Bitmap/Histogram: Difference between revisions

<lang Julia>

using Color, Images, FixedPointNumbers

ima = imread("bitmap_histogram_in.jpg")

imb = convert(Image{Gray{Ufixed8}}, ima)

# calculate histogram

a = map(x->x.val.i, imb.data)

(nothing, h) = hist(reshape(a, length(a)), -1:typemax(Uint8))

g = float(imb.data)

b = g .> median(g)

fill!(imb, Gray(0.0))

imb[b] = Gray(1.0)

imwrite(imb, "bitmap_histogram_out.png")

</lang>

This solution calculates the histogram, <tt>h</tt>, to comply with the letter of the task description. However, because it is easiest to calculate the median luminosity directly, <tt>h</tt> is not used to calculate the black to white threshold used to create the output image.

{{out}}

The [https://raw.githubusercontent.com/MichaeLeroy/rosetta-code/master/julia/completed/bitmap_histogram_in.jpg input] and [https://raw.githubusercontent.com/MichaeLeroy/rosetta-code/master/julia/completed/bitmap_histogram_out.png output] files.