Adafruit-GFX-Library/Adafruit_GFX.cpp

#include "Adafruit_GFX.h"
#include "glcdfont.c"
#include <avr/pgmspace.h>

// draw a circle outline
void Adafruit_GFX::drawCircle(uint8_t x0, uint8_t y0, uint8_t r, 
			uint8_t color) {
  int8_t f = 1 - r;
  int8_t ddF_x = 1;
  int8_t ddF_y = -2 * r;
  int8_t x = 0;
  int8_t y = r;

  drawPixel(x0, y0+r, color);
  drawPixel(x0, y0-r, color);
  drawPixel(x0+r, y0, color);
  drawPixel(x0-r, y0, color);

  while (x<y) {
    if (f >= 0) {
      y--;
      ddF_y += 2;
      f += ddF_y;
    }
    x++;
    ddF_x += 2;
    f += ddF_x;
  
    drawPixel(x0 + x, y0 + y, color);
    drawPixel(x0 - x, y0 + y, color);
    drawPixel(x0 + x, y0 - y, color);
    drawPixel(x0 - x, y0 - y, color);
    
    drawPixel(x0 + y, y0 + x, color);
    drawPixel(x0 - y, y0 + x, color);
    drawPixel(x0 + y, y0 - x, color);
    drawPixel(x0 - y, y0 - x, color);
    
  }
}

void Adafruit_GFX::fillCircle(uint8_t x0, uint8_t y0, uint8_t r, 
			uint8_t color) {
  int8_t f = 1 - r;
  int8_t ddF_x = 1;
  int8_t ddF_y = -2 * r;
  int8_t x = 0;
  int8_t y = r;

  drawFastVLine(x0, y0-r, r*2+1, color);

  while (x<y) {
    if (f >= 0) {
      y--;
      ddF_y += 2;
      f += ddF_y;
    }
    x++;
    ddF_x += 2;
    f += ddF_x;

    drawFastVLine(x0+x, y0-y, y*2+1, color);
    drawFastVLine(x0-x, y0-y, y*2+1, color);

    drawFastVLine(x0+y, y0-x, x*2+1, color);
    drawFastVLine(x0-y, y0-x, x*2+1, color);
  }
}

// bresenham's algorithm - thx wikpedia
void Adafruit_GFX::drawLine(int16_t x0, int16_t y0, 
				int16_t x1, int16_t y1, 
				uint8_t color) {
  int16_t steep = abs(y1 - y0) > abs(x1 - x0);
  if (steep) {
    swap(x0, y0);
    swap(x1, y1);
  }

  if (x0 > x1) {
    swap(x0, x1);
    swap(y0, y1);
  }

  int16_t dx, dy;
  dx = x1 - x0;
  dy = abs(y1 - y0);

  int16_t err = dx / 2;
  int16_t ystep;

  if (y0 < y1) {
    ystep = 1;
  } else {
    ystep = -1;
  }

  for (; x0<=x1; x0++) {
    if (steep) {
      drawPixel(y0, x0, color);
    } else {
      drawPixel(x0, y0, color);
    }
    err -= dy;
    if (err < 0) {
      y0 += ystep;
      err += dx;
    }
  }
}


// draw a rectangle
void Adafruit_GFX::drawRect(uint8_t x, uint8_t y, 
				uint8_t w, uint8_t h, 
				uint8_t color) {
  // stupidest version - update in subclasses if desired!
  for (uint8_t i=x; i<x+w; i++) {
    drawPixel(i, y, color);
    drawPixel(i, y+h-1, color);
  }
  drawFastVLine(x, y, h, color);
  drawFastVLine(x+w-1, y, h, color);
}

void Adafruit_GFX::drawFastVLine(uint8_t x, uint8_t y, 
				     uint8_t h, uint8_t color) {
  // stupidest version - update in subclasses if desired!
  for (uint8_t j=y; j<y+h; j++) {
    drawPixel(x, j, color);
  }
}

void Adafruit_GFX::fillRect(uint8_t x, uint8_t y, uint8_t w, uint8_t h, 
		      uint8_t color) {
  // stupidest version - update in subclasses if desired!
  for (uint8_t i=x; i<x+w; i++) {
    drawFastVLine(i, y, h, color); 
  }
}

void Adafruit_GFX::drawBitmap(uint8_t x, uint8_t y, 
			const uint8_t *bitmap, uint8_t w, uint8_t h,
			uint8_t color) {
  for (uint8_t j=0; j<h; j++) {
    for (uint8_t i=0; i<w; i++ ) {
      if (pgm_read_byte(bitmap + i + (j/8)*w) & _BV(j%8)) {
	drawPixel(x+i, y+j, color);
      }
    }
  }
}


#if ARDUINO >= 100
size_t Adafruit_GFX::write(uint8_t c) {
#else
void Adafruit_GFX::write(uint8_t c) {
#endif
  if (c == '\n') {
    cursor_y += textsize*8;
    cursor_x = 0;
  } else if (c == '\r') {
    // skip em
  } else {
    drawChar(cursor_x, cursor_y, c, textcolor, textbgcolor, textsize);
    cursor_x += textsize*6;
  }
#if ARDUINO >= 100
  return 1;
#endif
}

// draw a character
void Adafruit_GFX::drawChar(uint8_t x, uint8_t y, char c,
				uint16_t color, uint16_t bg, uint8_t size) {
  for (uint8_t i=0; i<6; i++ ) {
    uint8_t line;
    if (i == 5) 
      line = 0x0;
    else 
      line = pgm_read_byte(font+(c*5)+i);
    for (uint8_t j = 0; j<8; j++) {
      if (line & 0x1) {
        if (size == 1) // default size
          drawPixel(x+i, y+j, color);
        else {  // big size
          fillRect(x+(i*size), y+(j*size), size, size, color);
        } 
      } else if (bg != color) {
        if (size == 1) // default size
          drawPixel(x+i, y+j, bg);
        else {  // big size
          fillRect(x+i*size, y+j*size, size, size, bg);
        } 	
      }
      line >>= 1;
    }
  }
}

void Adafruit_GFX::setCursor(uint16_t x, uint16_t y) {
  cursor_x = x;
  cursor_y = y;
}


void Adafruit_GFX::setTextSize(uint8_t s) {
  textsize = (s > 0) ? s : 1;
}


void Adafruit_GFX::setTextColor(uint16_t c) {
  textcolor = c;
  textbgcolor = c; 
  // for 'transparent' background, we'll set the bg 
  // to the same as fg instead of using a flag
}

 void Adafruit_GFX::setTextColor(uint16_t c, uint16_t b) {
  textcolor = c;
  textbgcolor = b; 
}