fontconvert: remap characters, for smaller custom fonts #395
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Add support for a new (optional) "remap" parameter for `fontconvert`.
If given, that parameter replaces the glyphs for certain characters
with glyphs of a different character.
This way a font can be created which contains a single contiguous
range of characters, without being limited to 7 bit ASCII.
The downside of this approach is, that the characters as they appear
in the code won't show up on screen the same way.
Example:
Suppose I need the following set of characters: `0123456789+-.%°`.
The first 14 characters are all in the ASCII plane, so without
remapping, I could get them by converting the range 37 (%) to 57 (9):
./fontconvert FreeSerifBold.ttf 24 37 57
(`°` is not on the ASCII plane, so I cannot get that character, no
matter the range).
Note that even though I needed only 15 characters, I had to specify a
20 character range to get only 14 of them. There are 6
characters (`&'()*,/`) for which glyphs will be included as well, but
I'll never use them.
This isn't ideal, so "remap" to the rescue!
First I'm choosing an ASCII range that includes as many of the
characters as I need, by having as little extra characters as
possible.
In this case that range is 43 (`+`) to 57 (`9`), which has two
characters I don't need: `,` and `/`. Luckily I also have two
characters which are *not* in that range (`%` and `°`).
By using the `°` glyph for the `,` character and the `%` glyph for the
`/` character, I get a contigious range of characters which contains
only the symbols I need:
| Charcode | ASCII | Glyph |
|----------|-------|-------|
| 43 | `+` | `+` |
| 44 | `,` | `°` |
| 45 | `-` | `-` |
| 46 | `.` | `.` |
| 47 | `/` | `%` |
| 48 | `0` | `0` |
| 49 | `1` | `1` |
| 50 | `2` | `2` |
| 51 | `3` | `3` |
| 52 | `4` | `4` |
| 53 | `5` | `5` |
| 54 | `6` | `6` |
| 55 | `7` | `7` |
| 56 | `8` | `8` |
| 57 | `9` | `9` |
The remap parameter for this case is `,°/%`:
./fontconvert FreeSerifBold.ttf 24 43 57 ,°/%
From arduino code then, I can just write:
display.display("37.5,");
Which will render "37.5°".
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@nilclass hello, |
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Unfortunately I cannot reproduce those issues.
Running works for me, and produces
Could you provide an example of:
|
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@nilclass Hi, |
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@liyong4github is there a space between the |
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@nilclass No space between , and °C, when running |
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And when I running |
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@liyong4github the command looks correct to me. This could be an encoding issue. The remap parameter is expected to be UTF8 encoded. It's possible your terminal is using a different encoding. |
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Switched to utf encoding by |
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It's really an encoding issue, as I running |
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@nilclass There's a confusing question. when I running And when running |
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@liyong4github it's possible your terminal is doing something weird with that comma. Try quoting the entire remap parameter |
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@nilclass It doesn't work either. I tried to print ℃ via fprintf，it works. There is garbled code when I put it in the remap parameters. |
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does this work for you? |
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@nilclass it works, thank u! |
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This change modifies
fontconvertto add support for a new (optional) "remap" parameter.If given, that parameter replaces the glyphs for certain characters with glyphs of a different character.
It's interpreted as a utf8 encoded string of pairs of characters, for example
xy! 😉would mean: for characterx, put the glyph ofyinto the font, and for the character!put the winking emoji into the font.This way a font can be created which still only contains a single contiguous range of characters (thus stays small), while no longer being limited to 7 bit ASCII.
The downside of this approach is, that the characters as they appear in the code won't show up on screen the same way.
Example:
Suppose I need the following set of characters:
0123456789+-.%°.The first 14 characters are all in the ASCII plane, so without remapping, I could get them by converting the range 37 (
%) to 57 (9):(
°is not on the ASCII plane, so I couldn't get that character this way, no matter the range).Note that even though I needed only 15 characters, I had to specify a 20 character range to get only 14 of them. There are 6
characters (
&'()*,/) for which glyphs will be included as well, but I'll never use those.This isn't ideal, so "remap" to the rescue!
First I'm choosing an ASCII range that includes as many of the characters as I need, by having as little extra characters as
possible.
In this case that range is 43 (
+) to 57 (9), which has two characters I don't need:,and/. Luckily I also have two characters which are not in that range (%and°).By using the
°glyph for the,character and the%glyph for the/character, I get a single range of characters which contains only the symbols I need:++,°--../%00112233445566778899The remap parameter for this case is
,°/%:From arduino code then, I can just write:
Which will render "37.5°".