27 lines
759 B
Lua
27 lines
759 B
Lua
function ConvertToGrayscaleImage( bitmap )
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local size_x, size_y = #bitmap, #bitmap[1]
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local gray_im = {}
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for i = 1, size_x do
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gray_im[i] = {}
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for j = 1, size_y do
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gray_im[i][j] = math.floor( 0.2126*bitmap[i][j][1] + 0.7152*bitmap[i][j][2] + 0.0722*bitmap[i][j][3] )
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end
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end
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return gray_im
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end
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function ConvertToColorImage( gray_im )
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local size_x, size_y = #gray_im, #gray_im[1]
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local bitmap = Allocate_Bitmap( size_x, size_y ) -- this function is defined at http://rosettacode.org/wiki/Basic_bitmap_storage#Lua
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for i = 1, size_x do
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for j = 1, size_y do
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bitmap[i][j] = { gray_im[i][j], gray_im[i][j], gray_im[i][j] }
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end
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end
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return bitmap
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end
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