/*
  An example analogue meter using a ILI9341 TFT LCD screen
 
  Needs Font 2 (also Font 4 if using large scale label)
 
  Make sure all the display driver and pin connections are correct by
  editing the User_Setup.h file in the TFT_eSPI library folder.
 
  #########################################################################
  ###### DON'T FORGET TO UPDATE THE User_Setup.h FILE IN THE LIBRARY ######
  #########################################################################
  
 Updated by Bodmer for variable meter size
  */
 
 // Define meter size as 1 for tft.rotation(0) or 1.3333 for tft.rotation(1)
 #define M_SIZE 1.3333
 
 #include <TFT_eSPI.h> // Hardware-specific library
 #include <SPI.h>
 
 TFT_eSPI tft = TFT_eSPI();       // Invoke custom library
 
 #define TFT_GREY 0x5AEB
 
 float ltx = 0;    // Saved x coord of bottom of needle
 uint16_t osx = M_SIZE*120, osy = M_SIZE*120; // Saved x & y coords
 uint32_t updateTime = 0;       // time for next update
 
 int old_analog =  -999; // Value last displayed
 
 int value[6] = {0, 0, 0, 0, 0, 0};
 int old_value[6] = { -1, -1, -1, -1, -1, -1};
 int d = 0;
 
 void setup(void) {
   tft.init();
   tft.setRotation(1);
   Serial.begin(57600); // For debug
   tft.fillScreen(TFT_BLACK);
 
   analogMeter(); // Draw analogue meter
 
   updateTime = millis(); // Next update time
 }
 
 
 void loop() {
   if (updateTime <= millis()) {
     updateTime = millis() + 35; // Update emter every 35 milliseconds
  
     // Create a Sine wave for testing
     d += 4; if (d >= 360) d = 0;
     value[0] = 50 + 50 * sin((d + 0) * 0.0174532925);
  
     plotNeedle(value[0], 0); // It takes between 2 and 12ms to replot the needle with zero delay
   }
 }
 
 
 // #########################################################################
 //  Draw the analogue meter on the screen
 // #########################################################################
 void analogMeter()
 {
 
   // Meter outline
   tft.fillRect(0, 0, M_SIZE*239, M_SIZE*126, TFT_GREY);
   tft.fillRect(5, 3, M_SIZE*230, M_SIZE*119, TFT_WHITE);
 
   tft.setTextColor(TFT_BLACK);  // Text colour
 
   // Draw ticks every 5 degrees from -50 to +50 degrees (100 deg. FSD swing)
   for (int i = -50; i < 51; i += 5) {
     // Long scale tick length
     int tl = 15;
 
     // Coodinates of tick to draw
     float sx = cos((i - 90) * 0.0174532925);
     float sy = sin((i - 90) * 0.0174532925);
     uint16_t x0 = sx * (M_SIZE*100 + tl) + M_SIZE*120;
     uint16_t y0 = sy * (M_SIZE*100 + tl) + M_SIZE*140;
     uint16_t x1 = sx * M_SIZE*100 + M_SIZE*120;
     uint16_t y1 = sy * M_SIZE*100 + M_SIZE*140;
 
     // Coordinates of next tick for zone fill
     float sx2 = cos((i + 5 - 90) * 0.0174532925);
     float sy2 = sin((i + 5 - 90) * 0.0174532925);
     int x2 = sx2 * (M_SIZE*100 + tl) + M_SIZE*120;
     int y2 = sy2 * (M_SIZE*100 + tl) + M_SIZE*140;
     int x3 = sx2 * M_SIZE*100 + M_SIZE*120;
     int y3 = sy2 * M_SIZE*100 + M_SIZE*140;
 
     // Yellow zone limits
     //if (i >= -50 && i < 0) {
     //  tft.fillTriangle(x0, y0, x1, y1, x2, y2, TFT_YELLOW);
     //  tft.fillTriangle(x1, y1, x2, y2, x3, y3, TFT_YELLOW);
     //}
 
     // Green zone limits
     if (i >= 0 && i < 25) {
       tft.fillTriangle(x0, y0, x1, y1, x2, y2, TFT_GREEN);
       tft.fillTriangle(x1, y1, x2, y2, x3, y3, TFT_GREEN);
     }
 
     // Orange zone limits
     if (i >= 25 && i < 50) {
       tft.fillTriangle(x0, y0, x1, y1, x2, y2, TFT_ORANGE);
       tft.fillTriangle(x1, y1, x2, y2, x3, y3, TFT_ORANGE);
     }
 
     // Short scale tick length
     if (i % 25 != 0) tl = 8;
 
     // Recalculate coords incase tick lenght changed
     x0 = sx * (M_SIZE*100 + tl) + M_SIZE*120;
     y0 = sy * (M_SIZE*100 + tl) + M_SIZE*140;
     x1 = sx * M_SIZE*100 + M_SIZE*120;
     y1 = sy * M_SIZE*100 + M_SIZE*140;
 
     // Draw tick
     tft.drawLine(x0, y0, x1, y1, TFT_BLACK);
 
     // Check if labels should be drawn, with position tweaks
     if (i % 25 == 0) {
       // Calculate label positions
       x0 = sx * (M_SIZE*100 + tl + 10) + M_SIZE*120;
       y0 = sy * (M_SIZE*100 + tl + 10) + M_SIZE*140;
       switch (i / 25) {
         case -2: tft.drawCentreString("0", x0, y0 - 12, 2); break;
         case -1: tft.drawCentreString("25", x0, y0 - 9, 2); break;
         case 0: tft.drawCentreString("50", x0, y0 - 7, 2); break;
         case 1: tft.drawCentreString("75", x0, y0 - 9, 2); break;
         case 2: tft.drawCentreString("100", x0, y0 - 12, 2); break;
       }
     }
 
     // Now draw the arc of the scale
     sx = cos((i + 5 - 90) * 0.0174532925);
     sy = sin((i + 5 - 90) * 0.0174532925);
     x0 = sx * M_SIZE*100 + M_SIZE*120;
     y0 = sy * M_SIZE*100 + M_SIZE*140;
     // Draw scale arc, don't draw the last part
     if (i < 50) tft.drawLine(x0, y0, x1, y1, TFT_BLACK);
   }
 
   tft.drawString("%RH", M_SIZE*(5 + 230 - 40), M_SIZE*(119 - 20), 2); // Units at bottom right
   tft.drawCentreString("%RH", M_SIZE*120, M_SIZE*70, 4); // Comment out to avoid font 4
   tft.drawRect(5, 3, M_SIZE*230, M_SIZE*119, TFT_BLACK); // Draw bezel line
 
   plotNeedle(0, 0); // Put meter needle at 0
 }
 
 // #########################################################################
 // Update needle position
 // This function is blocking while needle moves, time depends on ms_delay
 // 10ms minimises needle flicker if text is drawn within needle sweep area
 // Smaller values OK if text not in sweep area, zero for instant movement but
 // does not look realistic... (note: 100 increments for full scale deflection)
 // #########################################################################
 void plotNeedle(int value, byte ms_delay)
 {
   tft.setTextColor(TFT_BLACK, TFT_WHITE);
   char buf[8]; dtostrf(value, 4, 0, buf);
   tft.drawRightString(buf, M_SIZE*40, M_SIZE*(119 - 20), 2);
 
   if (value < -10) value = -10; // Limit value to emulate needle end stops
   if (value > 110) value = 110;
 
   // Move the needle until new value reached
   while (!(value == old_analog)) {
     if (old_analog < value) old_analog++;
     else old_analog--;
 
     if (ms_delay == 0) old_analog = value; // Update immediately if delay is 0
 
     float sdeg = map(old_analog, -10, 110, -150, -30); // Map value to angle
     // Calcualte tip of needle coords
     float sx = cos(sdeg * 0.0174532925);
     float sy = sin(sdeg * 0.0174532925);
 
     // Calculate x delta of needle start (does not start at pivot point)
     float tx = tan((sdeg + 90) * 0.0174532925);
 
     // Erase old needle image
     tft.drawLine(M_SIZE*(120 + 20 * ltx - 1), M_SIZE*(140 - 20), osx - 1, osy, TFT_WHITE);
     tft.drawLine(M_SIZE*(120 + 20 * ltx), M_SIZE*(140 - 20), osx, osy, TFT_WHITE);
     tft.drawLine(M_SIZE*(120 + 20 * ltx + 1), M_SIZE*(140 - 20), osx + 1, osy, TFT_WHITE);
 
     // Re-plot text under needle
     tft.setTextColor(TFT_BLACK);
     tft.drawCentreString("%RH", M_SIZE*120, M_SIZE*70, 4); // // Comment out to avoid font 4
 
     // Store new needle end coords for next erase
     ltx = tx;
     osx = M_SIZE*(sx * 98 + 120);
     osy = M_SIZE*(sy * 98 + 140);
 
     // Draw the needle in the new postion, magenta makes needle a bit bolder
     // draws 3 lines to thicken needle
     tft.drawLine(M_SIZE*(120 + 20 * ltx - 1), M_SIZE*(140 - 20), osx - 1, osy, TFT_RED);
     tft.drawLine(M_SIZE*(120 + 20 * ltx), M_SIZE*(140 - 20), osx, osy, TFT_MAGENTA);
     tft.drawLine(M_SIZE*(120 + 20 * ltx + 1), M_SIZE*(140 - 20), osx + 1, osy, TFT_RED);
 
     // Slow needle down slightly as it approaches new postion
     if (abs(old_analog - value) < 10) ms_delay += ms_delay / 5;
 
     // Wait before next update
     delay(ms_delay);
   }
 }
 

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