tweak, no "err°"

Author: thinkyhead

Marlin/src/lcd/HD44780/marlinui_HD44780.cpp

@@ -546,6 +546,7 @@ FORCE_INLINE void _draw_heater_status(const heater_id_t heater_id, const char pr
 
   if (prefix >= 0) lcd_put_lchar(prefix);
 
+  // TODO: Option to allow negative temperature
   lcd_put_u8str(t1 < 0 ? "err" : i16tostr3rj(t1));
   lcd_put_u8str(F("/"));
 

Marlin/src/lcd/dogm/status_screen_DOGM.cpp

@@ -192,18 +192,27 @@
 #define PROGRESS_BAR_WIDTH (LCD_PIXEL_WIDTH - PROGRESS_BAR_X)
 
 FORCE_INLINE void _draw_centered_temp(const celsius_t temp, const uint8_t tx, const uint8_t ty) {
-  const char *str;
-  uint8_t len;
-  if (temp > 0) {
-    str = i16tostr3rj(temp);
-    len = str[0] != ' ' ? 3 : str[1] != ' ' ? 2 : 1;
-  }
-  else {
-    str = "err";
-    len = 3;
+    const char *str;
+    uint8_t len;
+    if (temp < 0) {
+      #if DISABLED(SHOW_TEMPERATURE_ERROR_BELOW_ZERO)
+        lcd_put_u8str(tx + 1 - 3 * (INFO_FONT_WIDTH) / 2, ty, F("err"));
+        return;
+      #else
+        str = i16tostr3left(-temp);
+        len = strlen(str) + 1;
+        lcd_moveto(tx + 1 - len * (INFO_FONT_WIDTH) / 2, ty);
+        lcd_put_lchar('-');
+      #endif
+    }
+    else {
+      str = i16tostr3left(temp);
+      len = strlen(str);
+      lcd_moveto(tx + 1 - len * (INFO_FONT_WIDTH) / 2, ty);
+    }
+    lcd_put_u8str(str);
+    lcd_put_lchar(LCD_STR_DEGREE[0]);
   }
-  lcd_put_u8str(tx - len * (INFO_FONT_WIDTH) / 2 + 1, ty, &str[3-len]);
-  if (temp > 0) lcd_put_lchar(LCD_STR_DEGREE[0]);
 }
 
 #if DO_DRAW_FLOWMETER