Class 33 — Wednesday, November 10

Chrestomatics and patterning

I draw from the past – Wonder about the present – Think of the future

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Look both ways

• Back or ahead

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Agenda

• Problem solving

• Image manipulation

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Downloads

• Module mirror.py

• Current homework flip.py

• Current homework grey.py

• Next homework palette.py

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Photo-manipulation Python code

• Create a new image by making a copy that tweaks the original image

def manip( original, size=same_size, color=same_color, at=same_at ) :

  """ Tweaks the original image. The tweaking is governed by

  function size(): Determines new image size based on the original.

  The default is the same size

  function color(): Determines pixelation based on the original pixel.

  The default is the same color

  function at(): Determines orignal source location.

  The default is the same spot

  """

  # set dimensions of the new image

  nw, nh = size( original )

  # get a new appropriately sized image

  new_image = Image.new( 'RGB', ( nw, nh ) )

  # fill in every pixel of the new image

  for nx in range( 0, nw ) : # consider every x value for the new image

  for ny in range( 0, nh ) : # in tandem with every y value for the image

  # set the spot to be filled in the new image

  nspot = ( nx, ny )

  # determine the corresponding spot of interest in the original

  ospot = at( nspot, nw, nh )

  # get the pixel at the ospot

  opixel = original.getpixel( ospot )

  # determine the pixel for the new image

  npixel = color( opixel )

  # set the nspot in the new image

  new_image.putpixel( nspot, npixel )

  # return the filled in new image

  return new_image

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Module mirror.py

• Function mirror( nspot, nw, nh )

• Returns the correspondent of nspot in the nw x nh the unmirrored original.

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Module grey.py

• Function grey( opixel )

• Returns the correspondent of nspot in the nw x nh the unflipped original.

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Module flip.py

• Function flip( nspot, nw,nh )

• Returns the correspondent of nspot in the nw x nh the unflipped original.

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Module palette.py

• Function distance( p1, p2 )

• Returns the distance between pixels p1 and p2.

• Function closest( opixel )

• Returns the pixel in the pixel-list PALETTE that is closest to opixel

Function set_palette( p )

• Sets global PALETTE to pixel-list p.

Global variable PALETTE

• List of possible pixels for use in palette reduction

 

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