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