racket/collects/compiler/private/winicon.ss
2005-05-27 18:56:37 +00:00

856 lines
32 KiB
Scheme

(module winicon mzscheme
(require (lib "list.ss"))
(provide install-icon
extract-icons
parse-icon
build-icon)
(define (byte->integer p)
(read-byte p))
(define (word->integer p)
(integer-bytes->integer (read-bytes 2 p) #f #f))
(define (dword->integer p)
(integer-bytes->integer (read-bytes 4 p) #f #f))
;; The 0 added in the alpha position apparently means "ignore the alpha
;; and use the mask, instead"
(define (3/2word->integer p)
(integer-bytes->integer (bytes-append (read-bytes 3 p) #"\0") #f #f))
(define (integer->word i p)
(display (integer->integer-bytes i 2 #f #f) p))
(define (integer->dword i p)
(display (integer->integer-bytes i 4 #f #f) p))
(define (flag v)
(positive? (bitwise-and #x80000000 v)))
(define (value v)
(bitwise-and #x7FFFFFFF v))
(define (skip-to-image-headers-after-signature p)
;; p is expected to be a file port
(file-position p 60)
(let ([pos (word->integer p)])
;; pos points to IMAGE_NT_HEADERS
(file-position p pos)
(unless (= #x4550 (dword->integer p))
(error "bad signature"))
pos))
(define (get-image-base p)
(let ([pos (skip-to-image-headers-after-signature p)])
(file-position p (+ 4
20
28))
(dword->integer p)))
(define (find-section p find-name)
(let ([pos (skip-to-image-headers-after-signature p)])
(word->integer p) ; skip machine
(let ([num-sections (word->integer p)]
[_ (begin (dword->integer p)
(dword->integer p)
(dword->integer p))]
[size (word->integer p)])
(let ([pos (+ pos
4 ; Signature : DWORD
20 ; FileHeader: IMAGE_FILE_HEADER
size)]) ; "optional" header
(let sloop ([section 0][section-pos pos])
(if (= section num-sections)
(error 'find-section "can't find section: ~e" find-name)
(begin
(file-position p section-pos)
;; p points to an IMAGE_SECTION_HEADER
(let ([name (read-bytes 8 p)])
(if (bytes=? find-name name)
(let ([_ (dword->integer p)]) ; skip
(values (dword->integer p) ; virtual address
(dword->integer p) ; length
(dword->integer p))); file pos
(sloop (add1 section) (+ section-pos 40)))))))))))
(define (find-rsrc-start p re:rsrc)
(let-values ([(rsrc-virtual-addr rsrc-len rsrc-pos)
(find-section p #".rsrc\0\0\0")])
(let loop ([dir-pos 0][path ""])
(file-position p (+ rsrc-pos dir-pos 12))
(let ([num-named (word->integer p)]
[num-ided (word->integer p)])
(let iloop ([i 0])
(if (= i (+ num-ided num-named))
#f
(let ([name-delta (dword->integer p)]
[data-delta (dword->integer p)]
[next (file-position p)])
(or (let ([name (if (flag name-delta)
(begin
(file-position p (+ rsrc-pos (value name-delta)))
(let* ([len (word->integer p)])
;; len is in unicode chars...
(let ([unistr (read-bytes (* 2 len) p)])
;; Assume it fits into ASCII...
(regexp-replace* "\0"
(bytes->string/latin-1 unistr)
""))))
(value name-delta))])
;;(printf "Name: ~a~a = ~a~n" path name (+ rsrc-pos (value data-delta)))
(let ([full-name (format "~a~a" path name)])
(if (flag data-delta)
(loop (value data-delta) (string-append full-name "."))
;; Found the icon?
(and (regexp-match re:rsrc full-name)
;; Yes, so read IMAGE_RESOURCE_DATA_ENTRY
(begin
(file-position p (+ rsrc-pos (value data-delta)))
(cons
(+ (dword->integer p) ; offset (an RVA)
(- rsrc-pos
rsrc-virtual-addr))
(dword->integer p))))))) ; size
(begin
(file-position p next)
(iloop (add1 i)))))))))))
;; >>> Probably doesn't work <<<
(define (find-import-names p)
(let-values ([(seg-virtual-addr seg-len seg-pos)
(find-section p #".idata\0\0")])
(let loop ([pos seg-pos])
;; pos points to an IMAGE_IMPORT_DESCRIPTOR;
;; skip first 4 fields
(file-position p pos)
(if (zero? (dword->integer p)) ; 0 is terminator
null
(begin
(dword->integer p)
(dword->integer p)
;; next field is name
(let ([name-pos (+ (dword->integer p) ; RVA to nul-terminated name
(- seg-pos seg-virtual-addr))])
(file-position p name-pos)
(let ([name (regexp-match "^[^\0]*" p)])
(cons (cons (car name) name-pos)
(loop (+ pos 20))))))))))
;; >>> Doesn't work <<<
(define (find-delay-loads p)
(let-values ([(seg-virtual-addr seg-len seg-pos)
(find-section p #".text\0\0")])
(let ([pos (skip-to-image-headers-after-signature p)]
[image-base (get-image-base p)])
(let ([pos (+ pos
4 ; Signature : DWORD
20 ; FileHeader: IMAGE_FILE_HEADER
96 ; IMAGE_OPTIONAL_HEADER up to directory
104)] ; skip 13 directory entries
[vdelta image-base])
(file-position p pos)
(let loop ([delay-pos (dword->integer p)])
(printf "~a ~a~n" delay-pos vdelta)
(file-position p (+ delay-pos vdelta))
(dword->integer p) ; skip attributes
(let ([name-pos (dword->integer p)])
(printf "~a ~a~n" name-pos vdelta)
(file-position p (+ name-pos vdelta))
(let ([name (regexp-match "^[^\0]*" p)])
(printf "~a~n" name))))))))
(define-struct icon (desc data))
;; desc is (list width height colors 0 planes bitcount)
;; data is (cons pos string)
(define (num-colors l)
(let ([n (caddr l)])
(if (zero? n)
(arithmetic-shift 1 (list-ref l 5))
n)))
(define (install-icon exe-file ico-file . extra-icons)
(let ([ico-icons (append (if ico-file
(extract-icons ico-file)
null)
extra-icons)]
[exe-icons (extract-icons exe-file)])
(let ([p (open-output-file exe-file 'update)])
(dynamic-wind
void
(lambda ()
(for-each (lambda (exe-icon)
(let ([best-ico-icon
;; Find exact match?
(ormap (lambda (ico-icon)
(let ([le (icon-desc exe-icon)]
[li (icon-desc ico-icon)])
(and (= (car li) (car le))
(= (cadr li) (cadr le))
(= (num-colors li) (num-colors le))
(= (bytes-length (cdr (icon-data exe-icon)))
(bytes-length (cdr (icon-data ico-icon))))
ico-icon)))
ico-icons)])
(let ([ico-icon (or best-ico-icon
;; Look for a conversion, if we
;; need a 16x16, 32x32, or 48x48
;; icon
(and
(= (car (icon-desc exe-icon))
(cadr (icon-desc exe-icon)))
(memq (car (icon-desc exe-icon))
'(16 32 48))
(let ([biggest-colorest #f])
(for-each
(lambda (ico-icon)
(let ([w (car (icon-desc ico-icon))]
[exew (car (icon-desc exe-icon))])
(when (and
(= w
(cadr (icon-desc ico-icon)))
(memq w '(16 32 48))
(or
(not biggest-colorest)
(and (= w exew)
(not (= exew (car (icon-desc biggest-colorest)))))
(and (= w exew)
(> (num-colors (icon-desc ico-icon))
(num-colors (icon-desc biggest-colorest))))
(and (not (= exew (car (icon-desc biggest-colorest))))
(or (> w (car (icon-desc biggest-colorest)))
(> (num-colors (icon-desc ico-icon))
(num-colors (icon-desc biggest-colorest)))))))
(set! biggest-colorest ico-icon))))
ico-icons)
(and
biggest-colorest
;; Convert...
(let* ([src-size (car (icon-desc biggest-colorest))]
[dest-size (car (icon-desc exe-icon))]
[src (parse-icon biggest-colorest)]
[image (list-ref src 3)]
[mask (list-ref src 4)]
[has-alpha? (<= 256 (num-colors (icon-desc biggest-colorest)))])
(if (= src-size dest-size)
(build-icon exe-icon
(if has-alpha?
image
(mask->alpha image mask))
mask)
(let ([cvt
(cond
[(and (= src-size 32) (= dest-size 16))
(lambda (i) (48->16 (32->48 i)))]
[(and (= src-size 32) (= dest-size 48))
32->48]
[(and (= src-size 48) (= dest-size 16))
48->16]
[(and (= src-size 48) (= dest-size 32))
48->32]
[(and (= src-size 16) (= dest-size 32))
16->32]
[(and (= src-size 16) (= dest-size 48))
(lambda (i) (32->48 (16->32 i)))])])
(let ([mask (cvt mask)])
(build-icon exe-icon
(if has-alpha?
image
(mask->alpha (cvt image) mask))
mask)))))))))])
(unless ico-icon (printf "no! ~a~n" (icon-desc exe-icon)))
(when ico-icon
(file-position p (car (icon-data exe-icon)))
(display (cdr (icon-data ico-icon)) p)))))
exe-icons))
(lambda () (close-output-port p))))))
;; ------------------------------
;; Image parsing
;; ------------------------------
(define (get-icons file res?)
(let ([p (if (input-port? file)
file
(open-input-file file))])
(dynamic-wind
void
(lambda ()
(unless (= 0 (word->integer p))
(error 'get-icons "~a doesn't start with 0" file))
(unless (= 1 (word->integer p))
(error "type isn't 1"))
(let ([cnt (word->integer p)])
(let ([icons (let loop ([i 0])
(if (= i cnt)
null
(cons
(make-icon
(list (byte->integer p) ; w
(byte->integer p) ; h
(byte->integer p) ; colors
(byte->integer p) ; 0
(word->integer p) ; planes
(word->integer p)) ; bitcount
(list (dword->integer p) ; bytes
((if res? ; where or icon id
word->integer
dword->integer)
p)))
(loop (add1 i)))))])
;; (printf "~a~n" icons)
(for-each (lambda (icon)
(set-icon-data!
icon
(let ([size (car (icon-data icon))]
[where (cadr (icon-data icon))])
(let ([icon-pos (if res?
;; last number is icon id:
(car (find-rsrc-start p (format "^3[.]~a[.]" where)))
;; last number is file position:
where)])
(file-position p icon-pos)
(cons icon-pos
(read-bytes size p)))))
;; If colors, planes, and bitcount are all 0,
;; get the info from the DIB data
(let ([desc (icon-desc icon)])
(when (and (zero? (list-ref desc 2))
(zero? (list-ref desc 4))
(zero? (list-ref desc 5)))
(let ([bi (bitmapinfo icon)])
(set-car! (list-tail desc 4)
(list-ref bi 3))
(set-car! (list-tail desc 5)
(list-ref bi 4))))))
icons)
icons)))
(lambda ()
(when (path-string? file)
(close-input-port p))))))
(define (bitmapinfo icon)
(let ([p (open-input-bytes (cdr (icon-data icon)))])
(list (dword->integer p) ; size == 40 in practice
(dword->integer p) ; width
(dword->integer p) ; height
(word->integer p) ; planes
(word->integer p) ; bitcount
(dword->integer p) ; compression == 0
(dword->integer p) ; size image
(dword->integer p) ; x pixels per meter == 0
(dword->integer p) ; y pixels per meter == 0
(dword->integer p) ; used == 0
(dword->integer p)))) ; important == 0
;; Assumes that bits-per-pixel is 1, 2, 4, 8, 24, or 32.
;; Also assumes that (bits-per-pixel * width) is a multiple of 8.
(define (parse-dib icon)
(let* ([bi (bitmapinfo icon)]
[header-size (list-ref bi 0)]
[num-colors (caddr (icon-desc icon))]
[w (list-ref bi 1)]
[h (/ (list-ref bi 2) 2)]
[bits-per-pixel (list-ref bi 4)])
(let ([p (open-input-bytes (cdr (icon-data icon)))])
;; Skip header
(read-bytes header-size p)
(let* ([read-n
(lambda (n read-one combine)
(let loop ([i n][r null])
(if (= i 0)
(reverse! r)
(loop (sub1 i)
(combine (read-one p) r)))))]
[read-lines
(lambda (w h read-one combine)
(if (zero? (modulo w 4))
(read-n (* w h) read-one combine)
(let loop ([h h])
(if (zero? h)
null
(append (read-n w read-one combine)
(begin
;; pad line to dword:
(read-n (- 4 (modulo w 4)) byte->integer cons)
;; read next line:
(loop (sub1 h))))))))]
[split-bits (lambda (b)
(list
(bitwise-and b 1)
(arithmetic-shift (bitwise-and b 2) -1)
(arithmetic-shift (bitwise-and b 4) -2)
(arithmetic-shift (bitwise-and b 8) -3)
(arithmetic-shift (bitwise-and b 16) -4)
(arithmetic-shift (bitwise-and b 32) -5)
(arithmetic-shift (bitwise-and b 64) -6)
(arithmetic-shift (bitwise-and b 128) -7)))])
(let ([main-image
(cond
[(= bits-per-pixel 32)
;; RGB mode:
(read-n (* w h) dword->integer cons)]
[(= bits-per-pixel 24)
;; RGB mode:
(read-n (* w h) 3/2word->integer cons)]
[else
;; Index mode:
(let ([color-table (list->vector
(read-n (if (zero? num-colors)
(arithmetic-shift 1 bits-per-pixel)
num-colors)
dword->integer cons))]
[image (read-lines (/ w (/ 8 bits-per-pixel))
h
(lambda (p)
(let ([b (byte->integer p)])
(case bits-per-pixel
[(1) (split-bits b)]
[(2)
(list
(bitwise-and b 3)
(arithmetic-shift (bitwise-and b 12) -2)
(arithmetic-shift (bitwise-and b 48) -4)
(arithmetic-shift (bitwise-and b 192) -6))]
[(4)
(list
(bitwise-and b 15)
(arithmetic-shift (bitwise-and b 240) -4))]
[(8) (list b)])))
append)])
(map (lambda (i) (vector-ref color-table i)) image))])])
(let ([mask (read-lines (/ w 8)
h
(lambda (p) (split-bits (byte->integer p)))
append)])
(unless (eof-object? (read-char p))
(error 'parse-dib "not extactly at end"))
(list main-image mask)))))))
;; rgb->indexed
;; The color-reduction strategy isn't great, and because it
;; depends on hash-table order, it's non-deterministic in
;; principle. But the actual hash-table implementatin is
;; deterministic, of course. Also, the re-ordering of the
;; image via the hash tables tends to produce better
;; (pseudo-random) representatives of the image for colors.
(define (rgb->indexed image num-colors)
(let ([image (map (lambda (i) (bitwise-and #xFFFFFF i)) image)] ; drop alphas, if any
[table (make-vector num-colors 0)]
[ht (make-hash-table 'equal)]
[map-ht (make-hash-table 'equal)]
[color-dist (lambda (a b)
(sqrt (+ (expt (- (bitwise-and #xFF a)
(bitwise-and #xFF b))
2)
(expt (- (arithmetic-shift (bitwise-and #xFF00 a) -8)
(arithmetic-shift (bitwise-and #xFF00 b) -8))
2)
(expt (- (arithmetic-shift (bitwise-and #xFF0000 a) -16)
(arithmetic-shift (bitwise-and #xFF0000 b) -16))
2))))])
(for-each (lambda (c)
(hash-table-put!
ht
c
(add1
(hash-table-get ht c (lambda () 0)))))
image)
(let ([kv-sorted
(quicksort (hash-table-map ht cons)
(lambda (a b)
(< (cdr a) (cdr b))))])
(let ([n 0])
(for-each (lambda (kv)
(let ([key (car kv)])
(let ([n (if (< n (sub1 num-colors))
n
;; Find closest match:
(let ([n 0])
(let loop ([i 1])
(unless (= i num-colors)
(when (< (color-dist key (vector-ref table i))
(color-dist key (vector-ref table n)))
(set! n i))
(loop (add1 i))))
n))])
(vector-set! table n key)
(hash-table-put! map-ht key n))
(when (< n (sub1 num-colors))
(set! n (add1 n)))))
kv-sorted)))
(values (vector->list table)
(map (lambda (c) (hash-table-get map-ht c)) image))))
;; Assumes that bits-per-pixel is 1, 2, 4, 8, or 32.
;; Also assumes that (bits-per-pixel * width) is a multiple of 8.
(define (build-dib icon image mask)
(let* ([bi (bitmapinfo icon)]
[header-size (list-ref bi 0)]
[num-colors (caddr (icon-desc icon))]
[w (list-ref bi 1)]
[h (/ (list-ref bi 2) 2)]
[bits-per-pixel (list-ref bi 4)])
(let ([orig-p (open-input-bytes (cdr (icon-data icon)))]
[result-p (open-output-bytes)])
;; Copy header:
(display (read-bytes header-size orig-p) result-p)
(let ([get-lines (lambda (image bits-per-pixel)
(map (lambda (line)
;; pad line to dword boundary
(let ([line-bytes (/ (* w bits-per-pixel) 8)])
(if (zero? (modulo line-bytes 4))
line
(append line
(vector->list
(make-vector (* (- 4 (modulo line-bytes 4))
(/ 8 bits-per-pixel))
0))))))
;; break out lines
(let loop ([l image])
(if (null? l)
null
(cons (let loop ([l l][i 0])
(if (= i w)
null
(cons (car l) (loop (cdr l) (add1 i)))))
(loop (list-tail l w)))))))]
[bits->dwords (lambda (l bpp)
(let ([chunk-size (/ 32 bpp)]
[1byte (lambda (l)
(bitwise-ior
(arithmetic-shift (list-ref l 0) 7)
(arithmetic-shift (list-ref l 1) 6)
(arithmetic-shift (list-ref l 2) 5)
(arithmetic-shift (list-ref l 3) 4)
(arithmetic-shift (list-ref l 4) 3)
(arithmetic-shift (list-ref l 5) 2)
(arithmetic-shift (list-ref l 6) 1)
(arithmetic-shift (list-ref l 7) 0)))]
[2byte (lambda (l)
(bitwise-ior
(arithmetic-shift (list-ref l 0) 6)
(arithmetic-shift (list-ref l 1) 4)
(arithmetic-shift (list-ref l 2) 2)
(arithmetic-shift (list-ref l 3) 0)))]
[4byte (lambda (l)
(bitwise-ior
(arithmetic-shift (list-ref l 0) 4)
(arithmetic-shift (list-ref l 1) 0)))])
(let loop ([l l])
(if (null? l)
null
(cons (case bpp
[(1) (bitwise-ior
(arithmetic-shift (1byte (list-tail l 0)) 0)
(arithmetic-shift (1byte (list-tail l 8)) 8)
(arithmetic-shift (1byte (list-tail l 16)) 16)
(arithmetic-shift (1byte (list-tail l 24)) 24))]
[(2) (bitwise-ior
(2byte l)
(arithmetic-shift (2byte (list-tail l 4)) 8)
(arithmetic-shift (2byte (list-tail l 8)) 16)
(arithmetic-shift (2byte (list-tail l 12)) 24))]
[(4) (bitwise-ior
(4byte l)
(arithmetic-shift (4byte (list-tail l 2)) 8)
(arithmetic-shift (4byte (list-tail l 4)) 16)
(arithmetic-shift (4byte (list-tail l 6)) 24))]
[(8) (bitwise-ior
(car l)
(arithmetic-shift (list-ref l 1) 8)
(arithmetic-shift (list-ref l 2) 16)
(arithmetic-shift (list-ref l 3) 24))])
(loop (list-tail l chunk-size)))))))])
(if (= bits-per-pixel 32)
(for-each (lambda (col) (integer->dword col result-p))
image)
(let-values ([(colors indexed-image) (rgb->indexed image (arithmetic-shift 1 bits-per-pixel))])
;; color table
(for-each (lambda (col) (integer->dword col result-p))
colors)
(let* ([lines (get-lines indexed-image bits-per-pixel)]
[dwords (apply append (map (lambda (l) (bits->dwords l bits-per-pixel))
lines))])
(for-each (lambda (col) (integer->dword col result-p))
dwords))))
(let* ([lines (get-lines mask 1)]
[dwords (apply append (map (lambda (l) (bits->dwords l 1)) lines))])
(for-each (lambda (col) (integer->dword col result-p))
dwords))
(let ([s (get-output-bytes result-p)])
(unless (= (bytes-length s) (bytes-length (cdr (icon-data icon))))
(error 'build-dib "bad result size ~a != ~a"
(bytes-length s) (bytes-length (cdr (icon-data icon)))))
s)))))
(define (parse-icon icon)
(let ([image (parse-dib icon)])
(list (car (icon-desc icon))
(cadr (icon-desc icon))
(let ([cols (caddr (icon-desc icon))])
(if (zero? cols)
(expt 2 (list-ref (icon-desc icon) 5))
cols))
(car image)
(cadr image))))
(define (build-icon base-icon image mask)
(make-icon (icon-desc base-icon)
(cons (car (icon-desc base-icon))
(build-dib base-icon image mask))))
(define (extract-icons file)
(if (regexp-match #rx"[.]ico$" (if (path? file)
(path->string file)
file))
(get-icons-in-ico file)
(get-icons-in-exe file)))
(define (get-icons-in-ico ico-file)
(get-icons ico-file #f))
(define (get-icons-in-exe exe-file)
(let ([p (open-input-file exe-file)])
(dynamic-wind
void
(lambda ()
(let ([pos+size (find-rsrc-start p "^14[.]")])
(file-position p (car pos+size))
(get-icons p #t)))
(lambda () (close-input-port p)))))
;; The following is useful for bitmap->icon,
;; but it uses MrEd, and this module is used by
;; Setup PLT. Probably this code should just be
;; moved somewhere else.
#;
(begin
(require (lib "mred.ss" "mred")
(lib "class.ss"))
(define (bitmap%->icon bm)
(let* ([w (send bm get-width)]
[h (send bm get-height)]
[argb (make-bytes (* w h 4))]
[mdc (make-object bitmap-dc% bm)])
(send mdc get-argb-pixels 0 0 w h argb)
(send mdc set-bitmap #f)
;; Get mask (inverse alpha), if any:
(let ([mask-argb (make-bytes (* w h 4) #o377)]
[mbm (send bm get-loaded-mask)])
(when mbm
(send mdc set-bitmap mbm)
(send mdc get-argb-pixels 0 0 w h mask-argb)
(send mdc set-bitmap #f))
(bitmap->icon w h argb mask-argb)))))
(define (bitmap->icon w h argb mask-argb)
(let ([o (open-output-bytes)])
(integer->dword 40 o) ; size
(integer->dword w o) ; width
(integer->dword (* 2 h) o) ; height
(integer->word 1 o) ; planes
(integer->word 32 o) ; bitcount
(integer->dword 0 o) ; compression
(integer->dword 0 o) ; size image
(integer->dword 0 o) ; x pixels per meter
(integer->dword 0 o) ; y pixels per meter
(integer->dword 0 o) ; used
(integer->dword 0 o) ; important
;; Got ARGB, need BGRA
(let* ([flip-pixels (lambda (s)
(let ([s (bytes-copy s)])
(let loop ([p 0])
(unless (= p (bytes-length s))
(let ([a (bytes-ref s p)]
[r (bytes-ref s (+ p 1))]
[g (bytes-ref s (+ p 2))]
[b (bytes-ref s (+ p 3))])
(bytes-set! s p b)
(bytes-set! s (+ p 1) g)
(bytes-set! s (+ p 2) r)
(bytes-set! s (+ p 3) a)
(loop (+ p 4)))))
s))]
[rgba (flip-pixels argb)]
[mask-rgba (flip-pixels mask-argb)]
[row-size (if (zero? (modulo w 32))
w
(+ w (- 32 (remainder w 32))))]
[mask (make-bytes (* h row-size 1/8) 0)])
(let loop ([i (* w h 4)])
(unless (zero? i)
(let ([mr (bytes-ref mask-rgba (- i 2))]
[mg (bytes-ref mask-rgba (- i 3))]
[mb (bytes-ref mask-rgba (- i 4))]
[a (- i 1)])
(let ([alpha (- 255
(floor (/ (+ mr mg mb)
3)))])
(if (< alpha 10)
;; white mask -> zero alpha; add white pixel to mask
(begin
(bytes-set! rgba a 0)
(let ([pos (+ (* (quotient (sub1 (/ i 4)) w) row-size)
(remainder (sub1 (/ i 4)) w))])
(bytes-set! mask
(quotient pos 8)
(bitwise-ior
(arithmetic-shift 1 (- 7 (remainder pos 8)))
(bytes-ref mask (quotient pos 8))))))
;; non-white mask -> non-zero alpha
(bytes-set! rgba a alpha))))
(loop (- i 4))))
;; Windows icons are upside-down:
(let ([flip (lambda (str row-width)
(apply
bytes-append
(reverse
(let loop ([pos 0])
(if (= pos (bytes-length str))
null
(cons (subbytes str pos (+ pos row-width))
(loop (+ pos row-width))))))))])
(display (flip rgba (* w 4)) o)
(display (flip mask (/ row-size 8)) o))
(make-icon (list w h 0 0 1 32)
(cons 0 (get-output-bytes o))))))
;; ------------------------------
;; Image conversion
;; ------------------------------
(define (mask->alpha image mask)
(map (lambda (i m)
(if (zero? m)
(bitwise-ior #xFF000000 i)
m))
image mask))
(define (first-n n l)
(let loop ([l l][i n])
(if (zero? i)
null
(cons (car l) (loop (cdr l) (sub1 i))))))
(define (16->32 l)
(let loop ([l l])
(if (null? l)
null
(let ([l2 (let loop ([l (first-n 16 l)])
(if (null? l)
null
(list* (car l) (car l) (loop (cdr l)))))])
(append l2 l2
(loop (list-tail l 16)))))))
(define (32->48 l)
(let loop ([l l][dup? #t])
(if (null? l)
null
(let ([l2 (let loop ([l (first-n 32 l)])
(if (null? l)
null
(list* (car l) (car l) (cadr l)
(loop (cddr l)))))])
(append l2
(if dup? l2 null)
(loop (list-tail l 32) (not dup?)))))))
(define (48->16 l)
(let loop ([l l])
(if (null? l)
null
(let ([l2 (let loop ([l (first-n 48 l)])
(if (null? l)
null
(cons (car l) (loop (cdddr l)))))])
(append l2
(loop (list-tail l 144)))))))
(define (48->32 l)
(let loop ([l l][step 0])
(if (null? l)
null
(let ([l2 (let loop ([l (first-n 48 l)][step 0])
(if (null? l)
null
(if (= 1 (modulo step 3))
(loop (cdr l) 2)
(cons (car l) (loop (cdr l) (add1 step))))))])
(append (if (= 1 (modulo step 3)) null l2)
(loop (list-tail l 48) (add1 step))))))))
#|
;; ----------------------------------------
;; Test code
(define icons (extract-icons "e:/matthew/plt/mred.exe"))
(define (show-icon w h col-count image mask)
(let* ([f (make-object frame% (format "~a x ~a (~a) Image" w h col-count))]
[bm (make-object bitmap% w h)]
[mbm (make-object bitmap% w h)]
[c (instantiate canvas% (f)
[paint-callback (lambda (c dc)
(send dc draw-bitmap bm 0 0)
(send dc draw-bitmap mbm w 0))])])
(let ([mdc (make-object bitmap-dc% bm)]
[col (make-object color%)])
(let loop ([l image][i 0][j 0])
(unless (= j h)
(let ([v (car l)])
(send col set
(bitwise-and v #xFF)
(arithmetic-shift (bitwise-and v #xFF00) -8)
(arithmetic-shift (bitwise-and v #xFF0000) -16))
(send mdc set-pixel i j col)
(if (= (add1 i) w)
(loop (cdr l) 0 (add1 j))
(loop (cdr l) (add1 i) j)))))
(send mdc set-bitmap mbm)
(let loop ([l (if (col-count . > . 256) image mask)][i 0][j 0])
(unless (= j h)
(let ([v (if (col-count . > . 256)
(- 255 (arithmetic-shift (bitwise-and (car l) #xFF000000) -24))
(if (zero? (car l))
0
255))])
(send col set v v v)
(send mdc set-pixel i j col)
(if (= (add1 i) w)
(loop (cdr l) 0 (add1 j))
(loop (cdr l) (add1 i) j)))))
(send mdc set-bitmap #f))
(send c min-client-width (* 2 w))
(send c min-client-height h)
(send c stretchable-width #f)
(send c stretchable-height #f)
(send f show #t)))
(define (find-icon icons w h colors)
(ormap (lambda (i)
(let ([p (parse-icon i)])
(and (= w (car p))
(= h (cadr p))
(= colors (caddr p))
i)))
icons))
(let ([orig (find-icon icons 48 48 (expt 2 32))]
[target (find-icon icons 32 32 256)])
(apply show-icon (parse-icon orig))
(apply show-icon (parse-icon target))
(apply show-icon
(parse-icon
(let* ([p (parse-icon orig)]
[mask (48->32(list-ref p 4))]
[image (mask->alpha (48->32 (list-ref p 3)) mask)])
(build-icon target image mask)))))
;; ----------------------------------------
;; End test code
|#