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SSD1306UTF8

SSD1306UTF8 is an unbuffered character only library for small OLED displays like the Adafruit 1.3" and 0.96" Monochrome displays (SSD1306/SH1106).

This respository is an extended fork of the SSD1306ASCII Library, since the original one will not provide UTF8 support.

Introduction

SSD1306Ascii runs on Arduino AVR boards, Arduino Due and many other Arduino style boards that have the SPI or Wire library.

Please read the html documentation in the SSD1306Ascii/doc folder.

Click on SSD1306Ascii.html in the doc folder.

Several options can be set by editing src/SSD1306Ascii.h.

The SSD1306Ascii library only requires a few bytes of RAM.

Here is Uno memory use for the SPI "Hello world!" example with scrolling disabled:

Sketch uses 2928 bytes (9%) of program storage space. Maximum is 32256 bytes.

Global variables use 54 bytes (2%) of dynamic memory, leaving 1994 bytes for local variables. Maximum is 2048 bytes.

About Fonts

The idea of this library is to minize both RAM and ROM usages, so no general utf8 font will be provided, probrbly.

Hence, You have to make your custom font to display UTF8 characters. In order to do that, here is a brief explain about how a font is structured.

The struct of font is seperated in two sections, defined as follows. You may reference fonts/HelloWorldUTF8.h for example.

ASCII section

font_Type_Indicator

  • uint16_t
  • Indicates the type of the font, defined as follows:
    • 00 00 (ASCII only, fixed width font with 1 padding pixel on right and below)
    • 00 01 (ASCII only, fixed width font with no padding pixels)
    • 00 02 (with utf-8 multi byte support, fixed width font with 1 padding pixel on right and below for ASCII chars)
    • 00 03 (with utf-8 multi byte support, fixed width font with no padding pixels for ASCII chars)
    • 00 04 (with utf-8 multi byte support, variable width font with for ASCII chars)
    • 00 05 (ASCII only, variable width font with)

font_Width_in_Pixel_for_fixed_drawing

  • uint8_t
  • Char width for ASCII characters, if font_Type_Indicator equals 0, 1, 2, or 3. DO NOT OBMIT, set a random value if not used.

font_Height_in_Pixel_for_all_characters

  • uint8_t
  • Char height for ASCII characters.

font_First_Char

  • uint8_t
  • The ascii value of the first char in ASCII table.

font_Ascii_Char_Count

  • uint8_t
  • How many ASCII characters in the font. The value of last char equals font_First_Char + font_Char_Count - 1.

font_Utf8_Section_Start;

  • uint16_t
  • Indicates the start position of utf8 section, exists only if font_Type_Indicator equals 2, 3 or 4.

font_Char_Widths

  • uint8_t[font_Last_Char - font_First_Char +1]
  • The width table of every ASCII characters. For each character the separate width in pixels, characters < 128 have an implicit virtual right empty row.

font_data

  • uint8_t[]
  • Bit field of ASCII characters.
  • For each glyph, each byte represents 8 vertical mono pixels, with lower bits for pixels with smaller vertical coords. The bytes "scans" horizontally from left to right with 8 vertical pixels each time, until it comes to the glyph width. That is, the first Glyph_Width - 1th bytes represents the area from (0, 0) to (Glyph_Width - 1, 7); the area (0, 8) to (Glyph_Width - 1, 15) is represented by bytes from Glyph_Widthth to Glyph_Width * 2 - 1th. The correponding mode is usually called as Vertical - Horizon, or Column - Row mode in the Font-LCD dot converters.

UTF8 Section

font_Utf8_Indicator

  • uint16_t
  • Indicates properities of utf8 section, defined as follows:
    • bit0: Whether utf8 characters are fixed width (uesful for Chinese, Japanese & Korean)
    • bit1: Enable right and bottom padding
    • bit2: Enable extension planes (this will make glyph sizes in glyph table 3 bytes each instead of 2)
    • bit3: Enable 24bit glyph address (enable if your font is larger than 65535 bytes)

font_Utf8_Glyph_Width

  • uint8_t
  • Char width for utf8 characters, if utf8 fixed width is not enabled. DO NOT OBMIT, set a random value if not used.

font_Utf8_Glyph_Count

  • uint16_t
  • Count of utf8 glyphs in the font.

utf8_Glyph_Metadata

  • uint8_t[font_Utf8_Glyph_Count * Glyph_Metadata_Length]
  • Glyph_Metadata_Length = (use_utf8_extension_plane ? 3 : 2) + (utf8_fixed_width ? 0 : 1) + (use_24bit_address ? 3 : 2)
  • Table of utf8 glyph metadata, includes Unicode, width and address for each glyph.

utf8_Glyph_Data

  • uint8_t[]
  • Bit data of utf8 glyphs.
  • same format with ASCII font data.