REBOL [ author: "François Jouen" title: "Visual Illusions Series: Heaver Illusion" date: 16-Jun-2005 File: %heaver.r Purpose: { show some visual illusions with rebol (view 1.3) } library: [ level: 'intermediate platform: 'win type: [tool demo] domain: [gui] tested-under: "View 1.3 " support: none license: 'pd ] ] c1: 270x190 c2: 370x290 b1x: b3x: 219 b2x: b4x: 321 B1y: b2y: 169 b3y: b4y: 271 rot: 0.0 tr: 255 r: 9 tr: 0 cl: to-tuple reduce [255 0 0 tr] target: copy [ transform rot 320x240 1.0 1.0 0x0 fill-pen 0.255.0.0 pen none box c1 c2 ] occlusion: copy [ fill-pen cl pen none box 0x0 100x100] win: layout/size [ origin 0x0 across at 0x0 t1: tog 100 "Start" "Stop" [either face/state [bx/rate: 15] [bx/rate: none] show bx] btn 100 "Quit" [Quit] at 0x30 bx: box 640x480 white effect [draw target] feel [ engage: func [f a e][ rot: rot + 1 if rot > 180 [rot: 0.0] show bx ] ] at as-pair b1x b1y b1: box 100x100 effect [draw occlusion] at as-pair b2x b2y b2: box 100x100 effect [draw occlusion] at as-pair b3x b3y b3: box 100x100 effect [draw occlusion] at as-pair b4x b4y b4: box 100x100 effect [draw occlusion] at 0x520 sl: scroller 520x25 [val: round (sl/data * 50) b1/offset/x: b1x - val b1/offset/y: b1y - val b2/offset/x: b2x + val b2/offset/y: b2y - val b3/offset/x: b3x - val b3/offset/y: b3y + val b4/offset/x: b4x + val b4/offset/y: b4y + val show [b1 b2 b3 b4] ] info 100 "Occlusion" center at 0x550 sl2: scroller 520x25 [ v: round (sl2/data * 50) if t1/state [bx/rate: 15 + v ]] info 100 "Velocity" center at 0x580 sl3: scroller 520x25 [tr: round (sl3/data * 255) cl: to-tuple reduce [255 0 0 tr] show [b1 b2 b3 b4] ] info 100 "Transparency" center ]640x610 view center-face Win