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table_vorg.go
51 lines (46 loc) · 1.04 KB
/
table_vorg.go
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package truetype
import (
"encoding/binary"
"errors"
)
type tableVorg struct {
metrics []struct {
glyph GID
origin int16
}
defaultOrigin int16
}
func (t tableVorg) getYOrigin(glyph GID) int16 {
// binary search
for i, j := 0, len(t.metrics); i < j; {
h := i + (j-i)/2
entry := t.metrics[h]
if glyph < entry.glyph {
j = h
} else if entry.glyph < glyph {
i = h + 1
} else {
return entry.origin
}
}
return t.defaultOrigin
}
func parseTableVorg(data []byte) (out tableVorg, err error) {
if len(data) < 8 {
return out, errors.New("invalid 'vorg' table (EOF)")
}
out.defaultOrigin = int16(binary.BigEndian.Uint16(data[4:]))
count := int(binary.BigEndian.Uint16(data[6:]))
if len(data) < 8+4*count {
return out, errors.New("invalid 'vorg' table (EOF)")
}
out.metrics = make([]struct {
glyph GID
origin int16
}, count)
for i := range out.metrics {
out.metrics[i].glyph = GID(binary.BigEndian.Uint16(data[8+4*i:]))
out.metrics[i].origin = int16(binary.BigEndian.Uint16(data[8+4*i+2:]))
}
return out, nil
}