Bitmap/Histogram: Difference between revisions
→{{header|Phix}}
(→{{header|Julia}}: A new entry for Julia) |
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Line 809:
ibw( img <= m ) = 0;
jpgwrite("lennamed.jpg", ibw, 100);</lang>
=={{header|Phix}}==
Requires read_ppm() from [[Bitmap/Read_a_PPM_file#Phix|Read_a_PPM_file]], write_ppm() from [[Bitmap/Write_a_PPM_file#Phix|Write_a_PPM_file]].
Uses lena.ppm, which you will have to find/download to demo/rosetta yourself.
Included as demo\rosetta\Bitmap_Histogram.exw, results may be verified with demo\rosetta\viewppm.exw
<lang Phix>function to_bw(sequence image)
sequence color
integer lum
sequence hist = repeat(0,256)
integer l = 1, r = 256
integer ltot, rtot
for i=1 to length(image) do
for j=1 to length(image[i]) do
color = sq_div(sq_and_bits(image[i][j], {#FF0000,#FF00,#FF}),
{#010000,#0100,#01})
lum = floor(0.2126*color[1] + 0.7152*color[2] + 0.0722*color[3])
image[i][j] = lum
hist[lum+1] += 1
end for
end for
ltot = hist[l]
rtot = hist[r]
while l!=r do
if ltot<rtot then
l += 1
ltot += hist[l]
else
r -= 1
rtot += hist[r]
end if
end while
lum = l
for i=1 to length(image) do
for j=1 to length(image[i]) do
image[i][j] = iff(image[i][j]<lum?black:white)
end for
end for
return image
end function
sequence img = read_ppm("Lena.ppm")
img = to_bw(img)
write_ppm("LenaBW.ppm",img)</lang>
=={{header|PHP}}==
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