RGB LED Matrix + Raspberry Pi = Analog Clock

analog-clock.cc

// -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
// Small example how to use the library.
// For more examples, look at demo-main.cc
//
// This code is public domain
// (but note, that the led-matrix library this depends on is GPL v2)

#include "led-matrix.h"

#include <unistd.h>
#include <math.h>
#include <stdio.h>
#include <signal.h>
#include <getopt.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

using rgb_matrix::GPIO;
using rgb_matrix::RGBMatrix;
using rgb_matrix::Canvas;

// IntPoint data type
struct IntPoint
{
	int X;
	int Y;
	IntPoint(int InX, int InY)
	{
		X = InX;
		Y = InY;
	}
};

// Color data type
struct Color
{
	int R;
	int G;
	int B;
	Color(int InR, int InG, int InB)
	{
		R = InR;
		G = InG;
		B = InB;
	}
};

volatile bool interrupt_received = false;
static void InterruptHandler(int signo) {
  interrupt_received = true;
}
/*
static int abs(int n)
{
  if (n >= 0)
    return n;
  else
    return n * -1;
}
*/
// Parse a string into a color
static bool parseColor(Color *color, const char *str)
{
  return sscanf(str, "%hhu,%hhu,%hhu", &color->R, &color->G, &color->B) == 3;
}

// Function do draw a circle with given radius and center point
static void DrawCircle(Canvas *canvas, float radius, IntPoint center, Color color)
{
    /*float angleStep = 1.0 / 360;

    for (float a = 0, r = 0; r < radius; a+= angleStep, r+= angleStep) {
        float dotX = cos(a * 2 * M_PI) * r;
        float dotY = sin(a * 2 * M_PI) * r;

        canvas->SetPixel(center.X + dotX, center.Y + dotY, color.R, color.G, color.B);
    }*/
    
    for (int y = -radius; y <= radius; y++)
    {
      for(int x = -radius; x <= radius; x++)
      {
        if (x*x + y*y <= radius*radius + radius * 0.8)
        {
          canvas->SetPixel(center.X + x, center.Y + y, color.R, color.G, color.B);
        }
      }
    }
}

// Function to fill a specific area with color
static void FillArea(Canvas *canvas, IntPoint topLeft, IntPoint bottomRight, Color color)
{
	for (int x = topLeft.X; x <= bottomRight.X; x++)
	{
		for (int y = topLeft.Y; y <= bottomRight.Y; y++)
		{
			canvas->SetPixel(x, y, color.R, color.G, color.B);
		}
	}
}

// Function to draw a line from point A to point B
static void DrawLine(Canvas *canvas, IntPoint A, IntPoint B, Color color)
{
  int deltaX = B.X - A.X;
  signed char const ix = (deltaX > 0) - (deltaX < 0);
  deltaX = 2 * abs(deltaX);
  
  int deltaY = B.Y - A.Y;
  signed char const iy = (deltaY > 0) - (deltaY < 0);
  deltaY = 2 * abs(deltaY);
  
  int x1 = A.X;
  int y1 = A.Y;
  int x2 = B.X;
  int y2 = B.Y;
  
  canvas->SetPixel(x1, y1, color.R, color.G, color.B);
  
  if (deltaX >= deltaY)
  {
    int error = deltaY - (deltaX / 2);
    
    while (x1 != x2)
    {
      if ((error > 0) || (!error && (ix > 0)))
      {
        error -= deltaX;
        y1 += iy;
      }
      
      error += deltaY;
      x1 += ix;
      
      canvas->SetPixel(x1, y1, color.R, color.G, color.B);
    }
  } 
  else
  {
    int error = deltaX - (deltaY / 2);
    
    while (y1 != y2)
    {
      if ((error > 0) || (!error && (iy > 0)))
      {
        error -= deltaY;
        x1 += ix;
      }
      
      error += deltaX;
      y1 += iy;
      
      canvas->SetPixel(x1, y1, color.R, color.G, color.B);
    }
  }
}

static IntPoint CalculatePointerEndPoint(float progress, int pointerLength, IntPoint origin)
{
  IntPoint result = IntPoint(0,0);
  
  result.X = origin.X + pointerLength * cos((progress * 2 * M_PI) - M_PI / 2);
  result.Y = origin.Y + pointerLength * sin((progress * 2 * M_PI) - M_PI / 2);

  //printf("Progress: %f, Angle: %f, nPi: %f, res: %d,%d\n", progress, progress * 360.0, progress * 2 * M_PI, result.X, result.Y);

  return result;
}

static void printUsage()
{
  printf("Invalid command line. Options:\n");
  printf("\t-o <r,g,b>  : Clock circle and center point color. Default 255,0,0.\n");
  printf("\t-h <r,g,b>  : Hour pointer color. Default 0,255,0.\n");
  printf("\t-m <r,g,b>  : Minute pointer color. Default 0,255,0.\n");
  printf("\t-s <r,g,b>  : Second pointer color. Default 0,0,255.\n");
  printf("\t-r <radius> : Clock radius. Default 25.\n");
  printf("\t-d <depth>  : Outer circle depth. Default 2.\n");
}

// Main function
int main(int argc, char *argv[])
{
	// Set up display
	RGBMatrix::Options defaults;
	defaults.hardware_mapping = "regular";  // or e.g. "adafruit-hat"
	defaults.rows = 64;
	defaults.chain_length = 2;
	defaults.parallel = 1;
	defaults.show_refresh_rate = true;

	Canvas *canvas = rgb_matrix::CreateMatrixFromFlags(&argc, &argv, &defaults);
	if (canvas == NULL)
		return 1;
   
  // Adjustable settings
  Color outlineColor = Color(255,0,0);
  Color hourPointerColor = Color(0,255,0);
  Color minPointerColor = Color(0,255,0);
  Color secPointerColor = Color(0,0,255);
  int clockRadius = 25;
  int circleDepth = 2;
 
  int opt;
  while ((opt = getopt(argc, argv, "o:h:m:s:r:d:")) != -1)
  {
    switch(opt)
    {
      case 'o':
        if (!parseColor(&outlineColor, optarg))
        {
          printf("Invalid outline color: %s\n", optarg);
          printUsage();
        }
        break;
      case 'h':
        if (!parseColor(&hourPointerColor, optarg))
        {
          printf("Invalid hour pointer color: %s\n", optarg);
          printUsage();
        }
        break;
      case 'm':
        if (!parseColor(&minPointerColor, optarg))
        {
          printf("Invalid min pointer color: %s\n", optarg);
          printUsage();
        }
        break;
      case 's':
        if (!parseColor(&secPointerColor, optarg))
        {
          printf("Invalid sec pointer color: %s\n", optarg);
          printUsage();
        }
        break;
      case 'r': clockRadius = atoi(optarg); break;
      case 'd': circleDepth = atoi(optarg); break;
      default:
        printUsage();
        break;
    }
  }
 
	// Set up interrupt handlers
	signal(SIGTERM, InterruptHandler);
	signal(SIGINT, InterruptHandler);
	
	IntPoint centerOfScreen = IntPoint(canvas->width() / 2, canvas->height() / 2);
	
	// Draw clock circle
	DrawCircle(canvas, clockRadius, centerOfScreen, outlineColor);
	DrawCircle(canvas, clockRadius - circleDepth, centerOfScreen, Color(0,0,0));
	
	// Draw center clock point
	FillArea(canvas, IntPoint(centerOfScreen.X - 1, centerOfScreen.Y - 1), IntPoint(centerOfScreen.X + 1, centerOfScreen.Y + 1), Color(255,0,0));

  struct timespec next_time;
  next_time.tv_sec = time(NULL);
  next_time.tv_nsec = 0;
  struct tm tm;
  
  IntPoint lastHourPointerEnd = IntPoint(0,0);
  
  while (!interrupt_received)
  {
    localtime_r(&next_time.tv_sec, &tm);
    
    // Remove pointers from last tick
    DrawLine(canvas, centerOfScreen, lastHourPointerEnd, Color(0,0,0));
    DrawLine(canvas, centerOfScreen, CalculatePointerEndPoint((tm.tm_min - 1) / 60.0, clockRadius - 5, centerOfScreen), Color(0,0,0));
    DrawLine(canvas, centerOfScreen, CalculatePointerEndPoint((tm.tm_sec - 1) / 60.0, clockRadius - 8, centerOfScreen), Color(0,0,0));
    
    // Draw new pointers
    lastHourPointerEnd = CalculatePointerEndPoint((tm.tm_hour / 12.0) + (tm.tm_min / 600.0), clockRadius - 11, centerOfScreen);
    DrawLine(canvas, centerOfScreen, lastHourPointerEnd, hourPointerColor);
    DrawLine(canvas, centerOfScreen, CalculatePointerEndPoint(tm.tm_min / 60.0, clockRadius - 5, centerOfScreen), minPointerColor);
    DrawLine(canvas, centerOfScreen, CalculatePointerEndPoint(tm.tm_sec / 60.0, clockRadius - 8, centerOfScreen), secPointerColor);
    
    // Draw center point on top
 	  FillArea(canvas, IntPoint(centerOfScreen.X - 1, centerOfScreen.Y - 1), IntPoint(centerOfScreen.X + 1, centerOfScreen.Y + 1), outlineColor);
    
    // Sleep for a second
    clock_nanosleep(CLOCK_REALTIME, TIMER_ABSTIME, &next_time, NULL);
    next_time.tv_sec += 1;
  }
	
	canvas->Clear();
	delete canvas;
	
	return 0;
}