Adafruit_GFX.cpp

/*
This is the core graphics library for all our displays, providing a common
set of graphics primitives (points, lines, circles, etc.).  It needs to be
paired with a hardware-specific library for each display device we carry
(to handle the lower-level functions).
 
Adafruit invests time and resources providing this open source code, please
support Adafruit & open-source hardware by purchasing products from Adafruit!
 
Copyright (c) 2013 Adafruit Industries.  All rights reserved.
 
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
 
- Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
 
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
 */
 
#include "Adafruit_GFX.h"
#include "glcdfont.c"
#ifdef __AVR__
#include <avr/pgmspace.h>
#elif defined(ESP8266) || defined(ESP32)
#include <pgmspace.h>
#endif
 
// Many (but maybe not all) non-AVR board installs define macros
// for compatibility with existing PROGMEM-reading AVR code.
// Do our own checks and defines here for good measure...
 
#ifndef pgm_read_byte
#define pgm_read_byte(addr) (*(const unsigned char *)(addr))
#endif
#ifndef pgm_read_word
#define pgm_read_word(addr) (*(const unsigned short *)(addr))
#endif
#ifndef pgm_read_dword
#define pgm_read_dword(addr) (*(const unsigned long *)(addr))
#endif
 
// Pointers are a peculiar case...typically 16-bit on AVR boards,
// 32 bits elsewhere.  Try to accommodate both...
 
#if !defined(__INT_MAX__) || (__INT_MAX__ > 0xFFFF)
#define pgm_read_pointer(addr) ((void *)pgm_read_dword(addr))
#else
#define pgm_read_pointer(addr) ((void *)pgm_read_word(addr))
#endif
 
inline GFXglyph *pgm_read_glyph_ptr(const GFXfont *gfxFont, uint8_t c) {
#ifdef __AVR__
  return &(((GFXglyph *)pgm_read_pointer(&gfxFont->glyph))[c]);
#else
  // expression in __AVR__ section may generate "dereferencing type-punned
  // pointer will break strict-aliasing rules" warning In fact, on other
  // platforms (such as STM32) there is no need to do this pointer magic as
  // program memory may be read in a usual way So expression may be simplified
  return gfxFont->glyph + c;
#endif //__AVR__
}
 
inline uint8_t *pgm_read_bitmap_ptr(const GFXfont *gfxFont) {
#ifdef __AVR__
  return (uint8_t *)pgm_read_pointer(&gfxFont->bitmap);
#else
  // expression in __AVR__ section generates "dereferencing type-punned pointer
  // will break strict-aliasing rules" warning In fact, on other platforms (such
  // as STM32) there is no need to do this pointer magic as program memory may
  // be read in a usual way So expression may be simplified
  return gfxFont->bitmap;
#endif //__AVR__
}
 
#ifndef min
#define min(a, b) (((a) < (b)) ? (a) : (b))
#endif
 
#ifndef _swap_int16_t
#define _swap_int16_t(a, b)                                                    \
  {                                                                            \
    int16_t t = a;                                                             \
    a = b;                                                                     \
    b = t;                                                                     \
  }
#endif
 
/**************************************************************************/
Adafruit_GFX::Adafruit_GFX(int16_t w, int16_t h) : WIDTH(w), HEIGHT(h) {
  _width = WIDTH;
  _height = HEIGHT;
  rotation = 0;
  cursor_y = cursor_x = 0;
  textsize_x = textsize_y = 1;
  textcolor = textbgcolor = 0xFFFF;
  wrap = true;
  _cp437 = false;
  gfxFont = NULL;
}
 
/**************************************************************************/
void Adafruit_GFX::writeLine(int16_t x0, int16_t y0, int16_t x1, int16_t y1,
                             uint16_t color) {
#if defined(ESP8266)
  yield();
#endif
  int16_t steep = abs(y1 - y0) > abs(x1 - x0);
  if (steep) {
    _swap_int16_t(x0, y0);
    _swap_int16_t(x1, y1);
  }
 
  if (x0 > x1) {
    _swap_int16_t(x0, x1);
    _swap_int16_t(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) {
      writePixel(y0, x0, color);
    } else {
      writePixel(x0, y0, color);
    }
    err -= dy;
    if (err < 0) {
      y0 += ystep;
      err += dx;
    }
  }
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::startWrite() {}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::writePixel(int16_t x, int16_t y, uint16_t color) {
  drawPixel(x, y, color);
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::writeFastVLine(int16_t x, int16_t y, int16_t h,
                                  uint16_t color) {
  // Overwrite in subclasses if startWrite is defined!
  // Can be just writeLine(x, y, x, y+h-1, color);
  // or writeFillRect(x, y, 1, h, color);
  drawFastVLine(x, y, h, color);
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::writeFastHLine(int16_t x, int16_t y, int16_t w,
                                  uint16_t color) {
  // Overwrite in subclasses if startWrite is defined!
  // Example: writeLine(x, y, x+w-1, y, color);
  // or writeFillRect(x, y, w, 1, color);
  drawFastHLine(x, y, w, color);
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::writeFillRect(int16_t x, int16_t y, int16_t w, int16_t h,
                                 uint16_t color) {
  // Overwrite in subclasses if desired!
  fillRect(x, y, w, h, color);
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::endWrite() {}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawFastVLine(int16_t x, int16_t y, int16_t h,
                                 uint16_t color) {
  startWrite();
  writeLine(x, y, x, y + h - 1, color);
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawFastHLine(int16_t x, int16_t y, int16_t w,
                                 uint16_t color) {
  startWrite();
  writeLine(x, y, x + w - 1, y, color);
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::fillRect(int16_t x, int16_t y, int16_t w, int16_t h,
                            uint16_t color) {
  startWrite();
  for (int16_t i = x; i < x + w; i++) {
    writeFastVLine(i, y, h, color);
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::fillScreen(uint16_t color) {
  fillRect(0, 0, _width, _height, color);
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawLine(int16_t x0, int16_t y0, int16_t x1, int16_t y1,
                            uint16_t color) {
  // Update in subclasses if desired!
  if (x0 == x1) {
    if (y0 > y1)
      _swap_int16_t(y0, y1);
    drawFastVLine(x0, y0, y1 - y0 + 1, color);
  } else if (y0 == y1) {
    if (x0 > x1)
      _swap_int16_t(x0, x1);
    drawFastHLine(x0, y0, x1 - x0 + 1, color);
  } else {
    startWrite();
    writeLine(x0, y0, x1, y1, color);
    endWrite();
  }
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawEllipse(int16_t x0, int16_t y0, int16_t rw, int16_t rh,
                               uint16_t color) {
#if defined(ESP8266)
  yield();
#endif
  // Bresenham's ellipse algorithm
  int16_t x = 0, y = rh;
  int32_t rw2 = rw * rw, rh2 = rh * rh;
  int32_t twoRw2 = 2 * rw2, twoRh2 = 2 * rh2;
 
  int32_t decision = rh2 - (rw2 * rh) + (rw2 / 4);
 
  startWrite();
 
  // region 1
  while ((twoRh2 * x) < (twoRw2 * y)) {
    writePixel(x0 + x, y0 + y, color);
    writePixel(x0 - x, y0 + y, color);
    writePixel(x0 + x, y0 - y, color);
    writePixel(x0 - x, y0 - y, color);
    x++;
    if (decision < 0) {
      decision += rh2 + (twoRh2 * x);
    } else {
      decision += rh2 + (twoRh2 * x) - (twoRw2 * y);
      y--;
    }
  }
 
  // region 2
  decision = ((rh2 * (2 * x + 1) * (2 * x + 1)) >> 2) +
             (rw2 * (y - 1) * (y - 1)) - (rw2 * rh2);
  while (y >= 0) {
    writePixel(x0 + x, y0 + y, color);
    writePixel(x0 - x, y0 + y, color);
    writePixel(x0 + x, y0 - y, color);
    writePixel(x0 - x, y0 - y, color);
    y--;
    if (decision > 0) {
      decision += rw2 - (twoRw2 * y);
    } else {
      decision += rw2 + (twoRh2 * x) - (twoRw2 * y);
      x++;
    }
  }
 
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::fillEllipse(int16_t x0, int16_t y0, int16_t rw, int16_t rh,
                               uint16_t color) {
#if defined(ESP8266)
  yield();
#endif
  // Bresenham's ellipse algorithm
  int16_t x = 0, y = rh;
  int32_t rw2 = rw * rw, rh2 = rh * rh;
  int32_t twoRw2 = 2 * rw2, twoRh2 = 2 * rh2;
 
  int32_t decision = rh2 - (rw2 * rh) + (rw2 / 4);
 
  startWrite();
 
  // region 1
  while ((twoRh2 * x) < (twoRw2 * y)) {
    x++;
    if (decision < 0) {
      decision += rh2 + (twoRh2 * x);
    } else {
      decision += rh2 + (twoRh2 * x) - (twoRw2 * y);
      drawFastHLine(x0 - (x - 1), y0 + y, 2 * (x - 1) + 1, color);
      drawFastHLine(x0 - (x - 1), y0 - y, 2 * (x - 1) + 1, color);
      y--;
    }
  }
 
  // region 2
  decision = ((rh2 * (2 * x + 1) * (2 * x + 1)) >> 2) +
             (rw2 * (y - 1) * (y - 1)) - (rw2 * rh2);
  while (y >= 0) {
    drawFastHLine(x0 - x, y0 + y, 2 * x + 1, color);
    drawFastHLine(x0 - x, y0 - y, 2 * x + 1, color);
 
    y--;
    if (decision > 0) {
      decision += rw2 - (twoRw2 * y);
    } else {
      decision += rw2 + (twoRh2 * x) - (twoRw2 * y);
      x++;
    }
  }
 
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawCircle(int16_t x0, int16_t y0, int16_t r,
                              uint16_t color) {
#if defined(ESP8266)
  yield();
#endif
  int16_t f = 1 - r;
  int16_t ddF_x = 1;
  int16_t ddF_y = -2 * r;
  int16_t x = 0;
  int16_t y = r;
 
  startWrite();
  writePixel(x0, y0 + r, color);
  writePixel(x0, y0 - r, color);
  writePixel(x0 + r, y0, color);
  writePixel(x0 - r, y0, color);
 
  while (x < y) {
    if (f >= 0) {
      y--;
      ddF_y += 2;
      f += ddF_y;
    }
    x++;
    ddF_x += 2;
    f += ddF_x;
 
    writePixel(x0 + x, y0 + y, color);
    writePixel(x0 - x, y0 + y, color);
    writePixel(x0 + x, y0 - y, color);
    writePixel(x0 - x, y0 - y, color);
    writePixel(x0 + y, y0 + x, color);
    writePixel(x0 - y, y0 + x, color);
    writePixel(x0 + y, y0 - x, color);
    writePixel(x0 - y, y0 - x, color);
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawCircleHelper(int16_t x0, int16_t y0, int16_t r,
                                    uint8_t cornername, uint16_t color) {
  int16_t f = 1 - r;
  int16_t ddF_x = 1;
  int16_t ddF_y = -2 * r;
  int16_t x = 0;
  int16_t y = r;
 
  while (x < y) {
    if (f >= 0) {
      y--;
      ddF_y += 2;
      f += ddF_y;
    }
    x++;
    ddF_x += 2;
    f += ddF_x;
    if (cornername & 0x4) {
      writePixel(x0 + x, y0 + y, color);
      writePixel(x0 + y, y0 + x, color);
    }
    if (cornername & 0x2) {
      writePixel(x0 + x, y0 - y, color);
      writePixel(x0 + y, y0 - x, color);
    }
    if (cornername & 0x8) {
      writePixel(x0 - y, y0 + x, color);
      writePixel(x0 - x, y0 + y, color);
    }
    if (cornername & 0x1) {
      writePixel(x0 - y, y0 - x, color);
      writePixel(x0 - x, y0 - y, color);
    }
  }
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::fillCircle(int16_t x0, int16_t y0, int16_t r,
                              uint16_t color) {
  startWrite();
  writeFastVLine(x0, y0 - r, 2 * r + 1, color);
  fillCircleHelper(x0, y0, r, 3, 0, color);
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::fillCircleHelper(int16_t x0, int16_t y0, int16_t r,
                                    uint8_t corners, int16_t delta,
                                    uint16_t color) {
 
  int16_t f = 1 - r;
  int16_t ddF_x = 1;
  int16_t ddF_y = -2 * r;
  int16_t x = 0;
  int16_t y = r;
  int16_t px = x;
  int16_t py = y;
 
  delta++; // Avoid some +1's in the loop
 
  while (x < y) {
    if (f >= 0) {
      y--;
      ddF_y += 2;
      f += ddF_y;
    }
    x++;
    ddF_x += 2;
    f += ddF_x;
    // These checks avoid double-drawing certain lines, important
    // for the SSD1306 library which has an INVERT drawing mode.
    if (x < (y + 1)) {
      if (corners & 1)
        writeFastVLine(x0 + x, y0 - y, 2 * y + delta, color);
      if (corners & 2)
        writeFastVLine(x0 - x, y0 - y, 2 * y + delta, color);
    }
    if (y != py) {
      if (corners & 1)
        writeFastVLine(x0 + py, y0 - px, 2 * px + delta, color);
      if (corners & 2)
        writeFastVLine(x0 - py, y0 - px, 2 * px + delta, color);
      py = y;
    }
    px = x;
  }
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawRect(int16_t x, int16_t y, int16_t w, int16_t h,
                            uint16_t color) {
  startWrite();
  writeFastHLine(x, y, w, color);
  writeFastHLine(x, y + h - 1, w, color);
  writeFastVLine(x, y, h, color);
  writeFastVLine(x + w - 1, y, h, color);
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawRoundRect(int16_t x, int16_t y, int16_t w, int16_t h,
                                 int16_t r, uint16_t color) {
  int16_t max_radius = ((w < h) ? w : h) / 2; // 1/2 minor axis
  if (r > max_radius)
    r = max_radius;
  // smarter version
  startWrite();
  writeFastHLine(x + r, y, w - 2 * r, color);         // Top
  writeFastHLine(x + r, y + h - 1, w - 2 * r, color); // Bottom
  writeFastVLine(x, y + r, h - 2 * r, color);         // Left
  writeFastVLine(x + w - 1, y + r, h - 2 * r, color); // Right
  // draw four corners
  drawCircleHelper(x + r, y + r, r, 1, color);
  drawCircleHelper(x + w - r - 1, y + r, r, 2, color);
  drawCircleHelper(x + w - r - 1, y + h - r - 1, r, 4, color);
  drawCircleHelper(x + r, y + h - r - 1, r, 8, color);
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::fillRoundRect(int16_t x, int16_t y, int16_t w, int16_t h,
                                 int16_t r, uint16_t color) {
  int16_t max_radius = ((w < h) ? w : h) / 2; // 1/2 minor axis
  if (r > max_radius)
    r = max_radius;
  // smarter version
  startWrite();
  writeFillRect(x + r, y, w - 2 * r, h, color);
  // draw four corners
  fillCircleHelper(x + w - r - 1, y + r, r, 1, h - 2 * r - 1, color);
  fillCircleHelper(x + r, y + r, r, 2, h - 2 * r - 1, color);
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawRotatedRect(int16_t cenX, int16_t cenY, int16_t w,
                                   int16_t h, int16_t angleDeg,
                                   uint16_t color) {
 
  if (w < 1 || h < 1)
    return; // We don't draw zero dimensioned objects
 
  int16_t W = w - 1;
  int16_t H = h - 1;
 
  int16_t halfW = (W / 2); // Midpoint should always be integer
  int16_t halfH = (H / 2); // Midpoint should always be integer
 
  int16_t x0 = W - halfW; // bottom-right
  int16_t y0 = H - halfH; // bottom-right
  int16_t x1 = -halfW;    // bottom-left
  int16_t y1 = H - halfH; // bottom-left
  int16_t x2 = -halfW;    // top-left
  int16_t y2 = -halfH;    // top-left
  int16_t x3 = W - halfW; // top-right
  int16_t y3 = -halfH;    // top-right
 
  rotatePoint(x0, y0, angleDeg);
  rotatePoint(x1, y1, angleDeg);
  rotatePoint(x2, y2, angleDeg);
  rotatePoint(x3, y3, angleDeg);
 
  x0 += cenX;
  x1 += cenX;
  x2 += cenX;
  x3 += cenX;
 
  y0 += cenY;
  y1 += cenY;
  y2 += cenY;
  y3 += cenY;
 
  drawLine(x0, y0, x1, y1, color); // bottom right to bottom left
  drawLine(x1, y1, x2, y2, color); // bottom left to top left
  drawLine(x2, y2, x3, y3, color); // top left to top right
  drawLine(x3, y3, x0, y0, color); // top right to bottom right
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::fillRotatedRect(int16_t cenX, int16_t cenY, int16_t w,
                                   int16_t h, int16_t angleDeg,
                                   uint16_t color) {
 
  if (w < 1 || h < 1)
    return; // We don't draw zero dimensioned objects
 
  int16_t W = w - 1;
  int16_t H = h - 1;
 
  int16_t halfW = (W / 2); // Midpoint should always be integer
  int16_t halfH = (H / 2); // Midpoint should always be integer
 
  int16_t x0 = W - halfW; // bottom-right
  int16_t y0 = H - halfH; // bottom-right
  int16_t x1 = -halfW;    // bottom-left
  int16_t y1 = H - halfH; // bottom-left
  int16_t x2 = -halfW;    // top-left
  int16_t y2 = -halfH;    // top-left
  int16_t x3 = W - halfW; // top-right
  int16_t y3 = -halfH;    // top-right
 
  rotatePoint(x0, y0, angleDeg);
  rotatePoint(x1, y1, angleDeg);
  rotatePoint(x2, y2, angleDeg);
  rotatePoint(x3, y3, angleDeg);
 
  x0 += cenX;
  x1 += cenX;
  x2 += cenX;
  x3 += cenX;
 
  y0 += cenY;
  y1 += cenY;
  y2 += cenY;
  y3 += cenY;
 
  fillTriangle(x0, y0, x1, y1, x2, y2, color);
  fillTriangle(x2, y2, x3, y3, x0, y0, color);
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::rotatePoint(int16_t &x0, int16_t &y0, int16_t angleDeg) {
  float angleRad = radians(angleDeg);
  float s = sin(angleRad);
  float c = cos(angleRad);
 
  float x = x0;
  float y = y0;
 
  // Rotate point
  x0 = (int16_t)((x * c) - (y * s));
  y0 = (int16_t)((x * s) + (y * c));
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawTriangle(int16_t x0, int16_t y0, int16_t x1, int16_t y1,
                                int16_t x2, int16_t y2, uint16_t color) {
  drawLine(x0, y0, x1, y1, color);
  drawLine(x1, y1, x2, y2, color);
  drawLine(x2, y2, x0, y0, color);
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::fillTriangle(int16_t x0, int16_t y0, int16_t x1, int16_t y1,
                                int16_t x2, int16_t y2, uint16_t color) {
 
  int16_t a, b, y, last;
 
  // Sort coordinates by Y order (y2 >= y1 >= y0)
  if (y0 > y1) {
    _swap_int16_t(y0, y1);
    _swap_int16_t(x0, x1);
  }
  if (y1 > y2) {
    _swap_int16_t(y2, y1);
    _swap_int16_t(x2, x1);
  }
  if (y0 > y1) {
    _swap_int16_t(y0, y1);
    _swap_int16_t(x0, x1);
  }
 
  startWrite();
  if (y0 == y2) { // Handle awkward all-on-same-line case as its own thing
    a = b = x0;
    if (x1 < a)
      a = x1;
    else if (x1 > b)
      b = x1;
    if (x2 < a)
      a = x2;
    else if (x2 > b)
      b = x2;
    writeFastHLine(a, y0, b - a + 1, color);
    endWrite();
    return;
  }
 
  int16_t dx01 = x1 - x0, dy01 = y1 - y0, dx02 = x2 - x0, dy02 = y2 - y0,
          dx12 = x2 - x1, dy12 = y2 - y1;
  int32_t sa = 0, sb = 0;
 
  // For upper part of triangle, find scanline crossings for segments
  // 0-1 and 0-2.  If y1=y2 (flat-bottomed triangle), the scanline y1
  // is included here (and second loop will be skipped, avoiding a /0
  // error there), otherwise scanline y1 is skipped here and handled
  // in the second loop...which also avoids a /0 error here if y0=y1
  // (flat-topped triangle).
  if (y1 == y2)
    last = y1; // Include y1 scanline
  else
    last = y1 - 1; // Skip it
 
  for (y = y0; y <= last; y++) {
    a = x0 + sa / dy01;
    b = x0 + sb / dy02;
    sa += dx01;
    sb += dx02;
    /* longhand:
    a = x0 + (x1 - x0) * (y - y0) / (y1 - y0);
    b = x0 + (x2 - x0) * (y - y0) / (y2 - y0);
    */
    if (a > b)
      _swap_int16_t(a, b);
    writeFastHLine(a, y, b - a + 1, color);
  }
 
  // For lower part of triangle, find scanline crossings for segments
  // 0-2 and 1-2.  This loop is skipped if y1=y2.
  sa = (int32_t)dx12 * (y - y1);
  sb = (int32_t)dx02 * (y - y0);
  for (; y <= y2; y++) {
    a = x1 + sa / dy12;
    b = x0 + sb / dy02;
    sa += dx12;
    sb += dx02;
    /* longhand:
    a = x1 + (x2 - x1) * (y - y1) / (y2 - y1);
    b = x0 + (x2 - x0) * (y - y0) / (y2 - y0);
    */
    if (a > b)
      _swap_int16_t(a, b);
    writeFastHLine(a, y, b - a + 1, color);
  }
  endWrite();
}
 
// BITMAP / XBITMAP / GRAYSCALE / RGB BITMAP FUNCTIONS ---------------------
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawBitmap(int16_t x, int16_t y, const uint8_t bitmap[],
                              int16_t w, int16_t h, uint16_t color) {
 
  int16_t byteWidth = (w + 7) / 8; // Bitmap scanline pad = whole byte
  uint8_t b = 0;
 
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      if (i & 7)
        b <<= 1;
      else
        b = pgm_read_byte(&bitmap[j * byteWidth + i / 8]);
      if (b & 0x80)
        writePixel(x + i, y, color);
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawBitmap(int16_t x, int16_t y, const uint8_t bitmap[],
                              int16_t w, int16_t h, uint16_t color,
                              uint16_t bg) {
 
  int16_t byteWidth = (w + 7) / 8; // Bitmap scanline pad = whole byte
  uint8_t b = 0;
 
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      if (i & 7)
        b <<= 1;
      else
        b = pgm_read_byte(&bitmap[j * byteWidth + i / 8]);
      writePixel(x + i, y, (b & 0x80) ? color : bg);
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawBitmap(int16_t x, int16_t y, uint8_t *bitmap, int16_t w,
                              int16_t h, uint16_t color) {
 
  int16_t byteWidth = (w + 7) / 8; // Bitmap scanline pad = whole byte
  uint8_t b = 0;
 
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      if (i & 7)
        b <<= 1;
      else
        b = bitmap[j * byteWidth + i / 8];
      if (b & 0x80)
        writePixel(x + i, y, color);
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawBitmap(int16_t x, int16_t y, uint8_t *bitmap, int16_t w,
                              int16_t h, uint16_t color, uint16_t bg) {
 
  int16_t byteWidth = (w + 7) / 8; // Bitmap scanline pad = whole byte
  uint8_t b = 0;
 
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      if (i & 7)
        b <<= 1;
      else
        b = bitmap[j * byteWidth + i / 8];
      writePixel(x + i, y, (b & 0x80) ? color : bg);
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawXBitmap(int16_t x, int16_t y, const uint8_t bitmap[],
                               int16_t w, int16_t h, uint16_t color) {
 
  int16_t byteWidth = (w + 7) / 8; // Bitmap scanline pad = whole byte
  uint8_t b = 0;
 
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      if (i & 7)
        b >>= 1;
      else
        b = pgm_read_byte(&bitmap[j * byteWidth + i / 8]);
      // Nearly identical to drawBitmap(), only the bit order
      // is reversed here (left-to-right = LSB to MSB):
      if (b & 0x01)
        writePixel(x + i, y, color);
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawGrayscaleBitmap(int16_t x, int16_t y,
                                       const uint8_t bitmap[], int16_t w,
                                       int16_t h) {
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      writePixel(x + i, y, (uint8_t)pgm_read_byte(&bitmap[j * w + i]));
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawGrayscaleBitmap(int16_t x, int16_t y, uint8_t *bitmap,
                                       int16_t w, int16_t h) {
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      writePixel(x + i, y, bitmap[j * w + i]);
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawGrayscaleBitmap(int16_t x, int16_t y,
                                       const uint8_t bitmap[],
                                       const uint8_t mask[], int16_t w,
                                       int16_t h) {
  int16_t bw = (w + 7) / 8; // Bitmask scanline pad = whole byte
  uint8_t b = 0;
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      if (i & 7)
        b <<= 1;
      else
        b = pgm_read_byte(&mask[j * bw + i / 8]);
      if (b & 0x80) {
        writePixel(x + i, y, (uint8_t)pgm_read_byte(&bitmap[j * w + i]));
      }
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawGrayscaleBitmap(int16_t x, int16_t y, uint8_t *bitmap,
                                       uint8_t *mask, int16_t w, int16_t h) {
  int16_t bw = (w + 7) / 8; // Bitmask scanline pad = whole byte
  uint8_t b = 0;
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      if (i & 7)
        b <<= 1;
      else
        b = mask[j * bw + i / 8];
      if (b & 0x80) {
        writePixel(x + i, y, bitmap[j * w + i]);
      }
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawRGBBitmap(int16_t x, int16_t y, const uint16_t bitmap[],
                                 int16_t w, int16_t h) {
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      writePixel(x + i, y, pgm_read_word(&bitmap[j * w + i]));
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawRGBBitmap(int16_t x, int16_t y, uint16_t *bitmap,
                                 int16_t w, int16_t h) {
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      writePixel(x + i, y, bitmap[j * w + i]);
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawRGBBitmap(int16_t x, int16_t y, const uint16_t bitmap[],
                                 const uint8_t mask[], int16_t w, int16_t h) {
  int16_t bw = (w + 7) / 8; // Bitmask scanline pad = whole byte
  uint8_t b = 0;
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      if (i & 7)
        b <<= 1;
      else
        b = pgm_read_byte(&mask[j * bw + i / 8]);
      if (b & 0x80) {
        writePixel(x + i, y, pgm_read_word(&bitmap[j * w + i]));
      }
    }
  }
  endWrite();
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawRGBBitmap(int16_t x, int16_t y, uint16_t *bitmap,
                                 uint8_t *mask, int16_t w, int16_t h) {
  int16_t bw = (w + 7) / 8; // Bitmask scanline pad = whole byte
  uint8_t b = 0;
  startWrite();
  for (int16_t j = 0; j < h; j++, y++) {
    for (int16_t i = 0; i < w; i++) {
      if (i & 7)
        b <<= 1;
      else
        b = mask[j * bw + i / 8];
      if (b & 0x80) {
        writePixel(x + i, y, bitmap[j * w + i]);
      }
    }
  }
  endWrite();
}
 
// TEXT- AND CHARACTER-HANDLING FUNCTIONS ----------------------------------
 
// Draw a character
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawChar(int16_t x, int16_t y, unsigned char c,
                            uint16_t color, uint16_t bg, uint8_t size) {
  drawChar(x, y, c, color, bg, size, size);
}
 
// Draw a character
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::drawChar(int16_t x, int16_t y, unsigned char c,
                            uint16_t color, uint16_t bg, uint8_t size_x,
                            uint8_t size_y) {
 
  if (!gfxFont) { // 'Classic' built-in font
 
    if ((x >= _width) ||              // Clip right
        (y >= _height) ||             // Clip bottom
        ((x + 6 * size_x - 1) < 0) || // Clip left
        ((y + 8 * size_y - 1) < 0))   // Clip top
      return;
 
    if (!_cp437 && (c >= 176))
      c++; // Handle 'classic' charset behavior
 
    startWrite();
    for (int8_t i = 0; i < 5; i++) { // Char bitmap = 5 columns
      uint8_t line = pgm_read_byte(&font[c * 5 + i]);
      for (int8_t j = 0; j < 8; j++, line >>= 1) {
        if (line & 1) {
          if (size_x == 1 && size_y == 1)
            writePixel(x + i, y + j, color);
          else
            writeFillRect(x + i * size_x, y + j * size_y, size_x, size_y,
                          color);
        } else if (bg != color) {
          if (size_x == 1 && size_y == 1)
            writePixel(x + i, y + j, bg);
          else
            writeFillRect(x + i * size_x, y + j * size_y, size_x, size_y, bg);
        }
      }
    }
    if (bg != color) { // If opaque, draw vertical line for last column
      if (size_x == 1 && size_y == 1)
        writeFastVLine(x + 5, y, 8, bg);
      else
        writeFillRect(x + 5 * size_x, y, size_x, 8 * size_y, bg);
    }
    endWrite();
 
  } else { // Custom font
 
    // Character is assumed previously filtered by write() to eliminate
    // newlines, returns, non-printable characters, etc.  Calling
    // drawChar() directly with 'bad' characters of font may cause mayhem!
 
    c -= (uint8_t)pgm_read_byte(&gfxFont->first);
    GFXglyph *glyph = pgm_read_glyph_ptr(gfxFont, c);
    uint8_t *bitmap = pgm_read_bitmap_ptr(gfxFont);
 
    uint16_t bo = pgm_read_word(&glyph->bitmapOffset);
    uint8_t w = pgm_read_byte(&glyph->width), h = pgm_read_byte(&glyph->height);
    int8_t xo = pgm_read_byte(&glyph->xOffset),
           yo = pgm_read_byte(&glyph->yOffset);
    uint8_t xx, yy, bits = 0, bit = 0;
    int16_t xo16 = 0, yo16 = 0;
 
    if (size_x > 1 || size_y > 1) {
      xo16 = xo;
      yo16 = yo;
    }
 
    // Todo: Add character clipping here
 
    // NOTE: THERE IS NO 'BACKGROUND' COLOR OPTION ON CUSTOM FONTS.
    // THIS IS ON PURPOSE AND BY DESIGN.  The background color feature
    // has typically been used with the 'classic' font to overwrite old
    // screen contents with new data.  This ONLY works because the
    // characters are a uniform size; it's not a sensible thing to do with
    // proportionally-spaced fonts with glyphs of varying sizes (and that
    // may overlap).  To replace previously-drawn text when using a custom
    // font, use the getTextBounds() function to determine the smallest
    // rectangle encompassing a string, erase the area with fillRect(),
    // then draw new text.  This WILL infortunately 'blink' the text, but
    // is unavoidable.  Drawing 'background' pixels will NOT fix this,
    // only creates a new set of problems.  Have an idea to work around
    // this (a canvas object type for MCUs that can afford the RAM and
    // displays supporting setAddrWindow() and pushColors()), but haven't
    // implemented this yet.
 
    startWrite();
    for (yy = 0; yy < h; yy++) {
      for (xx = 0; xx < w; xx++) {
        if (!(bit++ & 7)) {
          bits = pgm_read_byte(&bitmap[bo++]);
        }
        if (bits & 0x80) {
          if (size_x == 1 && size_y == 1) {
            writePixel(x + xo + xx, y + yo + yy, color);
          } else {
            writeFillRect(x + (xo16 + xx) * size_x, y + (yo16 + yy) * size_y,
                          size_x, size_y, color);
          }
        }
        bits <<= 1;
      }
    }
    endWrite();
 
  } // End classic vs custom font
}
/**************************************************************************/
/**************************************************************************/
size_t Adafruit_GFX::write(uint8_t c) {
  if (!gfxFont) { // 'Classic' built-in font
 
    if (c == '\n') {              // Newline?
      cursor_x = 0;               // Reset x to zero,
      cursor_y += textsize_y * 8; // advance y one line
    } else if (c != '\r') {       // Ignore carriage returns
      if (wrap && ((cursor_x + textsize_x * 6) > _width)) { // Off right?
        cursor_x = 0;                                       // Reset x to zero,
        cursor_y += textsize_y * 8; // advance y one line
      }
      drawChar(cursor_x, cursor_y, c, textcolor, textbgcolor, textsize_x,
               textsize_y);
      cursor_x += textsize_x * 6; // Advance x one char
    }
 
  } else { // Custom font
 
    if (c == '\n') {
      cursor_x = 0;
      cursor_y +=
          (int16_t)textsize_y * (uint8_t)pgm_read_byte(&gfxFont->yAdvance);
    } else if (c != '\r') {
      uint8_t first = pgm_read_byte(&gfxFont->first);
      if ((c >= first) && (c <= (uint8_t)pgm_read_byte(&gfxFont->last))) {
        GFXglyph *glyph = pgm_read_glyph_ptr(gfxFont, c - first);
        uint8_t w = pgm_read_byte(&glyph->width),
                h = pgm_read_byte(&glyph->height);
        if ((w > 0) && (h > 0)) { // Is there an associated bitmap?
          int16_t xo = (int8_t)pgm_read_byte(&glyph->xOffset); // sic
          if (wrap && ((cursor_x + textsize_x * (xo + w)) > _width)) {
            cursor_x = 0;
            cursor_y += (int16_t)textsize_y *
                        (uint8_t)pgm_read_byte(&gfxFont->yAdvance);
          }
          drawChar(cursor_x, cursor_y, c, textcolor, textbgcolor, textsize_x,
                   textsize_y);
        }
        cursor_x +=
            (uint8_t)pgm_read_byte(&glyph->xAdvance) * (int16_t)textsize_x;
      }
    }
  }
  return 1;
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::setTextSize(uint8_t s) { setTextSize(s, s); }
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::setTextSize(uint8_t s_x, uint8_t s_y) {
  textsize_x = (s_x > 0) ? s_x : 1;
  textsize_y = (s_y > 0) ? s_y : 1;
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::setRotation(uint8_t x) {
  rotation = (x & 3);
  switch (rotation) {
  case 0:
  case 2:
    _width = WIDTH;
    _height = HEIGHT;
    break;
  case 1:
  case 3:
    _width = HEIGHT;
    _height = WIDTH;
    break;
  }
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::setFont(const GFXfont *f) {
  if (f) {          // Font struct pointer passed in?
    if (!gfxFont) { // And no current font struct?
      // Switching from classic to new font behavior.
      // Move cursor pos down 6 pixels so it's on baseline.
      cursor_y += 6;
    }
  } else if (gfxFont) { // NULL passed.  Current font struct defined?
    // Switching from new to classic font behavior.
    // Move cursor pos up 6 pixels so it's at top-left of char.
    cursor_y -= 6;
  }
  gfxFont = (GFXfont *)f;
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::charBounds(unsigned char c, int16_t *x, int16_t *y,
                              int16_t *minx, int16_t *miny, int16_t *maxx,
                              int16_t *maxy) {
 
  if (gfxFont) {
 
    if (c == '\n') { // Newline?
      *x = 0;        // Reset x to zero, advance y by one line
      *y += textsize_y * (uint8_t)pgm_read_byte(&gfxFont->yAdvance);
    } else if (c != '\r') { // Not a carriage return; is normal char
      uint8_t first = pgm_read_byte(&gfxFont->first),
              last = pgm_read_byte(&gfxFont->last);
      if ((c >= first) && (c <= last)) { // Char present in this font?
        GFXglyph *glyph = pgm_read_glyph_ptr(gfxFont, c - first);
        uint8_t gw = pgm_read_byte(&glyph->width),
                gh = pgm_read_byte(&glyph->height),
                xa = pgm_read_byte(&glyph->xAdvance);
        int8_t xo = pgm_read_byte(&glyph->xOffset),
               yo = pgm_read_byte(&glyph->yOffset);
        if (wrap && ((*x + (((int16_t)xo + gw) * textsize_x)) > _width)) {
          *x = 0; // Reset x to zero, advance y by one line
          *y += textsize_y * (uint8_t)pgm_read_byte(&gfxFont->yAdvance);
        }
        int16_t tsx = (int16_t)textsize_x, tsy = (int16_t)textsize_y,
                x1 = *x + xo * tsx, y1 = *y + yo * tsy, x2 = x1 + gw * tsx - 1,
                y2 = y1 + gh * tsy - 1;
        if (x1 < *minx)
          *minx = x1;
        if (y1 < *miny)
          *miny = y1;
        if (x2 > *maxx)
          *maxx = x2;
        if (y2 > *maxy)
          *maxy = y2;
        *x += xa * tsx;
      }
    }
 
  } else { // Default font
 
    if (c == '\n') {        // Newline?
      *x = 0;               // Reset x to zero,
      *y += textsize_y * 8; // advance y one line
      // min/max x/y unchaged -- that waits for next 'normal' character
    } else if (c != '\r') { // Normal char; ignore carriage returns
      if (wrap && ((*x + textsize_x * 6) > _width)) { // Off right?
        *x = 0;                                       // Reset x to zero,
        *y += textsize_y * 8;                         // advance y one line
      }
      int x2 = *x + textsize_x * 6 - 1, // Lower-right pixel of char
          y2 = *y + textsize_y * 8 - 1;
      if (x2 > *maxx)
        *maxx = x2; // Track max x, y
      if (y2 > *maxy)
        *maxy = y2;
      if (*x < *minx)
        *minx = *x; // Track min x, y
      if (*y < *miny)
        *miny = *y;
      *x += textsize_x * 6; // Advance x one char
    }
  }
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::getTextBounds(const char *str, int16_t x, int16_t y,
                                 int16_t *x1, int16_t *y1, uint16_t *w,
                                 uint16_t *h) {
 
  uint8_t c; // Current character
  int16_t minx = 0x7FFF, miny = 0x7FFF, maxx = -1, maxy = -1; // Bound rect
  // Bound rect is intentionally initialized inverted, so 1st char sets it
 
  *x1 = x; // Initial position is value passed in
  *y1 = y;
  *w = *h = 0; // Initial size is zero
 
  while ((c = *str++)) {
    // charBounds() modifies x/y to advance for each character,
    // and min/max x/y are updated to incrementally build bounding rect.
    charBounds(c, &x, &y, &minx, &miny, &maxx, &maxy);
  }
 
  if (maxx >= minx) {     // If legit string bounds were found...
    *x1 = minx;           // Update x1 to least X coord,
    *w = maxx - minx + 1; // And w to bound rect width
  }
  if (maxy >= miny) { // Same for height
    *y1 = miny;
    *h = maxy - miny + 1;
  }
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::getTextBounds(const String &str, int16_t x, int16_t y,
                                 int16_t *x1, int16_t *y1, uint16_t *w,
                                 uint16_t *h) {
  if (str.length() != 0) {
    getTextBounds(const_cast<char *>(str.c_str()), x, y, x1, y1, w, h);
  }
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::getTextBounds(const __FlashStringHelper *str, int16_t x,
                                 int16_t y, int16_t *x1, int16_t *y1,
                                 uint16_t *w, uint16_t *h) {
  uint8_t *s = (uint8_t *)str, c;
 
  *x1 = x;
  *y1 = y;
  *w = *h = 0;
 
  int16_t minx = _width, miny = _height, maxx = -1, maxy = -1;
 
  while ((c = pgm_read_byte(s++)))
    charBounds(c, &x, &y, &minx, &miny, &maxx, &maxy);
 
  if (maxx >= minx) {
    *x1 = minx;
    *w = maxx - minx + 1;
  }
  if (maxy >= miny) {
    *y1 = miny;
    *h = maxy - miny + 1;
  }
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX::invertDisplay(bool i) {
  // Do nothing, must be subclassed if supported by hardware
  (void)i; // disable -Wunused-parameter warning
}
 
/***************************************************************************/
 
/**************************************************************************/
/**************************************************************************/
Adafruit_GFX_Button::Adafruit_GFX_Button(void) { _gfx = 0; }
 
/**************************************************************************/
/**************************************************************************/
// Classic initButton() function: pass center & size
void Adafruit_GFX_Button::initButton(Adafruit_GFX *gfx, int16_t x, int16_t y,
                                     uint16_t w, uint16_t h, uint16_t outline,
                                     uint16_t fill, uint16_t textcolor,
                                     char *label, uint8_t textsize) {
  // Tweak arguments and pass to the newer initButtonUL() function...
  initButtonUL(gfx, x - (w / 2), y - (h / 2), w, h, outline, fill, textcolor,
               label, textsize);
}
 
/**************************************************************************/
/**************************************************************************/
// Classic initButton() function: pass center & size
void Adafruit_GFX_Button::initButton(Adafruit_GFX *gfx, int16_t x, int16_t y,
                                     uint16_t w, uint16_t h, uint16_t outline,
                                     uint16_t fill, uint16_t textcolor,
                                     char *label, uint8_t textsize_x,
                                     uint8_t textsize_y) {
  // Tweak arguments and pass to the newer initButtonUL() function...
  initButtonUL(gfx, x - (w / 2), y - (h / 2), w, h, outline, fill, textcolor,
               label, textsize_x, textsize_y);
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX_Button::initButtonUL(Adafruit_GFX *gfx, int16_t x1,
                                       int16_t y1, uint16_t w, uint16_t h,
                                       uint16_t outline, uint16_t fill,
                                       uint16_t textcolor, char *label,
                                       uint8_t textsize) {
  initButtonUL(gfx, x1, y1, w, h, outline, fill, textcolor, label, textsize,
               textsize);
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX_Button::initButtonUL(Adafruit_GFX *gfx, int16_t x1,
                                       int16_t y1, uint16_t w, uint16_t h,
                                       uint16_t outline, uint16_t fill,
                                       uint16_t textcolor, char *label,
                                       uint8_t textsize_x, uint8_t textsize_y) {
  _x1 = x1;
  _y1 = y1;
  _w = w;
  _h = h;
  _outlinecolor = outline;
  _fillcolor = fill;
  _textcolor = textcolor;
  _textsize_x = textsize_x;
  _textsize_y = textsize_y;
  _gfx = gfx;
  strncpy(_label, label, 9);
  _label[9] = 0; // strncpy does not place a null at the end.
                 // When 'label' is >9 characters, _label is not terminated.
}
 
/**************************************************************************/
/**************************************************************************/
void Adafruit_GFX_Button::drawButton(bool inverted) {
  uint16_t fill, outline, text;
 
  if (!inverted) {
    fill = _fillcolor;
    outline = _outlinecolor;
    text = _textcolor;
  } else {
    fill = _textcolor;
    outline = _outlinecolor;
    text = _fillcolor;
  }
 
  uint8_t r = min(_w, _h) / 4; // Corner radius
  _gfx->fillRoundRect(_x1, _y1, _w, _h, r, fill);
  _gfx->drawRoundRect(_x1, _y1, _w, _h, r, outline);
 
  _gfx->setCursor(_x1 + (_w / 2) - (strlen(_label) * 3 * _textsize_x),
                  _y1 + (_h / 2) - (4 * _textsize_y));
  _gfx->setTextColor(text);
  _gfx->setTextSize(_textsize_x, _textsize_y);
  _gfx->print(_label);
}
 
/**************************************************************************/
/**************************************************************************/
bool Adafruit_GFX_Button::contains(int16_t x, int16_t y) {
  return ((x >= _x1) && (x < (int16_t)(_x1 + _w)) && (y >= _y1) &&
          (y < (int16_t)(_y1 + _h)));
}
 
/**************************************************************************/
/**************************************************************************/
bool Adafruit_GFX_Button::justPressed() { return (currstate && !laststate); }
 
/**************************************************************************/
/**************************************************************************/
bool Adafruit_GFX_Button::justReleased() { return (!currstate && laststate); }
 
// -------------------------------------------------------------------------
 
// GFXcanvas1, GFXcanvas8 and GFXcanvas16 (currently a WIP, don't get too
// comfy with the implementation) provide 1-, 8- and 16-bit offscreen
// canvases, the address of which can be passed to drawBitmap() or
// pushColors() (the latter appears only in a couple of GFX-subclassed TFT
// libraries at this time).  This is here mostly to help with the recently-
// added proportionally-spaced fonts; adds a way to refresh a section of the
// screen without a massive flickering clear-and-redraw...but maybe you'll
// find other uses too.  VERY RAM-intensive, since the buffer is in MCU
// memory and not the display driver...GXFcanvas1 might be minimally useful
// on an Uno-class board, but this and the others are much more likely to
// require at least a Mega or various recent ARM-type boards (recommended,
// as the text+bitmap draw can be pokey).  GFXcanvas1 requires 1 bit per
// pixel (rounded up to nearest byte per scanline), GFXcanvas8 is 1 byte
// per pixel (no scanline pad), and GFXcanvas16 uses 2 bytes per pixel (no
// scanline pad).
// NOT EXTENSIVELY TESTED YET.  MAY CONTAIN WORST BUGS KNOWN TO HUMANKIND.
 
#ifdef __AVR__
// Bitmask tables of 0x80>>X and ~(0x80>>X), because X>>Y is slow on AVR
const uint8_t PROGMEM GFXcanvas1::GFXsetBit[] = {0x80, 0x40, 0x20, 0x10,
                                                 0x08, 0x04, 0x02, 0x01};
const uint8_t PROGMEM GFXcanvas1::GFXclrBit[] = {0x7F, 0xBF, 0xDF, 0xEF,
                                                 0xF7, 0xFB, 0xFD, 0xFE};
#endif
 
/**************************************************************************/
/**************************************************************************/
GFXcanvas1::GFXcanvas1(uint16_t w, uint16_t h, bool allocate_buffer)
    : Adafruit_GFX(w, h), buffer_owned(allocate_buffer) {
  if (allocate_buffer) {
    uint32_t bytes = ((w + 7) / 8) * h;
    if ((buffer = (uint8_t *)malloc(bytes))) {
      memset(buffer, 0, bytes);
    }
  } else {
    buffer = nullptr;
  }
}
 
/**************************************************************************/
/**************************************************************************/
GFXcanvas1::~GFXcanvas1(void) {
  if (buffer && buffer_owned)
    free(buffer);
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas1::drawPixel(int16_t x, int16_t y, uint16_t color) {
  if (buffer) {
    if ((x < 0) || (y < 0) || (x >= _width) || (y >= _height))
      return;
 
    int16_t t;
    switch (rotation) {
    case 1:
      t = x;
      x = WIDTH - 1 - y;
      y = t;
      break;
    case 2:
      x = WIDTH - 1 - x;
      y = HEIGHT - 1 - y;
      break;
    case 3:
      t = x;
      x = y;
      y = HEIGHT - 1 - t;
      break;
    }
 
    uint8_t *ptr = &buffer[(x / 8) + y * ((WIDTH + 7) / 8)];
#ifdef __AVR__
    if (color)
      *ptr |= pgm_read_byte(&GFXsetBit[x & 7]);
    else
      *ptr &= pgm_read_byte(&GFXclrBit[x & 7]);
#else
    if (color)
      *ptr |= 0x80 >> (x & 7);
    else
      *ptr &= ~(0x80 >> (x & 7));
#endif
  }
}
 
/**********************************************************************/
bool GFXcanvas1::getPixel(int16_t x, int16_t y) const {
  int16_t t;
  switch (rotation) {
  case 1:
    t = x;
    x = WIDTH - 1 - y;
    y = t;
    break;
  case 2:
    x = WIDTH - 1 - x;
    y = HEIGHT - 1 - y;
    break;
  case 3:
    t = x;
    x = y;
    y = HEIGHT - 1 - t;
    break;
  }
  return getRawPixel(x, y);
}
 
/**********************************************************************/
bool GFXcanvas1::getRawPixel(int16_t x, int16_t y) const {
  if ((x < 0) || (y < 0) || (x >= WIDTH) || (y >= HEIGHT))
    return 0;
  if (buffer) {
    uint8_t *ptr = &buffer[(x / 8) + y * ((WIDTH + 7) / 8)];
 
#ifdef __AVR__
    return ((*ptr) & pgm_read_byte(&GFXsetBit[x & 7])) != 0;
#else
    return ((*ptr) & (0x80 >> (x & 7))) != 0;
#endif
  }
  return 0;
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas1::fillScreen(uint16_t color) {
  if (buffer) {
    uint32_t bytes = ((WIDTH + 7) / 8) * HEIGHT;
    memset(buffer, color ? 0xFF : 0x00, bytes);
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas1::drawFastVLine(int16_t x, int16_t y, int16_t h,
                               uint16_t color) {
 
  if (h < 0) { // Convert negative heights to positive equivalent
    h *= -1;
    y -= h - 1;
    if (y < 0) {
      h += y;
      y = 0;
    }
  }
 
  // Edge rejection (no-draw if totally off canvas)
  if ((x < 0) || (x >= width()) || (y >= height()) || ((y + h - 1) < 0)) {
    return;
  }
 
  if (y < 0) { // Clip top
    h += y;
    y = 0;
  }
  if (y + h > height()) { // Clip bottom
    h = height() - y;
  }
 
  if (getRotation() == 0) {
    drawFastRawVLine(x, y, h, color);
  } else if (getRotation() == 1) {
    int16_t t = x;
    x = WIDTH - 1 - y;
    y = t;
    x -= h - 1;
    drawFastRawHLine(x, y, h, color);
  } else if (getRotation() == 2) {
    x = WIDTH - 1 - x;
    y = HEIGHT - 1 - y;
 
    y -= h - 1;
    drawFastRawVLine(x, y, h, color);
  } else if (getRotation() == 3) {
    int16_t t = x;
    x = y;
    y = HEIGHT - 1 - t;
    drawFastRawHLine(x, y, h, color);
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas1::drawFastHLine(int16_t x, int16_t y, int16_t w,
                               uint16_t color) {
  if (w < 0) { // Convert negative widths to positive equivalent
    w *= -1;
    x -= w - 1;
    if (x < 0) {
      w += x;
      x = 0;
    }
  }
 
  // Edge rejection (no-draw if totally off canvas)
  if ((y < 0) || (y >= height()) || (x >= width()) || ((x + w - 1) < 0)) {
    return;
  }
 
  if (x < 0) { // Clip left
    w += x;
    x = 0;
  }
  if (x + w >= width()) { // Clip right
    w = width() - x;
  }
 
  if (getRotation() == 0) {
    drawFastRawHLine(x, y, w, color);
  } else if (getRotation() == 1) {
    int16_t t = x;
    x = WIDTH - 1 - y;
    y = t;
    drawFastRawVLine(x, y, w, color);
  } else if (getRotation() == 2) {
    x = WIDTH - 1 - x;
    y = HEIGHT - 1 - y;
 
    x -= w - 1;
    drawFastRawHLine(x, y, w, color);
  } else if (getRotation() == 3) {
    int16_t t = x;
    x = y;
    y = HEIGHT - 1 - t;
    y -= w - 1;
    drawFastRawVLine(x, y, w, color);
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas1::drawFastRawVLine(int16_t x, int16_t y, int16_t h,
                                  uint16_t color) {
  // x & y already in raw (rotation 0) coordinates, no need to transform.
  int16_t row_bytes = ((WIDTH + 7) / 8);
  uint8_t *ptr = &buffer[(x / 8) + y * row_bytes];
 
  if (color > 0) {
#ifdef __AVR__
    uint8_t bit_mask = pgm_read_byte(&GFXsetBit[x & 7]);
#else
    uint8_t bit_mask = (0x80 >> (x & 7));
#endif
    for (int16_t i = 0; i < h; i++) {
      *ptr |= bit_mask;
      ptr += row_bytes;
    }
  } else {
#ifdef __AVR__
    uint8_t bit_mask = pgm_read_byte(&GFXclrBit[x & 7]);
#else
    uint8_t bit_mask = ~(0x80 >> (x & 7));
#endif
    for (int16_t i = 0; i < h; i++) {
      *ptr &= bit_mask;
      ptr += row_bytes;
    }
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas1::drawFastRawHLine(int16_t x, int16_t y, int16_t w,
                                  uint16_t color) {
  // x & y already in raw (rotation 0) coordinates, no need to transform.
  int16_t rowBytes = ((WIDTH + 7) / 8);
  uint8_t *ptr = &buffer[(x / 8) + y * rowBytes];
  size_t remainingWidthBits = w;
 
  // check to see if first byte needs to be partially filled
  if ((x & 7) > 0) {
    // create bit mask for first byte
    uint8_t startByteBitMask = 0x00;
    for (int8_t i = (x & 7); ((i < 8) && (remainingWidthBits > 0)); i++) {
#ifdef __AVR__
      startByteBitMask |= pgm_read_byte(&GFXsetBit[i]);
#else
      startByteBitMask |= (0x80 >> i);
#endif
      remainingWidthBits--;
    }
    if (color > 0) {
      *ptr |= startByteBitMask;
    } else {
      *ptr &= ~startByteBitMask;
    }
 
    ptr++;
  }
 
  // do the next remainingWidthBits bits
  if (remainingWidthBits > 0) {
    size_t remainingWholeBytes = remainingWidthBits / 8;
    size_t lastByteBits = remainingWidthBits % 8;
    uint8_t wholeByteColor = color > 0 ? 0xFF : 0x00;
 
    memset(ptr, wholeByteColor, remainingWholeBytes);
 
    if (lastByteBits > 0) {
      uint8_t lastByteBitMask = 0x00;
      for (size_t i = 0; i < lastByteBits; i++) {
#ifdef __AVR__
        lastByteBitMask |= pgm_read_byte(&GFXsetBit[i]);
#else
        lastByteBitMask |= (0x80 >> i);
#endif
      }
      ptr += remainingWholeBytes;
 
      if (color > 0) {
        *ptr |= lastByteBitMask;
      } else {
        *ptr &= ~lastByteBitMask;
      }
    }
  }
}
 
/**************************************************************************/
/**************************************************************************/
GFXcanvas8::GFXcanvas8(uint16_t w, uint16_t h, bool allocate_buffer)
    : Adafruit_GFX(w, h), buffer_owned(allocate_buffer) {
  if (allocate_buffer) {
    uint32_t bytes = w * h;
    if ((buffer = (uint8_t *)malloc(bytes))) {
      memset(buffer, 0, bytes);
    }
  } else
    buffer = nullptr;
}
 
/**************************************************************************/
/**************************************************************************/
GFXcanvas8::~GFXcanvas8(void) {
  if (buffer && buffer_owned)
    free(buffer);
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas8::drawPixel(int16_t x, int16_t y, uint16_t color) {
  if (buffer) {
    if ((x < 0) || (y < 0) || (x >= _width) || (y >= _height))
      return;
 
    int16_t t;
    switch (rotation) {
    case 1:
      t = x;
      x = WIDTH - 1 - y;
      y = t;
      break;
    case 2:
      x = WIDTH - 1 - x;
      y = HEIGHT - 1 - y;
      break;
    case 3:
      t = x;
      x = y;
      y = HEIGHT - 1 - t;
      break;
    }
 
    buffer[x + y * WIDTH] = color;
  }
}
 
/**********************************************************************/
/**********************************************************************/
uint8_t GFXcanvas8::getPixel(int16_t x, int16_t y) const {
  int16_t t;
  switch (rotation) {
  case 1:
    t = x;
    x = WIDTH - 1 - y;
    y = t;
    break;
  case 2:
    x = WIDTH - 1 - x;
    y = HEIGHT - 1 - y;
    break;
  case 3:
    t = x;
    x = y;
    y = HEIGHT - 1 - t;
    break;
  }
  return getRawPixel(x, y);
}
 
/**********************************************************************/
/**********************************************************************/
uint8_t GFXcanvas8::getRawPixel(int16_t x, int16_t y) const {
  if ((x < 0) || (y < 0) || (x >= WIDTH) || (y >= HEIGHT))
    return 0;
  if (buffer) {
    return buffer[x + y * WIDTH];
  }
  return 0;
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas8::fillScreen(uint16_t color) {
  if (buffer) {
    memset(buffer, color, WIDTH * HEIGHT);
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas8::drawFastVLine(int16_t x, int16_t y, int16_t h,
                               uint16_t color) {
  if (h < 0) { // Convert negative heights to positive equivalent
    h *= -1;
    y -= h - 1;
    if (y < 0) {
      h += y;
      y = 0;
    }
  }
 
  // Edge rejection (no-draw if totally off canvas)
  if ((x < 0) || (x >= width()) || (y >= height()) || ((y + h - 1) < 0)) {
    return;
  }
 
  if (y < 0) { // Clip top
    h += y;
    y = 0;
  }
  if (y + h > height()) { // Clip bottom
    h = height() - y;
  }
 
  if (getRotation() == 0) {
    drawFastRawVLine(x, y, h, color);
  } else if (getRotation() == 1) {
    int16_t t = x;
    x = WIDTH - 1 - y;
    y = t;
    x -= h - 1;
    drawFastRawHLine(x, y, h, color);
  } else if (getRotation() == 2) {
    x = WIDTH - 1 - x;
    y = HEIGHT - 1 - y;
 
    y -= h - 1;
    drawFastRawVLine(x, y, h, color);
  } else if (getRotation() == 3) {
    int16_t t = x;
    x = y;
    y = HEIGHT - 1 - t;
    drawFastRawHLine(x, y, h, color);
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas8::drawFastHLine(int16_t x, int16_t y, int16_t w,
                               uint16_t color) {
 
  if (w < 0) { // Convert negative widths to positive equivalent
    w *= -1;
    x -= w - 1;
    if (x < 0) {
      w += x;
      x = 0;
    }
  }
 
  // Edge rejection (no-draw if totally off canvas)
  if ((y < 0) || (y >= height()) || (x >= width()) || ((x + w - 1) < 0)) {
    return;
  }
 
  if (x < 0) { // Clip left
    w += x;
    x = 0;
  }
  if (x + w >= width()) { // Clip right
    w = width() - x;
  }
 
  if (getRotation() == 0) {
    drawFastRawHLine(x, y, w, color);
  } else if (getRotation() == 1) {
    int16_t t = x;
    x = WIDTH - 1 - y;
    y = t;
    drawFastRawVLine(x, y, w, color);
  } else if (getRotation() == 2) {
    x = WIDTH - 1 - x;
    y = HEIGHT - 1 - y;
 
    x -= w - 1;
    drawFastRawHLine(x, y, w, color);
  } else if (getRotation() == 3) {
    int16_t t = x;
    x = y;
    y = HEIGHT - 1 - t;
    y -= w - 1;
    drawFastRawVLine(x, y, w, color);
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas8::drawFastRawVLine(int16_t x, int16_t y, int16_t h,
                                  uint16_t color) {
  // x & y already in raw (rotation 0) coordinates, no need to transform.
  uint8_t *buffer_ptr = buffer + y * WIDTH + x;
  for (int16_t i = 0; i < h; i++) {
    (*buffer_ptr) = color;
    buffer_ptr += WIDTH;
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas8::drawFastRawHLine(int16_t x, int16_t y, int16_t w,
                                  uint16_t color) {
  // x & y already in raw (rotation 0) coordinates, no need to transform.
  memset(buffer + y * WIDTH + x, color, w);
}
 
/**************************************************************************/
/**************************************************************************/
GFXcanvas16::GFXcanvas16(uint16_t w, uint16_t h, bool allocate_buffer)
    : Adafruit_GFX(w, h), buffer_owned(allocate_buffer) {
  if (allocate_buffer) {
    uint32_t bytes = w * h * 2;
    if ((buffer = (uint16_t *)malloc(bytes))) {
      memset(buffer, 0, bytes);
    }
  } else {
    buffer = nullptr;
  }
}
 
/**************************************************************************/
/**************************************************************************/
GFXcanvas16::~GFXcanvas16(void) {
  if (buffer && buffer_owned)
    free(buffer);
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas16::drawPixel(int16_t x, int16_t y, uint16_t color) {
  if (buffer) {
    if ((x < 0) || (y < 0) || (x >= _width) || (y >= _height))
      return;
 
    int16_t t;
    switch (rotation) {
    case 1:
      t = x;
      x = WIDTH - 1 - y;
      y = t;
      break;
    case 2:
      x = WIDTH - 1 - x;
      y = HEIGHT - 1 - y;
      break;
    case 3:
      t = x;
      x = y;
      y = HEIGHT - 1 - t;
      break;
    }
 
    buffer[x + y * WIDTH] = color;
  }
}
 
/**********************************************************************/
/**********************************************************************/
uint16_t GFXcanvas16::getPixel(int16_t x, int16_t y) const {
  int16_t t;
  switch (rotation) {
  case 1:
    t = x;
    x = WIDTH - 1 - y;
    y = t;
    break;
  case 2:
    x = WIDTH - 1 - x;
    y = HEIGHT - 1 - y;
    break;
  case 3:
    t = x;
    x = y;
    y = HEIGHT - 1 - t;
    break;
  }
  return getRawPixel(x, y);
}
 
/**********************************************************************/
/**********************************************************************/
uint16_t GFXcanvas16::getRawPixel(int16_t x, int16_t y) const {
  if ((x < 0) || (y < 0) || (x >= WIDTH) || (y >= HEIGHT))
    return 0;
  if (buffer) {
    return buffer[x + y * WIDTH];
  }
  return 0;
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas16::fillScreen(uint16_t color) {
  if (buffer) {
    uint8_t hi = color >> 8, lo = color & 0xFF;
    if (hi == lo) {
      memset(buffer, lo, WIDTH * HEIGHT * 2);
    } else {
      uint32_t i, pixels = WIDTH * HEIGHT;
      for (i = 0; i < pixels; i++)
        buffer[i] = color;
    }
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas16::byteSwap(void) {
  if (buffer) {
    uint32_t i, pixels = WIDTH * HEIGHT;
    for (i = 0; i < pixels; i++)
      buffer[i] = __builtin_bswap16(buffer[i]);
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas16::drawFastVLine(int16_t x, int16_t y, int16_t h,
                                uint16_t color) {
  if (h < 0) { // Convert negative heights to positive equivalent
    h *= -1;
    y -= h - 1;
    if (y < 0) {
      h += y;
      y = 0;
    }
  }
 
  // Edge rejection (no-draw if totally off canvas)
  if ((x < 0) || (x >= width()) || (y >= height()) || ((y + h - 1) < 0)) {
    return;
  }
 
  if (y < 0) { // Clip top
    h += y;
    y = 0;
  }
  if (y + h > height()) { // Clip bottom
    h = height() - y;
  }
 
  if (getRotation() == 0) {
    drawFastRawVLine(x, y, h, color);
  } else if (getRotation() == 1) {
    int16_t t = x;
    x = WIDTH - 1 - y;
    y = t;
    x -= h - 1;
    drawFastRawHLine(x, y, h, color);
  } else if (getRotation() == 2) {
    x = WIDTH - 1 - x;
    y = HEIGHT - 1 - y;
 
    y -= h - 1;
    drawFastRawVLine(x, y, h, color);
  } else if (getRotation() == 3) {
    int16_t t = x;
    x = y;
    y = HEIGHT - 1 - t;
    drawFastRawHLine(x, y, h, color);
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas16::drawFastHLine(int16_t x, int16_t y, int16_t w,
                                uint16_t color) {
  if (w < 0) { // Convert negative widths to positive equivalent
    w *= -1;
    x -= w - 1;
    if (x < 0) {
      w += x;
      x = 0;
    }
  }
 
  // Edge rejection (no-draw if totally off canvas)
  if ((y < 0) || (y >= height()) || (x >= width()) || ((x + w - 1) < 0)) {
    return;
  }
 
  if (x < 0) { // Clip left
    w += x;
    x = 0;
  }
  if (x + w >= width()) { // Clip right
    w = width() - x;
  }
 
  if (getRotation() == 0) {
    drawFastRawHLine(x, y, w, color);
  } else if (getRotation() == 1) {
    int16_t t = x;
    x = WIDTH - 1 - y;
    y = t;
    drawFastRawVLine(x, y, w, color);
  } else if (getRotation() == 2) {
    x = WIDTH - 1 - x;
    y = HEIGHT - 1 - y;
 
    x -= w - 1;
    drawFastRawHLine(x, y, w, color);
  } else if (getRotation() == 3) {
    int16_t t = x;
    x = y;
    y = HEIGHT - 1 - t;
    y -= w - 1;
    drawFastRawVLine(x, y, w, color);
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas16::drawFastRawVLine(int16_t x, int16_t y, int16_t h,
                                   uint16_t color) {
  // x & y already in raw (rotation 0) coordinates, no need to transform.
  uint16_t *buffer_ptr = buffer + y * WIDTH + x;
  for (int16_t i = 0; i < h; i++) {
    (*buffer_ptr) = color;
    buffer_ptr += WIDTH;
  }
}
 
/**************************************************************************/
/**************************************************************************/
void GFXcanvas16::drawFastRawHLine(int16_t x, int16_t y, int16_t w,
                                   uint16_t color) {
  // x & y already in raw (rotation 0) coordinates, no need to transform.
  uint32_t buffer_index = y * WIDTH + x;
  for (uint32_t i = buffer_index; i < buffer_index + w; i++) {
    buffer[i] = color;
  }
}