directory move

picocalc/libraries/TFT_eSPI/examples/320 x 240/TFT_Pie_Chart/TFT_Pie_Chart.ino

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+// This sketch includes a function to draw circle segments
+// for pie charts in 1 degree increments
+
+#include <TFT_eSPI.h> // Hardware-specific library
+#include <SPI.h>
+
+TFT_eSPI tft = TFT_eSPI(); // Invoke custom library
+
+#define DEG2RAD 0.0174532925
+
+byte inc = 0;
+unsigned int col = 0;
+
+
+void setup(void)
+{
+  tft.begin();
+
+  tft.setRotation(1);
+
+  tft.fillScreen(TFT_BLACK);
+}
+
+void loop() {
+
+  // Draw 4 pie chart segments
+  fillSegment(160, 120, 0, 60, 100, TFT_RED);
+  fillSegment(160, 120, 60, 30, 100, TFT_GREEN);
+  fillSegment(160, 120, 60 + 30, 120, 100, TFT_BLUE);
+  fillSegment(160, 120, 60 + 30 + 120, 150, 100, TFT_YELLOW);
+
+  delay(4000);
+
+  // Erase old chart with 360 degree black plot
+  fillSegment(160, 120, 0, 360, 100, TFT_BLACK);
+}
+
+
+// #########################################################################
+// Draw circle segments
+// #########################################################################
+
+// x,y == coords of centre of circle
+// start_angle = 0 - 359
+// sub_angle   = 0 - 360 = subtended angle
+// r = radius
+// colour = 16 bit colour value
+
+int fillSegment(int x, int y, int start_angle, int sub_angle, int r, unsigned int colour)
+{
+  // Calculate first pair of coordinates for segment start
+  float sx = cos((start_angle - 90) * DEG2RAD);
+  float sy = sin((start_angle - 90) * DEG2RAD);
+  uint16_t x1 = sx * r + x;
+  uint16_t y1 = sy * r + y;
+
+  // Draw colour blocks every inc degrees
+  for (int i = start_angle; i < start_angle + sub_angle; i++) {
+
+    // Calculate pair of coordinates for segment end
+    int x2 = cos((i + 1 - 90) * DEG2RAD) * r + x;
+    int y2 = sin((i + 1 - 90) * DEG2RAD) * r + y;
+
+    tft.fillTriangle(x1, y1, x2, y2, x, y, colour);
+
+    // Copy segment end to sgement start for next segment
+    x1 = x2;
+    y1 = y2;
+  }
+}
+
+
+// #########################################################################
+// Return the 16 bit colour with brightness 0-100%
+// #########################################################################
+unsigned int brightness(unsigned int colour, int brightness)
+{
+  byte red   = colour >> 11;
+  byte green = (colour & 0x7E0) >> 5;
+  byte blue  = colour & 0x1F;
+
+  blue =  (blue * brightness)/100;
+  green = (green * brightness)/100;
+  red =   (red * brightness)/100;
+
+  return (red << 11) + (green << 5) + blue;
+}
+