Class 40 — Wednesday, April 27

Chrestomatics and patterning

It’s simply smashing — For visitors on the Lawn — If they watch their steps

---

Look both ways

• Back or ahead

---

Agenda

• Problem solving

• Image manipulation

---

To do

• Complete Rachel's feedback form

• More fun with images

• Homework

---

Downloads

• Module image_fx.py

• Module half_flip.py

• Module noisify.py

• Module manip.py

---

Photo-manipulation Python code

• Review: Create a new image by making a copy that tweaks the original image's size, color, or pixel locations

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

---

Module image_fx.py

• Function brighten( opixel )

• Returns the twice-as-bright new color of opixel from the full-color original.

---

Module image_fx.py

• Function darken( opixel )

• Returns the twice-as-dark new color of opixel from the full-color original.

---

Module image_fx.py

• Function sepia( opixel )

• Returns the sepia-tone new color of opixel from the full-color original.

---

Module half_flip.py

• Function half_flip( nspot, nw, nh )

• Returns the correspondent of nspot in the nw x nh un-half-flipped original.

---

Module noisify.py

• Function noise( opixel )

• Returns the additive-noise-version of the new color of opixel from the full-color original.

 

---

🦆 © 2022 Jim Cohoon

Resources from previous semesters are available.