Attempt to workaround the M73 C0|D0 visual issue (#3067)

Attempt to workaround the M73 C0|D0 visual issue

This is an attempt to enable alternation of time to print finish and time
to color change even in the last minute of time to color change, i.e. be
able to print "0:00C".

The proposed solution leverages the capability of the current FW to read
float values from the C|D parameter. This could have the raw benefit of
being able still to alternate this time on the LCD as "0:00C" (or
"<1min") if the slicer sends a non-zero but <1 time right before the
color change.

Co-authored-by: D.R.racer <drracer@drracer.eu>
Co-authored-by: 3d-gussner <3d.gussner@gmail.com>

Firmware/Marlin.h

@@ -363,8 +363,8 @@ extern bool mmu_print_saved;
 
 //estimated time to end of the print
 extern uint8_t print_percent_done_normal;
-extern uint16_t print_time_remaining_normal;
 extern uint8_t print_percent_done_silent;
+extern uint16_t print_time_remaining_normal;
 extern uint16_t print_time_remaining_silent;
 extern uint16_t print_time_to_change_normal;
 extern uint16_t print_time_to_change_silent;
@@ -376,7 +376,7 @@ extern uint16_t gcode_in_progress;
 
 extern LongTimer safetyTimer;
 
-#define PRINT_PERCENT_DONE_INIT   0xff
+#define PRINT_PERCENT_DONE_INIT 0xff
 #define PRINTER_ACTIVE (IS_SD_PRINTING || is_usb_printing || isPrintPaused || (custom_message_type == CustomMsg::TempCal) || saved_printing || (lcd_commands_type == LcdCommands::Layer1Cal) || mmu_print_saved || homing_flag || mesh_bed_leveling_flag)
 
 //! Beware - mcode_in_progress is set as soon as the command gets really processed,

Firmware/Marlin_main.cpp

@@ -313,8 +313,8 @@ bool mmu_print_saved = false;
 
 // storing estimated time to end of print counted by slicer
 uint8_t print_percent_done_normal = PRINT_PERCENT_DONE_INIT;
-uint16_t print_time_remaining_normal = PRINT_TIME_REMAINING_INIT; //estimated remaining print time in minutes
 uint8_t print_percent_done_silent = PRINT_PERCENT_DONE_INIT;
+uint16_t print_time_remaining_normal = PRINT_TIME_REMAINING_INIT; //estimated remaining print time in minutes
 uint16_t print_time_remaining_silent = PRINT_TIME_REMAINING_INIT; //estimated remaining print time in minutes
 uint16_t print_time_to_change_normal = PRINT_TIME_REMAINING_INIT; //estimated remaining time to next change in minutes
 uint16_t print_time_to_change_silent = PRINT_TIME_REMAINING_INIT; //estimated remaining time to next change in minutes
@@ -6389,14 +6389,19 @@ Sigma_Exit:
         if(code_seen('R')) print_time_remaining_normal = code_value();
         if(code_seen('Q')) print_percent_done_silent = code_value();
         if(code_seen('S')) print_time_remaining_silent = code_value();
-        if(code_seen('C')) print_time_to_change_normal = code_value();
-        if(code_seen('D')) print_time_to_change_silent = code_value();
-
-    {
-        const char* _msg_mode_done_remain = _N("%S MODE: Percent done: %d; print time remaining in mins: %d; Change in mins: %d\n");
-        printf_P(_msg_mode_done_remain, _N("NORMAL"), int(print_percent_done_normal), print_time_remaining_normal, print_time_to_change_normal);
-        printf_P(_msg_mode_done_remain, _N("SILENT"), int(print_percent_done_silent), print_time_remaining_silent, print_time_to_change_silent);
-    }
+        if(code_seen('C')){
+            float print_time_to_change_normal_f = code_value_float();
+            print_time_to_change_normal = ( print_time_to_change_normal_f <= 0 ) ? PRINT_TIME_REMAINING_INIT : print_time_to_change_normal_f;
+        }
+        if(code_seen('D')){
+            float print_time_to_change_silent_f = code_value_float();
+            print_time_to_change_silent = ( print_time_to_change_silent_f <= 0 ) ? PRINT_TIME_REMAINING_INIT : print_time_to_change_silent_f;
+        }
+        {
+            const char* _msg_mode_done_remain = _N("%S MODE: Percent done: %hhd; print time remaining in mins: %d; Change in mins: %d\n");
+            printf_P(_msg_mode_done_remain, _N("NORMAL"), int8_t(print_percent_done_normal), print_time_remaining_normal, print_time_to_change_normal);
+            printf_P(_msg_mode_done_remain, _N("SILENT"), int8_t(print_percent_done_silent), print_time_remaining_silent, print_time_to_change_silent);
+        }
         break;
     }
     /*!

Firmware/ultralcd.cpp

@@ -510,9 +510,9 @@ void lcdui_print_time(void)
     //if remaining print time estimation is available print it else print elapsed time
     int chars = 0;
     if (PRINTER_ACTIVE) {
-        uint16_t print_t = 0;
-        uint16_t print_tr = 0;
-        uint16_t print_tc = 0;
+        uint16_t print_t = PRINT_TIME_REMAINING_INIT;
+        uint16_t print_tr = PRINT_TIME_REMAINING_INIT;
+        uint16_t print_tc = PRINT_TIME_REMAINING_INIT;
         char suff = ' ';
         char suff_doubt = ' ';
 
@@ -542,12 +542,12 @@ void lcdui_print_time(void)
 
         clock_interval++;
 
-        if (print_tc != 0 && clock_interval > CLOCK_INTERVAL_TIME) {
+        if (print_tc != PRINT_TIME_REMAINING_INIT && clock_interval > CLOCK_INTERVAL_TIME) {
             print_t = print_tc;
             suff = 'C';
         } else
 //#endif //CLOCK_INTERVAL_TIME 
-        if (print_tr != 0) {
+        if (print_tr != PRINT_TIME_REMAINING_INIT) {
             print_t = print_tr;
             suff = 'R';
         } else