png-image: Library to view and modify PNG chunks.
procedure
img : (or/c path-string? bytes?)
procedure
(png->hash img) → (and/c hash? immutable?)
img : png?
The chunk hashes have the keys '(type data length crc32).
About text chunks:
* tEXt data hashes have the keys '(keyword text).
* zTXt data hashes have the keys '(keyword compression-method text).
* iTXt data hashes have the keys '(keyword compression-flag compression-method language-tag translated-keyword text).
* The only valid compression-method value is #"\0".
procedure
(text-data->hash bstr) → hash?
bstr : bytes?
procedure
(ztxt-data->hash bstr) → hash?
bstr : bytes?
procedure
(itxt-data->hash bstr) → hash?
bstr : bytes?
procedure
(text-hash->data hsh) → bytes?
hsh : hash?
procedure
(ztxt-hash->data hsh) → bytes?
hsh : hash?
procedure
(itxt-hash->data hsh) → bytes?
hsh : hash?
procedure
(make-text-chunk keyword [str]) → bytes?
keyword : string? str : string? = ""
procedure
(make-ztxt-chunk keyword [str]) → bytes?
keyword : string? str : string? = ""
procedure
(make-itxt-chunk keyword [ str language-tag translated-kw]) → bytes? keyword : string? str : string? = "" language-tag : string? = "" translated-kw : string? = ""
procedure
(make-text-hash chunk) → hash?
chunk : bytes?
procedure
(make-ztxt-hash chunk) → hash?
chunk : bytes?
procedure
(make-itxt-hash chunk) → hash?
chunk : bytes?
procedure
(bytes-crc32 bstr) → integer?
bstr : bytes?
procedure
(bytes-adler32 bstr) → integer?
bstr : bytes?