Segment Displays: Stack vs Replace Option

mpf/config_spec.yaml

@@ -1479,6 +1479,7 @@ segment_displays:
     default_transition_update_hz: single|float_or_token|30
     platform_settings: single|dict|None
     platform: single|str|None
+    update_method: single|str|None
 light_segment_displays_device:
     lights: list|dict(str:machine(lights))|None
     light_groups: list|machine(neoseg_displays)|None

mpf/devices/segment_display/segment_display.py

@@ -127,18 +127,38 @@ def validate_and_parse_config(self, config: dict, is_mode_config: bool, debug_pr
         platform.assert_has_feature("segment_displays")
         config['platform_settings'] = platform.validate_segment_display_section(self,
                                                                                 config.get('platform_settings', None))
+
+        # For backwards compatibility, an undefined update_method config will be mapped
+        # to "stack". However the default in a future version will be "replace", so inform
+        # the user that they should explicitly define "stack" to avoid a breaking change.
+        if config['update_method'] is None:
+            self.warning_log("Segment display update_method will default to 'replace' in a future MPF release. "
+                             "You have no config value specified and are currently getting 'stack' for backwards "
+                             "compatibility. To avoid a breaking change, please set 'update_method: \"stack\"' "
+                             "in your segment display config.")
+            config['update_method'] = "stack"
         return config
 
     # pylint: disable-msg=too-many-arguments
     def add_text_entry(self, text, color, flashing, flash_mask, transition, transition_out, priority, key):
-        """Add text to display stack.
+        """Add text to display stack, or send it directly to the display.
 
         This will replace texts with the same key.
         """
-        # remove old text in case it has the same key
-        self._text_stack[key] = TextStackEntry(
-            text, color, flashing, flash_mask, transition, transition_out, priority, key)
-        self._update_stack()
+        if self.config['update_method'] == "stack":
+            self._text_stack[key] = TextStackEntry(
+                text, color, flashing, flash_mask, transition, transition_out, priority, key)
+            self._update_stack()
+            return
+
+        if self.config['update_method'] != "replace":
+            raise ValueError(f"Unknown update_method '{self.config['update_method']}' for segment display {self.name}")
+
+        # For the replace-text update method, skip the stack and write straight to the display
+        new_text = TextTemplate(self.machine, text).evaluate({})
+        text = SegmentDisplayText.from_str(new_text, self.size, self.config['integrated_dots'],
+                                           self.config['integrated_commas'], color)
+        self._update_display(SegmentDisplayState(text, flashing, flash_mask))
 
     def add_text(self, text: str, priority: int = 0, key: str = None) -> None:
         """Add text to display stack.
@@ -149,6 +169,10 @@ def add_text(self, text: str, priority: int = 0, key: str = None) -> None:
 
     def remove_text_by_key(self, key: Optional[str]):
         """Remove entry from text stack."""
+        if self.config['update_method'] != "stack":
+            self.info_log("Segment display 'remove' action is TBD.")
+            return
+
         if key in self._text_stack:
             del self._text_stack[key]
             self._update_stack()

mpf/platforms/fast/communicators/seg.py

@@ -39,6 +39,7 @@ def _update_segs(self, **kwargs):
 
             if s.next_color:
                 self.send_and_forget(('PC:{},{}').format(s.hex_id, s.next_color))
+                s.current_color = s.next_color
                 s.next_color = None
 
     async def soft_reset(self):
@@ -49,3 +50,4 @@ def stopping(self):
             self.send_and_forget(f'PA:{s.hex_id},')
             s.next_text = None
             s.next_color = None
+            s.current_color = None

mpf/platforms/fast/fast_segment_display.py

@@ -14,7 +14,7 @@ class FASTSegmentDisplay(SegmentDisplayPlatformInterface):
 
     """FAST segment display."""
 
-    __slots__ = ["serial", "hex_id", "next_color", "next_text"]
+    __slots__ = ["serial", "hex_id", "next_color", "next_text", "current_color"]
 
     def __init__(self, index, communicator):
         """Initialize alpha numeric display."""
@@ -23,6 +23,7 @@ def __init__(self, index, communicator):
         self.hex_id = Util.int_to_hex_string(index * 7)
         self.next_color = None
         self.next_text = None
+        self.current_color = None
 
     def set_text(self, text: ColoredSegmentDisplayText, flashing: FlashingType, flash_mask: str) -> None:
         """Set digits to display."""
@@ -36,6 +37,12 @@ def set_text(self, text: ColoredSegmentDisplayText, flashing: FlashingType, flas
     def _set_color(self, colors: List[RGBColor]) -> None:
         """Set display color."""
         if len(colors) == 1:
-            self.next_color = (RGBColor(colors[0]).hex + ',') * 7
+            next_color = (RGBColor(colors[0]).hex + ',') * 7
         else:
-            self.next_color = ','.join([RGBColor(color).hex for color in colors]) + ','
+            next_color = ','.join([RGBColor(color).hex for color in colors]) + ','
+
+        # Current color is set by the FastSegCommunicator after the serial
+        # command is written to set the color (which happens automatically
+        # on the next loop whenever self.next_color is set).
+        if next_color != self.current_color:
+            self.next_color = next_color

mpf/tests/machine_files/segment_display/config/config.yaml

@@ -19,6 +19,12 @@ segment_displays:
     number: 1
     size: 10
     integrated_dots: true
+  display_stack:
+    number: 4
+    update_method: stack
+  display_replace:
+    number: 5
+    update_method: replace
 
 segment_display_player:
   test_event1:

mpf/tests/test_SegmentDisplay.py

@@ -197,6 +197,21 @@ def test_game(self):
         self.assertEqual("       ", display5.hw_display.text)
         self.assertEqual(FlashingType.NO_FLASH, display5.hw_display.flashing)
 
+    def test_update_method(self):
+        display_stack = self.machine.segment_displays["display_stack"]
+        display_replace = self.machine.segment_displays["display_replace"]
+
+        for i in range(0, 10):
+            display_stack.add_text(f"STACK {i}", key=i, priority=i)
+            display_replace.add_text(f"REPLC {i}", key=i, priority=i)
+            self.advance_time_and_run(0.5)
+
+        self.assertEqual("STACK 9", display_stack.hw_display.text)
+        self.assertEqual("REPLC 9", display_replace.hw_display.text)
+
+        self.assertEqual(len(display_stack._text_stack), 10)
+        self.assertEqual(len(display_replace._text_stack), 0)
+
     def test_player(self):
         display1 = self.machine.segment_displays["display1"]
         display2 = self.machine.segment_displays["display2"]