TTF / OTF fonts

Status

What it is

TTF and OTF files are font binaries used for deterministic text outlines. They are not embroidery machine files.

Satin Studio behavior

Satin Studio stores uploaded fonts with the project so text objects can compile from exact font outlines.

Versions and variants

Satin Studio checks the file signature and dialect rather than trusting the extension. An unrecognized version remains unopened, with the original file preserved for inspection.

File identification notes

Static TrueType/OpenType font binaries.

Observed structure notes

• TTF and OTF are SFNT containers with a big-endian offset table and per-table records.
• Common table tags relevant to embroidery text include cmap for character mapping, glyf/loca or CFF for outlines, head/hhea/hmtx for metrics, name for names, GSUB for substitutions, and GPOS for positioning.
• Font parsing gives outlines and shaping facts. It does not choose stitch type, density, underlay, or pull compensation.
• All multi-byte integers in SFNT directory tables are big-endian. Table checksums and offsets are validated before reading table payloads.
• TrueType outlines use glyf plus loca; CFF-flavored OpenType uses CFF or CFF2 data instead. Both require shaping before Satin Studio can place glyph outlines correctly.

Structure sketch

TTF and OTF are SFNT-family font containers. Satin Studio uses them as project assets, not as embroidery files.

struct SfntFont<'a> {
    offset_table: SfntOffsetTable,
    table_records: &'a [SfntTableRecord],
    table_data: &'a [u8],
}

struct SfntOffsetTable {
    sfnt_version: [u8; 4],              // 0x00010000 for TTF, "OTTO" for CFF OTF
    num_tables: u16,                    // big-endian on disk
    search_range: u16,
    entry_selector: u16,
    range_shift: u16,
}

struct SfntTableRecord {
    tag: [u8; 4],
    checksum: u32,
    offset: u32,
    length: u32,
}

Compatibility evidence

Compatibility checks cover signatures, metadata, command boundaries, malformed records, and files from the machines and software named above. Unsupported variants stop with a specific report instead of being silently rewritten.