REBOL [ author: "François Jouen" title: "Visual Illusions Series: Kanizsa's Figures" date: 15-Jun-2005 File: %kanizsa.r Purpose: { show some visual illusions with rebol (view 1.3) } library: [ level: 'intermediate platform: 'win type: [tool demo] domain: [gui] tested-under: "win " support: none license: 'pd ] ] xr: yr: 60 c1: 190x130 c2: 390x130 c3: 190x330 c4: 390x330 t1: 290x130 t2: 190x330 t3: 390x330 sq: false n: 2 bcolor: 255.187.0 fcolor: white cplot: copy [ pen fcolor line-width n circle c1 xr yr circle c2 xr yr circle c3 xr yr circle c4 xr yr pen none none fill-pen bcolor polygon c1 c2 c4 c3 ] tplot: copy [pen fcolor line-width n circle t1 xr yr circle t2 xr yr circle t3 xr yr pen none none fill-pen bcolor triangle t1 t2 t3 bcolor bcolor bcolor 0.0] Show_Square: does [append clear cplot [pen fcolor line-width n circle c1 xr yr circle c2 xr yr circle c3 xr yr circle c4 xr yr pen none none fill-pen bcolor polygon c1 c2 c4 c3] ] Show_Triangle: does [append clear tplot [pen fcolor line-width n circle t1 xr yr circle t2 xr yr circle t3 xr yr pen none none fill-pen bcolor triangle t1 t2 t3 bcolor bcolor bcolor 0.0] ] Win: layout/size [ origin 0x0 across bck: backdrop bcolor at 30x5 btn 100 "Square" [sq: true sl/data: 0 n: 1 append clear bx/effect reduce['draw cplot] show [sl bx] ] btn 100 "Triangle" [sq: false sl/data: 0 n: 1 append clear bx/effect reduce['draw tplot] show [sl bx]] btn 100 "Back Color" [tcolor: request-color/color bcolor if not none? tcolor [bcolor: tcolor bck/color: bcolor] show win] btn 100 "Object Color" [tcolor: request-color/color fcolor if not none? tcolor [fcolor: tcolor] show bx] pad 50 btn 100 "Quit" [Quit] at 30x30 bx: box 580x450 bottom edge [size: 1x1] at 30x490 sl: slider 580x20 [n: 1 + (sl/data * yr) either sq [Show_Square n] [Show_Triangle n] show bx] at 30x515 info center 580 "Select a figure and play with the slider. Enjoy!" ] 640x550 view center-face Win