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authorRicardo Wurmus <rekado@elephly.net>2019-02-09 14:11:03 +0100
committerRicardo Wurmus <rekado@elephly.net>2019-02-09 14:11:03 +0100
commitb3ea95906ce328555b8e3ed19ad68b56c9af7fdf (patch)
tree4faef8ee4b523bbbcee24dfd378ef1f8cc18c140
parent7c76696cc319d8778534377186069031ca9ac3ad (diff)
pict: Support loading of PNGs.
* pict.scm (pict-from-file): Detect and support PNGs. (png-size): New procedure. * pict/base64.scm: New file.
-rw-r--r--pict.scm62
-rw-r--r--pict/base64.scm256
2 files changed, 306 insertions, 12 deletions
diff --git a/pict.scm b/pict.scm
index c755aed..b26a60d 100644
--- a/pict.scm
+++ b/pict.scm
@@ -19,10 +19,13 @@
(define-module (pict)
#:use-module (pict sxml)
+ #:use-module (pict base64)
#:use-module ((sxml simple) #:hide (xml->sxml))
#:use-module (sxml transform)
#:use-module (sxml fold)
#:use-module ((sxml xpath) #:hide (filter))
+ #:use-module (ice-9 binary-ports)
+ #:use-module (rnrs bytevectors)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-9 gnu)
@@ -148,21 +151,56 @@ list VALS."
'(0 . ())
(cons 0 vals))))
+(define (png-size file-name)
+ "Return two values: width and height of the PNG file at FILE-NAME."
+ (define (bv->size bv)
+ (car (bytevector->uint-list bv (endianness big) 4)))
+ (call-with-input-file file-name
+ (lambda (port)
+ (get-bytevector-n port 8) ; throw away header
+ (get-bytevector-n port 4) ; throw away first chunk length
+ (if (bytevector=? (get-bytevector-n port 4)
+ #vu8(73 72 68 82)) ; IHDR
+ (values
+ (bv->size (get-bytevector-n port 4)) ; width
+ (bv->size (get-bytevector-n port 4))) ; height
+ (values #f #f)))))
+
(define (pict-from-file file-name)
"Attempt to read FILE-NAME, convert its contents to SXML and wrap it
in a <PICT> record. If this fails return #F."
- (catch 'parser-error
- (lambda ()
- (make-pict
- (match (call-with-input-file file-name xml->sxml)
- (('*TOP* ('*PI* . rest) svg) svg)
- (('*TOP* svg) svg))))
- (lambda _
- (format (current-error-port)
- "Failed to parse picture from file `~a'.~%\
-Is this really an SVG file?~%"
- file-name)
- #f)))
+ (let ((header (call-with-input-file file-name
+ (lambda (port) (get-bytevector-n port 8)))))
+ (make-pict
+ (match header
+ (#vu8(137 80 78 71 13 10 26 10) ; PNG
+ (call-with-values
+ (lambda () (png-size file-name))
+ (lambda (width height)
+ `(svg (@ (width ,width)
+ (height ,height)
+ (xmlns "http://www.w3.org/2000/svg")
+ (xmlns:xlink "http://www.w3.org/1999/xlink"))
+ (image (@ (width ,width)
+ (height ,height)
+ (xlink:href
+ ,(string-append
+ "data:image/png;base64,"
+ (call-with-input-file file-name
+ (lambda (port)
+ (base64-encode (get-bytevector-all port)))
+ #:binary #t)))))))))
+ (_ ; Assume SVG
+ (catch 'parser-error
+ (lambda ()
+ (match (call-with-input-file file-name xml->sxml)
+ (('*TOP* ('*PI* . rest) svg) svg)
+ (('*TOP* svg) svg)))
+ (lambda args
+ (format (current-error-port)
+ "Failed to load picture from file `~a'.~%Only PNG or SVG are supported.~%~a~%"
+ file-name args)
+ #f)))))))
;;; SXML utilities
diff --git a/pict/base64.scm b/pict/base64.scm
new file mode 100644
index 0000000..21c0d26
--- /dev/null
+++ b/pict/base64.scm
@@ -0,0 +1,256 @@
+;; -*- mode: scheme; coding: utf-8 -*-
+;;
+;; This module was taken from the Guix sources and renamed to
+;; (pict base64) on February 9, 2019.
+;;
+;; This module was renamed from (weinholt text base64 (1 0 20100612)) to
+;; (guix base64) by Nikita Karetnikov <nikita@karetnikov.org> on
+;; February 12, 2014.
+;;
+;; Some optimizations made by Ludovic Courtès <ludo@gnu.org>, 2015.
+;; Turned into a Guile module (instead of R6RS).
+;;
+;; This program is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+;;
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;; GNU General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with this program. If not, see <http://www.gnu.org/licenses/>.
+;;
+;; This file incorporates work covered by the following copyright and
+;; permission notice:
+;;
+;; Copyright © 2009, 2010 Göran Weinholt <goran@weinholt.se>
+;;
+;; Permission is hereby granted, free of charge, to any person obtaining a
+;; copy of this software and associated documentation files (the "Software"),
+;; to deal in the Software without restriction, including without limitation
+;; the rights to use, copy, modify, merge, publish, distribute, sublicense,
+;; and/or sell copies of the Software, and to permit persons to whom the
+;; Software is furnished to do so, subject to the following conditions:
+;;
+;; The above copyright notice and this permission notice shall be included in
+;; all copies or substantial portions of the Software.
+;;
+;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+;; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+;; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+;; THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+;; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+;; FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+;; DEALINGS IN THE SOFTWARE.
+
+;; RFC 4648 Base-N Encodings
+
+(define-module (pict base64)
+ #:export (base64-encode
+ base64-decode
+ base64-alphabet
+ base64url-alphabet
+ get-delimited-base64
+ put-delimited-base64)
+ #:use-module (rnrs)
+ #:use-module ((srfi srfi-13)
+ #:select (string-index
+ string-prefix? string-suffix?
+ string-concatenate string-trim-both)))
+
+
+(define-syntax define-alias
+ (syntax-rules ()
+ ((_ new old)
+ (define-syntax new (identifier-syntax old)))))
+
+;; Force the use of Guile's own primitives to avoid the overhead of its 'fx'
+;; procedures.
+
+(define-alias fxbit-field bitwise-bit-field)
+(define-alias fxarithmetic-shift ash)
+(define-alias fxarithmetic-shift-left ash)
+(define-alias fxand logand)
+(define-alias fxior logior)
+(define-alias fxxor logxor)
+
+(define base64-alphabet
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
+
+(define base64url-alphabet
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_")
+
+(define base64-encode
+ (case-lambda
+ ;; Simple interface. Returns a string containing the canonical
+ ;; base64 representation of the given bytevector.
+ ((bv)
+ (base64-encode bv 0 (bytevector-length bv) #f #f base64-alphabet #f))
+ ((bv start)
+ (base64-encode bv start (bytevector-length bv) #f #f base64-alphabet #f))
+ ((bv start end)
+ (base64-encode bv start end #f #f base64-alphabet #f))
+ ((bv start end line-length)
+ (base64-encode bv start end line-length #f base64-alphabet #f))
+ ((bv start end line-length no-padding)
+ (base64-encode bv start end line-length no-padding base64-alphabet #f))
+ ((bv start end line-length no-padding alphabet)
+ (base64-encode bv start end line-length no-padding alphabet #f))
+ ;; Base64 encodes the bytes [start,end[ in the given bytevector.
+ ;; Lines are limited to line-length characters (unless #f),
+ ;; which must be a multiple of four. To omit the padding
+ ;; characters (#\=) set no-padding to a true value. If port is
+ ;; #f, returns a string.
+ ((bv start end line-length no-padding alphabet port)
+ (assert (or (not line-length) (zero? (mod line-length 4))))
+ (let-values (((p extract) (if port
+ (values port (lambda () (values)))
+ (open-string-output-port))))
+ (letrec ((put (if line-length
+ (let ((chars 0))
+ (lambda (p c)
+ (when (fx=? chars line-length)
+ (set! chars 0)
+ (put-char p #\linefeed))
+ (set! chars (fx+ chars 1))
+ (put-char p c)))
+ put-char)))
+ (let lp ((i start))
+ (cond ((= i end))
+ ((<= (+ i 3) end)
+ (let ((x (bytevector-uint-ref bv i (endianness big) 3)))
+ (put p (string-ref alphabet (fxbit-field x 18 24)))
+ (put p (string-ref alphabet (fxbit-field x 12 18)))
+ (put p (string-ref alphabet (fxbit-field x 6 12)))
+ (put p (string-ref alphabet (fxbit-field x 0 6)))
+ (lp (+ i 3))))
+ ((<= (+ i 2) end)
+ (let ((x (fxarithmetic-shift-left (bytevector-u16-ref bv i (endianness big)) 8)))
+ (put p (string-ref alphabet (fxbit-field x 18 24)))
+ (put p (string-ref alphabet (fxbit-field x 12 18)))
+ (put p (string-ref alphabet (fxbit-field x 6 12)))
+ (unless no-padding
+ (put p #\=))))
+ (else
+ (let ((x (fxarithmetic-shift-left (bytevector-u8-ref bv i) 16)))
+ (put p (string-ref alphabet (fxbit-field x 18 24)))
+ (put p (string-ref alphabet (fxbit-field x 12 18)))
+ (unless no-padding
+ (put p #\=)
+ (put p #\=)))))))
+ (extract)))))
+
+ ;; Decodes a base64 string. The string must contain only pure
+ ;; unpadded base64 data.
+
+(define base64-decode
+ (case-lambda
+ ((str)
+ (base64-decode str base64-alphabet #f))
+ ((str alphabet)
+ (base64-decode str alphabet #f))
+ ((str alphabet port)
+ (unless (zero? (mod (string-length str) 4))
+ (error 'base64-decode
+ "input string must be a multiple of four characters"))
+ (let-values (((p extract) (if port
+ (values port (lambda () (values)))
+ (open-bytevector-output-port))))
+ (do ((i 0 (+ i 4)))
+ ((= i (string-length str))
+ (extract))
+ (let ((c1 (string-ref str i))
+ (c2 (string-ref str (+ i 1)))
+ (c3 (string-ref str (+ i 2)))
+ (c4 (string-ref str (+ i 3))))
+ ;; TODO: be more clever than string-index
+ (let ((i1 (string-index alphabet c1))
+ (i2 (string-index alphabet c2))
+ (i3 (string-index alphabet c3))
+ (i4 (string-index alphabet c4)))
+ (cond ((and i1 i2 i3 i4)
+ (let ((x (fxior (fxarithmetic-shift-left i1 18)
+ (fxarithmetic-shift-left i2 12)
+ (fxarithmetic-shift-left i3 6)
+ i4)))
+ (put-u8 p (fxbit-field x 16 24))
+ (put-u8 p (fxbit-field x 8 16))
+ (put-u8 p (fxbit-field x 0 8))))
+ ((and i1 i2 i3 (char=? c4 #\=)
+ (= i (- (string-length str) 4)))
+ (let ((x (fxior (fxarithmetic-shift-left i1 18)
+ (fxarithmetic-shift-left i2 12)
+ (fxarithmetic-shift-left i3 6))))
+ (put-u8 p (fxbit-field x 16 24))
+ (put-u8 p (fxbit-field x 8 16))))
+ ((and i1 i2 (char=? c3 #\=) (char=? c4 #\=)
+ (= i (- (string-length str) 4)))
+ (let ((x (fxior (fxarithmetic-shift-left i1 18)
+ (fxarithmetic-shift-left i2 12))))
+ (put-u8 p (fxbit-field x 16 24))))
+ (else
+ (error 'base64-decode "invalid input"
+ (list c1 c2 c3 c4)))))))))))
+
+(define (get-line-comp f port)
+ (if (port-eof? port)
+ (eof-object)
+ (f (get-line port))))
+
+ ;; Reads the common -----BEGIN/END type----- delimited format from
+ ;; the given port. Returns two values: a string with the type and a
+ ;; bytevector containing the base64 decoded data. The second value
+ ;; is the eof object if there is an eof before the BEGIN delimiter.
+
+(define (get-delimited-base64 port)
+ (define (get-first-data-line port)
+ ;; Some MIME data has header fields in the same format as mail
+ ;; or http. These are ignored.
+ (let ((line (get-line-comp string-trim-both port)))
+ (cond ((eof-object? line) line)
+ ((string-index line #\:)
+ (let lp () ;read until empty line
+ (let ((line (get-line-comp string-trim-both port)))
+ (if (string=? line "")
+ (get-line-comp string-trim-both port)
+ (lp)))))
+ (else line))))
+ (let ((line (get-line-comp string-trim-both port)))
+ (cond ((eof-object? line)
+ (values "" (eof-object)))
+ ((string=? line "")
+ (get-delimited-base64 port))
+ ((and (string-prefix? "-----BEGIN " line)
+ (string-suffix? "-----" line))
+ (let* ((type (substring line 11 (- (string-length line) 5)))
+ (endline (string-append "-----END " type "-----")))
+ (let-values (((outp extract) (open-bytevector-output-port)))
+ (let lp ((line (get-first-data-line port)))
+ (cond ((eof-object? line)
+ (error 'get-delimited-base64
+ "unexpected end of file"))
+ ((string-prefix? "-" line)
+ (unless (string=? line endline)
+ (error 'get-delimited-base64
+ "bad end delimiter" type line))
+ (values type (extract)))
+ (else
+ (unless (and (= (string-length line) 5)
+ (string-prefix? "=" line)) ;Skip Radix-64 checksum
+ (base64-decode line base64-alphabet outp))
+ (lp (get-line-comp string-trim-both port))))))))
+ (else ;skip garbage (like in openssl x509 -in foo -text output).
+ (get-delimited-base64 port)))))
+
+(define put-delimited-base64
+ (case-lambda
+ ((port type bv line-length)
+ (display (string-append "-----BEGIN " type "-----\n") port)
+ (base64-encode bv 0 (bytevector-length bv)
+ line-length #f base64-alphabet port)
+ (display (string-append "\n-----END " type "-----\n") port))
+ ((port type bv)
+ (put-delimited-base64 port type bv 76))))