# Last edited on 2010-07-02 16:56:10 by stolfi
# Creating a noisy version of Lula's picture

The original Lula picture was 238x320.  Cropping to a nicer size:

  convert data/ula-1.ppm -crop '224x320+7+0' out/ula-a.ppm
  
Creating reduced versions out/ula-{a,b,c,d,e,f}:

  convert out/ula-a.ppm -resize '112x160' out/ula-b.ppm
  convert out/ula-b.ppm -resize '56x80'   out/ula-c.ppm
  convert out/ula-c.ppm -resize '28x40'   out/ula-d.ppm
  convert out/ula-d.ppm -resize '14x20'   out/ula-e.ppm
  convert out/ula-e.ppm -resize '7x10'    out/ula-f.ppm
  
Creating noise fields out/rnd-{a,b,c,d,e,f}.ppm with the same sizes:

  foreach z ( a b c d e f )
    seed=`cat out/ula-${z}.ppm | wc -c`
    pnmwiggle -seed ${seed} 1.00 out/ula-${z}.ppm \
      | convert PPM:- -resize '224x320' out/rnd-${z}.ppm
  end

Creating a fractal noise field:

  cp -p out/rnd-f.ppm out/frn-f.ppm
  cp -p out/frn-f.ppm out/tmp.ppm
  foreach z ( e d c b a )
    pnmxarith -mix 0.50 0.50 out/tmp.ppm out/rnd-${z}.ppm > out/frn-${z}.ppm
    cp -p out/frn-${z}.ppm out/tmp.ppm
  end
  display -title '%f' -filter box -resize '224x320^' out/frn*.ppm

Mixing the fractal noise with the original image:

  pnmxarith -mix 0.70 0.30 out/ula-a.ppm out/frn-a.ppm > out/ula-m.ppm
  display -title '%f' out/ula-m.ppm

Export to parent's data diretory:

  cp -p out/ula-m.ppm ../data