racket/collects/deinprogramm/image.rkt
2010-04-27 16:50:15 -06:00

869 lines
26 KiB
Racket

#lang scheme/base
#|
The test suite for this code is in
plt/collects/tests/deinprogramm/image.ss
|#
(require mred
mzlib/class
mrlib/cache-image-snip
mzlib/math
lang/prim
lang/posn
lang/private/imageeq
htdp/error
deinprogramm/contract/contract-syntax
(only-in deinprogramm/DMdA integer natural))
(provide ; #### -primitives doesn't work for us
image?
image-width
image-height
empty-image
overlay
above
beside
clip
pad
rectangle
circle
ellipse
triangle
line
text
image-inside?
find-image
image->color-list
color-list->image
image->alpha-color-list
alpha-color-list->image
image-color?
make-color
color-red
color-green
color-blue
color?
make-alpha-color
alpha-color-alpha
alpha-color-red
alpha-color-green
alpha-color-blue
alpha-color?
octet rgb-color mode image image-color
h-place v-place h-mode v-mode)
;; ----------------------------------------
(define (color-list? l)
(and (list? l) (andmap image-color? l)))
(define (alpha-color-list? l)
(and (list? l) (andmap alpha-color? l)))
(define-struct color (red green blue) #:inspector (make-inspector))
(define-struct alpha-color (alpha red green blue) #:inspector (make-inspector))
;; ----------------------------------------
(define (check name p? v desc arg-posn) (check-arg name (p? v) desc arg-posn v))
(define (check-coordinate name val arg-posn) (check name finite-real? val "real" arg-posn))
(define (check-integer-coordinate name val arg-posn) (check name nii? val "integer" arg-posn))
(define (check-size name val arg-posn) (check name pos-real? val "positive real" arg-posn))
(define (check-posi-size name val arg-posn) (check name pos-integer? val "positive integer" arg-posn))
(define (check-size/0 name val arg-posn) (check name nn-real? val "non-negative real" arg-posn))
(define (check-h-place name val arg-posn)
(check name h-place? val
"non-negative exact integer or horizontal alignment position"
arg-posn))
(define (check-v-place name val arg-posn)
(check name v-place? val
"non-negative exact integer or vertical alignment position"
arg-posn))
(define (check-image name val arg-posn) (check name image? val "image" arg-posn))
(define (check-image-color name val arg-posn)
(let ([simple-check (lambda (x) (or (string? x) (symbol? x) (color? x)))])
(check name simple-check val "image-color" arg-posn)
(unless (image-color? val)
(error name "~e is not a valid color name" val))))
(define (check-mode name val arg-posn) (check name mode? val mode-str arg-posn))
(define (pos-real? i) (and (real? i) (positive? i)))
(define (pos-integer? i) (and (integer? i) (positive? i)))
(define (nn-real? i) (and (real? i) (or (zero? i) (positive? i))))
(define (nii? x) (and (integer? x) (not (= x +inf.0)) (not (= x -inf.0))))
(define (finite-real? x) (and (real? x) (not (= x +inf.0)) (not (= x -inf.0))))
(define (check-sizes who w h)
(unless (and (< 0 w 10000) (< 0 h 10000))
(error (format "cannot make ~a x ~a image" w h))))
(define (mode? x)
(member x '(solid "solid" outline "outline")))
(define mode-str "'solid \"solid\" 'outline or \"outline\"")
(define (mode->brush-symbol m)
(cond
[(member m '(solid "solid"))
'solid]
[(member m '(outline "outline"))
'transparent]))
(define (mode->pen-symbol m)
(cond
[(member m '(solid "solid")) 'transparent]
[(member m '(outline "outline")) 'solid]))
(define (h-place? x)
(or (nn-real? x)
(h-mode? x)))
(define (v-place? x)
(or (nn-real? x)
(v-mode? x)))
(define (h-mode? x)
(member x '(left "left" right "right" "center")))
(define (v-mode? x)
(member x '(top "top" bottom "bottom" center "center")))
(define (make-color% c)
(cond
[(string? c) (send the-color-database find-color c)]
[(symbol? c) (send the-color-database find-color (symbol->string c))]
[(color? c) (make-object color%
(color-red c)
(color-green c)
(color-blue c))]
[else #f]))
(define (image-color? c)
(cond
[(color? c) #t]
[(string? c) (and (send the-color-database find-color c) #t)]
[(symbol? c) (and (send the-color-database find-color (symbol->string c)) #t)]
[else #f]))
(define (image-width a)
(check-image 'image-width a "first")
(let-values ([(w h) (snip-size a)])
(inexact->exact (ceiling w))))
(define (image-height a)
(check-image 'image-height a "first")
(let-values ([(w h) (snip-size a)])
(inexact->exact (ceiling h))))
(define (overlay a b h-place v-place)
(overlay-helper 'overlay a b h-place v-place))
(define (overlay-helper name a b h-place v-place)
(check-image name a "first")
(check-image name b "second")
(check-h-place name h-place "third")
(check-v-place name v-place "fourth")
(let ((dx (h-place->delta-x h-place a b))
(dy (v-place->delta-y v-place a b)))
(real-overlay name
a
(inexact->exact (floor dx))
(inexact->exact (floor dy))
b)))
(define (h-place->delta-x h-place a b)
(cond
((real? h-place) (inexact->exact (floor h-place)))
((member h-place '(left "left")) 0)
((member h-place '(right "right"))
(- (image-width a) (image-width b)))
((member h-place '(center "center"))
(- (quotient (image-width a) 2)
(quotient (image-width b) 2)))))
(define (v-place->delta-y v-place a b)
(cond
((real? v-place) (inexact->exact (floor v-place)))
((member v-place '(top "top")) 0)
((member v-place '(bottom "bottom"))
(- (image-height a) (image-height b)))
((member v-place '(center "center"))
(- (quotient (image-height a) 2)
(quotient (image-height b) 2)))))
(define (above a b h-mode)
(overlay-helper 'above a b h-mode (image-height a)))
(define (beside a b v-mode)
(overlay-helper 'beside a b (image-width a) v-mode))
(define (real-overlay name raw-a delta-x delta-y raw-b)
(let ([a (coerce-to-cache-image-snip raw-a)]
[b (coerce-to-cache-image-snip raw-b)])
(let-values ([(a-w a-h) (snip-size a)]
[(b-w b-h) (snip-size b)])
(let* ([left (min 0 delta-x)]
[top (min 0 delta-y)]
[right (max (+ delta-x b-w) a-w)]
[bottom (max (+ delta-y b-h) a-h)]
[new-w (inexact->exact (ceiling (- right left)))]
[new-h (inexact->exact (ceiling (- bottom top)))]
[a-dx (inexact->exact (round (- left)))]
[a-dy (inexact->exact (round (- top)))]
[b-dx (inexact->exact (round (- delta-x left)))]
[b-dy (inexact->exact (round (- delta-y top)))]
[combine (lambda (a-f b-f)
(lambda (dc dx dy)
(a-f dc (+ dx a-dx) (+ dy a-dy))
(b-f dc (+ dx b-dx) (+ dy b-dy))))])
(check-sizes name new-w new-h)
(new cache-image-snip%
[dc-proc (combine (send a get-dc-proc)
(send b get-dc-proc))]
[argb-proc (combine (send a get-argb-proc)
(send b get-argb-proc))]
[width new-w]
[height new-h]
;; match what image=? expects, so we don't get false negatives
[px (floor (/ new-w 2))]
[py (floor (/ new-h 2))])))))
;; ------------------------------------------------------------
(define (clip raw-img delta-w delta-h width height)
(check-image 'clip raw-img "first")
(check-size/0 'clip delta-w "second")
(check-size/0 'clip delta-h "third")
(check-size/0 'clip width "fourth")
(check-size/0 'clip height "fifth")
(let ((delta-w (inexact->exact (floor delta-w)))
(delta-h (inexact->exact (floor delta-h)))
(width (inexact->exact (floor width)))
(height (inexact->exact (floor height))))
(let ([img (coerce-to-cache-image-snip raw-img)])
(let-values ([(i-width i-height) (send img get-size)])
(let* ([dc-proc (send img get-dc-proc)]
[argb-proc (send img get-argb-proc)])
(new cache-image-snip%
[dc-proc (lambda (dc dx dy)
(let ([clip (send dc get-clipping-region)]
[rgn (make-object region% dc)])
(send rgn set-rectangle dx dy width height)
(when clip
(send rgn intersect clip))
(send dc set-clipping-region rgn)
(dc-proc dc (- dx delta-w) (- dy delta-h))
(send dc set-clipping-region clip)))]
[argb-proc (lambda (argb dx dy) (argb-proc argb (- dx delta-w) (- dy delta-h)))]
[width width]
[height height]
;; match what image=? expects, so we don't get false negatives
[px (floor (/ width 2))] [py (floor (/ height 2))]))))))
(define (pad raw-img left right top bottom)
(check-image 'pad raw-img "first")
(check-size/0 'pad left "second")
(check-size/0 'pad right "third")
(check-size/0 'pad top "fourth")
(check-size/0 'pad bottom "fifth")
(let ((left (inexact->exact (floor left)))
(right (inexact->exact (floor right)))
(top (inexact->exact (floor top)))
(bottom (inexact->exact (floor bottom))))
(let ([img (coerce-to-cache-image-snip raw-img)])
(let-values ([(i-width i-height) (send img get-size)])
(let ((width (+ left i-width right))
(height (+ top i-height bottom)))
(let* ([dc-proc (send img get-dc-proc)]
[argb-proc (send img get-argb-proc)])
(new cache-image-snip%
[dc-proc (lambda (dc dx dy)
(let ([clip (send dc get-clipping-region)]
[rgn (make-object region% dc)])
(send rgn set-rectangle dx dy width height)
(when clip
(send rgn intersect clip))
(send dc set-clipping-region rgn)
(dc-proc dc (+ dx left) (+ dy top))
(send dc set-clipping-region clip)))]
[argb-proc (lambda (argb dx dy) (argb-proc argb (+ dx left) (+ dy top)))]
[width width]
[height height]
;; match what image=? expects, so we don't get false negatives
[px (floor (/ width 2))] [py (floor (/ height 2))])))))))
;; ------------------------------------------------------------
;; test what happens when the line moves out of the box.
(define (line width height pre-x1 pre-y1 pre-x2 pre-y2 color-in)
(check-size/0 'line width "first")
(check-size/0 'line height "second")
(check-coordinate 'line pre-x1 "third")
(check-coordinate 'line pre-y1 "fourth")
(check-coordinate 'line pre-x2 "fifth")
(check-coordinate 'line pre-y2 "sixth")
(check-image-color 'line color-in "seventh")
(let ((width (inexact->exact (floor width)))
(height (inexact->exact (floor height))))
(let-values ([(x1 y1 x2 y2)
(if (<= pre-x1 pre-x2)
(values pre-x1 pre-y1 pre-x2 pre-y2)
(values pre-x2 pre-y2 pre-x1 pre-y1))])
(define do-draw
(lambda (dc dx dy)
(let ([clip (send dc get-clipping-region)]
[rgn (make-object region% dc)])
(send rgn set-rectangle dx dy width height)
(when clip
(send rgn intersect clip))
(send dc set-clipping-region rgn)
(send dc draw-line
(+ x1 dx) (+ y1 dy) (+ x2 dx) (+ y2 dy))
(send dc set-clipping-region clip))))
(let ([draw-proc
(make-color-wrapper color-in 'transparent 'solid do-draw)]
[mask-proc
(make-color-wrapper 'black 'transparent 'solid do-draw)])
(make-simple-cache-image-snip width height draw-proc mask-proc)))))
(define (text str size color-in)
(check 'text string? str "string" "first")
(check 'text (lambda (x) (and (integer? x) (<= 1 x 255))) size "integer between 1 and 255" "second")
(check-image-color 'text color-in "third")
(cond
[(string=? str "")
(let-values ([(tw th) (get-text-size size "dummyX")])
(rectangle 0 th 'solid 'black))]
[else
(let ([color (make-color% color-in)])
(let-values ([(tw th) (get-text-size size str)])
(let ([draw-proc
(lambda (txt-color mode dc dx dy)
(let ([old-mode (send dc get-text-mode)]
[old-fore (send dc get-text-foreground)]
[old-font (send dc get-font)])
(send dc set-text-mode mode)
(send dc set-text-foreground txt-color)
(send dc set-font (get-font size))
(send dc draw-text str dx dy)
(send dc set-text-mode old-mode)
(send dc set-text-foreground old-fore)
(send dc set-font old-font)))])
(new cache-image-snip%
[dc-proc (lambda (dc dx dy) (draw-proc color 'transparent dc dx dy))]
[argb-proc
(lambda (argb dx dy)
(let ([bm-color
(build-bitmap
(lambda (dc)
(send dc set-pen (send the-pen-list find-or-create-pen "black" 1 'transparent))
(send dc set-brush (send the-brush-list find-or-create-brush color 'solid))
(send dc draw-rectangle 0 0 tw th))
tw
th)]
[bm-mask
(build-bitmap
(lambda (dc)
(draw-proc
(send the-color-database find-color "black")
'solid dc 0 0))
tw
th)])
(overlay-bitmap argb dx dy bm-color bm-mask)))]
[width tw]
[height th]
;; match what image=? expects, so we don't get false negatives
[px (floor (/ tw 2))] [py (floor (/ th 2))]))))]))
(define cached-bdc-for-text-size (make-thread-cell #f))
(define (get-text-size size string)
(unless (thread-cell-ref cached-bdc-for-text-size)
(let* ([bm (make-object bitmap% 1 1)]
[dc (make-object bitmap-dc% bm)])
(thread-cell-set! cached-bdc-for-text-size dc)))
(let ([dc (thread-cell-ref cached-bdc-for-text-size)])
(let-values ([(w h _1 _2) (send dc get-text-extent string (get-font size))])
(values (inexact->exact (ceiling w))
(inexact->exact (ceiling h))))))
(define (get-font size)
(send the-font-list find-or-create-font size
'default 'normal 'normal #f
(case (system-type)
[(macosx) 'partly-smoothed]
[else 'smoothed])))
(define (a-rect/circ do-draw w h color brush pen)
(let* ([dc-proc (make-color-wrapper color brush pen do-draw)]
[mask-proc (make-color-wrapper 'black brush pen do-draw)])
(make-simple-cache-image-snip w h dc-proc mask-proc)))
(define (rectangle w h mode color)
(check-size/0 'rectangle w "first")
(check-size/0 'rectangle h "second")
(check-mode 'rectangle mode "third")
(check-image-color 'rectangle color "fourth")
(let ((w (inexact->exact (floor w)))
(h (inexact->exact (floor h))))
(a-rect/circ (lambda (dc dx dy) (send dc draw-rectangle dx dy w h))
w h color (mode->brush-symbol mode) (mode->pen-symbol mode))))
(define (ellipse w h mode color)
(check-size/0 'ellipse w "first")
(check-size/0 'ellipse h "second")
(check-mode 'ellipse mode "third")
(check-image-color 'ellipse color "fourth")
(let ((w (inexact->exact (floor w)))
(h (inexact->exact (floor h))))
(a-rect/circ (lambda (dc dx dy) (send dc draw-ellipse dx dy w h))
w h color (mode->brush-symbol mode) (mode->pen-symbol mode))))
(define (circle r mode color)
(check-size/0 'circle r "first")
(check-mode 'circle mode "second")
(check-image-color 'circle color "third")
(let ((r (inexact->exact (floor r))))
(a-rect/circ (lambda (dc dx dy) (send dc draw-ellipse dx dy (* 2 r) (* 2 r)))
(* 2 r) (* 2 r) color (mode->brush-symbol mode) (mode->pen-symbol mode))))
(define (triangle size mode color)
(check 'triangle
(lambda (x) (and (real? x) (< 2 x 10000)))
size
"positive real number bigger than 2"
"first")
(check-mode 'triangle mode "second")
(check-image-color 'triangle color "third")
(let* ([size (inexact->exact (floor size))]
[right (- size 1)]
[bottom (inexact->exact (ceiling (* size (sin (* 2/3 pi)))))]
[points (list (make-object point% 0 bottom)
(make-object point% right bottom)
(make-object point% (/ size 2) 0))])
(let ([draw (make-color-wrapper
color (mode->brush-symbol mode) 'solid
(lambda (dc dx dy)
(send dc draw-polygon points dx dy)))]
[mask-draw (make-color-wrapper
'black (mode->brush-symbol mode) 'solid
(lambda (dc dx dy)
(send dc draw-polygon points dx dy)))]
[w size]
[h (+ bottom 1)])
(make-simple-cache-image-snip w h draw mask-draw))))
(define (make-simple-cache-image-snip w h dc-proc mask-proc)
(let ([w (inexact->exact (ceiling w))]
[h (inexact->exact (ceiling h))])
(let ([argb-proc
(if (or (zero? w) (zero? h))
void
(lambda (argb-vector dx dy)
(let ([c-bm (build-bitmap (lambda (dc) (dc-proc dc 0 0)) w h)]
[m-bm (build-bitmap (lambda (dc) (mask-proc dc 0 0)) w h)])
(overlay-bitmap argb-vector dx dy c-bm m-bm))))])
(new cache-image-snip%
[dc-proc dc-proc]
[argb-proc argb-proc]
[width w]
[height h]
;; match what image=? expects, so we don't get false negatives
[px (floor (/ w 2))] [py (floor (/ h 2))]))))
(define (make-color-wrapper color-in brush pen rest)
(let ([color (make-color% color-in)])
(lambda (dc dx dy)
(let ([old-brush (send dc get-brush)]
[old-pen (send dc get-pen)])
(send dc set-brush (send the-brush-list find-or-create-brush color brush))
(send dc set-pen (send the-pen-list find-or-create-pen color 1 pen))
(rest dc dx dy)
(send dc set-pen old-pen)
(send dc set-brush old-brush)))))
;; ------------------------------------------------------------
(define (image-inside? i a)
(and (locate-image 'image-inside?
(coerce-to-cache-image-snip i)
(coerce-to-cache-image-snip a))
#t))
(define (find-image i a)
(or (locate-image 'find-image
(coerce-to-cache-image-snip i)
(coerce-to-cache-image-snip a))
(error 'find-image
"the second image does not appear within the first image")))
(define (locate-image who i a)
(check-image who i "first")
(check-image who a "second")
(let-values ([(iw ih) (snip-size i)]
[(aw ah) (snip-size a)])
(and (iw . >= . aw)
(ih . >= . ah)
(let ([i-argb-vector (argb-vector (send i get-argb))]
[a-argb-vector (argb-vector (send a get-argb))])
(let ([al (let loop ([offset 0])
(cond
[(= offset (* ah aw 4)) null]
[else (cons (subvector a-argb-vector offset (+ offset (* 4 aw)))
(loop (+ offset (* 4 aw))))]))])
(let yloop ([dy 0])
(and (dy . <= . (- ih ah))
(let xloop ([dx 0])
(if (dx . <= . (- iw aw))
(if (let loop ([al al][dd 0])
(or (null? al)
(and (first-in-second?
i-argb-vector
(car al)
(* 4 (+ (* (+ dy dd) iw) dx)))
(loop (cdr al) (add1 dd)))))
(make-posn dx dy)
(xloop (add1 dx)))
(yloop (add1 dy)))))))))))
(define (subvector orig i j)
(let ([v (make-vector (- j i) #f)])
(let loop ([x i])
(when (< x j)
(vector-set! v (- x i) (vector-ref orig x))
(loop (+ x 1))))
v))
#|
(initial inequalities thanks to Matthew (thanks!!))
We know that, for a combination:
m3 = (m1+m2-m1*m2) and
b3 = (m1*b1*(1-m2) + m2*b2)/m3
So, we need to figure out what m1 & m2 might have been,
given the other values.
Check m3:
m3 = m2 when m1 = 0
m3 = 1 when m1 = 1
[deriv of m3 with respect to m1 = 1 - m2, which is positive]
so check that m3 is between m2 and 1
Then check m3*b3:
b3*m3 = m2*b2 when m1 = 0 or b1 = 0
b3*m3 = (1 - m2) + m2*b2 when m1 = b1 = 1
[deriv with respect to m1 is b1*(1-m2), which is positive]
[deriv with respect to b1 is m1*(1-m2), which is positive]
So check that m3*b3 is between m2*b2 and (1 - m2) + m2*b2
This is all in alphas from 0 to 1 and needs to be from 255 to 0.
Converting (but using the same names) for the alpha test, we get:
(<= (- 1 (/ m2 255))
(- 1 (/ m3 255))
1)
sub1 to each:
(<= (- (/ m2 255))
(- (/ m3 255))
0)
mult by 255:
(<= (- m2)
(- m3)
0)
negate and flip ineq:
(>= m2 m3 0)
flip ineq back:
(<= 0 m3 m2)
Here's the original scheme expression for the second check:
(<= (* m2 b2)
(* m3 b3)
(+ (- 1 m2) (* m2 b2))
converting from the computer's coordinates, we get:
(<= (* (- 1 (/ m2 255)) (- 1 (/ b2 255)))
(* (- 1 (/ m3 255)) (- 1 (/ b3 255)))
(+ (- 1 (- 1 (/ m2 255)))
(* (- 1 (/ m2 255)) (- 1 (/ b2 255)))))
;; multiplying out the binomials:
(<= (+ 1
(- (/ m2 255))
(- (/ b2 255))
(/ (* m2 b2) (* 255 255)))
(+ 1
(- (/ m3 255))
(- (/ b3 255))
(/ (* m3 b3) (* 255 255)))
(+ (- 1 (- 1 (/ m2 255)))
(+ 1
(- (/ m2 255))
(- (/ b2 255))
(/ (* m2 b2) (* 255 255)))))
;; simplifying the last term
(<= (+ 1
(- (/ m2 255))
(- (/ b2 255))
(/ (* m2 b2) (* 255 255)))
(+ 1
(- (/ m3 255))
(- (/ b3 255))
(/ (* m3 b3) (* 255 255)))
(+ 1
(- (/ b2 255))
(/ (* m2 b2) (* 255 255))))
;; multiply thru by 255:
(<= (+ 255
(- m2)
(- b2)
(* m2 b2 1/255))
(+ 255
(- m3)
(- b3)
(* m3 b3 1/255))
(+ 255
(- b2)
(* m2 b2 1/255)))
;; subtract out 255 from each:
(<= (+ (- m2)
(- b2)
(* m2 b2 1/255))
(+ (- m3)
(- b3)
(* m3 b3 1/255))
(+ (- b2)
(* m2 b2 1/255)))
;; negate them all, and reverse the inequality
(>= (+ m2 b2 (* m2 b2 -1/255))
(+ m3 b3 (* m3 b3 -1/255))
(+ b2 (* m2 b2 -1/255)))
;; aka
(<= (+ b2 (* m2 b2 -1/255))
(+ m3 b3 (* m3 b3 -1/255))
(+ m2 b2 (* m2 b2 -1/255)))
|#
;; in the above, m3 & b3 come from iv
;; and m2 & b2 come from av
(define (first-in-second? iv av xd)
(let loop ([i (vector-length av)])
(or (zero? i)
(let ([a (- i 4)]
[r (- i 3)]
[g (- i 2)]
[b (- i 1)])
(let* ([m2 (vector-ref av a)]
[m3 (vector-ref iv (+ xd a))]
[test
(lambda (b2 b3)
(<= (+ b2 (* m2 b2 -1/255))
(+ m3 b3 (* m3 b3 -1/255))
(+ m2 b2 (* m2 b2 -1/255))))])
(and (<= 0 m3 m2)
(test (vector-ref av r) (vector-ref iv (+ xd r)))
(test (vector-ref av g) (vector-ref iv (+ xd g)))
(test (vector-ref av b) (vector-ref iv (+ xd b)))
(loop (- i 4))))))))
;; ----------------------------------------
(define (image->color-list i-raw)
(check-image 'image->color-list i-raw "first")
(let* ([cis (coerce-to-cache-image-snip i-raw)]
[i (send cis get-bitmap)])
(cond
[(not i) '()]
[else
(let* ([iw (send i get-width)]
[ih (send i get-height)]
[new-bitmap (make-object bitmap% iw ih)]
[bdc (make-object bitmap-dc% new-bitmap)])
(send bdc clear)
(send bdc draw-bitmap i 0 0 'solid
(send the-color-database find-color "black")
(send i get-loaded-mask))
(let ([is (make-bytes (* 4 iw ih))]
[cols (make-vector (* iw ih))])
(send bdc get-argb-pixels 0 0 iw ih is)
(let yloop ([y 0][pos 0])
(unless (= y ih)
(let xloop ([x 0][pos pos])
(if (= x iw)
(yloop (add1 y) pos)
(begin
(vector-set! cols (+ x (* y iw))
(make-color (bytes-ref is (+ 1 pos))
(bytes-ref is (+ 2 pos))
(bytes-ref is (+ 3 pos))))
(xloop (add1 x) (+ pos 4)))))))
(send bdc set-bitmap #f)
(vector->list cols)))])))
(define (image->alpha-color-list i)
(check-image 'image->alpha-color-list i "first")
(let* ([argb (cond
[(is-a? i image-snip%)
(send (coerce-to-cache-image-snip i) get-argb)]
[(is-a? i cache-image-snip%) (send i get-argb)])]
[v (argb-vector argb)])
(let loop ([i (vector-length v)]
[a null])
(cond
[(zero? i) a]
[else (loop (- i 4)
(cons (make-alpha-color
(vector-ref v (- i 4))
(vector-ref v (- i 3))
(vector-ref v (- i 2))
(vector-ref v (- i 1)))
a))]))))
(define (color-list->image cl in-w in-h)
(check 'color-list->image color-list? cl "list-of-colors" "first")
(check-size/0 'color-list->image in-w "second")
(check-size/0 'color-list->image in-h "third")
(let ([w (inexact->exact in-w)]
[h (inexact->exact in-h)])
(let ([px (floor (/ w 2))] [py (floor (/ h 2))])
(unless (= (* w h) (length cl))
(error 'color-list->image
"given width times given height is ~a, but the given color list has ~a items"
(* w h)
(length cl)))
(cond
[(or (equal? w 0) (equal? h 0))
(rectangle w h 'solid 'black)]
[else
(unless (and (< 0 w 10000) (< 0 h 10000))
(error 'color-list->image "cannot make ~a x ~a image" w h))
(let* ([bm (make-object bitmap% w h)]
[mask-bm (make-object bitmap% w h)]
[dc (make-object bitmap-dc% bm)]
[mask-dc (make-object bitmap-dc% mask-bm)])
(unless (send bm ok?)
(error (format "cannot make ~a x ~a image" w h)))
(let ([is (make-bytes (* 4 w h) 0)]
[mask-is (make-bytes (* 4 w h) 0)]
[cols (list->vector (map (lambda (x)
(or (make-color% x)
(error 'color-list->image "color ~e is unknown" x)))
cl))])
(let yloop ([y 0][pos 0])
(unless (= y h)
(let xloop ([x 0][pos pos])
(if (= x w)
(yloop (add1 y) pos)
(let* ([col (vector-ref cols (+ x (* y w)))]
[r (pk (send col red))]
[g (pk (send col green))]
[b (pk (send col blue))])
(bytes-set! is (+ 1 pos) r)
(bytes-set! is (+ 2 pos) g)
(bytes-set! is (+ 3 pos) b)
(when (= 255 r g b)
(bytes-set! mask-is (+ 1 pos) 255)
(bytes-set! mask-is (+ 2 pos) 255)
(bytes-set! mask-is (+ 3 pos) 255))
(xloop (add1 x) (+ pos 4)))))))
(send dc set-argb-pixels 0 0 w h is)
(send mask-dc set-argb-pixels 0 0 w h mask-is))
(send dc set-bitmap #f)
(send mask-dc set-bitmap #f)
(bitmaps->cache-image-snip bm mask-bm px py))]))))
(define (pk col) (min 255 (max 0 col)))
(define (alpha-color-list->image cl in-w in-h)
(check 'alpha-color-list->image alpha-color-list? cl "list-of-alpha-colors" "first")
(check-size/0 'alpha-color-list->image in-w "second")
(check-size/0 'alpha-color-list->image in-h "third")
(let ([w (inexact->exact in-w)]
[h (inexact->exact in-h)])
(let ([px (floor (/ w 2))] [py (floor (/ h 2))])
(unless (= (* w h) (length cl))
(error 'alpha-color-list->image
"given width times given height is ~a, but the given color list has ~a items"
(* w h) (length cl)))
(cond
[(or (equal? w 0) (equal? h 0))
(rectangle w h 'solid 'black)]
[else
(unless (and (< 0 w 10000) (< 0 h 10000))
(error 'alpha-color-list->image format "cannot make ~a x ~a image" w h))
(let ([index-list (alpha-colors->ent-list cl)])
(argb->cache-image-snip (make-argb (list->vector index-list) w h) px py))]))))
;; alpha-colors->ent-list : (listof alpha-color) -> (listof number)
(define (alpha-colors->ent-list cl)
(let loop ([cl cl])
(cond
[(null? cl) null]
[else
(let ([ac (car cl)])
(list* (alpha-color-alpha ac)
(alpha-color-red ac)
(alpha-color-green ac)
(alpha-color-blue ac)
(loop (cdr cl))))])))
(define empty-image
(make-simple-cache-image-snip 0 0 void void))
(define octet (contract (combined natural (predicate (lambda (n) (<= n 255))))))
(define rgb-color (contract (predicate color?)))
(define mode (contract (one-of "solid" "outline")))
(define image (contract (predicate image?)))
(define image-color (contract (predicate image-color?)))
(define h-place (contract (mixed integer (one-of "left" "right" "center"))))
(define v-place (contract (mixed integer (one-of "top" "bottom" "center"))))
(define h-mode (contract (one-of "left" "right" "center")))
(define v-mode (contract (one-of "top" "bottom" "center")))