racket/collects/plot/common/draw.rkt
2011-10-07 18:05:54 -06:00

154 lines
6.5 KiB
Racket

#lang racket/base
;; Extra drawing, font, color and style functions.
(require racket/draw racket/class racket/vector racket/match racket/list racket/contract
"math.rkt"
"contract.rkt" "contract-doc.rkt")
(provide (all-defined-out))
;; ===================================================================================================
;; Drawing text rotated around an anchor point
(define (draw-text/anchor dc str x y [anchor 'top-left] [combine? #f] [offset 0] [angle 0])
(define-values (width height _1 _2) (send dc get-text-extent str #f combine? offset))
(define dx (case anchor
[(top-left left bottom-left) 0]
[(top center bottom) (* 1/2 width)]
[(top-right right bottom-right) width]
[else (raise-type-error 'draw-text/anchor "anchor/c" anchor)]))
(define dy (case anchor
[(top-left top top-right) 0]
[(left center right) (* 1/2 height)]
[(bottom-left bottom bottom-right) height]))
(define rdx (+ (* (sin angle) dy) (* (cos angle) dx)))
(define rdy (- (* (cos angle) dy) (* (sin angle) dx)))
(send dc draw-text str (- x rdx) (- y rdy) combine? offset angle))
(define (get-text-corners/anchor dc str x y [anchor 'top-left] [combine? #f] [offset 0] [angle 0])
(define-values (width height _1 _2) (send dc get-text-extent str #f combine? offset))
(define dxs (case anchor
[(top-left left bottom-left) (list 0 width)]
[(top center bottom) (list (* -1/2 width) (* 1/2 width))]
[(top-right right bottom-right) (list (- width) 0)]
[else (raise-type-error 'get-text-corners/anchor "anchor/c" anchor)]))
(define dys (case anchor
[(top-left top top-right) (list 0 height)]
[(left center right) (list (* -1/2 height) (* 1/2 width))]
[(bottom-left bottom bottom-right) (list (- height) 0)]))
(for*/list ([dx (in-list dxs)] [dy (in-list dys)])
(define rdx (+ (* (sin angle) dy) (* (cos angle) dx)))
(define rdy (- (* (cos angle) dy) (* (sin angle) dx)))
(vector (+ x rdx) (+ y rdy))))
;; ===================================================================================================
;; Draw paramter normalization
(define (real->font-size size)
(define i (inexact->exact (round size)))
(min (max i 1) 255))
(define (real->color-byte f)
(define i (inexact->exact (floor f)))
(min (max i 0) 255))
(define (color%? c) (is-a? c color%))
(defproc (->color [c color/c]) (list/c real? real? real?)
(match c
[(? color%?) (list (send c red) (send c green) (send c blue))]
[(? string?) (define color (send the-color-database find-color c))
(when (not color) (error 'decode-color "unknown color name ~e" c))
(->color color)]
[(list (? real?) (? real?) (? real?)) c]
[(? symbol?) (->color (symbol->string c))]
[_ (error '->color "unable to convert to color triple: ~e" c)]))
(define (color->color% c)
(match-define (list r g b) c)
(make-object color% (real->color-byte r) (real->color-byte g) (real->color-byte b)))
(define pen-colors
'#((0 0 0) ; black
(128 0 0) ; red
(0 96 0) ; green
(0 0 160) ; blue
(192 96 0) ; yellow
(0 112 128) ; cyan
(160 32 240) ; magenta
(160 160 160))) ; gray
(defproc (->pen-color [c plot-color/c]) (list/c real? real? real?)
(cond [(exact-integer? c) (vector-ref pen-colors (remainder (abs c) 8))]
[else (->color c)]))
(define brush-colors
'#((255 255 255) ; white
(255 192 192) ; red
(192 255 192) ; green
(212 224 240) ; blue
(255 248 192) ; yellow
(192 240 255) ; cyan
(240 224 255) ; magenta
(212 212 212))) ; gray
(defproc (->brush-color [c plot-color/c]) (list/c real? real? real?)
(cond [(exact-integer? c) (vector-ref brush-colors (remainder (abs c) 8))]
[else (->color c)]))
(defproc (->pen-style [s plot-pen-style/c]) symbol?
(cond [(exact-integer? s) (case (remainder (abs s) 5)
[(0) 'solid]
[(1) 'dot]
[(2) 'long-dash]
[(3) 'short-dash]
[(4) 'dot-dash])]
[(symbol? s) s]
[else (raise-type-error '->pen-style "symbol or integer" s)]))
(defproc (->brush-style [s plot-brush-style/c]) symbol?
(cond [(exact-integer? s) (case (remainder (abs s) 7)
[(0) 'solid]
[(1) 'bdiagonal-hatch]
[(2) 'fdiagonal-hatch]
[(3) 'crossdiag-hatch]
[(4) 'horizontal-hatch]
[(5) 'vertical-hatch]
[(6) 'cross-hatch])]
[(symbol? s) s]
[else (raise-type-error '->brush-style "symbol or integer" s)]))
;; ===================================================================================================
;; Color functions
(defproc (color-seq [c1 color/c] [c2 color/c] [num exact-nonnegative-integer?]
[#:start? start? boolean? #t]
[#:end? end? boolean? #t]) (listof (list/c real? real? real?))
(match-define (list r1 g1 b1) (->color c1))
(match-define (list r2 g2 b2) (->color c2))
(define rs (linear-seq r1 r2 num #:start? start? #:end? end?))
(define gs (linear-seq g1 g2 num #:start? start? #:end? end?))
(define bs (linear-seq b1 b2 num #:start? start? #:end? end?))
(map list rs gs bs))
(defproc (color-seq* [colors (listof color/c)] [num exact-nonnegative-integer?]
[#:start? start? boolean? #t]
[#:end? end? boolean? #t]) (listof (list/c real? real? real?))
(when (empty? colors) (raise-type-error 'color-seq* "nonempty (listof plot-color/c)" colors))
(match-define (list (list rs gs bs) ...) (map ->color colors))
(let ([rs (linear-seq* rs num #:start? start? #:end? end?)]
[gs (linear-seq* gs num #:start? start? #:end? end?)]
[bs (linear-seq* bs num #:start? start? #:end? end?)])
(map list rs gs bs)))
;; Returns an alpha value b such that, if
(define (alpha-expt a n)
(- 1 (expt (- 1 a) n)))
(define (maybe-apply/list list-or-proc xs)
(cond [(procedure? list-or-proc) (list-or-proc xs)]
[else list-or-proc]))