// base class GxEPD2_GFX can be used to pass references or pointers to the display instance as parameter, uses ~1.2k more code
// enable or disable GxEPD2_GFX base class
#define ENABLE_GxEPD2_GFX 0

#include <GxEPD2_BW.h>
#include <GxEPD2_3C.h>
#include <Fonts/FreeMonoBold9pt7b.h>

// ESP32-C3 SS=7,SCL(SCK)=4,SDA(MOSI)=6,BUSY=3,RST=2,DC=1 
GxEPD2_BW<GxEPD2_213_B74, GxEPD2_213_B74::HEIGHT> display(GxEPD2_213_B74(/*CS=5*/ SS, /*DC=*/ 1, /*RST=*/ 2, /*BUSY=*/ 3)); // GDEM0213B74 122x250, SSD1680
//GxEPD2_3C<GxEPD2_213_Z98c, GxEPD2_213_Z98c::HEIGHT> display(GxEPD2_213_Z98c(/*CS=5*/ SS, /*DC=*/ 1, /*RST=*/ 2, /*BUSY=*/ 3)); // GDEY0213Z98 122x250, SSD1680

void setup()
{
  pinMode(8, OUTPUT);
  digitalWrite(8, HIGH);
    
  display.init(115200,true,50,false);
  helloWorld();
  display.hibernate();
}

const char HelloWorld[] = "Hello World!";
const char HelloWeACtStudio[] = "Hello WeAct Studio!";

void helloWorld()
{
  display.setRotation(1);
  display.setFont(&FreeMonoBold9pt7b);
  display.setTextColor(GxEPD_BLACK);
  int16_t tbx, tby; uint16_t tbw, tbh;
  display.getTextBounds(HelloWorld, 0, 0, &tbx, &tby, &tbw, &tbh);
  // center the bounding box by transposition of the origin:
  uint16_t x = ((display.width() - tbw) / 2) - tbx;
  uint16_t y = ((display.height() - tbh) / 2) - tby;
  display.setFullWindow();
  display.firstPage();
  do
  {
    display.fillScreen(GxEPD_WHITE);
    display.setCursor(x, y-tbh);
    display.print(HelloWorld);
    display.setTextColor(display.epd2.hasColor ? GxEPD_RED : GxEPD_BLACK);
    display.getTextBounds(HelloWeACtStudio, 0, 0, &tbx, &tby, &tbw, &tbh);
    x = ((display.width() - tbw) / 2) - tbx;
    display.setCursor(x, y+2*tbh);
    display.print(HelloWeACtStudio);
  }
  while (display.nextPage());
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(8, HIGH);
  delay(1000);
  digitalWrite(8, LOW);
  delay(1000);  
}