display: Support requesting a screen redraw on a menu key press

Add a request_redraw() method and call it when a key menu event
occurs.  Limit these proactive screen redraws to no more than 4 per
second.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/extras/display/display.py

@@ -100,9 +100,12 @@ class PrinterLCD:
         self.show_data_group = self.display_data_groups.get(dgroup)
         if self.show_data_group is None:
             raise config.error("Unknown display_data group '%s'" % (dgroup,))
+        # Screen updating
         self.printer.register_event_handler("klippy:ready", self.handle_ready)
         self.screen_update_timer = self.reactor.register_timer(
             self.screen_update_event)
+        self.redraw_request_pending = False
+        self.redraw_time = 0.
         # Register g-code commands
         gcode = self.printer.lookup_object("gcode")
         gcode.register_mux_command('SET_DISPLAY_GROUP', 'DISPLAY', name,
@@ -111,6 +114,8 @@ class PrinterLCD:
         if name == 'display':
             gcode.register_mux_command('SET_DISPLAY_GROUP', 'DISPLAY', None,
                                        self.cmd_SET_DISPLAY_GROUP)
+    def get_dimensions(self):
+        return self.lcd_chip.get_dimensions()
     # Configurable display
     def _parse_glyph(self, config, glyph_name, data, width, height):
         glyph_data = []
@@ -184,19 +189,28 @@ class PrinterLCD:
         self.reactor.update_timer(self.screen_update_timer, self.reactor.NOW)
     # Screen updating
     def screen_update_event(self, eventtime):
+        if self.redraw_request_pending:
+            self.redraw_request_pending = False
+            self.redraw_time = eventtime + 0.250
+        self.lcd_chip.clear()
         # update menu component
         if self.menu is not None:
             ret = self.menu.screen_update_event(eventtime)
             if ret:
-                return ret
+                self.lcd_chip.flush()
+                return eventtime + .500
         # Update normal display
-        self.lcd_chip.clear()
         try:
             self.show_data_group.show(self, self.display_templates, eventtime)
         except:
             logging.exception("Error during display screen update")
         self.lcd_chip.flush()
         return eventtime + .500
+    def request_redraw(self):
+        if self.redraw_request_pending:
+            return
+        self.redraw_request_pending = True
+        self.reactor.update_timer(self.screen_update_timer, self.redraw_time)
     def draw_text(self, row, col, mixed_text, eventtime):
         pos = col
         for i, text in enumerate(mixed_text.split('~')):

klippy/extras/display/menu.py

@@ -616,7 +616,6 @@ menu_items = {
 }
 
 
-MENU_UPDATE_DELAY = .100
 TIMER_DELAY = .100
 
 
@@ -636,7 +635,7 @@ class MenuManager:
         self.context = {}
         self.root = None
         self._root = config.get('menu_root', '__main')
-        self.cols, self.rows = self.display.lcd_chip.get_dimensions()
+        self.cols, self.rows = self.display.get_dimensions()
         self.timeout = config.getint('menu_timeout', 0)
         self.timer = 0
         self.eventtime = 0
@@ -808,14 +807,11 @@ class MenuManager:
 
     def screen_update_event(self, eventtime):
         # screen update
-        if self.is_running():
-            self.display.lcd_chip.clear()
-            for y, line in enumerate(self.render(eventtime)):
-                self.display.draw_text(y, 0, line, eventtime)
-            self.display.lcd_chip.flush()
-            return eventtime + MENU_UPDATE_DELAY
-        else:
-            return 0
+        if not self.is_running():
+            return False
+        for y, line in enumerate(self.render(eventtime)):
+            self.display.draw_text(y, 0, line, eventtime)
+        return True
 
     def up(self, fast_rate=False):
         container = self.stack_peek()
@@ -998,6 +994,7 @@ class MenuManager:
             self.down(True)
         elif key == 'back':
             self.back()
+        self.display.request_redraw()
 
     # Collection of manager class helper methods