Open Font Render

TTF font render support library for microcomputer using Arduino IDE.
This library can render TTF font files in the SD card or TTF font files embedded in the program.

This program is inspired by M5FontRender.
Any small contribution is welcome.

Features

• Available for a variety of hardware using the Arduino IDE
• Draws beautiful, anti-aliased fonts
• Can be loaded from font data embedded in code (no SD card required)
• Can use any drawing library
• Can be changed to any version of FreeType.

Installation

Clone this repository into Arduino library folder.

API and Usage

See GitHub Pages for a list of available APIs. Bellow is only a part of the sample code.
More detailed examples can be found in examples.

Load from array (Wio Terminal)

#include "TFT_eSPI.h"
#include "binaryttf.h"
#include "OpenFontRender.h"
 
TFT_eSPI tft;
OpenFontRender render;
 
void setup()
{
    // put your setup code here, to run once:
    Serial.begin(115200);
    Serial.flush();
    delay(50);
 
    tft.begin();
    tft.setRotation(3);
    tft.fillScreen(TFT_BLACK);
    digitalWrite(LCD_BACKLIGHT, HIGH); // turn on the backlight
 
    render.setSerial(Serial);     // Need to print render library message
    render.showFreeTypeVersion(); // print FreeType version
    render.showCredit();          // print FTL credit
 
    if (render.loadFont(binaryttf, sizeof(binaryttf)))
    {
        Serial.println("Render initialize error");
        return;
    }
 
    render.setDrawer(tft); // Set drawer object
    /* You can also be written as follows. */
    // render.setDrawPixel(tft.drawPixel);
    // render.setDrawFastHLine(tft.drawFastHLine); // optional
    // render.setStartWrite(tft.startWrite);       // optional
    // render.setEndWrite(tft.endWrite);           // optional
 
    unsigned long t_start = millis();
 
    render.setFontColor(TFT_WHITE);
    render.printf("Hello World\n");
    render.seekCursor(0, 10);
 
    render.setFontSize(30);
    render.setFontColor(TFT_GREEN);
    render.printf("完全なUnicodeサポート\n");
    render.seekCursor(0, 10);
 
    render.setFontSize(40);
    render.setFontColor(TFT_ORANGE);
    render.printf("こんにちは世界\n");
 
    unsigned long t_end = millis();
    Serial.printf("Time: %ld ms\n", t_end - t_start);
}
 
void loop()
{
    // put your main code here, to run repeatedly:
}

Load from SD card (M5Stack)

#include <Arduino.h>
#include <M5Unified.h>
#include <SD.h>
 
#include "OpenFontRender.h"          // Include after M5Unified.h
#include "ofrfs/M5Stack_SD_Preset.h" // Use preset
 
OpenFontRender render;
 
void setup()
{
    // put your setup code here, to run once:
    auto cfg = M5.config();
    M5.begin(cfg);
    M5.Display.fillScreen(TFT_BLACK);
 
    SD.begin(GPIO_NUM_4, SPI, 40000000);
 
    render.setSerial(Serial);     // Need to print render library message
    render.showFreeTypeVersion(); // print FreeType version
    render.showCredit();          // print FTL credit
 
    if (render.loadFont("/JKG-M_3_Tiny.ttf"))
    {
        Serial.println("Render initialize error");
        return;
    }
 
    render.setDrawer(M5.Display); // Set drawer object
    /* You can also be written as follows. */
    // render.setDrawPixel(M5.Display.drawPixel);
    // render.setDrawFastHLine(M5.Display.drawFastHLine); // optional
    // render.setStartWrite(M5.Display.startWrite);       // optional
    // render.setEndWrite(M5.Display.endWrite);           // optional
 
    unsigned long t_start = millis();
 
    render.setFontColor(TFT_WHITE);
    render.printf("Hello World\n");
    render.seekCursor(0, 10);
 
    render.setFontSize(30);
    render.setFontColor(TFT_GREEN);
    render.printf("完全なUnicodeサポート\n");
    render.seekCursor(0, 10);
 
    render.setFontSize(40);
    render.setFontColor(TFT_ORANGE);
    render.printf("こんにちは世界\n");
 
    unsigned long t_end = millis();
    Serial.printf("Time: %ld ms\n", t_end - t_start);
}
 
void loop()
{
    // put your main code here, to run repeatedly:
}

How to create binary TTF file

We use binary2ttf.py in tools directory to create binary TTF font file.
The binary2ttf.py is provided in the M5EPD library. The same program is included in tools directory in this repo.
You only execute below command.

python3 binary2ttf.py your_font_file.ttf

Switch draw function

In this library, you can change the drawing-related operations to your favorite functions (e.g. LavyonGFX).
To change it, use the following function.

render.setDrawPixel(my_draw_function);         // necessary
 
render.setDrawFastHLine(my_draw_fast_h_line);  // optional
render.setStartWrite(my_start_write_function); // optional
render.setEndWrite(my_end_write_function);     // optional

If you have an object for drawing and it contains the necessary methods, you can also use setDrawer method instead.

render.setDrawer(my_draw_object);   // Set drawer object

Switch other FreeType version

You can switch to any FreeType version in this library.
We have confirmed that it works with 2.4.12 and 2.12.1.
Default version is 2.4.12 because it was the version that worked most stably.

How to switch

1. Download the version of FreeType that you like.
2. Place the downloaded FreeType folder directly under OpenFontRender.
3. Execute AutoRun script.

Note

If you are using FreeRTOS, some versions may become unstable.
You may have to increase the stack size or enable useRenderTask to get it to work.

How to load font files from SD/TF cards, SPIFFS, and so on

Control of file systems such as SD/TF cards and SPIFFS is strongly hardware-dependent. OpenFontRender supports the following reads as presets.

• M5Stack
  • SD/TF (ofrfs/M5Stack_SD_Preset.h)
  • SPIFFS (ofrfs/M5Stack_SPIFFS_Preset.h)
• Wio Terminal
  • SD/TF (ofrfs/WioTerminal_SD_Preset.h)

If you want to load font file from unsupported file system, you will need to overwrite some functions on the user code.

See the documentation for details on how to overwrite them. If you created a new preset, it would be great if you could provide us with the code.

Test

Tested Hardware

This library has been tested on the following hardware.
We would be happy to receive reports on hardware not listed here.

• Arduino IDE 2.0
  • Seeed SAMD Boards (Board Manager v1.8.3)
    • Wio Terminal
  • M5Stack (Board Manager v2.0.4)
    • M5Stack Basic (Library v0.1.4)
    • M5Stack Core2 (Library v0.4.0)
• PlatformIO
  • M5Stack Basic (Library v2.0.4)
  • M5Stack Core2 (Library v2.0.4)
• ESP-IDF (4.4)
  • M5Stack Basic

Rendering speed

The table below shows the time taken to draw the sample program when it was run. Note: the time depends on the hardware settings or font file, so this is for reference only.

	Load from SD	Load from array	Load from array (Use LavyonGFX)
Wio Terminal	576 ms	491 ms	405 ms
M5Stack Basic	227 ms	230 ms	98 ms
M5Stack Core2	346 ms	281 ms	148 ms

LICENSE

This library is provided under the FTL license.
It is a BSD-style license with a credit clause.
All programs and binaries created using this library must be credited (as shown at the bottom of this README).

However, some files that are not related to FreeType can be used under the MIT license (See each files).

For more information about FTL licenses, see FTL.TXT in this repository or FreeType Licenses.

Sample font

We have used below font file for the sample program.
We would like to thank sozai-font-hako for providing us with an easy-to-use license for these wonderful fonts.

Font	Copyright
JK Gothic M	Copyright (c) 2014 M+ FONTS PROJECT Copyright (c) 2015 JK FONTS

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Portions of this software are copyright © The FreeTypeProject (www.freetype.org). All rights reserved.