add SHOW_CUSTOM_BOOTSCREEN support to HD44780

Marlin/Configuration_adv.h

@@ -1584,7 +1584,7 @@
     #if HAS_MARLINUI_U8GLIB
       //#define BOOT_MARLIN_LOGO_ANIMATED // Animated Marlin logo. Costs ~3260 (or ~940) bytes of flash.
     #endif
-    #if ANY(HAS_MARLINUI_U8GLIB, TOUCH_UI_FTDI_EVE)
+    #if ANY(HAS_MARLINUI_U8GLIB, TOUCH_UI_FTDI_EVE, HAS_MARLINUI_HD44780)
       //#define SHOW_CUSTOM_BOOTSCREEN    // Show the bitmap in Marlin/_Bootscreen.h on startup.
     #endif
   #endif

Marlin/src/inc/SanityCheck.h

@@ -388,8 +388,8 @@ static_assert(COUNT(arm) == LOGICAL_AXES, "AXIS_RELATIVE_MODES must contain " _L
 /**
  * Custom Boot and Status screens
  */
-#if ENABLED(SHOW_CUSTOM_BOOTSCREEN) && NONE(HAS_MARLINUI_U8GLIB, TOUCH_UI_FTDI_EVE, IS_DWIN_MARLINUI)
-  #error "SHOW_CUSTOM_BOOTSCREEN requires Graphical LCD or TOUCH_UI_FTDI_EVE."
+#if ENABLED(SHOW_CUSTOM_BOOTSCREEN) && NONE(HAS_MARLINUI_HD44780, HAS_MARLINUI_U8GLIB, TOUCH_UI_FTDI_EVE, IS_DWIN_MARLINUI)
+  #error "SHOW_CUSTOM_BOOTSCREEN requires Character LCD, Graphical LCD, or TOUCH_UI_FTDI_EVE."
 #elif ENABLED(SHOW_CUSTOM_BOOTSCREEN) && DISABLED(SHOW_BOOTSCREEN)
   #error "SHOW_CUSTOM_BOOTSCREEN requires SHOW_BOOTSCREEN."
 #elif ENABLED(CUSTOM_STATUS_SCREEN_IMAGE) && !HAS_MARLINUI_U8GLIB

Marlin/src/lcd/HD44780/marlinui_HD44780.cpp

@@ -331,15 +331,24 @@ void MarlinUI::set_custom_characters(const HD44780CharSet screen_charset/*=CHARS
 
   #endif // HAS_MEDIA
 
-  #if ENABLED(SHOW_BOOTSCREEN)
-    // Set boot screen corner characters
-    if (screen_charset == CHARSET_BOOT) {
-      for (uint8_t i = 4; i--;)
-        createChar_P(i, corner[i]);
-    }
-    else
-  #endif
-    { // Info Screen uses 5 special characters
+  switch (screen_charset) {
+
+    #if ENABLED(SHOW_BOOTSCREEN)
+      case CHARSET_BOOT: {
+        // Set boot screen corner characters
+        for (uint8_t i = 4; i--;) createChar_P(i, corner[i]);
+      } break;
+    #endif
+
+    #if ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+      case CHARSET_BOOT_CUSTOM: {
+        for (uint8_t i = COUNT(customBootChars); i--;)
+          createChar_P(i, customBootChars[i]);
+      } break;
+    #endif
+
+    default: {
+      // Info Screen uses 5 special characters
       createChar_P(LCD_STR_BEDTEMP[0], bedTemp);
       createChar_P(LCD_STR_DEGREE[0], degree);
       createChar_P(LCD_STR_THERMOMETER[0], thermometer);
@@ -361,7 +370,9 @@ void MarlinUI::set_custom_characters(const HD44780CharSet screen_charset/*=CHARS
             createChar_P(LCD_STR_FOLDER[0], folder);
           #endif
         }
-    }
+    } break;
+
+  }
 
 }
 
@@ -400,6 +411,42 @@ bool MarlinUI::detected() {
   return TERN1(DETECT_I2C_LCD_DEVICE, lcd.LcdDetected() == 1);
 }
 
+#if ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+
+  #ifndef CUSTOM_BOOTSCREEN_X
+    #define CUSTOM_BOOTSCREEN_X -1
+  #endif
+  #ifndef CUSTOM_BOOTSCREEN_Y
+    #define CUSTOM_BOOTSCREEN_Y ((LCD_HEIGHT - COUNT(custom_boot_lines)) / 2)
+  #endif
+  #ifndef CUSTOM_BOOTSCREEN_TIMEOUT
+    #define CUSTOM_BOOTSCREEN_TIMEOUT 2500
+  #endif
+
+  void MarlinUI::draw_custom_bootscreen(const uint8_t/*=0*/) {
+    set_custom_characters(CHARSET_BOOT_CUSTOM);
+    lcd.clear();
+    const int8_t sx = CUSTOM_BOOTSCREEN_X;
+    const uint8_t sy = CUSTOM_BOOTSCREEN_Y;
+    for (lcd_uint_t i = 0; i < COUNT(custom_boot_lines); ++i) {
+      PGM_P const pstr = (PGM_P)pgm_read_ptr(&custom_boot_lines[i]);
+      const uint8_t clen = utf8_strlen_P(pstr);
+      const lcd_uint_t x = sx >= 0 ? sx : (LCD_WIDTH - clen) / 2;
+      for (lcd_uint_t j = 0; j < clen; ++j) {
+        const lchar_t c = pgm_read_byte(&pstr[j]);
+        lcd_put_lchar(x + j, sy + i, c == '\x08' ? '\x00' : c);
+      }
+    }
+  }
+
+  // Shows the custom bootscreen and delays
+  void MarlinUI::show_custom_bootscreen() {
+    draw_custom_bootscreen();
+    safe_delay(CUSTOM_BOOTSCREEN_TIMEOUT);
+  }
+
+#endif // SHOW_CUSTOM_BOOTSCREEN
+
 #if HAS_SLOW_BUTTONS
   uint8_t MarlinUI::read_slow_buttons() {
     #if ENABLED(LCD_I2C_TYPE_MCP23017)
@@ -466,6 +513,8 @@ void MarlinUI::clear_lcd() { lcd.clear(); }
   }
 
   void MarlinUI::show_bootscreen() {
+    TERN_(SHOW_CUSTOM_BOOTSCREEN, show_custom_bootscreen());
+
     set_custom_characters(CHARSET_BOOT);
     lcd.clear();
 

Marlin/src/lcd/HD44780/marlinui_HD44780.h

@@ -27,6 +27,20 @@
 
 #include "../../inc/MarlinConfig.h"
 
+#if ENABLED(SHOW_CUSTOM_BOOTSCREEN)
+
+  #include "../../../_Bootscreen.h"
+
+  #ifdef CUSTOM_BOOTSCREEN_Y
+    #define CUSTOM_BOOT_LAST COUNT(custom_boot_lines) + CUSTOM_BOOTSCREEN_Y
+  #else
+    #define CUSTOM_BOOT_LAST COUNT(custom_boot_lines)
+  #endif
+
+  static_assert(CUSTOM_BOOT_LAST <= LCD_HEIGHT, "custom_boot_lines (plus CUSTOM_BOOTSCREEN_Y) doesn't fit on the selected LCD.");
+
+#endif
+
 #if ENABLED(LCD_I2C_TYPE_PCF8575)
 
   // NOTE: These are register-mapped pins on the PCF8575 controller, not Arduino pins.

Marlin/src/lcd/marlinui.h

@@ -105,7 +105,8 @@ typedef bool (*statusResetFunc_t)();
   enum HD44780CharSet : uint8_t {
     CHARSET_MENU,
     CHARSET_INFO,
-    CHARSET_BOOT
+    CHARSET_BOOT,
+    CHARSET_BOOT_CUSTOM
   };
 #endif
 

ini/native.ini

@@ -113,7 +113,7 @@ build_flags = ${simulator_linux.build_flags} ${simulator_linux.release_flags}
 [simulator_macos]
 build_unflags     = -lGL -fstack-protector-strong
 build_flags       =
-  -DHAS_LIBBSD
+  -DHAS_LIBBSD -DGLM_ENABLE_EXPERIMENTAL
   -I/opt/local/include
   -I/opt/local/include/freetype2
   -I/opt/local/include/SDL2/