67 lines
2.1 KiB
Scheme
67 lines
2.1 KiB
Scheme
;; Author: David Frese
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;; make-color creates a color with the given r,g,b values, which should be
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;; values between 0.0 to 1.0 inclusive.
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(define (my-floor v)
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(if (exact? v)
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(floor v)
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(floor (inexact->exact v))))
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(define (make-color r g b)
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(create-color (my-floor (* r 65535))
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(my-floor (* g 65535))
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(my-floor (* b 65535))))
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;; color-rgb-values returns a list of the rgb-values (see make-color).
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(define (color-rgb-values color)
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(map (lambda (x)
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(/ x 65535)) ;; exact<->inexact?
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(extract-rgb-values color)))
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;; query-color returns the color of the given pixel in the given colormap.
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;; See XQueryColor.
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(define (query-color colormap pixel)
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(apply create-color
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(%query-color (colormap-Xcolormap colormap)
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(pixel-Xpixel pixel)
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(display-Xdisplay (colormap-display colormap)))))
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(import-lambda-definition %query-color (Xcolormap Xpixel Xdisplay)
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"scx_Query_Color")
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;; query-colors does the same as query-color but on vectors of pixels and
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;; colors. See XQueryColors.
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(define (query-colors colormap pixels)
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(let ((res (%query-colors (colormap-Xcolormap colormap)
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(vector-map! pixel-Xpixel (list->vector pixels))
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(display-Xdisplay (colormap-display colormap)))))
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(vector->list (vector-map! (lambda (r-g-b)
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(apply create-color r-g-b))
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res))))
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(import-lambda-definition %query-colors (Xcolormap Xpixels Xdisplay)
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"scx_Query_Colors")
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;; lookup-color takes the name of a color (a string or symbol) looks it up in
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;; the colormap and returns a pair of colors: the exact color and the closest
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;; color provided by the screen associated to the colormap. If the color-name
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;; can't be found an error is raised. See XLookupColor.
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(define (lookup-color colormap color-name)
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(let ((r (%lookup-color (colormap-Xcolormap colormap)
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(display-Xdisplay (colormap-display colormap))
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(if (symbol? color-name)
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(symbol->string color-name)
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color-name))))
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(if r
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(cons (apply create-color (car r))
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(apply create-color (cdr r)))
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(error "no such color:" color-name))))
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(import-lambda-definition %lookup-color (Xcolormap Xdisplay name)
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"scx_Lookup_Color")
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