FontEdit: The FYSOS Font Creator

Reasoning:

To Create a new Font

• A font can have a fixed width or variable width characters, but must have a fixed height, predetermined at creation time. If you choose a fixed width, all characters will use the same number of pixels in the horizontal direction. If you leave the 'fixed' checkbox clear, they will use an average size, each character adjustable in width. This simply displays this many horizontal pixels per character, but you can modify the width at each character.
• The height is a fixed height, again predetermined. Every character will have this same height in pixels.
• The starting character number is usually 0 if you follow the ASCII notation, however it can be any valid Unicode number from 0x000000 to 0x10FFFF. This is usually the character offset. For example, if you only want to support 'A' through 'Z', use a value of 65 for this starting number. Please note that this is not a requirement. It is up to your Font Engine to do what it wants to with this entry. However, this makes it easy if you pass an 24-bit value as the character offset to your Engine.
• Ending number should be the last Unicode value you include. For example, if you follow the ASCII notation, this can be 127 or 255. This value gives this app a count so that it can create the correct number of characters. For example, a starting value of 65 (Unicode 0x000041) with an ending value of 90 (Unicode 0x00005A) is the English letters 'A' through 'Z', giving a count of 26 characters.
• You can give it a name. This has nothing to do with the file name. This is simply for your Engine's sake. For example, if the file name is 'frnkgoth.fnt', the user may not know exactly what font it is. However, when asked to list all the available fonts, your Engine can display a name: 'Franklin Gothic'. Please note that only 32 bytes of UTF-8 characters are allowed and must include the null termination.

Creating a Character

• Now you can start to create each character's bitmap. Click on one of the white boxes to turn it black. A white box means clear, a black box means set.
• Once you have created this character, use the "Next" button to move to the next.
• Looking back to the image above, using the buttons on the left, you can manipulate the bitmap for this character, or move to the previous or next character.
• The 'U', 'L', 'R', and 'D' buttons will move the pixels in that direction. However, note that if you move a pixel off of the board, it is gone. Moving back in the other direction will leave the pixel clear.
• In non-fixed-width fonts, the 'Minus' and 'Plus' buttons will allow you to change the width of the character. This only changes the width of the current character. Again, if you shrink the width, losing pixels on the right side, they are lost.
• The 'Invert' button does just that. It inverts the pixels. Makes all clear pixels set, and all set pixels clear.
• The 'Restore' button will restore a character back to what it was before you modified this character. However, please note that the restoration point is the character's bitmap at the time when you moved to this character. For example, if you modify the character, then press 'next' to go to the next character, pressing 'prev' to come back to this character saves the restore state. i.e.: The current bitmap, before you make a modification, is what will be restored if you hit the 'restore' button.
• The two 'Flip' buttons simply flip in the respected direction.
• The three Delta controls gives your Engine the ability to move the character up and down or give it an extra width value. These are not used here in the font editor, but can be used in your Font Engine. For example, if you create a subscript character, you can put a positive value in the Vertical Delta field. Then your Font Engine can move down the screen this many pixels to display this character.

Other Functions

• You can save the font at any time using the 'Save as' and 'Save' menu items.
• You can open an existing font using the 'Open' menu item. If the current font is not saved, it will prompt you to save it.
• You can 'copy' a character, then 'paste' it to another character. Note that if the copied character is wider than the current character, the right side will be lost. Add pixels in the horizontal direction (Plus button) to hold the newly copied character before you paste it.
• You can 'go to' a character using an offset.
• The Mark as non-fixed menu item will simply mark the current open font as non-fixed, if it isn't already. You can then modify the width of individual characters. All PSF fonts are initially fixed when opened. If you mark as non-fixed and modify the width of one or more characters, when you save it as a PSF font, all characters will be expanded to the width of the widest character. If the font was opened as a PSFv1 font, if the new width is no longer 8, you will be asked to save as a PSFv2 font. If you do not, all characters will be expanded/truncated to 8 pixels wide.
• You can change the name of a font using the 'Name...' menu item.
• You can dump the contents of the font to a file. This will dump the bytes to a file in ascii format ready for a "C/C++" source code file. Here is a dump of the System128.fnt font.
• You can load a Linux PSFv1 or PSFv2 Font file and save it back as either format, preserving the Unicode table. In other words, you can open any of the three formats, and then save as any of the three formats. The format you save it as does not have to be the format you opened it as. However, saving as a FNT format will lose the Unicode table if it was found on the opened PSFv1 or PSFv2 format.
  • Load any of the four formats via the filename, the filename's extension does not indicate which format it is. The FileOpen() routine checks for the signatures to indicate which format it is.
  • To save in a specified format, the filename's extension does indicate what format to save as.
    • '.fnt' is the format described on this page.
    • '.psf' is the Linux PSF version 1 format. Note that if the width is not 8 bits, anything wider will be lost. If the count of chars is not 256 or 512, blank chars will be added.
    • '.psfu' is the Linux PSF version 2 format.
  • You can also load a Grub PFF2 font file. However, at the time of this writing, you can only save it as one of the other three mentioned formats. Saving back as a Grub PFF2 font file is not yet implemented.
  • Please note that this function, loading and saving as other formats, is currently experimental.

The All-Important File Format:

  #define MAX_NAME_LEN  32
  
  struct FONT {
    bit8u  sig[4];       // 'Font'
    bit8u  height;       // height of char set
    bit8u  max_width;    // width of widest char in set
    bit16u info_start;   // zero based offset to the first FONT_INFO block
    bit32s start;        // starting value (first entry in font == this value) (*** Signed ***)
    bit32s count;        // count of chars in set ( 0 < count <= 0x10FFFF ) (*** Signed ***)
    bit32u datalen;      // len of the data section in bytes
    bit32u total_size;   // total size of this file in bytes
    bit32u flags;        // bit 0 = fixed width font, remaining bits are reserved
    bit8u  name[MAX_NAME_LEN]; // utf-8 null terminated
    bit8u  resv[36];     // reserved and preserved
  };

• The sig[4] member was 'FONT' in the old version of this font file. I have now made it 'Font' so that a font engine won't mistakenly think an older file is valid.
• The height field is the height of this font in pixels. Every character in the font has this many pixels in the vertical direction.
• The max_width field is the width of the widest character in the font file.
• The info_start field points to the start of the next section. This is normally a value of 96, the size of this header. However, this field is included so that a later version of this font file can have a new section between this Header and the FONT_INFO section, yet current source code can still use this font file with no modification.
• The start field is the starting character code of the first character in the font file. For example, if you start with the English character of 'A', this value would be 65 (0x000041).
• The count field is the count of characters in the font file. For example, if you start with the English character of 'A' and end with 'Z', this value would be 26.
• The datalen field is the count of bytes in the bitstream section.
• The total_size field is the count of bytes in this file.
• The flags field is 32 one-bit flags. Currently only bit 0 is used and indicates that this font has a fixed width. i.e.: The width must not be changed. Any remaining bits must be preserved if written to.
• The name field is a 32-byte UTF-8 NULL terminated string of the name of this font. This is used within your engine to find or display a readable name.
• The resv field is to be written as zeros when creating a font file, and preserved when updating an existing file.

• The count limit of 0x10FFFF is the inherent limit due to limit of the Unicode specification. The included source to this App has a smaller limit (64k) simply to save memory and make it easier to code.
• The max_width and height fields have an inherent limit of 255 each. However, this App has a limit of 24 for each, simply to keep the code sane.
• The start and count fields are signed 32-bit members. This is for ease of use in your code. However, with 0x10FFFF max characters allowed in the Unicode system, these fields should never have bit 31 set, which would indicate a negative number on an Intel-based system.)

    00000000  46 6F 6E 74 0A 08 60 00-20 00 00 00 5F 00 00 00     Font..`....._...
    00000010  B6 03 00 00 8A 08 00 00-01 00 00 00 43 6F 75 72     ............Cour
    00000020  69 65 72 20 4E 65 77 00-00 00 00 00 00 00 00 00     ier.New.........
    00000030  00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00     ................
    00000040  00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00     ................
    00000050  00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00     ................
    
    00000000  46 6F 6E 74    // sig = 'Font'
              0A             // height = 10 bits
              08             // width of widest char = 8 bits
              60 00          // zero based offset to the first FONT_INFO block
              20 00 00 00    // starting ascii char = 32 = space character
              5F 00 00 00    // count of chars in set = 95
              B6 03 00 00    // bytes in data section (950 bytes)
              8A 08 00 00    // bytes in whole file (2,186 bytes)
              01 00 00 00    // flags: bit 0 set = fixed width font

              43 6F 75 72 69 65 72 20 4E 65 77 00 00 00 00 00 // Name: "Courier New" + ASCIIZ
              00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00

              00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00
              00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00
              00 00 00 00

    struct FONT_INFO {
      bit32u index;   // index of this character in data section
      bit8u  width;   // Width of character
      char   deltax;  // +/- offset to print char 
      char   deltay;  // +/- offset to print char (allows for drop chars, etc)
      char   deltaw;  // +/- offset to combine with width above when moving to the next char
      bit8u  resv[4]; // reserved
    };

• The index field is the byte offset within the data section of the first byte containing the bitmap for this character.
• The width field is the width of the character in bits. (The height is found in the first 96 bytes of the file).
• The three delta fields are used to display a character at a given delta from the current position. Used only by your Engine. Has no affect on the characters in the file.
  For example, if the deltay value is +1, the engine should display the character one pixel down the screen. Used for characters such as a 'p' character.
  The deltaw member overrides the width of the character and allows you to display the next character closer or further apart.

  00000060  00 00 00 00 08 00 00 00-00 00 00 00
            0A 00 00 00 08 00 00 00 00 00 00 00
  
  00000060  00 00 00 00  // offset is zero.  First character in the data stream
            08           // 8 bits wide
            00           // signed delta 'x'
            00           // signed delta 'y' 
            00           // signed delta 'w'
            00 00 00 00  // reserved

  0000006C  0A 00 00 00  // offset is 10.  Ten bytes from beginning of data stream
            08           // 8 bits wide
            00           // signed delta 'x'
            00           // signed delta 'y' 
            00           // signed delta 'w'
            00 00 00 00  // reserved
  

   /* character 27 */
   0x00, 0x24, 0x02, 0x50, 0x00,
   /* Bitmap:
    ...
    ...
    ...
    .1.
    .1.
    ...
    ...
    .1.
    .1.
    1..
    ...
    ...
    */
  

• This app is for Windows only. I use WinXP but have tested with later versions of Windows as well as 64-bit machines.
• No installation or removal. Simply copy the .exe file to a new directory and run it. Removal: Simply delete the file.
• To use, simply execute and use the "FILE" menu to open or create a new font file.
• Use at your own risk.
• If you use this utility to create a font for your system, please send me the font file. I would love to add it to my collection of fonts as well as the list below.