/*
  This sketch uses Smooth fonts stored in FLASH program memory. It uses a method
  for rendering anti-aliased fonts on a graded background. This is achieved by
  telling the TFT_eSPI library the pixel color at each point on the screen. In
  this sketch a background colour gradient is drawn, the color of each pixel can
  therefore be determined by a function. The TFT does not need to support reading
  of the graphics memory. The sketch could be adapted so any part of the screen
  has a color gradient.

  The TFT_eSPI library must be given the name of the function in the sketch that
  will return the pixel color at a position x,y on the TFT. In this sketch that
  function is called gradientColor, so this line is included in setup():

    tft.setCallback(gradientColor);

  TFT_eSPI will call this function during the rendering of the anti-aliased
  font to blend the edges of each character with the returned color.

  If the TFT supports reading the screen RAM then the returned value can be
  tft.readPixel(x,y) and anti-aliased text can the be drawn over any screen
  image. See "Smooth_font_over_image" example.
*/
//  The fonts are stored in arrays within the sketch tabs.

//  A processing sketch to create new fonts can be found in the Tools folder of TFT_eSPI
//  https://github.com/Bodmer/TFT_eSPI/tree/master/Tools/Create_Smooth_Font/Create_font

//  This sketch uses fonts created from the Noto family of fonts:
//  https://www.google.com/get/noto/

#include "NotoSansBold15.h"
#include "NotoSansBold36.h"

// Do not include "" around the array name!
#define AA_FONT_SMALL NotoSansBold15
#define AA_FONT_LARGE NotoSansBold36

#include <SPI.h>
#include <TFT_eSPI.h>       // Hardware-specific library

TFT_eSPI tft = TFT_eSPI();

#define TOP_COLOR    TFT_RED
#define BOTTOM_COLOR TFT_BLACK

#define GRADIENT_HEIGHT (9 + tft.fontHeight() * 5) // Gradient over 5 lines
#define OUTSIDE_GRADIENT TFT_BLUE

uint16_t gradientColor(uint16_t x, uint16_t y)
{
  if (y > GRADIENT_HEIGHT) return OUTSIDE_GRADIENT;   // Outside gradient area
  uint8_t alpha = (255 * y) / GRADIENT_HEIGHT;        // alpha is a value in the range 0-255
  return tft.alphaBlend(alpha, BOTTOM_COLOR, TOP_COLOR);
}

void fillGradient() {
  uint16_t w = tft.width();
  for (uint16_t y = 0; y < tft.height(); ++y) {
    uint16_t color = gradientColor(0, y); // x not used here
    tft.drawFastHLine(0, y, w, color);
  }
}

void setup(void) {
  Serial.begin(115200);

  tft.begin();

  tft.setCallback(gradientColor); // Switch on color callback for anti-aliased fonts
  //tft.setCallback(nullptr);     // Switch off callback (off by default)

  tft.setRotation(1);
}

void loop() {

  // Select a font size commensurate with screen size
  if (tft.width()>= 320)
    tft.loadFont(AA_FONT_LARGE);
  else
    tft.loadFont(AA_FONT_SMALL);

  fillGradient(); // Put here after selecting the font so fontHeight() is already set

  tft.setTextColor(TFT_WHITE); // Background color is ignored in gradient area
  tft.setCursor(0, 10); // Set cursor at top left of screen

  uint32_t t = millis();
  tft.println(" Ode to a small\n lump of green\n putty I found\n in my armpit\n one midsummer\n morning ");
  Serial.println(t = millis()-t);

  tft.unloadFont(); // Remove the font to recover memory used

  delay(2000);
}
