#include <Adafruit_GFX.h>          
#include <Adafruit_ILI9341.h>     
#include <SD.h>                

#define SD_CS   4 // SD card select pin
#define TFT_CS 10 // TFT select pin
#define TFT_DC  8 // TFT display/command pin
#define TFT_RST 9 // TFT reset pin

#define MAX_Y 300

File f;
int char_height, y;
String filename;

Adafruit_ILI9341     tft    = Adafruit_ILI9341(TFT_CS, TFT_DC, TFT_RST);

void setup(void) {
  Serial.begin(9600);
  tft.begin();          // Initialize screen

  Serial.print("Setup filesystem...");
  if( !SD.begin( SD_CS ) ) { 
    Serial.println("SD begin() failed");
    while (1) ;
  }
  Serial.println("OK!");

  tft.setRotation(0);
  tft.setTextSize(2);

  tft.setCursor(0,0); tft.println(); char_height = tft.getCursorY(); 
  Serial.println( char_height );

  show_files();
  delay(1000);
  
  f = SD.open("text.txt");
  if ( f ) {
    show_one_page();

    f.close();
  }
  else {
    Serial.println("File not found!");
  }

}

void show_files(){
  tft.fillScreen( ILI9341_BLACK );
  tft.setCursor(0,0);
  tft.setTextSize(3);
  File dir = SD.open("/");
  while (1) {
    File fff =  dir.openNextFile();
    if ( fff == 0 ) break;
    tft.println( fff.name() );
    filename = fff.name();
  }
  f.close();
  tft.setTextSize(2);
  Serial.println( filename );
}

void show_one_page() {

  tft.fillScreen( ILI9341_BLACK );
  tft.setCursor(0,0);
  y = 0;
  while ( f.available() > 0 && y < MAX_Y ) {
    char ch = f.read();
    Serial.write( ch );
    tft.write(ch);
    y = tft.getCursorY();
  }
  Serial.print("y="); Serial.println(y);
}

void loop() {

}