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Adding new fonts


Editing

All the fonts were created using Fony but any other font editor such as Fontforge should be able to edit them.

Exporting

Marlin can’t use directly the fon font format, it must be exported to a C/C++ byte array. The workflow is very simple, just open a font file using Fony and export it to the bdf format. Next we must use the bdf2u8g.exe converter in order to obtain a C/C++ header file.

On the Fony window select the first “symbol” from your font file (1) and see it’s index (3), in the following example the index of our first symbol is 32. Next you must repeat the operation for the last symbol (2), in our example the value is 255.

Figure #001

Open a terminal window and execute, on the same folder where the bdf file is located, the following command:

.\bdf2u8g.exe -b <start> -e <end> <font_name>.bdf <font_name> dogm_font_data_<font_name>.h

You must replace <start>/<end> by your indexes and <font_name> by your font’s file name.

Edit the generated dogm_font_data_<font_name>.h and do the following changes to it:

  • Replace #include "u8g.h" with #include <U8glib.h>
  • Replace U8G_FONT_SECTION with U8G_SECTION
  • Insert .progmem. right after the first quote " on U8G_SECTION

Original:

#include "u8g.h"
const u8g_fntpgm_uint8_t Marlin_symbols[140] U8G_FONT_SECTION("Marlin_symbols") = {

Edited:

#include <U8glib.h>
const u8g_fntpgm_uint8_t Marlin_symbols[140] U8G_SECTION(".progmem.Marlin_symbols") = {

You must now copy the edited C/C++ header file to the Marlin source folder and make Marlin aware of the new font file by editing the ultralcd_impl_DOGM.h before the #else // fall-back line:

#elif ENABLED(DISPLAY_CHARSET_NEWNAME)
  #include "dogm_font_data_yourfont.h"
  #define FONT_MENU_NAME YOURFONTNAME
#else // fall-back

The last step is to add your font to the list of permitted fonts in language_en.h like so:

... || ENABLED(DISPLAY_CHARSET_YOUR_NEW_FONT) ... )

We distribute with Marlin the make_fonts.bat which is a helper script which automates most of the previous steps for our core font files, manual editing of the header files is still necessary.

Implementation and limits

The current limit symbol limit per font is 256.

Marlin uses a menu system with 5 lines, on a display with 64 pixel height. That means each line can have at maximum 12 pixels height. but as a small gap between the lines is a requirement, the final symbol height can’t be no more than 10 pixel height. In some cases it may be desirable to make the gap between lines smaller so more information can fit the screen [even if it causes a small loss of readability], if TALL_FONT_CORRECTION is set to 1 when loading the font then each symbol may have up to 11 pixels height.

To fit 22 symbols on the a 128 pixel width screen, the symbols can’t be wider than 5 pixel for the first 128 symbols, for the last 128 symbols Marlin supports up to 11 pixel width bitmaps.