/* Tiny TFT Graphics Library v2 - see http://www.technoblogy.com/show?L6I

   David Johnson-Davies - www.technoblogy.com - 14th January 2020
   ATtiny85 @ 8 MHz (internal oscillator; BOD disabled)
   
   CC BY 4.0
   Licensed under a Creative Commons Attribution 4.0 International license: 
   http://creativecommons.org/licenses/by/4.0/
*/

// Display dimensions - uncomment the one you want to use

// Adafruit 0.96" 80x160 display
int const ysize = 80, xsize = 160, yoff = 24, xoff = 0, invert = 0, rotate = 0;

// AliExpress 0.96" 80x160 display
//int const ysize = 80, xsize = 160, yoff = 26, xoff = 1, invert = 1, rotate = 0;

// Adafruit 1.44" 128x128 display
//int const ysize = 128, xsize = 128, yoff = 3, xoff = 2, invert = 0, rotate = 5;

// Adafruit 1.8" 128x160 display
//int const ysize = 128, xsize = 160, yoff = 0, xoff = 0, invert = 0, rotate = 0;

// Adafruit 1.54" 240x240 display and Adafruit 1.3" 240x240 display
//int const ysize = 240, xsize = 240, yoff = 0, xoff = 0, invert = 1, rotate = 3;

// ATtiny85 pins
int const dc = 0;
int const mosi = 1;
int const sck = 2;
int const cs = 3;

// Character set for text - stored in program memory
const uint8_t CharMap[96][6] PROGMEM = {
{ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }, 
{ 0x00, 0x00, 0x5F, 0x00, 0x00, 0x00 }, 
{ 0x00, 0x07, 0x00, 0x07, 0x00, 0x00 }, 
{ 0x14, 0x7F, 0x14, 0x7F, 0x14, 0x00 }, 
{ 0x24, 0x2A, 0x7F, 0x2A, 0x12, 0x00 }, 
{ 0x23, 0x13, 0x08, 0x64, 0x62, 0x00 }, 
{ 0x36, 0x49, 0x56, 0x20, 0x50, 0x00 }, 
{ 0x00, 0x08, 0x07, 0x03, 0x00, 0x00 }, 
{ 0x00, 0x1C, 0x22, 0x41, 0x00, 0x00 }, 
{ 0x00, 0x41, 0x22, 0x1C, 0x00, 0x00 }, 
{ 0x2A, 0x1C, 0x7F, 0x1C, 0x2A, 0x00 }, 
{ 0x08, 0x08, 0x3E, 0x08, 0x08, 0x00 }, 
{ 0x00, 0x80, 0x70, 0x30, 0x00, 0x00 }, 
{ 0x08, 0x08, 0x08, 0x08, 0x08, 0x00 }, 
{ 0x00, 0x00, 0x60, 0x60, 0x00, 0x00 }, 
{ 0x20, 0x10, 0x08, 0x04, 0x02, 0x00 }, 
{ 0x3E, 0x51, 0x49, 0x45, 0x3E, 0x00 }, 
{ 0x00, 0x42, 0x7F, 0x40, 0x00, 0x00 }, 
{ 0x72, 0x49, 0x49, 0x49, 0x46, 0x00 }, 
{ 0x21, 0x41, 0x49, 0x4D, 0x33, 0x00 }, 
{ 0x18, 0x14, 0x12, 0x7F, 0x10, 0x00 }, 
{ 0x27, 0x45, 0x45, 0x45, 0x39, 0x00 }, 
{ 0x3C, 0x4A, 0x49, 0x49, 0x31, 0x00 }, 
{ 0x41, 0x21, 0x11, 0x09, 0x07, 0x00 }, 
{ 0x36, 0x49, 0x49, 0x49, 0x36, 0x00 }, 
{ 0x46, 0x49, 0x49, 0x29, 0x1E, 0x00 }, 
{ 0x00, 0x00, 0x14, 0x00, 0x00, 0x00 }, 
{ 0x00, 0x40, 0x34, 0x00, 0x00, 0x00 }, 
{ 0x00, 0x08, 0x14, 0x22, 0x41, 0x00 }, 
{ 0x14, 0x14, 0x14, 0x14, 0x14, 0x00 }, 
{ 0x00, 0x41, 0x22, 0x14, 0x08, 0x00 }, 
{ 0x02, 0x01, 0x59, 0x09, 0x06, 0x00 }, 
{ 0x3E, 0x41, 0x5D, 0x59, 0x4E, 0x00 }, 
{ 0x7C, 0x12, 0x11, 0x12, 0x7C, 0x00 }, 
{ 0x7F, 0x49, 0x49, 0x49, 0x36, 0x00 }, 
{ 0x3E, 0x41, 0x41, 0x41, 0x22, 0x00 }, 
{ 0x7F, 0x41, 0x41, 0x41, 0x3E, 0x00 }, 
{ 0x7F, 0x49, 0x49, 0x49, 0x41, 0x00 }, 
{ 0x7F, 0x09, 0x09, 0x09, 0x01, 0x00 }, 
{ 0x3E, 0x41, 0x41, 0x51, 0x73, 0x00 }, 
{ 0x7F, 0x08, 0x08, 0x08, 0x7F, 0x00 }, 
{ 0x00, 0x41, 0x7F, 0x41, 0x00, 0x00 }, 
{ 0x20, 0x40, 0x41, 0x3F, 0x01, 0x00 }, 
{ 0x7F, 0x08, 0x14, 0x22, 0x41, 0x00 }, 
{ 0x7F, 0x40, 0x40, 0x40, 0x40, 0x00 }, 
{ 0x7F, 0x02, 0x1C, 0x02, 0x7F, 0x00 }, 
{ 0x7F, 0x04, 0x08, 0x10, 0x7F, 0x00 }, 
{ 0x3E, 0x41, 0x41, 0x41, 0x3E, 0x00 }, 
{ 0x7F, 0x09, 0x09, 0x09, 0x06, 0x00 }, 
{ 0x3E, 0x41, 0x51, 0x21, 0x5E, 0x00 }, 
{ 0x7F, 0x09, 0x19, 0x29, 0x46, 0x00 }, 
{ 0x26, 0x49, 0x49, 0x49, 0x32, 0x00 }, 
{ 0x03, 0x01, 0x7F, 0x01, 0x03, 0x00 }, 
{ 0x3F, 0x40, 0x40, 0x40, 0x3F, 0x00 }, 
{ 0x1F, 0x20, 0x40, 0x20, 0x1F, 0x00 }, 
{ 0x3F, 0x40, 0x38, 0x40, 0x3F, 0x00 }, 
{ 0x63, 0x14, 0x08, 0x14, 0x63, 0x00 }, 
{ 0x03, 0x04, 0x78, 0x04, 0x03, 0x00 }, 
{ 0x61, 0x59, 0x49, 0x4D, 0x43, 0x00 }, 
{ 0x00, 0x7F, 0x41, 0x41, 0x41, 0x00 }, 
{ 0x02, 0x04, 0x08, 0x10, 0x20, 0x00 }, 
{ 0x00, 0x41, 0x41, 0x41, 0x7F, 0x00 }, 
{ 0x04, 0x02, 0x01, 0x02, 0x04, 0x00 }, 
{ 0x40, 0x40, 0x40, 0x40, 0x40, 0x00 }, 
{ 0x00, 0x03, 0x07, 0x08, 0x00, 0x00 }, 
{ 0x20, 0x54, 0x54, 0x78, 0x40, 0x00 }, 
{ 0x7F, 0x28, 0x44, 0x44, 0x38, 0x00 }, 
{ 0x38, 0x44, 0x44, 0x44, 0x28, 0x00 }, 
{ 0x38, 0x44, 0x44, 0x28, 0x7F, 0x00 }, 
{ 0x38, 0x54, 0x54, 0x54, 0x18, 0x00 }, 
{ 0x00, 0x08, 0x7E, 0x09, 0x02, 0x00 }, 
{ 0x18, 0xA4, 0xA4, 0x9C, 0x78, 0x00 }, 
{ 0x7F, 0x08, 0x04, 0x04, 0x78, 0x00 }, 
{ 0x00, 0x44, 0x7D, 0x40, 0x00, 0x00 }, 
{ 0x20, 0x40, 0x40, 0x3D, 0x00, 0x00 }, 
{ 0x7F, 0x10, 0x28, 0x44, 0x00, 0x00 }, 
{ 0x00, 0x41, 0x7F, 0x40, 0x00, 0x00 }, 
{ 0x7C, 0x04, 0x78, 0x04, 0x78, 0x00 }, 
{ 0x7C, 0x08, 0x04, 0x04, 0x78, 0x00 }, 
{ 0x38, 0x44, 0x44, 0x44, 0x38, 0x00 }, 
{ 0xFC, 0x18, 0x24, 0x24, 0x18, 0x00 }, 
{ 0x18, 0x24, 0x24, 0x18, 0xFC, 0x00 }, 
{ 0x7C, 0x08, 0x04, 0x04, 0x08, 0x00 }, 
{ 0x48, 0x54, 0x54, 0x54, 0x24, 0x00 }, 
{ 0x04, 0x04, 0x3F, 0x44, 0x24, 0x00 }, 
{ 0x3C, 0x40, 0x40, 0x20, 0x7C, 0x00 }, 
{ 0x1C, 0x20, 0x40, 0x20, 0x1C, 0x00 }, 
{ 0x3C, 0x40, 0x30, 0x40, 0x3C, 0x00 }, 
{ 0x44, 0x28, 0x10, 0x28, 0x44, 0x00 }, 
{ 0x4C, 0x90, 0x90, 0x90, 0x7C, 0x00 }, 
{ 0x44, 0x64, 0x54, 0x4C, 0x44, 0x00 }, 
{ 0x00, 0x08, 0x36, 0x41, 0x00, 0x00 }, 
{ 0x00, 0x00, 0x77, 0x00, 0x00, 0x00 }, 
{ 0x00, 0x41, 0x36, 0x08, 0x00, 0x00 }, 
{ 0x00, 0x06, 0x09, 0x06, 0x00, 0x00 },  // degree symbol = '~'
{ 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00 }
};

// TFT colour display **********************************************

int const CASET = 0x2A; // Define column address
int const RASET = 0x2B; // Define row address
int const RAMWR = 0x2C; // Write to display RAM

// Current plot position and colours
int x0, y0;
int fore = 0xFFFF; // White
int back = 0;      // Black
int scale = 1;     // Text scale

// Send a byte to the display
void Data (uint8_t d) {
  for (uint8_t bit = 0x80; bit; bit >>= 1) {
    PINB = 1<<sck;                         // sck low
    if (d & bit) PORTB = PORTB | (1<<mosi); else PORTB = PORTB & ~(1<<mosi);
    PINB = 1<<sck;                         // sck high
  }
}

// Send a command to the display
void Command (uint8_t c) {
    PINB = 1<<dc;                          // dc low
    Data(c);
    PINB = 1<<dc;                          // dc high again
}

// Send a command followed by two data words
void Command2 (uint8_t c, uint16_t d1, uint16_t d2) {
    PINB = 1<<dc;                          // dc low
    Data(c);
    PINB = 1<<dc;                          // dc high again
    Data(d1>>8); Data(d1); Data(d2>>8); Data(d2);
}
  
void InitDisplay () {
  DDRB = 1<<dc | 1<<cs | 1<<mosi | 1<<sck; // All outputs
  PORTB = 1<<sck | 1<<cs | 1<<dc;          // clk, dc, and cs high
  PINB = 1<<cs;                            // cs low
  Command(0x01);                           // Software reset
  delay(150);                              // delay 150 ms
  Command(0x11);                           // Out of sleep mode
  delay(500);                              // delay 500 ms
  Command(0x3A); Data(0x05);               // Set color mode - 16-bit color
  Command(0x20+invert);                    // Invert
  Command(0x36); Data(rotate<<5);          // Set orientation
  PINB = 1<<cs;                            // cs high
}

void DisplayOn () {
  PINB = 1<<cs;                            // cs low
  Command(0x29);                           // Display on
  delay(100);
  PINB = 1<<cs;                            // cs high
}

void ClearDisplay () {
  PINB = 1<<cs;                            // cs low
  Command2(CASET, yoff, yoff + ysize - 1);
  Command2(RASET, xoff, xoff + xsize - 1);
  Command(0x3A); Data(0x03);               // 12-bit colour
  Command(RAMWR);
  for (int i=0; i<xsize/2; i++) {
    for (int j=0; j<ysize * 3; j++) {
      Data(0);
    }
  }
  Command(0x3A); Data(0x05);               // Back to 16-bit colour
  PINB = 1<<cs;                            // cs high
}

unsigned int Colour (int r, int g, int b) {
  return (r & 0xf8)<<8 | (g & 0xfc)<<3 | b>>3;
}

// Move current plot position to x,y
void MoveTo (int x, int y) {
  x0 = x; y0 = y;
}

// Plot point at x,y
void PlotPoint (int x, int y) {
  PINB = 1<<cs;                            // cs low
  Command2(CASET, yoff+y, yoff+y);
  Command2(RASET, xoff+x, xoff+x);
  Command(RAMWR); Data(fore>>8); Data(fore & 0xff);
  PINB = 1<<cs;                            // cs high
}

// Draw a line to x,y
void DrawTo (int x, int y) {
  int sx, sy, e2, err;
  int dx = abs(x - x0);
  int dy = abs(y - y0);
  if (x0 < x) sx = 1; else sx = -1;
  if (y0 < y) sy = 1; else sy = -1;
  err = dx - dy;
  for (;;) {
    PlotPoint(x0, y0);
    if (x0==x && y0==y) return;
    e2 = err<<1;
    if (e2 > -dy) { err = err - dy; x0 = x0 + sx; }
    if (e2 < dx) { err = err + dx; y0 = y0 + sy; }
  }
}

void FillRect (int w, int h) {
  PINB = 1<<cs;                            // cs low
  Command2(CASET, y0+yoff, y0+yoff+h-1);
  Command2(RASET, x0+xoff, x0+xoff+w-1);
  Command(RAMWR);
  for (int p=0; p<w*h*2; p++) {
    Data(fore>>8); Data(fore & 0xff);
  }
  PINB = 1<<cs;                            // cs high
}

// Plot an ASCII character with bottom left corner at x,y
void PlotChar (char c) {
  int colour;
  PINB = 1<<cs;                            // cs low
  Command2(CASET, yoff+y0, yoff+y0+8*scale-1);
  Command2(RASET, xoff+x0, xoff+x0+6*scale-1);
  Command(RAMWR);
  for (int xx=0; xx<6; xx++) {
    int bits = pgm_read_byte(&CharMap[c-32][xx]);
    for (int xr=0; xr<scale; xr++) {
      for (int yy=0; yy<8; yy++) {
        if (bits>>(7-yy) & 1) colour = fore; else colour = back;
        for (int yr=0; yr<scale; yr++) {
          Data(colour>>8); Data(colour & 0xFF);
        }
      }
    }
  }
  PINB = 1<<cs;                            // cs high
  x0 = x0 + 6*scale;
}

// Plot text starting at the current plot position
void PlotText(PGM_P p) {
  while (1) {
    char c = pgm_read_byte(p++);
    if (c == 0) return;
    PlotChar(c);
  }
}

void TestChart () {
  MoveTo(0,0);
  DrawTo(xsize-1, 0); DrawTo(xsize-1, ysize-1);
  DrawTo(0, ysize-1); DrawTo(0, 0);
  scale=8;
  MoveTo((xsize-40)/2, (ysize-64)/2); PlotChar('F');
}

// Setup **********************************************

void setup() {
  InitDisplay();
  ClearDisplay();
  DisplayOn();
  MoveTo(0,0);
}

void loop () {
  // Plot bar chart
  int x1 = 15, y1 = 11;                    // Origin
  MoveTo((xsize-x1-90)/2+x1, ysize-8); PlotText(PSTR("Sensor Readings"));
  // Horizontal axis
  int xinc = (xsize-x1)/20;
  MoveTo(x1, y1); DrawTo(xsize-1, y1);
  for (int i=0; i<=20; i=i+4) {
    int mark = x1+i*xinc;
    MoveTo(mark, y1); DrawTo(mark, y1-2);
    // Draw histogram
    if (i != 20) {
      int bar = xinc*4/3;
      fore = Colour(0, 0, 255);
      MoveTo(mark+bar*2-1,y1+1); FillRect(bar, 5+random(ysize-y1-20));
      fore = Colour(0, 255, 0);
      MoveTo(mark+bar,y1+1); FillRect(bar, 5+random(ysize-y1-20));
      fore = Colour(255, 0, 0);
      MoveTo(mark+1,y1+1); FillRect(bar, 5+random(ysize-y1-20));
      fore = 0xFFFF;
    }
    int tens = i/10;
    if (tens != 0) {
      MoveTo(mark-7, y1-11); PlotChar(tens+'0');
      MoveTo(mark-1, y1-11); PlotChar(i%10+'0');
    } else { MoveTo(mark-3, y1-11); PlotChar(i%10+'0'); }
  }
  // Vertical axis
  int yinc = (ysize-y1)/20;
  MoveTo(x1, y1); DrawTo(x1, ysize-1);
  for (int i=0; i<=20; i=i+5) {
    int mark = y1+i*yinc;
    MoveTo(x1, mark); DrawTo(x1-2, mark);
    int tens = i/10;
    if (tens != 0) { MoveTo(x1-15, mark-3); PlotChar(tens+'0'); }
    MoveTo(x1-9, mark-3); PlotChar(i%10+'0');
  }
  for (;;);
}