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Example 2: Image Manipulations with Media Comp.

Brief Description
Assignment	Image manipulations in Media Computation
Course	CS1124
Level	Early examples
Language	Java, Python
More Info...	Download Media Comp book classes in Java BlueJ project CS1124 Project 1
Media Computation is an approach originated at Georgia Tech by Dr. Mark Guzdial. It uses digital media (pictures, sounds, movies) as source of data for introducing algorithms and computation concepts. He has books available in Python and Java. At VT, CS1124 is in Python following his book.

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Introduction

Programs as "recipes"
Data as representations, encoding, naming of encodings and values
Star playing with language to open and show images...
Setup your environment with MediaComp Java classes

Start with this file template, lets try it...

  path = FileChooser.pickAFile();   // returns path to file
  Picture p = new Picture(path);    // builds Picture
  p.show();                         // shows the picture

Accessing picture elements (pixels)

Easy way to access and modify picture elements

  Picture pict = ...
  Pixel[] pixelArray = pict.getPixels();
  for (Pixel pix : pixelArray) {
    // iterate over all pixels
  }

For each pixel, we can get/setRed(), get/setGreen(), get/setBlue()
Try this inside the loop above...
```
  pix.setRed(pix.getRed() * 0.5);
```

Posterization of images

Original Image	Results
Map a range of colors to a single color

Write a recipe that takes an image and turns it into a 3 color posterized image. The recipe converts colors of a luminance of less than 85 to blue, colors of luminance between 86 and 150 to orange, and the rest of the colors to yellow.

Selectively changing colors - if color is red, keep it, else replace to monochrome
Original Image	Results

Problem from Exam

Description: Given an image and three integers representing a color, apply that color as a tint over the image. Your recipe must blend 50% of each of the three components of the pixel colors with 50% of each of the three components passed as parameters. The effect is like adding a color glass over the image. At the bottom of the problem you see several images with the color tint applied.