22 lines
509 B
Lua
22 lines
509 B
Lua
local nw = require("nw")
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local app = nw:app()
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local cw, ch = 320, 240
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local win = app:window(cw, ch, "Grayscale Bars", false)
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function win:repaint()
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local cr = win:bitmap():cairo()
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local ystride = ch/4
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for y = 0, 3 do
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local i, n = 1, 2^(y+3)
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local xstride = cw/n
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for x = 0, n-1 do
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cr:rectangle(x*xstride, y*ystride, xstride, ystride)
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local gray = x / (n-1)
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if y%2>0 then gray=1-gray end
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cr:rgb(gray, gray, gray)
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cr:fill()
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end
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end
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end
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win:show()
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app:run()
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