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arduino-libraries / LiquidCrystal

Liquid Crystal Library for Arduino
http://arduino.cc/
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createChar from PROGMEM #34

Open jweglinski opened 4 years ago

jweglinski commented 4 years ago

Hello! I think it would be useful to have PROGMEM ready createChar variant - creating custom characters is usually done only once, so wasting RAM for bitmap could be avoided by loading it directly from program memory. I wonder if something like this would be sufficient?


    void createCharProgMem(uint8_t location, const uint8_t charmap[]) {
      location &= 0x7; // we only have 8 locations 0-7
      command(LCD_SETCGRAMADDR | (location << 3));
      for (uint8_t i = 0; i < 8; i++) {
        write(pgm_read_byte_near(charmap + i));
      }
    }
    void createChar(uint8_t location, const __FlashStringHelper *buf) {
      location &= 0x7; // we only have 8 locations 0-7
      command(LCD_SETCGRAMADDR | (location << 3));
      for (uint8_t i = 0; i < 8; i++) {
        write(pgm_read_byte_near((const uint8_t *)buf + i));
      }
    }