font command

Synopsis

font list
font select [<name> [<size>]]
font size [<size>]
font info

Description

The font command allows selection of the font to use on the video console. This is available when the TrueType console is in use.

font list

This lists the available fonts, using the name of the font file in the build. Any enabled bitmap fonts are listed as well.

font select

This selects a new font and optionally changes the size. If the name is not provided, the default font is used.

font size

This changes the font size only. With no argument it shows the current size.

font info

This shows glyph rendering statistics, specifically the number of glyphs rendered since the video console was set up.

This subcommand requires CONFIG_VIDEO_GLYPH_STATS=y.

Examples

=> font list
nimbus_sans_l_regular
cantoraone_regular
=> font size
30
=> font size 40
=> font select cantoraone_regular 20
=>

This shows an example of selecting a bitmap font when Truetype is active:

=> font list
8x16
12x22
nimbus_sans_l_regular
cantoraone_regular
=> font sel 8x16

This shows glyph rendering statistics:

=> font info
glyphs rendered: 32705

Configuration

The command is only available if CONFIG_CONSOLE_TRUETYPE=y.

CONFIG_CONSOLE_TRUETYPE_GLYPH_BUF enables a pre-allocated buffer for glyph rendering, avoiding malloc/free per character. The buffer starts at 4KB and grows as needed via realloc().

CONFIG_CONSOLE_TRUETYPE_SCRATCH enables a scratch buffer for internal stbtt allocations. Without this, the TrueType library performs around 5 allocations per character (totalling ~26KB), creating malloc/free overhead and heap fragmentation. With the scratch buffer, memory is allocated once at probe time and reused for each character. CONFIG_CONSOLE_TRUETYPE_SCRATCH_SIZE sets the buffer size (default 32KB), which is sufficient for most Latin characters. Complex glyphs (CJK, emoji) or very large font sizes may need 64KB or more. Allocations exceeding the buffer size fall back to malloc transparently.

CONFIG_VIDEO_GLYPH_STATS enables tracking of glyph-rendering statistics.