diff options
Diffstat (limited to 'vendor/golang.org/x/image/font/plan9font/plan9font.go')
| -rw-r--r-- | vendor/golang.org/x/image/font/plan9font/plan9font.go | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/vendor/golang.org/x/image/font/plan9font/plan9font.go b/vendor/golang.org/x/image/font/plan9font/plan9font.go index af57c55e1..315e793aa 100644 --- a/vendor/golang.org/x/image/font/plan9font/plan9font.go +++ b/vendor/golang.org/x/image/font/plan9font/plan9font.go @@ -174,6 +174,31 @@ func (f *face) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool) { return 0, false } +// For subfont files, if reading the given file name fails, we try appending +// ".n" where n is the log2 of the grayscale depth in bits (so at most 3) and +// then work down to 0. This was done in Plan 9 when antialiased fonts were +// introduced so that the 1-bit displays could keep using the 1-bit forms but +// higher depth displays could use the antialiased forms. +var subfontSuffixes = [...]string{ + "", + ".3", + ".2", + ".1", + ".0", +} + +func (f *face) readSubfontFile(name string) ([]byte, error) { + var firstErr error + for _, suffix := range subfontSuffixes { + if b, err := f.readFile(name + suffix); err == nil { + return b, nil + } else if firstErr == nil { + firstErr = err + } + } + return nil, firstErr +} + func (f *face) subface(r rune) (*subface, rune) { // Fall back on U+FFFD if we can't find r. for _, rr := range [2]rune{r, '\ufffd'} { @@ -188,7 +213,7 @@ func (f *face) subface(r rune) (*subface, rune) { continue } if x.subface == nil { - data, err := f.readFile(x.relFilename) + data, err := f.readSubfontFile(x.relFilename) if err != nil { log.Printf("plan9font: couldn't read subfont %q: %v", x.relFilename, err) x.bad = true |