// Sketch to demonstrate smooth (anti-aliased) graphics funtions:
 // Smooth graphics result in less pixel resolution jaggedness.
 
 #include <TFT_eSPI.h> // Master copy here: https://github.com/Bodmer/TFT_eSPI
 
 TFT_eSPI tft = TFT_eSPI();  // Invoke library, pins defined in User_Setup.h
 
 TFT_eSprite spr = TFT_eSprite(&tft);
 
 // =========================================================================
 // Setup
 // =========================================================================
 void setup() {
   Serial.begin(115200);
   Serial.println("Booting...");
 
   // Initialise the screen
   tft.init();
 
   // Ideally set orientation for good viewing angle range because
   // the anti-aliasing effectiveness varies with screen viewing angle
   tft.setRotation(0);
 
   tft.fillScreen(TFT_BLACK);
 
   // Small sprite for spot demo
   spr.createSprite(23, 23);
 }
 
 // =========================================================================
 // Loop
 // =========================================================================
 void loop() {
 
   // drawSpot is for small anti-aliased circles, coordinates and radius are
   // floating point to allow sub-pixel positioning (large circles will
   // be slow to draw). Use fillSmoothCircle() for large circles.
   // In this case black is the backgorund colour for the anti-aliasing
   float x = 10.5;
   float y = 10.5;
   float r = 8.6;
   tft.drawSpot(x, y, r, TFT_WHITE, TFT_BLACK);
 
   // Fill sprite with a colour
   spr.fillSprite(TFT_RED);
   // Draw spot in sprite, the backgorund colour is ommitted so function
   // reads background colour for aliasing. (To use this method with direct write
   // to TFT (tft.drawSpot...) requires the capability to read data from the TFT!)
   spr.drawSpot(x, y, r, TFT_WHITE);
   spr.pushSprite(21, 0);
 
 
   // Draw a segmented ring meter type display
   // Centre of screen
   int cx = tft.width()  / 2;
   int cy = tft.height() / 2;
 
   // Inner and outer radius of ring
   float r1 = min(cx, cy) - 40.0;
   float r2 = min(cx, cy) - 10.0;
 
   // Inner and outer line width
   int w1 = r1 / 25;
   int w2 = r2 / 20;
 
   // The following will be updated by the getCoord function
   float px1 = 0.0;
   float py1 = 0.0;
   float px2 = 0.0;
   float py2 = 0.0;
 
   // Wedge line function, an anti-aliased wide line between 2 points, with different
   // line widths at the two ends. Background colour is black.
   for (int angle = -130; angle <= 130; angle += 10) {
     getCoord(cx, cy, &px1, &py1, &px2, &py2, r1, r2, angle);
     uint16_t colour = rainbow(map(angle, -130, 130, 0, 127));
     if (angle > 45) colour = TFT_DARKGREY;
     tft.drawWedgeLine(px1, py1, px2, py2, w1, w2, colour, TFT_BLACK);
   }
 
   // Smooth dark red filled circle
   tft.fillSmoothCircle(cx, cy, r1 - 8, TFT_MAROON, TFT_BLACK);
 
   // Draw a white dial pointer using wedge line function
   getCoord(cx, cy, &px1, &py1, &px2, &py2, 0, r1 - 10, 45);
   // Magenta wedge line pointer on red background
   // Line tapers from radius 5 to zero
   tft.drawWedgeLine(cx, cy, px2, py2, 5, 0, TFT_WHITE, TFT_MAROON);
 
   delay(5000);
 
   // Test wideLine function
   tft.fillScreen(TFT_BLACK);
 
   // Line width
   int wd = 5;
 
   // Screen limits
   int w = tft.width() - wd;
   int h = tft.height() - wd;
 
   // Line end coords
   int x1 = w - 1;
   int x2 = w - 1;
   int y1 = h - 1;
   int y2 = wd;
 
   for (x2 = wd; x2 < w; x2 += wd * 3) tft.drawWideLine(x1, y1, x2, y2, wd, TFT_WHITE, TFT_BLACK);
 
   x2    = wd;
   for (y2 = wd; y2 < h; y2 += wd * 4) tft.drawWideLine(x1, y1, x2, y2, wd, TFT_WHITE, TFT_BLACK);
 
   delay(5000);
 
   // Demo filled smooth rounded rectangle
   tft.fillScreen(TFT_BLACK);
 
   x1 = 30;
   y1 = 30;
   w = tft.width() - 2 * x1;
   h = tft.height() - 2 * y1;
   int rad = 30;
 
   tft.fillSmoothRoundRect(x1, y1, w, h, rad, TFT_CYAN, TFT_BLACK);
 
   // Wait forever
   while (1) delay(100);
 }
 
 
 // =========================================================================
 // Get coordinates of two ends of a line from r1 to r2, pivot at x,y, angle a
 // =========================================================================
 // Coordinates are returned to caller via the xp and yp pointers
 #define DEG2RAD 0.0174532925
 void getCoord(int16_t x, int16_t y, float *xp1, float *yp1, float *xp2, float *yp2, int16_t r1, int16_t r2, float a)
 {
   float sx = cos( (a - 90) * DEG2RAD);
   float sy = sin( (a - 90) * DEG2RAD);
   *xp1 =  sx * r1 + x;
   *yp1 =  sy * r1 + y;
   *xp2 =  sx * r2 + x;
   *yp2 =  sy * r2 + y;
 }
 
 // =========================================================================
 // Return a 16 bit rainbow colour
 // =========================================================================
 unsigned int rainbow(byte value)
 {
   // Value is expected to be in range 0-127
   // The value is converted to a spectrum colour from 0 = blue through to 127 = red
 
   byte red = 0; // Red is the top 5 bits of a 16 bit colour value
   byte green = 0;// Green is the middle 6 bits
   byte blue = 0; // Blue is the bottom 5 bits
 
   byte quadrant = value / 32;
 
   if (quadrant == 0) {
     blue = 31;
     green = 2 * (value % 32);
     red = 0;
   }
   if (quadrant == 1) {
     blue = 31 - (value % 32);
     green = 63;
     red = 0;
   }
   if (quadrant == 2) {
     blue = 0;
     green = 63;
     red = value % 32;
   }
   if (quadrant == 3) {
     blue = 0;
     green = 63 - 2 * (value % 32);
     red = 31;
   }
   return (red << 11) + (green << 5) + blue;
 }

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