Grayscale image: Difference between revisions

=={{header|Phix}}==

{{Trans|Euphoria}}

Requires read_ppm() from [[Bitmap/Read_a_PPM_file#Phix|Read_a_PPM_file]], see [[Bitmap/Write_a_PPM_file#Phix|Write_a_PPM_file]] for actual use.

Included as demo\rosetta\Bitmap_Greyscale.exw

<lang Phix>function to_gray(sequence image)

sequence color

for i=1 to length(image) do

for j=1 to length(image[i]) do

-- unpack color triple

color = sq_div(sq_and_bits(image[i][j], {#FF0000,#FF00,#FF}),

{#010000,#0100,#01})

image[i][j] = floor(0.2126*color[1] + 0.7152*color[2] + 0.0722*color[3])*#010101

end for

end for

return image

end function

sequence img = read_ppm("Lena.ppm")

img = to_gray(img)</lang>