):
         root_in_octave = self.root_note % 12
         
         # Get the interval for the selected scale degree
-        start_degree = self.scale_note_start % len(scale_intervals)
+        actual_start = self._get_actual_scale_note_start()
+        start_degree = actual_start % len(scale_intervals)
         start_interval = scale_intervals[start_degree]
         starting_note = base_octave * 12 + root_in_octave + start_interval
         
@@ -651,7 +659,8 @@ class ArpeggiatorEngine(QObject):
         root_in_octave = self.root_note % 12
         
         # Get the interval for the selected scale degree
-        start_degree = self.scale_note_start % len(scale_intervals)
+        actual_start = self._get_actual_scale_note_start()
+        start_degree = actual_start % len(scale_intervals)
         start_interval = scale_intervals[start_degree]
         starting_note = base_octave * 12 + root_in_octave + start_interval
         
@@ -695,7 +704,8 @@ class ArpeggiatorEngine(QObject):
         root_in_octave = self.root_note % 12
         
         # Get the interval for the selected scale degree
-        start_degree = self.scale_note_start % len(scale_intervals)
+        actual_start = self._get_actual_scale_note_start()
+        start_degree = actual_start % len(scale_intervals)
         
         # Generate only the number of notes specified by note_limit
         for i in range(self.note_limit):
@@ -713,6 +723,14 @@ class ArpeggiatorEngine(QObject):
         
         return notes
     
+    def _get_actual_scale_note_start(self) -> int:
+        """Get the actual scale note start index to use, handling random selection"""
+        if self.scale_note_start == "random":
+            scale_intervals = self.SCALES[self.scale]
+            return random.randint(0, len(scale_intervals) - 1)
+        else:
+            return self.scale_note_start
+    
     def _get_all_scale_notes(self) -> List[int]:
         """Get all available scale notes in both directions for patterns that need full range"""
         # Use limited scale notes if note_limit is less than full scale

gui/arpeggiator_controls.py

@@ -1347,6 +1347,21 @@ class ArpeggiatorControls(QWidget):
             self.scale_notes_buttons[i] = btn
             self.scale_notes_layout.addWidget(btn, 0, i)
         
+        # Add Random button as an additional option
+        random_btn = QPushButton("Random")
+        random_btn.setFixedSize(60, 25)
+        random_btn.setCheckable(True)
+        random_btn.setStyleSheet("background: #3a3a3a; color: #ffffff; font-size: 11px; font-weight: bold; padding: 0px; border: 1px solid #555555;")
+        random_btn.clicked.connect(lambda checked: self.on_scale_note_clicked("random"))
+        
+        # Check if random is currently selected
+        if self.current_scale_note_index == "random":
+            random_btn.setChecked(True)
+            random_btn.setStyleSheet("background: #ff8800; color: white; font-size: 11px; font-weight: bold; padding: 0px; border: 1px solid #ffaa00;")
+        
+        self.scale_notes_buttons["random"] = random_btn
+        self.scale_notes_layout.addWidget(random_btn, 0, len(scale_notes))
+    
     def on_scale_note_clicked(self, scale_note_index):
         """Handle scale note selection with armed state support"""
         if hasattr(self.arpeggiator, 'is_playing') and self.arpeggiator.is_playing:
@@ -1360,7 +1375,10 @@ class ArpeggiatorControls(QWidget):
                         break
                 if old_armed_index is not None:
                     if old_armed_index == self.current_scale_note_index:
-                        # It was the current active note, make it blue again
+                        # It was the current active note, restore its proper color
+                        if old_armed_index == "random":
+                            self.armed_scale_note_button.setStyleSheet("background: #ff8800; color: white; font-size: 11px; font-weight: bold; padding: 0px; border: 1px solid #ffaa00;")
+                        else:
                             self.armed_scale_note_button.setStyleSheet("background: #0099ff; color: white; font-size: 11px; font-weight: bold; padding: 0px; border: 1px solid #00bbff;")
                     else:
                         # It was just armed, make it gray again
@@ -1385,6 +1403,9 @@ class ArpeggiatorControls(QWidget):
             
             if scale_note_index in self.scale_notes_buttons:
                 self.scale_notes_buttons[scale_note_index].setChecked(True)
+                if scale_note_index == "random":
+                    self.scale_notes_buttons[scale_note_index].setStyleSheet("background: #ff8800; color: white; font-size: 11px; font-weight: bold; padding: 0px; border: 1px solid #ffaa00;")
+                else:
                     self.scale_notes_buttons[scale_note_index].setStyleSheet("background: #0099ff; color: white; font-size: 11px; font-weight: bold; padding: 0px; border: 1px solid #00bbff;")
             
             # Update arpeggiator engine with new starting scale note
@@ -1394,3 +1415,15 @@ class ArpeggiatorControls(QWidget):
         """Update the arpeggiator engine with the selected scale note starting position"""
         if hasattr(self.arpeggiator, 'set_scale_note_start'):
             self.arpeggiator.set_scale_note_start(self.current_scale_note_index)
+    
+    def on_random_scale_note_clicked(self):
+        """Select a random scale note"""
+        if self.scale_notes_buttons:
+            import random
+            # Get all available scale note indices
+            available_indices = list(self.scale_notes_buttons.keys())
+            if available_indices:
+                # Choose a random index
+                random_index = random.choice(available_indices)
+                # Trigger the scale note selection
+                self.on_scale_note_clicked(random_index)