/*
 
   This program provides cartesian type graph function
 
   Revisions
   rev     date        author      description
   1       12-24-2015  kasprzak    initial creation
 
   Updated by Bodmer to be an example for the library here:
   https://github.com/Bodmer/TFT_eSPI
   
 */
 
 #include <TFT_eSPI.h> // Hardware-specific library
 #include <SPI.h>
 
 TFT_eSPI tft = TFT_eSPI();                   // Invoke custom library with default width and height
 
 
 #define LTBLUE    0xB6DF
 #define LTTEAL    0xBF5F
 #define LTGREEN   0xBFF7
 #define LTCYAN    0xC7FF
 #define LTRED     0xFD34
 #define LTMAGENTA 0xFD5F
 #define LTYELLOW  0xFFF8
 #define LTORANGE  0xFE73
 #define LTPINK    0xFDDF
 #define LTPURPLE  0xCCFF
 #define LTGREY    0xE71C
 
 #define BLUE      0x001F
 #define TEAL      0x0438
 #define GREEN     0x07E0
 #define CYAN      0x07FF
 #define RED       0xF800
 #define MAGENTA   0xF81F
 #define YELLOW    0xFFE0
 #define ORANGE    0xFC00
 #define PINK      0xF81F
 #define PURPLE    0x8010
 #define GREY      0xC618
 #define WHITE     0xFFFF
 #define BLACK     0x0000
 
 #define DKBLUE    0x000D
 #define DKTEAL    0x020C
 #define DKGREEN   0x03E0
 #define DKCYAN    0x03EF
 #define DKRED     0x6000
 #define DKMAGENTA 0x8008
 #define DKYELLOW  0x8400
 #define DKORANGE  0x8200
 #define DKPINK    0x9009
 #define DKPURPLE  0x4010
 #define DKGREY    0x4A49
 
 // these are the only external variables used by the graph function
 // it's a flag to draw the coordinate system only on the first call to the Graph() function
 // and will mimize flicker
 // also create some variables to store the old x and y, if you draw 2 graphs on the same display
 // you will need to store ox and oy per each display
 bool display1 = true;
 bool update1 = true;
 
 double ox = -999, oy = -999; // Force them to be off screen
 
 /*
 
   function to draw a cartesian coordinate system and plot whatever data you want
   just pass x and y and the graph will be drawn
 
   huge arguement list
   &d name of your display object
   x = x data point
   y = y datapont
   gx = x graph location (lower left)
   gy = y graph location (lower left)
   w = width of graph
   h = height of graph
   xlo = lower bound of x axis
   xhi = upper bound of x asis
   xinc = division of x axis (distance not count)
   ylo = lower bound of y axis
   yhi = upper bound of y asis
   yinc = division of y axis (distance not count)
   title = title of graph
   xlabel = x asis label
   ylabel = y asis label
   &redraw = flag to redraw graph on first call only
   color = plotted trace colour
 */
 
 
 void Graph(TFT_eSPI &tft, double x, double y, byte dp,
                            double gx, double gy, double w, double h,
                            double xlo, double xhi, double xinc,
                            double ylo, double yhi, double yinc,
                            char *title, char *xlabel, char *ylabel,
                            bool &redraw, unsigned int color) {
 
   double ydiv, xdiv;
   double i;
   double temp;
   int rot, newrot;
 
   // gcolor = graph grid colors
   // acolor = axes line colors
   // pcolor = color of your plotted data
   // tcolor = text color
   // bcolor = background color
   unsigned int gcolor = DKBLUE;
   unsigned int acolor = RED;
   unsigned int pcolor = color;
   unsigned int tcolor = WHITE;
   unsigned int bcolor = BLACK;
 
   if (redraw == true) {
 
     redraw = false;
     // initialize old x and old y in order to draw the first point of the graph
     // but save the transformed value
     // note my transform funcition is the same as the map function, except the map uses long and we need doubles
     //ox = (x - xlo) * ( w) / (xhi - xlo) + gx;
     //oy = (y - ylo) * (gy - h - gy) / (yhi - ylo) + gy;
 
     tft.setTextDatum(MR_DATUM);
 
     // draw y scale
     for ( i = ylo; i <= yhi; i += yinc) {
       // compute the transform
       temp =  (i - ylo) * (gy - h - gy) / (yhi - ylo) + gy;
 
       if (i == 0) {
         tft.drawLine(gx, temp, gx + w, temp, acolor);
         tft.setTextColor(acolor, bcolor);
         tft.drawString(xlabel, (int)(gx + w) , (int)temp, 2);
       }
       else {
         tft.drawLine(gx, temp, gx + w, temp, gcolor);
       }
       // draw the axis labels
       tft.setTextColor(tcolor, bcolor);
       // precision is default Arduino--this could really use some format control
       tft.drawFloat(i, dp, gx - 4, temp, 1);
     }
 
     // draw x scale
     for (i = xlo; i <= xhi; i += xinc) {
 
       // compute the transform
       temp =  (i - xlo) * ( w) / (xhi - xlo) + gx;
       if (i == 0) {
         tft.drawLine(temp, gy, temp, gy - h, acolor);
         tft.setTextColor(acolor, bcolor);
         tft.setTextDatum(BC_DATUM);
         tft.drawString(ylabel, (int)temp, (int)(gy - h - 8) , 2);
       }
       else {
         tft.drawLine(temp, gy, temp, gy - h, gcolor);
       }
       // draw the axis labels
       tft.setTextColor(tcolor, bcolor);
       tft.setTextDatum(TC_DATUM);
       // precision is default Arduino--this could really use some format control
       tft.drawFloat(i, dp, temp, gy + 7, 1);
     }
 
     //now draw the graph labels
     tft.setTextColor(tcolor, bcolor);
     tft.drawString(title, (int)(gx + w / 2) , (int)(gy - h - 30), 4);
   }
 
   // the coordinates are now drawn, plot the data
   // the entire plotting code are these few lines...
   // recall that ox and oy are initialized above
   //x =  (x - xlo) * ( w) / (xhi - xlo) + gx;
   //y =  (y - ylo) * (gy - h - gy) / (yhi - ylo) + gy;
   //tft.drawLine(ox, oy, x, y, pcolor);
   // it's up to you but drawing 2 more lines to give the graph some thickness
   //tft.drawLine(ox, oy + 1, x, y + 1, pcolor);
   //tft.drawLine(ox, oy - 1, x, y - 1, pcolor);
   //ox = x;
   //oy = y;
 
 }
 
 void Trace(TFT_eSPI &tft, double x,  double y,  byte dp,
            double gx, double gy,
            double w, double h,
            double xlo, double xhi, double xinc,
            double ylo, double yhi, double yinc,
            char *title, char *xlabel, char *ylabel,
            bool &update1, unsigned int color)
 {
   double ydiv, xdiv;
   double i;
   double temp;
   int rot, newrot;
 
   //unsigned int gcolor = DKBLUE;   // gcolor = graph grid color
   unsigned int acolor = RED;        // acolor = main axes and label color
   unsigned int pcolor = color;      // pcolor = color of your plotted data
   unsigned int tcolor = WHITE;      // tcolor = text color
   unsigned int bcolor = BLACK;      // bcolor = background color
 
   // initialize old x and old y in order to draw the first point of the graph
   // but save the transformed value
   // note my transform funcition is the same as the map function, except the map uses long and we need doubles
   if (update1) {
     update1 = false;
     
     ox = (x - xlo) * ( w) / (xhi - xlo) + gx;
     oy = (y - ylo) * (gy - h - gy) / (yhi - ylo) + gy;
 
     if ((ox < gx) || (ox > gx+w)) {update1 = true; return;}
     if ((oy < gy-h) || (oy > gy)) {update1 = true; return;}
     
 
     tft.setTextDatum(MR_DATUM);
 
     // draw y scale
     for ( i = ylo; i <= yhi; i += yinc) {
       // compute the transform
       temp =  (i - ylo) * (gy - h - gy) / (yhi - ylo) + gy;
 
       if (i == 0) {
         tft.setTextColor(acolor, bcolor);
         tft.drawString(xlabel, (int)(gx + w) , (int)temp, 2);
       }
       // draw the axis labels
       tft.setTextColor(tcolor, bcolor);
       // precision is default Arduino--this could really use some format control
       tft.drawFloat(i, dp, gx - 4, temp, 1);
     }
 
     // draw x scale
     for (i = xlo; i <= xhi; i += xinc) {
 
       // compute the transform
       temp =  (i - xlo) * ( w) / (xhi - xlo) + gx;
       if (i == 0) {
         tft.setTextColor(acolor, bcolor);
         tft.setTextDatum(BC_DATUM);
         tft.drawString(ylabel, (int)temp, (int)(gy - h - 8) , 2);
       }
 
       // draw the axis labels
       tft.setTextColor(tcolor, bcolor);
       tft.setTextDatum(TC_DATUM);
       // precision is default Arduino--this could really use some format control
       tft.drawFloat(i, dp, temp, gy + 7, 1);
     }
 
     //now draw the graph labels
     tft.setTextColor(tcolor, bcolor);
     tft.drawString(title, (int)(gx + w / 2) , (int)(gy - h - 30), 4);
   }
 
   // the coordinates are now drawn, plot the data
   // the entire plotting code are these few lines...
   // recall that ox and oy are initialized above
   x =  (x - xlo) * ( w) / (xhi - xlo) + gx;
   y =  (y - ylo) * (gy - h - gy) / (yhi - ylo) + gy;
 
   if ((x < gx) || (x > gx+w)) {update1 = true; return;}
   if ((y < gy-h) || (y > gy)) {update1 = true; return;}
     
     
   tft.drawLine(ox, oy, x, y, pcolor);
   // it's up to you but drawing 2 more lines to give the graph some thickness
   //tft.drawLine(ox, oy + 1, x, y + 1, pcolor);
   //tft.drawLine(ox, oy - 1, x, y - 1, pcolor);
   ox = x;
   oy = y;
 
 }
 
 /*
 
   End of graphing function
 
 */
 
 
 
 void setup() {
   double x, y;
 
   tft.begin();
   tft.fillScreen(BLACK);
   tft.setRotation(1);
 
   Graph(tft, x, y, 1, 60, 290, 390, 260, 0, 6.5, 1, -1, 1, .25, "", "", "", display1, YELLOW);
 
   //delay(1000);
   
   update1 = true;
   for (x = 0; x <= 6.3; x += .1) {
     y = sin(x);
     Trace(tft, x, y, 1, 60, 290, 390, 260, 0, 6.5, 1, -1, 1, .25, "Sin(x)", "x", "fn(x)", update1, YELLOW);
   }
 
   delay(2000);
 
   update1 = true;
   for (x = 0; x <= 6.3; x += .1) {
     y = cos(x);
     Trace(tft, x, y, 1, 60, 290, 390, 260, 0, 6.5, 1, -1, 1, .25, "Sin(x) + Cos(x)", " x", "fn(x)", update1, TFT_PINK);
   }
 
   delay(2000);
   
   update1 = true;
   for (x = 0; x <= 6.3; x += .02) {
     y = tan(x);
     Trace(tft, x, y, 1, 60, 290, 390, 260, 0, 6.5, 1, -1, 1, .25, "Sin(x) + Cos(x) + Tan(x)", " x", "fn(x)", update1, CYAN);
   }
 }
 
 
 void loop(void) {
 
 }
 
 
 
 

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