How to create and edit fonts for the Adafruit GFX library?

I found an online editor that can parse Adafruit GFX font headers, modify, and export the result to create a new font header. It works very well. May be a bit late to help OP, but for anyone else looking...

It uses regexes to extract info from the header files, so it's pretty strict on following the layout of GFX font headers provided by Adafruit.

webpage: https://tchapi.github.io/Adafruit-GFX-Font-Customiser/
github: https://github.com/tchapi/Adafruit-GFX-Font-Customiser

One possible solution you might already have: There’s a small utility called fontconvert that’s part of the Adafruit GFX library. The source code is installed by default together with the Adafruit GFX library in Arduino/libraries/Adafruit_GFX_Library/fontconvert You need Linux to compile it from the provided source code. It also compiles and runs on a Raspberry Pi.

It takes care of converting TrueType fonts (completely or partially) to Adafruit GFX format. There’s some documentation on compiling and using it in the fontconvert directory.

I have used this website to generate various fonts, sizes, etc. with success.

http://oleddisplay.squix.ch/#/home

I have used truetype2gfx - Converting fonts from TrueType to Adafruit GFX.

It can make various sizes to a complete standard font.

I had the same issue. When using the custom fonts, numbers were overwriting the previous one.

I suggest you to use "canvas". Canvas is a defined area on the screen, and you can easily clear it without flickering. If you wanna see an example, visit below links:

Github - no flicker!

Youtube Video

    #include <Adafruit_GFX.h> //including the Adafruit GFX library
    #include <Adafruit_ST7735.h>  //including the Adafruit ST7735 library
    #include <spi_flash.h>
    
    #define TFT_CS 15 //defining Pins
    #define TFT_RST 0 //defining Pins
    #define TFT_DC 2 //defining Pins
    
    Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST); //setting the LCD with Pins defined.
    
    #include "Robot_Kicks_Italic20pt7b.h" // This is the custom font implemented.
    
    GFXcanvas16 canvas(160, 64); //Canvas is created for the specified area which is 160x64 pixels.
    
    
    void setup() 
    {
      tft.initR(INITR_BLACKTAB);  //initializing the TFT Screen
      tft.setRotation(3); // Setting the rotation 
      tft.fillScreen(ST7735_BLACK); // filling the screen with black color.
      
      canvas.setFont(&Robot_Kicks_Italic20pt7b); //setting the custom Font to canvas to use.
      canvas.setTextWrap(false); // setting for wrapping (false)
      
    }
    
    void loop() 
    {
      
    
      for(int i = 0; i <= 1000; i++) //counter starts from 0 to 1000
      {
        canvas.fillScreen(ST7735_BLACK); //fill only the defined canvas, not the whole screen. 
        canvas.setTextColor(ST7735_GREEN); // setting the font color to green
        canvas.setCursor(12, 30);   // Pos. is BASE LINE when using fonts!
        canvas.print(i);    //printing "i" from one to 1000
        tft.drawRGBBitmap(0, 45, canvas.getBuffer(), canvas.width(), canvas.height()); // this line pushes the entire thing above to the specified area, canvas.
      
      delay(25); //this is the delay of mili seconds for each element in the counter.
      }
      
      
    }