Merge pull request #5288 from thinkyhead/rc_selective_rendering

Optimize graphical display with selective rendering

Marlin/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/Cartesio/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/Felix/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/Hephestos/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/Hephestos_2/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   #define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/K8200/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/K8400/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/RigidBot/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/SCARA/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/TAZ4/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/WITBOX/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/delta/biv2.5/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/delta/generic/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/delta/kossel_mini/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/delta/kossel_pro/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/delta/kossel_xl/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/makibox/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/example_configurations/tvrrug/Round2/Configuration_adv.h

 
 #endif // SDSUPPORT
 
-// for dogm lcd displays you can choose some additional fonts:
+// Some additional options are available for graphical displays:
 #if ENABLED(DOGLCD)
-  // save 3120 bytes of PROGMEM by commenting out #define USE_BIG_EDIT_FONT
-  // we don't have a big font for Cyrillic, Kana
+  // A bigger font is available for edit items. Costs 3120 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_BIG_EDIT_FONT
 
-  // If you have spare 2300Byte of progmem and want to use a
-  // smaller font on the Info-screen uncomment the next line.
+  // A smaller font may be used on the Info Screen. Costs 2300 bytes of PROGMEM.
+  // Western only. Not available for Cyrillic, Kana, Turkish, Greek, or Chinese.
   //#define USE_SMALL_INFOFONT
+
+  // Enable this option and reduce the value to optimize screen updates.
+  // The normal delay is 10µs. Use the lowest value that still gives a reliable display.
+  //#define DOGM_SPI_DELAY_US 5
 #endif // DOGLCD
 
 // @section safety

Marlin/language.h

 
 #include INCLUDE_LANGUAGE
 
-#if DISABLED(SIMULATE_ROMFONT) && DISABLED(DISPLAY_CHARSET_ISO10646_1) && DISABLED(DISPLAY_CHARSET_ISO10646_5) && DISABLED(DISPLAY_CHARSET_ISO10646_KANA) && DISABLED(DISPLAY_CHARSET_ISO10646_GREEK) && DISABLED(DISPLAY_CHARSET_ISO10646_CN) && DISABLED(DISPLAY_CHARSET_ISO10646_TR)
+#if DISABLED(SIMULATE_ROMFONT) \
+ && DISABLED(DISPLAY_CHARSET_ISO10646_1) \
+ && DISABLED(DISPLAY_CHARSET_ISO10646_5) \
+ && DISABLED(DISPLAY_CHARSET_ISO10646_KANA) \
+ && DISABLED(DISPLAY_CHARSET_ISO10646_GREEK) \
+ && DISABLED(DISPLAY_CHARSET_ISO10646_CN) \
+ && DISABLED(DISPLAY_CHARSET_ISO10646_TR)
   #define DISPLAY_CHARSET_ISO10646_1 // use the better font on full graphic displays.
 #endif
 

Marlin/ultralcd.cpp

       END_SCREEN();
     }
 
-    void lcd_filament_change_show_message(FilamentChangeMessage message) {
+    void lcd_filament_change_show_message(const FilamentChangeMessage message) {
       switch (message) {
         case FILAMENT_CHANGE_MESSAGE_INIT:
           defer_return_to_status = true;
 
 bool lcd_hasstatus() { return (lcd_status_message[0] != '\0'); }
 
-void lcd_setstatus(const char* message, bool persist) {
+void lcd_setstatus(const char* const message, bool persist) {
   if (lcd_status_message_level > 0) return;
   strncpy(lcd_status_message, message, 3 * (LCD_WIDTH));
   lcd_finishstatus(persist);
 }
 
-void lcd_setstatuspgm(const char* message, uint8_t level) {
+void lcd_setstatuspgm(const char* const message, uint8_t level) {
   if (level < lcd_status_message_level) return;
   lcd_status_message_level = level;
   strncpy_P(lcd_status_message, message, 3 * (LCD_WIDTH));
   lcd_finishstatus(level > 0);
 }
 
-void lcd_setalertstatuspgm(const char* message) {
+void lcd_setalertstatuspgm(const char* const message) {
   lcd_setstatuspgm(message, 1);
   #if ENABLED(ULTIPANEL)
     lcd_return_to_status();
 void lcd_reset_alert_level() { lcd_status_message_level = 0; }
 
 #if HAS_LCD_CONTRAST
-  void set_lcd_contrast(int value) {
+  void set_lcd_contrast(const int value) {
     lcd_contrast = constrain(value, LCD_CONTRAST_MIN, LCD_CONTRAST_MAX);
     u8g.setContrast(lcd_contrast);
   }

Marlin/ultralcd.h

     void lcd_quick_feedback(); // Audible feedback for a button click - could also be visual
 
     #if ENABLED(FILAMENT_CHANGE_FEATURE)
-      void lcd_filament_change_show_message(FilamentChangeMessage message);
+      void lcd_filament_change_show_message(const FilamentChangeMessage message);
     #endif // FILAMENT_CHANGE_FEATURE
 
   #else
   inline void lcd_update() {}
   inline void lcd_init() {}
   inline bool lcd_hasstatus() { return false; }
-  inline void lcd_setstatus(const char* message, const bool persist=false) { UNUSED(message); UNUSED(persist); }
-  inline void lcd_setstatuspgm(const char* message, const uint8_t level=0) { UNUSED(message); UNUSED(level); }
+  inline void lcd_setstatus(const char* const message, const bool persist=false) { UNUSED(message); UNUSED(persist); }
+  inline void lcd_setstatuspgm(const char* const message, const uint8_t level=0) { UNUSED(message); UNUSED(level); }
   inline void lcd_buttons_update() {}
   inline void lcd_reset_alert_level() {}
   inline bool lcd_detected() { return true; }

Marlin/ultralcd_impl_DOGM.h

   #include "_Bootscreen.h"
 #endif
 
+// Only Western languages support big / small fonts
 #if DISABLED(DISPLAY_CHARSET_ISO10646_1)
   #undef USE_BIG_EDIT_FONT
   #undef USE_SMALL_INFOFONT
 #if ENABLED(USE_BIG_EDIT_FONT)
   #define FONT_MENU_EDIT_NAME u8g_font_9x18
   #define DOG_CHAR_WIDTH_EDIT  9
-  #define DOG_CHAR_HEIGHT_EDIT 18
+  #define DOG_CHAR_HEIGHT_EDIT 13
   #define LCD_WIDTH_EDIT       14
 #else
   #define FONT_MENU_EDIT_NAME FONT_MENU_NAME
 int lcd_contrast;
 static char currentfont = 0;
 
-static void lcd_setFont(char font_nr) {
-  switch(font_nr) {
+// The current graphical page being rendered
+u8g_page_t &page = ((u8g_pb_t *)((u8g.getU8g())->dev->dev_mem))->p;
+
+// For selective rendering within a Y range
+#define PAGE_UNDER(yb) (u8g.getU8g()->current_page.y0 <= (yb))
+#define PAGE_CONTAINS(ya, yb) (PAGE_UNDER(yb) && u8g.getU8g()->current_page.y1 >= (ya))
+
+static void lcd_setFont(const char font_nr) {
+  switch (font_nr) {
     case FONT_STATUSMENU : {u8g.setFont(FONT_STATUSMENU_NAME); currentfont = FONT_STATUSMENU;}; break;
     case FONT_MENU       : {u8g.setFont(FONT_MENU_NAME); currentfont = FONT_MENU;}; break;
     case FONT_SPECIAL    : {u8g.setFont(FONT_SPECIAL_NAME); currentfont = FONT_SPECIAL;}; break;
   }
 }
 
-void lcd_print(char c) {
+void lcd_print(const char c) {
   if ((c > 0) && (c <= LCD_STR_SPECIAL_MAX)) {
     u8g.setFont(FONT_SPECIAL_NAME);
     u8g.print(c);
   else charset_mapper(c);
 }
 
-char lcd_print_and_count(char c) {
+char lcd_print_and_count(const char c) {
   if ((c > 0) && (c <= LCD_STR_SPECIAL_MAX)) {
     u8g.setFont(FONT_SPECIAL_NAME);
     u8g.print(c);
   else return charset_mapper(c);
 }
 
-void lcd_print(const char* str) {
+void lcd_print(const char* const str) {
   for (uint8_t i = 0; char c = str[i]; ++i) lcd_print(c);
 }
 
       }
     #endif // SHOW_CUSTOM_BOOTSCREEN
 
-    int offx = (u8g.getWidth() - (START_BMPWIDTH)) / 2;
+    const uint8_t offx = (u8g.getWidth() - (START_BMPWIDTH)) / 2;
 
     #if ENABLED(START_BMPHIGH)
-      int offy = 0;
+      constexpr uint8_t offy = 0;
     #else
-      int offy = DOG_CHAR_HEIGHT;
+      constexpr uint8_t offy = DOG_CHAR_HEIGHT;
     #endif
 
-    int txt1X = (u8g.getWidth() - (sizeof(STRING_SPLASH_LINE1) - 1) * (DOG_CHAR_WIDTH)) / 2;
+    const uint8_t txt1X = (u8g.getWidth() - (sizeof(STRING_SPLASH_LINE1) - 1) * (DOG_CHAR_WIDTH)) / 2;
 
     if (show_bootscreen) {
       u8g.firstPage();
         #ifndef STRING_SPLASH_LINE2
           u8g.drawStr(txt1X, u8g.getHeight() - (DOG_CHAR_HEIGHT), STRING_SPLASH_LINE1);
         #else
-          int txt2X = (u8g.getWidth() - (sizeof(STRING_SPLASH_LINE2) - 1) * (DOG_CHAR_WIDTH)) / 2;
+          const uint8_t txt2X = (u8g.getWidth() - (sizeof(STRING_SPLASH_LINE2) - 1) * (DOG_CHAR_WIDTH)) / 2;
           u8g.drawStr(txt1X, u8g.getHeight() - (DOG_CHAR_HEIGHT) * 3 / 2, STRING_SPLASH_LINE1);
           u8g.drawStr(txt2X, u8g.getHeight() - (DOG_CHAR_HEIGHT) * 1 / 2, STRING_SPLASH_LINE2);
         #endif
 // Status Screen
 //
 
-FORCE_INLINE void _draw_centered_temp(int temp, int x, int y) {
-  int degsize = 6 * (temp >= 100 ? 3 : temp >= 10 ? 2 : 1); // number's pixel width
+FORCE_INLINE void _draw_centered_temp(const int temp, const uint8_t x, const uint8_t y) {
+  const uint8_t degsize = 6 * (temp >= 100 ? 3 : temp >= 10 ? 2 : 1); // number's pixel width
   u8g.setPrintPos(x - (18 - degsize) / 2, y); // move left if shorter
   lcd_print(itostr3(temp));
   lcd_printPGM(PSTR(LCD_STR_DEGREE " "));
 }
 
-FORCE_INLINE void _draw_heater_status(int x, int heater) {
+FORCE_INLINE void _draw_heater_status(const uint8_t x, const int8_t heater) {
   #if HAS_TEMP_BED
     bool isBed = heater < 0;
   #else
     const bool isBed = false;
   #endif
 
-  _draw_centered_temp((isBed ? thermalManager.degTargetBed() : thermalManager.degTargetHotend(heater)) + 0.5, x, 7);
+  if (PAGE_UNDER(7))
+    _draw_centered_temp((isBed ? thermalManager.degTargetBed() : thermalManager.degTargetHotend(heater)) + 0.5, x, 7);
 
-  _draw_centered_temp((isBed ? thermalManager.degBed() : thermalManager.degHotend(heater)) + 0.5, x, 28);
+  if (PAGE_CONTAINS(21, 28))
+    _draw_centered_temp((isBed ? thermalManager.degBed() : thermalManager.degHotend(heater)) + 0.5, x, 28);
 
-  int h = isBed ? 7 : 8,
-      y = isBed ? 18 : 17;
-  if (isBed ? thermalManager.isHeatingBed() : thermalManager.isHeatingHotend(heater)) {
-    u8g.setColorIndex(0); // white on black
-    u8g.drawBox(x + h, y, 2, 2);
-    u8g.setColorIndex(1); // black on white
-  }
-  else {
-    u8g.drawBox(x + h, y, 2, 2);
+  if (PAGE_CONTAINS(17, 20)) {
+    const uint8_t h = isBed ? 7 : 8,
+                  y = isBed ? 18 : 17;
+    if (isBed ? thermalManager.isHeatingBed() : thermalManager.isHeatingHotend(heater)) {
+      u8g.setColorIndex(0); // white on black
+      u8g.drawBox(x + h, y, 2, 2);
+      u8g.setColorIndex(1); // black on white
+    }
+    else {
+      u8g.drawBox(x + h, y, 2, 2);
+    }
   }
 }
 
-FORCE_INLINE void _draw_axis_label(AxisEnum axis, const char *pstr, bool blink) {
+FORCE_INLINE void _draw_axis_label(const AxisEnum axis, const char* const pstr, const bool blink) {
   if (blink)
     lcd_printPGM(pstr);
   else {
 //#define DOGM_SD_PERCENT
 
 static void lcd_implementation_status_screen() {
-  u8g.setColorIndex(1); // black on white
 
   bool blink = lcd_blink();
 
-  // Symbols menu graphics, animated fan
-  u8g.drawBitmapP(9, 1, STATUS_SCREENBYTEWIDTH, STATUS_SCREENHEIGHT,
-    #if HAS_FAN0
-      blink && fanSpeeds[0] ? status_screen0_bmp : status_screen1_bmp
-    #else
-      status_screen0_bmp
-    #endif
-  );
+  // Black color, white background
+  u8g.setColorIndex(1);
 
-  // Status Menu Font for SD info, Heater status, Fan, XYZ
+  // Status Menu Font
   lcd_setFont(FONT_STATUSMENU);
 
+  //
+  // Fan Animation
+  //
+
+  if (PAGE_UNDER(STATUS_SCREENHEIGHT + 1)) {
+
+    u8g.drawBitmapP(9, 1, STATUS_SCREENBYTEWIDTH, STATUS_SCREENHEIGHT,
+      #if HAS_FAN0
+        blink && fanSpeeds[0] ? status_screen0_bmp : status_screen1_bmp
+      #else
+        status_screen0_bmp
+      #endif
+    );
+
+  }
+
+  //
+  // Temperature Graphics and Info
+  //
+
+  if (PAGE_UNDER(28)) {
+    // Extruders
+    HOTEND_LOOP() _draw_heater_status(5 + e * 25, e);
+
+    // Heated bed
+    #if HOTENDS < 4 && HAS_TEMP_BED
+      _draw_heater_status(81, -1);
+    #endif
+
+    if (PAGE_CONTAINS(20, 27)) {
+      // Fan
+      u8g.setPrintPos(104, 27);
+      #if HAS_FAN0
+        int per = ((fanSpeeds[0] + 1) * 100) / 256;
+        if (per) {
+          lcd_print(itostr3(per));
+          u8g.print('%');
+        }
+      #endif
+    }
+  }
+
   #if ENABLED(SDSUPPORT)
+
+    //
     // SD Card Symbol
-    u8g.drawBox(42, 42 - (TALL_FONT_CORRECTION), 8, 7);
-    u8g.drawBox(50, 44 - (TALL_FONT_CORRECTION), 2, 5);
-    u8g.drawFrame(42, 49 - (TALL_FONT_CORRECTION), 10, 4);
-    u8g.drawPixel(50, 43 - (TALL_FONT_CORRECTION));
+    //
+
+    if (PAGE_CONTAINS(42 - (TALL_FONT_CORRECTION), 51 - (TALL_FONT_CORRECTION))) {
+      // Upper box
+      u8g.drawBox(42, 42 - (TALL_FONT_CORRECTION), 8, 7);     // 42-48 (or 41-47)
+      // Right edge
+      u8g.drawBox(50, 44 - (TALL_FONT_CORRECTION), 2, 5);     // 44-48 (or 43-47)
+      // Bottom hollow box
+      u8g.drawFrame(42, 49 - (TALL_FONT_CORRECTION), 10, 4);  // 49-52 (or 48-51)
+      // Corner pixel
+      u8g.drawPixel(50, 43 - (TALL_FONT_CORRECTION));         // 43 (or 42)
+    }
 
+    //
     // Progress bar frame
-    u8g.drawFrame(54, 49, 73, 4 - (TALL_FONT_CORRECTION));
+    //
+
+    if (PAGE_CONTAINS(49, 52 - (TALL_FONT_CORRECTION)))
+      u8g.drawFrame(54, 49, 73, 4 - (TALL_FONT_CORRECTION));  // 49-52 (or 49-51)
 
-    // SD Card Progress bar and clock
     if (IS_SD_PRINTING) {
+
+      //
       // Progress bar solid part
-      u8g.drawBox(55, 50, (unsigned int)(71 * card.percentDone() * 0.01), 2 - (TALL_FONT_CORRECTION));
-    
+      //
+
+      if (PAGE_CONTAINS(50, 51 - (TALL_FONT_CORRECTION)))
+        u8g.drawBox(55, 50, (unsigned int)(71 * card.percentDone() * 0.01), 2 - (TALL_FONT_CORRECTION));
+
+      //
+      // SD Percent Complete
+      //
+
       #if ENABLED(DOGM_SD_PERCENT)
-        // Percent complete
-        u8g.setPrintPos(55, 48);
-        u8g.print(itostr3(card.percentDone()));
-        u8g.print('%');
+        if (PAGE_CONTAINS(41, 48)) {
+          // Percent complete
+          u8g.setPrintPos(55, 48);
+          u8g.print(itostr3(card.percentDone()));
+          u8g.print('%');
+        }
       #endif
     }
 
-    char buffer[10];
-    duration_t elapsed = print_job_timer.duration();
-    bool has_days = (elapsed.value > 60*60*24L);
-    elapsed.toDigital(buffer, has_days);
+    //
+    // Elapsed Time
+    //
 
     #if DISABLED(DOGM_SD_PERCENT)
       #define SD_DURATION_X 71
       #define SD_DURATION_X 89
     #endif
 
-    u8g.setPrintPos(SD_DURATION_X + (has_days ? 0 : 9), 48);
-    lcd_print(buffer);
+    if (PAGE_CONTAINS(41, 48)) {
+
+      char buffer[10];
+      duration_t elapsed = print_job_timer.duration();
+      bool has_days = (elapsed.value > 60*60*24L);
+      elapsed.toDigital(buffer, has_days);
+
+      u8g.setPrintPos(SD_DURATION_X + (has_days ? 0 : 9), 48);
+      lcd_print(buffer);
+    }
 
   #endif
 
-  // Extruders
-  HOTEND_LOOP() _draw_heater_status(5 + e * 25, e);
+  //
+  // XYZ Coordinates
+  //
 
-  // Heated bed
-  #if HOTENDS < 4 && HAS_TEMP_BED
-    _draw_heater_status(81, -1);
+  #if ENABLED(USE_SMALL_INFOFONT)
+    #define INFO_FONT_HEIGHT 7
+  #else
+    #define INFO_FONT_HEIGHT 8
   #endif
 
-  // Fan
-  u8g.setPrintPos(104, 27);
-  #if HAS_FAN0
-    int per = ((fanSpeeds[0] + 1) * 100) / 256;
-    if (per) {
-      lcd_print(itostr3(per));
-      u8g.print('%');
-    }
+  #define XYZ_BASELINE (30 + INFO_FONT_HEIGHT)
+
+  #define X_LABEL_POS  3
+  #define X_VALUE_POS 11
+  #define XYZ_SPACING 40
+
+  // Enable to save many cycles by drawing a hollow frame
+  #define XYZ_HOLLOW_FRAME
+
+  #if ENABLED(XYZ_HOLLOW_FRAME)
+    #define XYZ_FRAME_TOP 29
+    #define XYZ_FRAME_HEIGHT INFO_FONT_HEIGHT + 3
+  #else
+    #define XYZ_FRAME_TOP 30
+    #define XYZ_FRAME_HEIGHT INFO_FONT_HEIGHT + 2
   #endif
 
-  // X, Y, Z-Coordinates
   // Before homing the axis letters are blinking 'X' <-> '?'.
   // When axis is homed but axis_known_position is false the axis letters are blinking 'X' <-> ' '.
   // When everything is ok you see a constant 'X'.
-  #define XYZ_BASELINE 38
 
-  #if ENABLED(USE_SMALL_INFOFONT)
-    u8g.drawBox(0, 30, LCD_PIXEL_WIDTH, 10);
-  #else
-    u8g.drawBox(0, 30, LCD_PIXEL_WIDTH, 9);
-  #endif
-  u8g.setColorIndex(0); // white on black
+  static char xstring[5], ystring[5], zstring[7];
 
-  u8g.setPrintPos(2, XYZ_BASELINE);
-  _draw_axis_label(X_AXIS, PSTR(MSG_X), blink);
-  u8g.setPrintPos(10, XYZ_BASELINE);
-  lcd_print(ftostr4sign(current_position[X_AXIS]));
+  // At the first page, regenerate the XYZ strings
+  if (page.page == 0) {
+    strcpy(xstring, ftostr4sign(current_position[X_AXIS]));
+    strcpy(ystring, ftostr4sign(current_position[Y_AXIS]));
+    strcpy(zstring, ftostr52sp(current_position[Z_AXIS] + 0.00001));
+  }
 
-  u8g.setPrintPos(43, XYZ_BASELINE);
-  _draw_axis_label(Y_AXIS, PSTR(MSG_Y), blink);
-  u8g.setPrintPos(51, XYZ_BASELINE);
-  lcd_print(ftostr4sign(current_position[Y_AXIS]));
+  if (PAGE_CONTAINS(XYZ_FRAME_TOP, XYZ_FRAME_TOP + XYZ_FRAME_HEIGHT - 1)) {
 
-  u8g.setPrintPos(83, XYZ_BASELINE);
-  _draw_axis_label(Z_AXIS, PSTR(MSG_Z), blink);
-  u8g.setPrintPos(91, XYZ_BASELINE);
-  lcd_print(ftostr52sp(current_position[Z_AXIS] + 0.00001));
+    #if ENABLED(XYZ_HOLLOW_FRAME)
+      u8g.drawFrame(0, XYZ_FRAME_TOP, LCD_PIXEL_WIDTH, XYZ_FRAME_HEIGHT); // 8: 29-40  7: 29-39
+    #else
+      u8g.drawBox(0, XYZ_FRAME_TOP, LCD_PIXEL_WIDTH, XYZ_FRAME_HEIGHT);   // 8: 30-39  7: 30-37
+    #endif
 
-  u8g.setColorIndex(1); // black on white
+    if (PAGE_CONTAINS(XYZ_BASELINE - (INFO_FONT_HEIGHT - 1), XYZ_BASELINE)) {
 
+      #if DISABLED(XYZ_HOLLOW_FRAME)
+        u8g.setColorIndex(0); // white on black
+      #endif
+
+      u8g.setPrintPos(0 * XYZ_SPACING + X_LABEL_POS, XYZ_BASELINE);
+      _draw_axis_label(X_AXIS, PSTR(MSG_X), blink);
+      u8g.setPrintPos(0 * XYZ_SPACING + X_VALUE_POS, XYZ_BASELINE);
+      lcd_print(xstring);
+
+      u8g.setPrintPos(1 * XYZ_SPACING + X_LABEL_POS, XYZ_BASELINE);
+      _draw_axis_label(Y_AXIS, PSTR(MSG_Y), blink);
+      u8g.setPrintPos(1 * XYZ_SPACING + X_VALUE_POS, XYZ_BASELINE);
+      lcd_print(ystring);
+
+      u8g.setPrintPos(2 * XYZ_SPACING + X_LABEL_POS, XYZ_BASELINE);
+      _draw_axis_label(Z_AXIS, PSTR(MSG_Z), blink);
+      u8g.setPrintPos(2 * XYZ_SPACING + X_VALUE_POS, XYZ_BASELINE);
+      lcd_print(zstring);
+
+      #if DISABLED(XYZ_HOLLOW_FRAME)
+        u8g.setColorIndex(1); // black on white
+      #endif
+    }
+  }
+
+  //
   // Feedrate
-  lcd_setFont(FONT_MENU);
-  u8g.setPrintPos(3, 49);
-  lcd_print(LCD_STR_FEEDRATE[0]);
+  //
 
-  lcd_setFont(FONT_STATUSMENU);
-  u8g.setPrintPos(12, 49);
-  lcd_print(itostr3(feedrate_percentage));
-  u8g.print('%');
+  if (PAGE_CONTAINS(50 - INFO_FONT_HEIGHT, 49)) {
+    lcd_setFont(FONT_MENU);
+    u8g.setPrintPos(3, 49);
+    lcd_print(LCD_STR_FEEDRATE[0]);
 
+    lcd_setFont(FONT_STATUSMENU);
+    u8g.setPrintPos(12, 49);
+    lcd_print(itostr3(feedrate_percentage));
+    u8g.print('%');
+  }
+
+  //
   // Status line
-  #if ENABLED(USE_SMALL_INFOFONT)
-    u8g.setPrintPos(0, 62);
-  #else
-    u8g.setPrintPos(0, 63);
-  #endif
-  #if DISABLED(FILAMENT_LCD_DISPLAY)
-    lcd_print(lcd_status_message);
-  #else
-    if (PENDING(millis(), previous_lcd_status_ms + 5000UL)) {  //Display both Status message line and Filament display on the last line
+  //
+
+  #define STATUS_BASELINE (54 + INFO_FONT_HEIGHT)
+
+  if (PAGE_CONTAINS(STATUS_BASELINE + 1 - INFO_FONT_HEIGHT, STATUS_BASELINE)) {
+    u8g.setPrintPos(0, STATUS_BASELINE);
+
+    #if DISABLED(FILAMENT_LCD_DISPLAY)
       lcd_print(lcd_status_message);
-    }
-    else {
-      lcd_printPGM(PSTR("dia:"));
-      lcd_print(ftostr12ns(filament_width_meas));
-      lcd_printPGM(PSTR(" factor:"));
-      lcd_print(itostr3(100.0 * volumetric_multiplier[FILAMENT_SENSOR_EXTRUDER_NUM]));
-      u8g.print('%');
-    }
-  #endif
+    #else
+      if (PENDING(millis(), previous_lcd_status_ms + 5000UL)) {  //Display both Status message line and Filament display on the last line
+        lcd_print(lcd_status_message);
+      }
+      else {
+        lcd_printPGM(PSTR("dia:"));
+        lcd_print(ftostr12ns(filament_width_meas));
+        lcd_printPGM(PSTR(" factor:"));
+        lcd_print(itostr3(100.0 * volumetric_multiplier[FILAMENT_SENSOR_EXTRUDER_NUM]));
+        u8g.print('%');
+      }
+    #endif
+  }
 }
 
 #if ENABLED(ULTIPANEL)
 
+  uint8_t row_y1, row_y2;
+
   // Set the colors for a menu item based on whether it is selected
-  static void lcd_implementation_mark_as_selected(uint8_t row, bool isSelected) {
+  static void lcd_implementation_mark_as_selected(const uint8_t row, const bool isSelected) {
+
+    row_y1 = row * (DOG_CHAR_HEIGHT) + 1;
+    row_y2 = row_y1 + (DOG_CHAR_HEIGHT) - 1;
+
+    if (!PAGE_CONTAINS(row_y1 + 2 - (TALL_FONT_CORRECTION), row_y2 + 2 - (TALL_FONT_CORRECTION))) return;
+
     if (isSelected) {
       u8g.setColorIndex(1);  // black on white
-      u8g.drawBox(0, row * (DOG_CHAR_HEIGHT) + 3 - (TALL_FONT_CORRECTION), LCD_PIXEL_WIDTH, DOG_CHAR_HEIGHT);
+      u8g.drawBox(0, row_y1 + 2 - (TALL_FONT_CORRECTION), LCD_PIXEL_WIDTH, DOG_CHAR_HEIGHT);
       u8g.setColorIndex(0);  // following text must be white on black
     }
     else {
       u8g.setColorIndex(1); // unmarked text is black on white
     }
-    u8g.setPrintPos((START_COL) * (DOG_CHAR_WIDTH), (row + 1) * (DOG_CHAR_HEIGHT));
+    u8g.setPrintPos((START_COL) * (DOG_CHAR_WIDTH), row_y2);
   }
 
   #if ENABLED(LCD_INFO_MENU) || ENABLED(FILAMENT_CHANGE_FEATURE)
 
     // Draw a static line of text in the same idiom as a menu item
-    static void lcd_implementation_drawmenu_static(uint8_t row, const char* pstr, bool center=true, bool invert=false, const char* valstr=NULL) {
+    static void lcd_implementation_drawmenu_static(const uint8_t row, const char* pstr, const bool center=true, const bool invert=false, const char* valstr=NULL) {
 
       lcd_implementation_mark_as_selected(row, invert);
 
+      if (!PAGE_CONTAINS(row_y1, row_y2)) return;
+
       char c;
       int8_t n = LCD_WIDTH - (START_COL);
 
   #endif // LCD_INFO_MENU || FILAMENT_CHANGE_FEATURE
 
   // Draw a generic menu item
-  static void lcd_implementation_drawmenu_generic(bool isSelected, uint8_t row, const char* pstr, char pre_char, char post_char) {
+  static void lcd_implementation_drawmenu_generic(const bool isSelected, const uint8_t row, const char* pstr, const char pre_char, const char post_char) {
     UNUSED(pre_char);
 
-    char c;
-    uint8_t n = LCD_WIDTH - (START_COL) - 2;
-
     lcd_implementation_mark_as_selected(row, isSelected);
 
-    while (c = pgm_read_byte(pstr)) {
+    if (!PAGE_CONTAINS(row_y1, row_y2)) return;
+
+    uint8_t n = LCD_WIDTH - (START_COL) - 2;
+    while (char c = pgm_read_byte(pstr)) {
       n -= lcd_print_and_count(c);
       pstr++;
     }
     while (n--) u8g.print(' ');
-    u8g.setPrintPos(LCD_PIXEL_WIDTH - (DOG_CHAR_WIDTH), (row + 1) * (DOG_CHAR_HEIGHT));
+    u8g.setPrintPos(LCD_PIXEL_WIDTH - (DOG_CHAR_WIDTH), row_y2);
     lcd_print(post_char);
     u8g.print(' ');
   }
   #define lcd_implementation_drawmenu_function(sel, row, pstr, data) lcd_implementation_drawmenu_generic(sel, row, pstr, '>', ' ')
 
   // Draw a menu item with an editable value
-  static void _drawmenu_setting_edit_generic(bool isSelected, uint8_t row, const char* pstr, const char* data, bool pgm) {
-    char c;
-    uint8_t vallen = (pgm ? lcd_strlen_P(data) : (lcd_strlen((char*)data)));
-    uint8_t n = LCD_WIDTH - (START_COL) - 2 - vallen;
+  static void _drawmenu_setting_edit_generic(const bool isSelected, const uint8_t row, const char* pstr, const char* const data, const bool pgm) {
 
     lcd_implementation_mark_as_selected(row, isSelected);
 
-    while (c = pgm_read_byte(pstr)) {
+    if (!PAGE_CONTAINS(row_y1, row_y2)) return;
+
+    const uint8_t vallen = (pgm ? lcd_strlen_P(data) : (lcd_strlen((char*)data)));
+    uint8_t n = LCD_WIDTH - (START_COL) - 2 - vallen;
+
+    while (char c = pgm_read_byte(pstr)) {
       n -= lcd_print_and_count(c);
       pstr++;
     }
     u8g.print(':');
     while (n--) u8g.print(' ');
-    u8g.setPrintPos(LCD_PIXEL_WIDTH - (DOG_CHAR_WIDTH) * vallen, (row + 1) * (DOG_CHAR_HEIGHT));
+    u8g.setPrintPos(LCD_PIXEL_WIDTH - (DOG_CHAR_WIDTH) * vallen, row_y2);
     if (pgm)  lcd_printPGM(data);  else  lcd_print((char*)data);
   }
 
   #define lcd_implementation_drawmenu_setting_edit_callback_long5(sel, row, pstr, pstr2, data, minValue, maxValue, callback) lcd_implementation_drawmenu_setting_edit_generic(sel, row, pstr, ftostr5rj(*(data)))
   #define lcd_implementation_drawmenu_setting_edit_callback_bool(sel, row, pstr, pstr2, data, callback) lcd_implementation_drawmenu_setting_edit_generic_P(sel, row, pstr, (*(data))?PSTR(MSG_ON):PSTR(MSG_OFF))
 
-  void lcd_implementation_drawedit(const char* pstr, const char* value=NULL) {
-    uint8_t rows = 1;
-    uint8_t lcd_width = LCD_WIDTH - (START_COL), char_width = DOG_CHAR_WIDTH;
-    uint8_t vallen = lcd_strlen(value);
+  void lcd_implementation_drawedit(const char* const pstr, const char* const value=NULL) {
+    const uint8_t labellen = lcd_strlen_P(pstr), vallen = lcd_strlen(value);
+    uint8_t lcd_width, char_width,
+            rows = (labellen > LCD_WIDTH - 2 - vallen) ? 2 : 1;
 
     #if ENABLED(USE_BIG_EDIT_FONT)
-      if (lcd_strlen_P(pstr) <= LCD_WIDTH_EDIT - 1) {
-        lcd_setFont(FONT_MENU_EDIT);
+      if (labellen <= LCD_WIDTH_EDIT - 1) {
+        if (labellen >= LCD_WIDTH_EDIT - vallen) rows = 2;
         lcd_width = LCD_WIDTH_EDIT + 1;
         char_width = DOG_CHAR_WIDTH_EDIT;
-        if (lcd_strlen_P(pstr) >= LCD_WIDTH_EDIT - vallen) rows = 2;
+        lcd_setFont(FONT_MENU_EDIT);
       }
       else {
+        lcd_width = LCD_WIDTH - (START_COL);
+        char_width = DOG_CHAR_WIDTH;
         lcd_setFont(FONT_MENU);
       }
+    #else
+      lcd_width = LCD_WIDTH - (START_COL);
+      char_width = DOG_CHAR_WIDTH;
     #endif
 
-    if (lcd_strlen_P(pstr) > LCD_WIDTH - 2 - vallen) rows = 2;
+    // Center either one or two rows
+    const uint8_t segmentHeight = u8g.getHeight() / (rows + 1); // 1 / (rows+1) = 1/2 or 1/3
+    uint8_t baseline = segmentHeight + (DOG_CHAR_HEIGHT_EDIT + 1) / 2;
 
-    const float kHalfChar = (DOG_CHAR_HEIGHT_EDIT) / 2;
-    float rowHeight = u8g.getHeight() / (rows + 1); // 1/(rows+1) = 1/2 or 1/3
+    if (PAGE_CONTAINS(baseline + 1 - (DOG_CHAR_HEIGHT_EDIT), baseline)) {
+      u8g.setPrintPos(0, baseline);
+      lcd_printPGM(pstr);
+    }
 
-    u8g.setPrintPos(0, rowHeight + kHalfChar);
-    lcd_printPGM(pstr);
     if (value != NULL) {
-      u8g.print(':');
-      u8g.setPrintPos((lcd_width - 1 - vallen) * char_width, rows * rowHeight + kHalfChar);
-      lcd_print(value);
+      baseline += (rows - 1) * segmentHeight;
+      if (PAGE_CONTAINS(baseline + 1 - (DOG_CHAR_HEIGHT_EDIT), baseline)) {
+        u8g.print(':');
+        u8g.setPrintPos((lcd_width - 1 - vallen) * char_width, baseline);
+        lcd_print(value);
+      }
     }
   }
 
   #if ENABLED(SDSUPPORT)
 
-    static void _drawmenu_sd(bool isSelected, uint8_t row, const char* pstr, const char* filename, char* const longFilename, bool isDir) {
+    static void _drawmenu_sd(const bool isSelected, const uint8_t row, const char* const pstr, const char* filename, char* const longFilename, const bool isDir) {
       UNUSED(pstr);
-      char c;
-      uint8_t n = LCD_WIDTH - (START_COL) - 1;
 
+      lcd_implementation_mark_as_selected(row, isSelected);
+
+      if (!PAGE_CONTAINS(row_y1, row_y2)) return;
+
+      uint8_t n = LCD_WIDTH - (START_COL) - 1;
       if (longFilename[0]) {
         filename = longFilename;
         longFilename[n] = '\0';
       }
 
-      lcd_implementation_mark_as_selected(row, isSelected);
-
       if (isDir) lcd_print(LCD_STR_FOLDER[0]);
-      while ((c = *filename)) {
+
+      while (char c = *filename) {
         n -= lcd_print_and_count(c);
         filename++;
       }

Marlin/ultralcd_impl_HD44780.h

 
 static void lcd_set_custom_characters(
   #if ENABLED(LCD_PROGRESS_BAR)
-    bool info_screen_charset = true
+    const bool info_screen_charset = true
   #endif
 ) {
   static byte bedTemp[8] = {
 
 static void lcd_implementation_init(
   #if ENABLED(LCD_PROGRESS_BAR)
-    bool info_screen_charset = true
+    const bool info_screen_charset = true
   #endif
 ) {
 
   for (; char c = pgm_read_byte(str); ++str) charset_mapper(c);
 }
 
-void lcd_print(const char* str) {
+void lcd_print(const char* const str) {
   for (uint8_t i = 0; char c = str[i]; ++i) charset_mapper(c);
 }
 
 
 #if ENABLED(SHOW_BOOTSCREEN)
 
-  void lcd_erase_line(int line) {
+  void lcd_erase_line(const int line) {
     lcd.setCursor(0, line);
-    for (int i = 0; i < LCD_WIDTH; i++)
+    for (uint8_t i = LCD_WIDTH + 1; --i;)
       lcd_print(' ');
   }
 
   // Scroll the PSTR 'text' in a 'len' wide field for 'time' milliseconds at position col,line
-  void lcd_scroll(int col, int line, const char* text, int len, int time) {
+  void lcd_scroll(const int col, const int line, const char* const text, const int len, const int time) {
     char tmp[LCD_WIDTH + 1] = {0};
     int n = max(lcd_strlen_P(text) - len, 0);
     for (int i = 0; i <= n; i++) {
     }
   }
 
-  static void logo_lines(const char *extra) {
+  static void logo_lines(const char* const extra) {
     int indent = (LCD_WIDTH - 8 - lcd_strlen_P(extra)) / 2;
     lcd.setCursor(indent, 0); lcd.print('\x00'); lcd_printPGM(PSTR( "------" ));  lcd.print('\x01');
     lcd.setCursor(indent, 1);                    lcd_printPGM(PSTR("|Marlin|"));  lcd_printPGM(extra);
   lcd_printPGM(PSTR(MSG_PLEASE_RESET));
 }
 
-FORCE_INLINE void _draw_axis_label(AxisEnum axis, const char *pstr, bool blink) {
+FORCE_INLINE void _draw_axis_label(const AxisEnum axis, const char* const pstr, const bool blink) {
   if (blink)
     lcd_printPGM(pstr);
   else {
 
   #if ENABLED(LCD_INFO_MENU) || ENABLED(FILAMENT_CHANGE_FEATURE)
 
-    static void lcd_implementation_drawmenu_static(uint8_t row, const char* pstr, bool center=true, bool invert=false, const char *valstr=NULL) {
+    static void lcd_implementation_drawmenu_static(const uint8_t row, const char* pstr, const bool center=true, const bool invert=false, const char *valstr=NULL) {
       UNUSED(invert);
       char c;
       int8_t n = LCD_WIDTH;
 
   #endif // LCD_INFO_MENU || FILAMENT_CHANGE_FEATURE
 
-  static void lcd_implementation_drawmenu_generic(bool sel, uint8_t row, const char* pstr, char pre_char, char post_char) {
+  static void lcd_implementation_drawmenu_generic(const bool sel, const uint8_t row, const char* pstr, const char pre_char, const char post_char) {
     char c;
     uint8_t n = LCD_WIDTH - 2;
     lcd.setCursor(0, row);
     lcd.print(post_char);
   }
 
-  static void lcd_implementation_drawmenu_setting_edit_generic(bool sel, uint8_t row, const char* pstr, char pre_char, char* data) {
+  static void lcd_implementation_drawmenu_setting_edit_generic(const bool sel, const uint8_t row, const char* pstr, const char pre_char, const char* const data) {
     char c;
     uint8_t n = LCD_WIDTH - 2 - lcd_strlen(data);
     lcd.setCursor(0, row);
     while (n--) lcd.print(' ');
     lcd_print(data);
   }
-  static void lcd_implementation_drawmenu_setting_edit_generic_P(bool sel, uint8_t row, const char* pstr, char pre_char, const char* data) {
+  static void lcd_implementation_drawmenu_setting_edit_generic_P(const bool sel, const uint8_t row, const char* pstr, const char pre_char, const char* const data) {
     char c;
     uint8_t n = LCD_WIDTH - 2 - lcd_strlen_P(data);
     lcd.setCursor(0, row);
   #define lcd_implementation_drawmenu_setting_edit_callback_long5(sel, row, pstr, pstr2, data, minValue, maxValue, callback) lcd_implementation_drawmenu_setting_edit_generic(sel, row, pstr, '>', ftostr5rj(*(data)))
   #define lcd_implementation_drawmenu_setting_edit_callback_bool(sel, row, pstr, pstr2, data, callback) lcd_implementation_drawmenu_setting_edit_generic_P(sel, row, pstr, '>', (*(data))?PSTR(MSG_ON):PSTR(MSG_OFF))
 
-  void lcd_implementation_drawedit(const char* pstr, const char* value=NULL) {
+  void lcd_implementation_drawedit(const char* pstr, const char* const value=NULL) {
     lcd.setCursor(1, 1);
     lcd_printPGM(pstr);
     if (value != NULL) {
 
   #if ENABLED(SDSUPPORT)
 
-    static void lcd_implementation_drawmenu_sd(bool sel, uint8_t row, const char* pstr, const char* filename, char* longFilename, uint8_t concat, char post_char) {
+    static void lcd_implementation_drawmenu_sd(const bool sel, const uint8_t row, const char* const pstr, const char* filename, char* const longFilename, const uint8_t concat, const char post_char) {
       UNUSED(pstr);
       char c;
       uint8_t n = LCD_WIDTH - concat;
       lcd.print(post_char);
     }
 
-    static void lcd_implementation_drawmenu_sdfile(bool sel, uint8_t row, const char* pstr, const char* filename, char* longFilename) {
+    static void lcd_implementation_drawmenu_sdfile(const bool sel, const uint8_t row, const char* pstr, const char* filename, char* const longFilename) {
       lcd_implementation_drawmenu_sd(sel, row, pstr, filename, longFilename, 2, ' ');
     }
 
-    static void lcd_implementation_drawmenu_sddirectory(bool sel, uint8_t row, const char* pstr, const char* filename, char* longFilename) {
+    static void lcd_implementation_drawmenu_sddirectory(const bool sel, const uint8_t row, const char* pstr, const char* filename, char* const longFilename) {
       lcd_implementation_drawmenu_sd(sel, row, pstr, filename, longFilename, 2, LCD_STR_FOLDER[0]);
     }
 

Marlin/ultralcd_st7920_u8glib_rrd.h

   ST7920_SND_BIT; // 8
 }
 
-#define ST7920_CS()              {WRITE(ST7920_CS_PIN,1);u8g_10MicroDelay();}
-#define ST7920_NCS()             {WRITE(ST7920_CS_PIN,0);}
-#define ST7920_SET_CMD()         {ST7920_SWSPI_SND_8BIT(0xf8);u8g_10MicroDelay();}
-#define ST7920_SET_DAT()         {ST7920_SWSPI_SND_8BIT(0xfa);u8g_10MicroDelay();}
-#define ST7920_WRITE_BYTE(a)     {ST7920_SWSPI_SND_8BIT((uint8_t)((a)&0xf0u));ST7920_SWSPI_SND_8BIT((uint8_t)((a)<<4u));u8g_10MicroDelay();}
-#define ST7920_WRITE_BYTES(p,l)  {uint8_t i;for(i=0;i<l;i++){ST7920_SWSPI_SND_8BIT(*p&0xf0);ST7920_SWSPI_SND_8BIT(*p<<4);p++;}u8g_10MicroDelay();}
+#if defined(DOGM_SPI_DELAY_US) && DOGM_SPI_DELAY_US > 0
+  #define U8G_DELAY() delayMicroseconds(DOGM_SPI_DELAY_US)
+#else
+  #define U8G_DELAY() u8g_10MicroDelay()
+#endif
+
+#define ST7920_CS()              { WRITE(ST7920_CS_PIN,1); U8G_DELAY(); }
+#define ST7920_NCS()             { WRITE(ST7920_CS_PIN,0); }
+#define ST7920_SET_CMD()         { ST7920_SWSPI_SND_8BIT(0xf8); U8G_DELAY(); }
+#define ST7920_SET_DAT()         { ST7920_SWSPI_SND_8BIT(0xfa); U8G_DELAY(); }
+#define ST7920_WRITE_BYTE(a)     { ST7920_SWSPI_SND_8BIT((uint8_t)((a)&0xf0u)); ST7920_SWSPI_SND_8BIT((uint8_t)((a)<<4u)); U8G_DELAY(); }
+#define ST7920_WRITE_BYTES(p,l)  { for (uint8_t i = l + 1; --i;) { ST7920_SWSPI_SND_8BIT(*p&0xf0); ST7920_SWSPI_SND_8BIT(*p<<4); p++; } U8G_DELAY(); }
 
 uint8_t u8g_dev_rrd_st7920_128x64_fn(u8g_t *u8g, u8g_dev_t *dev, uint8_t msg, void *arg) {
   uint8_t i, y;
     }
     break;
   }
-#if PAGE_HEIGHT == 8
-  return u8g_dev_pb8h1_base_fn(u8g, dev, msg, arg);
-#elif PAGE_HEIGHT == 16
-  return u8g_dev_pb16h1_base_fn(u8g, dev, msg, arg);
-#else
-  return u8g_dev_pb32h1_base_fn(u8g, dev, msg, arg);
-#endif
+  #if PAGE_HEIGHT == 8
+    return u8g_dev_pb8h1_base_fn(u8g, dev, msg, arg);
+  #elif PAGE_HEIGHT == 16
+    return u8g_dev_pb16h1_base_fn(u8g, dev, msg, arg);
+  #else
+    return u8g_dev_pb32h1_base_fn(u8g, dev, msg, arg);
+  #endif
 }
 
 uint8_t   u8g_dev_st7920_128x64_rrd_buf[(LCD_PIXEL_WIDTH) * (PAGE_HEIGHT) / 8] U8G_NOCOMMON;

Marlin/utf_mapper.h

     #if ENABLED(MAPPER_C2C3)
       const PROGMEM uint8_t utf_recode[] =
            { // 0    1    2    3    4    5    6    7    8    9    a    b    c    d    e    f          This is fair for symbols
-             0x20,0x3f,0xec,0xed,0x3f,0x5c,0x7c,0x3f,0x22,0x63,0x61,0x7f,0x3f,0x3f,0x52,0xb0,  // c2a
-  //          ' '       ¢    £         ­    l         "    c    a    «              R
-             0xdf,0x3f,0x32,0x33,0x27,0xe4,0xf1,0xa5,0x2c,0x31,0xdf,0x7e,0x3f,0x3f,0x3f,0x3f,  // c2b but relatively bad for letters.
-  //          °         2    3    `    N    p    .    ,    1    °    »
-             0x3f,0x3f,0x3f,0x3f,0xe1,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,  // c38
-  //                              ä
-             0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0xef,0x78,0x3f,0x3f,0x3f,0x3f,0xf5,0x3f,0x3f,0xe2,  // c39 missing characters display as '?'
-  //                                        ö     x                       ü              ß
-             0x3f,0x3f,0x3f,0x3f,0xe1,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,  // c3a
-  //                              ä
-             0x3f,0xee,0x3f,0x3f,0x3f,0x3f,0xef,0xfd,0x3f,0x3f,0x3f,0x3f,0xf5,0x3f,0x3f,0x3f   // c3b
-  //               n                        ö    ÷                        ü
+               0x20,0x3f,0xec,0xed,0x3f,0x5c,0x7c,0x3f,0x22,0x63,0x61,0x7f,0x3f,0x3f,0x52,0xb0,  // c2a
+             //' '        ¢    £         ­     l         "    c    a    «              R
+               0xdf,0x3f,0x32,0x33,0x27,0xe4,0xf1,0xa5,0x2c,0x31,0xdf,0x7e,0x3f,0x3f,0x3f,0x3f,  // c2b but relatively bad for letters.
+             // °         2    3    `    N    p    .    ,    1    °    »
+               0x3f,0x3f,0x3f,0x3f,0xe1,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,  // c38
+             //                     ä
+               0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0xef,0x78,0x3f,0x3f,0x3f,0x3f,0xf5,0x3f,0x3f,0xe2,  // c39 missing characters display as '?'
+             //                               ö    x                        ü              ß
+               0x3f,0x3f,0x3f,0x3f,0xe1,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,0x3f,  // c3a
+             //                     ä
+               0x3f,0xee,0x3f,0x3f,0x3f,0x3f,0xef,0xfd,0x3f,0x3f,0x3f,0x3f,0xf5,0x3f,0x3f,0x3f   // c3b
+             //      n                        ö    ÷                        ü
            };
     #elif ENABLED(MAPPER_E382E383)
       const PROGMEM uint8_t utf_recode[] =
            { // 0    1    2    3    4    5    6    7    8    9    a    b    c    d    e    f
-             0x3d,0xb1,0xb1,0xa8,0xb2,0xa9,0xb3,0xaa,0xb4,0xab,0xb5,0xb6,0xb6,0xb7,0xb7,0xb8,  // e382a Please test and correct
-  //          =    ア    ア    ィ    イ    ゥ    ウ    ェ    エ    ォ    オ   ガ    ガ    キ   キ    ク
-             0xb8,0xb9,0xb9,0xba,0xba,0xbb,0xbb,0xbc,0xbc,0xbd,0xbd,0xbe,0xbe,0xbf,0xbf,0xc0,  // e382b
-  //          ク    ケ    ケ   コ    コ    サ    サ    シ    シ   ス    ス    セ    セ    ソ   ソ    タ
-             0xc0,0xc1,0xc1,0xc2,0xc2,0xc2,0xc3,0xc3,0xc4,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,  // e3838
-  //          タ    チ    チ    ッ    ッ    ッ    テ   テ    ト    ト    ナ    ニ    ヌ    ネ   ノ    ハ
-             0xca,0xca,0xcb,0xcb,0xcb,0xcc,0xcc,0xcc,0xcd,0xcd,0xcd,0xce,0xce,0xce,0xcf,0xd0,  // e3839
-  //          ハ    ハ    ヒ   ヒ    ヒ     フ    フ   フ    ヘ    ヘ    ヘ    ホ    ホ    ホ   マ    ミ
-             0xd1,0xd2,0xd3,0xd4,0xd4,0xd5,0xd5,0xae,0xd6,0xd7,0xd8,0xd9,0xda,0xdb,0xdc,0xdc,  // e383a
-  //          ム    メ    モ    ャ   ャ    ユ    ユ    ョ    ヨ    ラ    リ    ル    レ    ロ   ワ    ワ
-             0xec,0xa7,0xa6,0xdd,0xcc,0x3f,0x3f,0x3f,0x3f,0x3f,0xa6,0xa5,0xb0,0xa4,0xa4,0x3f   // e383b
-  //          ヰ    ヱ    ヲ    ン    フ    ?    ?   ?    ?    ?    ヲ    ・    ー    ヽ    ヽ   ?
+               0x3d,0xb1,0xb1,0xa8,0xb2,0xa9,0xb3,0xaa,0xb4,0xab,0xb5,0xb6,0xb6,0xb7,0xb7,0xb8,  // e382a Please test and correct
+             // =    ア    ア    ィ    イ    ゥ    ウ    ェ    エ    ォ    オ   ガ    ガ    キ   キ    ク
+               0xb8,0xb9,0xb9,0xba,0xba,0xbb,0xbb,0xbc,0xbc,0xbd,0xbd,0xbe,0xbe,0xbf,0xbf,0xc0,  // e382b
+             // ク    ケ    ケ   コ    コ    サ    サ    シ    シ   ス    ス    セ    セ    ソ   ソ    タ
+               0xc0,0xc1,0xc1,0xc2,0xc2,0xc2,0xc3,0xc3,0xc4,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,  // e3838
+             // タ    チ    チ    ッ    ッ    ッ    テ   テ    ト    ト    ナ    ニ    ヌ    ネ   ノ    ハ
+               0xca,0xca,0xcb,0xcb,0xcb,0xcc,0xcc,0xcc,0xcd,0xcd,0xcd,0xce,0xce,0xce,0xcf,0xd0,  // e3839
+             // ハ    ハ    ヒ   ヒ    ヒ     フ    フ   フ    ヘ    ヘ    ヘ    ホ    ホ    ホ   マ    ミ
+               0xd1,0xd2,0xd3,0xd4,0xd4,0xd5,0xd5,0xae,0xd6,0xd7,0xd8,0xd9,0xda,0xdb,0xdc,0xdc,  // e383a
+             // ム    メ    モ    ャ   ャ    ユ    ユ    ョ    ヨ    ラ    リ    ル    レ    ロ   ワ    ワ
+               0xec,0xa7,0xa6,0xdd,0xcc,0x3f,0x3f,0x3f,0x3f,0x3f,0xa6,0xa5,0xb0,0xa4,0xa4,0x3f   // e383b
+             // ヰ    ヱ    ヲ    ン    フ    ?    ?   ?    ?    ?    ヲ    ・    ー    ヽ    ヽ   ?
            };
     #elif ENABLED(MAPPER_D0D1)
       #error "Cyrillic on a JAPANESE display makes no sense. There are no matching symbols."
     #if ENABLED(MAPPER_C2C3)
       const PROGMEM uint8_t utf_recode[] =
            { // 0    1    2    3    4    5    6    7    8    9    a    b    c    d    e    f   This is relative complete.
-             0x20,0xa1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,0x22,0xa9,0xaa,0xab,0x3f,0x3f,0xae,0x3f,  // c2a ¡¢£¤¥¦§¨©ª«¬­®¯
-  //         ' '   ¡    ¢    £    ¤    ¥    ¦    §    "    ©    ª    «    ?    ?    ®    ?
-             0xb0,0xb1,0xb2,0xb3,0x27,0xb5,0xb6,0xb7,0x2c,0xb9,0xba,0xbb,0xbc,0xbd,0xbe,0xbf,  // c2b °±²³´µ¶·¸¹º»¼½¾¿
-  //          °    ±    ³    ²    ?    µ    ¶    ·    ,    ¹    º    »    ¼    ½    ¾    ¿
-             0xc0,0xc1,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xcb,0xcc,0xcd,0xce,0xcf,  // c38 ÀÁÃÄÅÆÇÈÉÊËÌÍÎÏ
-  //          À    Á    Â    Ã    Ä    Å    Æ    Ç    È    É    Ê    Ë    Ì    Í    Î    Ï
-             0xd0,0xd1,0xd2,0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xdb,0xdc,0xdd,0xde,0xdf,  // c39 ÐÑÓÔÕÖ×ØÙÚÛÜÝÞß
-  //          Ð    Ñ    Ò    Ó    Ô    Õ    Ö    ×    Ø    Ù    Ú    Û    Ü    Ý    Þ    ß
-             0xe0,0xe1,0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,0xeb,0xec,0xed,0xee,0xef,  // c3a àáãäåæçèéêëìíîï
-  //          à    á    â    ã    ä    å    æ    ç    è    é    ê    ë    ì    í    î    ï
-             0xf0,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfe,0xff   // c3b ðñóôõö÷øùúûüýþÿ
-  //          ð    ñ    ò    ó    ô    õ    ö    ÷    ø    ù    ú    û    ü    ý    þ    ÿ
+               0x20,0xa1,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,0x22,0xa9,0xaa,0xab,0x3f,0x3f,0xae,0x3f,  // c2a ¡¢£¤¥¦§¨©ª«¬­®¯
+             //' '   ¡    ¢    £    ¤    ¥    ¦    §    "    ©    ª    «    ?    ?    ®    ?
+               0xb0,0xb1,0xb2,0xb3,0x27,0xb5,0xb6,0xb7,0x2c,0xb9,0xba,0xbb,0xbc,0xbd,0xbe,0xbf,  // c2b °±²³´µ¶·¸¹º»¼½¾¿
+             // °    ±    ³    ²    ?    µ    ¶    ·    ,    ¹    º    »    ¼    ½    ¾    ¿
+               0xc0,0xc1,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xcb,0xcc,0xcd,0xce,0xcf,  // c38 ÀÁÃÄÅÆÇÈÉÊËÌÍÎÏ
+             // À    Á    Â    Ã    Ä    Å    Æ    Ç    È    É    Ê    Ë    Ì    Í    Î    Ï
+               0xd0,0xd1,0xd2,0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xdb,0xdc,0xdd,0xde,0xdf,  // c39 ÐÑÓÔÕÖ×ØÙÚÛÜÝÞß
+             // Ð    Ñ    Ò    Ó    Ô    Õ    Ö    ×    Ø    Ù    Ú    Û    Ü    Ý    Þ    ß
+               0xe0,0xe1,0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,0xeb,0xec,0xed,0xee,0xef,  // c3a àáãäåæçèéêëìíîï
+             // à    á    â    ã    ä    å    æ    ç    è    é    ê    ë    ì    í    î    ï
+               0xf0,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfe,0xff   // c3b ðñóôõö÷øùúûüýþÿ
+             // ð    ñ    ò    ó    ô    õ    ö    ÷    ø    ù    ú    û    ü    ý    þ    ÿ
            };
     #elif ENABLED(MAPPER_D0D1)
       #define MAPPER_D0D1_MOD
       const PROGMEM uint8_t utf_recode[] =
            {//0    1    2    3    4    5    6    7    8    9    a    b    c    d    e    f
-             0x41,0x80,0x42,0x92,0x81,0x45,0x82,0x83,0x84,0x85,0x4b,0x86,0x4d,0x48,0x4f,0x87,  // d0a
-  //          A    Б    B    Г    Д    E    Ж    З    И    Й    K    Л    M    H    O    П
-             0x50,0x43,0x54,0x88,0xd8,0x58,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x62,0x8f,0xac,0xad,  // d0b
-  //          P    C    T    У    Ф    X    Ч    ч    Ш    Щ    Ъ    Ы    b    Э    Ю    Я
-             0x61,0x36,0x42,0x92,0x81,0x65,0x82,0xb3,0x84,0x85,0x6b,0x86,0x4d,0x48,0x6f,0x87,  // d18
-  //          a    6    B    Г    Д    e    Ж    ³    И    Й    k    Л    M    H    o    П
-             0x70,0x63,0x54,0x79,0xd8,0x78,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x62,0x8f,0xac,0xad   // d19
-  //          p    c    T    y    Ф    x    Ч    ч    Ш    Щ    Ъ    Ы    b    Э    Ю    Я
+               0x41,0x80,0x42,0x92,0x81,0x45,0x82,0x83,0x84,0x85,0x4b,0x86,0x4d,0x48,0x4f,0x87,  // d0a
+             // A    Б    B    Г    Д    E    Ж    З    И    Й    K    Л    M    H    O    П
+               0x50,0x43,0x54,0x88,0xd8,0x58,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x62,0x8f,0xac,0xad,  // d0b
+             // P    C    T    У    Ф    X    Ч    ч    Ш    Щ    Ъ    Ы    b    Э    Ю    Я
+               0x61,0x36,0x42,0x92,0x81,0x65,0x82,0xb3,0x84,0x85,0x6b,0x86,0x4d,0x48,0x6f,0x87,  // d18
+             // a    6    B    Г    Д    e    Ж    ³    И    Й    k    Л    M    H    o    П
+               0x70,0x63,0x54,0x79,0xd8,0x78,0x89,0x8a,0x8b,0x8c,0x8d,0x8e,0x62,0x8f,0xac,0xad   // d19
+             // p    c    T    y    Ф    x    Ч    ч    Ш    Щ    Ъ    Ы    b    Э    Ю    Я
             };
     #elif ENABLED(MAPPER_E382E383)
       #error "Katakana on a WESTERN display makes no sense. There are no matching symbols."
       // it is a Russian alphabet translation
       // except 0401 --> 0xa2 = Ё, 0451 --> 0xb5 = ё
       const PROGMEM uint8_t utf_recode[] =
-             { 0x41,0xa0,0x42,0xa1,0xe0,0x45,0xa3,0xa4,   // unicode U+0400 to U+047f
-             // A   Б->Ё  B    Г    Д    E    Ж    З      // 0  Ѐ Ё Ђ Ѓ Є Ѕ І Ї
-               0xa5,0xa6,0x4b,0xa7,0x4d,0x48,0x4f,0xa8,   //    Ј Љ Њ Ћ Ќ Ѝ Ў Џ
-             // И    Й    K    Л    M    H    O    П      // 1  А Б В Г Д Е Ж З
-               0x50,0x43,0x54,0xa9,0xaa,0x58,0xe1,0xab,   //    И Й К Л М Н О П
-             // P    C    T    У    Ф    X    Ч    ч      // 2  Р С Т У Ф Х Г Ч
-               0xac,0xe2,0xad,0xae,0x62,0xaf,0xb0,0xb1,   //    Ш Щ Ъ Ы Ь Э Ю Я
-             // Ш    Щ    Ъ    Ы    b    Э    Ю    Я      // 3  а б в г д е ж з
-               0x61,0xb2,0xb3,0xb4,0xe3,0x65,0xb6,0xb7,   //    и й к л м н о п
-             // a   б->ё  в    г    д    e    ж    з      // 4  р с т у ф х ц ч
-               0xb8,0xb9,0xba,0xbb,0xbc,0xbd,0x6f,0xbe,   //    ш щ ъ ы ь э ю я
-             // и    й    к    л    м    н    o    п      // 5  ѐ ё ђ ѓ є ѕ і ї
-               0x70,0x63,0xbf,0x79,0xe4,0x78,0xe5,0xc0,   //    ј љ њ ћ ќ ѝ ў џ
-             // p    c    т    y    ф    x    ц    ч      // 6  Ѡ ѡ Ѣ ѣ Ѥ ѥ Ѧ ѧ
-               0xc1,0xe6,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7    //    Ѫ ѩ Ѫ ѫ Ѭ ѭ Ѯ ѯ
-             // ш    щ    ъ    ы    ь    э    ю    я      // 7  Ѱ ѱ Ѳ ѳ Ѵ ѵ Ѷ ѷ
-             };                                           //    ѻ ѹ Ѻ ѻ Ѽ ѽ Ѿ ѿ
+               { 0x41,0xa0,0x42,0xa1,0xe0,0x45,0xa3,0xa4,   // unicode U+0400 to U+047f
+               // A   Б->Ё  B    Г    Д    E    Ж    З      // 0  Ѐ Ё Ђ Ѓ Є Ѕ І Ї
+                 0xa5,0xa6,0x4b,0xa7,0x4d,0x48,0x4f,0xa8,   //    Ј Љ Њ Ћ Ќ Ѝ Ў Џ
+               // И    Й    K    Л    M    H    O    П      // 1  А Б В Г Д Е Ж З
+                 0x50,0x43,0x54,0xa9,0xaa,0x58,0xe1,0xab,   //    И Й К Л М Н О П
+               // P    C    T    У    Ф    X    Ч    ч      // 2  Р С Т У Ф Х Г Ч
+                 0xac,0xe2,0xad,0xae,0x62,0xaf,0xb0,0xb1,   //    Ш Щ Ъ Ы Ь Э Ю Я
+               // Ш    Щ    Ъ    Ы    b    Э    Ю    Я      // 3  а б в г д е ж з
+                 0x61,0xb2,0xb3,0xb4,0xe3,0x65,0xb6,0xb7,   //    и й к л м н о п
+               // a   б->ё  в    г    д    e    ж    з      // 4  р с т у ф х ц ч
+                 0xb8,0xb9,0xba,0xbb,0xbc,0xbd,0x6f,0xbe,   //    ш щ ъ ы ь э ю я
+               // и    й    к    л    м    н    o    п      // 5  ѐ ё ђ ѓ є ѕ і ї
+                 0x70,0x63,0xbf,0x79,0xe4,0x78,0xe5,0xc0,   //    ј љ њ ћ ќ ѝ ў џ
+               // p    c    т    y    ф    x    ц    ч      // 6  Ѡ ѡ Ѣ ѣ Ѥ ѥ Ѧ ѧ
+                 0xc1,0xe6,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7    //    Ѫ ѩ Ѫ ѫ Ѭ ѭ Ѯ ѯ
+               // ш    щ    ъ    ы    ь    э    ю      я      // 7  Ѱ ѱ Ѳ ѳ Ѵ ѵ Ѷ ѷ
+             };                                             //    ѻ ѹ Ѻ ѻ Ѽ ѽ Ѿ ѿ
     #elif ENABLED(MAPPER_C2C3)
       #error "Western languages on a CYRILLIC display makes no sense. There are no matching symbols."
     #elif ENABLED(MAPPER_E382E383)
 
 #if ENABLED(MAPPER_C2C3)
 
-  char charset_mapper(char c) {
+  char charset_mapper(const char c) {
     static uint8_t utf_hi_char; // UTF-8 high part
     static bool seen_c2 = false;
     uint8_t d = c;
 
 #elif ENABLED(MAPPER_CECF)
 
-  char charset_mapper(char c) {
+  char charset_mapper(const char c) {
     static uint8_t utf_hi_char; // UTF-8 high part
     static bool seen_ce = false;
     uint8_t d = c;
 
 #elif ENABLED(MAPPER_CECF)
 
-  char charset_mapper(char c) {
+  char charset_mapper(const char c) {
     static uint8_t utf_hi_char; // UTF-8 high part
     static bool seen_ce = false;
     uint8_t d = c;
 
 #elif ENABLED(MAPPER_D0D1_MOD)
 
-  char charset_mapper(char c) {
+  char charset_mapper(const char c) {
     // it is a Russian alphabet translation
     // except 0401 --> 0xa2 = Ё, 0451 --> 0xb5 = ё
     static uint8_t utf_hi_char; // UTF-8 high part
 
 #elif ENABLED(MAPPER_D0D1)
 
-  char charset_mapper(char c) {
+  char charset_mapper(const char c) {
     static uint8_t utf_hi_char; // UTF-8 high part
     static bool seen_d5 = false;
     uint8_t d = c;
 
 #elif ENABLED(MAPPER_E382E383)
 
-  char charset_mapper(char c) {
+  char charset_mapper(const char c) {
     static uint8_t utf_hi_char; // UTF-8 high part
     static bool seen_e3 = false;
     static bool seen_82_83 = false;
 
   #define MAPPER_NON
 
-  char charset_mapper(char c) {
+  char charset_mapper(const char c) {
     HARDWARE_CHAR_OUT( c );
     return 1;
   }