93 lines
4.1 KiB
Scheme
93 lines
4.1 KiB
Scheme
#lang scheme/base
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(require scheme/gui/base
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scheme/class)
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(provide first-line-text-mixin)
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(define (first-line-text-mixin text%)
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(class text%
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(inherit get-text paragraph-end-position get-admin invalidate-bitmap-cache position-location)
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(define bx (box 0))
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(define by (box 0))
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(define bw (box 0))
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(define fancy-first-line? #t)
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(define/override (scroll-to snip localx localy width height refresh? [bias 'none])
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(printf "~s\n" (list 'scroll-to snip localx localy width height refresh? bias))
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(super scroll-to snip localx localy width height refresh? bias))
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(define/public (highlight-first-line on?)
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(set! fancy-first-line? on?)
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(invalidate-bitmap-cache)
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(send (send this get-canvas) refresh))
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(define/override (on-paint before? dc left top right bottom dx dy draw-caret)
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(unless before?
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(when fancy-first-line?
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(let ([admin (get-admin)])
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(when admin
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(send admin get-view bx by bw #f #f)
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(unless (= (unbox by) 0)
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(let ([first-line (get-text 0 (paragraph-end-position 0))]
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[old-pen (send dc get-pen)]
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[old-brush (send dc get-brush)]
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[old-smoothing (send dc get-smoothing)]
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[old-α (send dc get-alpha)]
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[old-font (send dc get-font)])
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(send dc set-font (get-font))
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(send dc set-smoothing 'aligned)
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(let-values ([(tw th _1 _2) (send dc get-text-extent first-line)])
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(let ([line-height (+ (unbox by) dy th 1)]
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[line-left (+ (unbox bx) dx)]
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[line-right (+ (unbox bx) dx (unbox bw))])
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(send dc set-pen "black" 1 'solid)
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(send dc draw-line line-left line-height line-right line-height)
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(when (eq? (send dc get-smoothing) 'aligned)
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(send dc set-pen "black" 1 'solid)
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(let loop ([i 10])
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(unless (zero? i)
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(let ([g (+ 200 (* i 5))])
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(send dc set-alpha (+ 1/5 (* i -1/50)))
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(send dc draw-line
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line-left
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(+ line-height i)
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line-right
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(+ line-height i)))
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(loop (- i 1))))))
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(send dc set-alpha 1)
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(send dc set-pen "gray" 1 'transparent)
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(send dc set-brush "white" 'solid)
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(send dc draw-rectangle
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(+ (unbox bx) dx)
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(+ (unbox by) dy)
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(unbox bw)
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th)
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(send dc draw-text first-line (+ (unbox bx) dx) (+ (unbox by) dy)))
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(send dc set-font old-font)
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(send dc set-pen old-pen)
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(send dc set-brush old-brush)
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(send dc set-alpha old-α)
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(send dc set-smoothing old-smoothing)))))))
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(super on-paint before? dc left top right bottom dx dy draw-caret))
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(inherit get-style-list)
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(define/private (get-font)
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(let* ([style-list (get-style-list)]
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[std (or (send style-list find-named-style "Standard")
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(send style-list find-named-style "Basic"))])
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(send std get-font)))
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(super-new)))
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(begin
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(define f (new frame% [label ""] [width 200] [height 200]))
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(define t (new (first-line-text-mixin text%)))
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(send t insert (apply string-append (map (λ (x) (build-string 100 (λ (i) (if (= i 99) #\newline x))))
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(string->list "abcdefghijklnopqrstuvwxyz"))))
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(define c (new editor-canvas% [parent f] [editor t]))
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(define b (new button% [callback (λ (c dc) (send t highlight-first-line #t))] [label "button"] [parent f]))
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(send f show #t)) |