============================== exercise with Colors

try some student suggestions...

255, 107, 0
0, 237, 0
128, 0, 255
255, 225, 0

============================== SLIDES ON REPRESENTATION AND ARRAYS...

rows first -OR- columns first
(common)        (math, images)

// *********** but early on we we will process all the pixels,
//             as if the pixels were in one long line

============================== ... then:

> double[] mileage; 
> mileage
null

> double[] mileageForWeek = {4.5, 7, 10, 6.5, 10, 0, 22};
> mileageForWeek[0]
3.0
> mileageForWeek[4]
10.0
> mileageForWeek[6]
22.2
> mileageForWeek
[D@eea96c                      // ???

// *********** but you will get your array of Pixels from a Picture

============================== exploring Pictures, Pixels, Colors

> Picture picture = new Picture( "/Users/wallingf/Desktop/wheaties-box.jpg" );
> picture
Picture, filename ...wheaties-box.jpg height 640 width 480
> Pixel pixel = picture.getPixel(320,240);
> pixel
Pixel red=188 green=128 blue=154
> pixel.getRed()
188
> picture.getPixel(320,240).getBlue()
154
> pixel.getColor()
java.awt.Color[r=188,g=128,b=154]

============================== class fields and methods; object methods

> FileChooser.pickAFile();
> Sound clip = FileChooser.pickAFile();
Error: Bad types in assignment

> Sound clip = new Sound( FileChooser.pickAFile() );
> clip.play();

> FileChooser.pickAFile();
> Sound.play();
Error: class SimpleSound.play() is not a static method.

> Integer.MAX_VALUE
2147483647

> Picture.negate();
Error: class Picture.negate() is not a static method.

============================== introducing the for loop

> pixel.setColor( Color.black );
Error: Undefined class 'Color'

> import java.awt.Color;
> pixel.setColor( Color.black );
> p.show();

> pixel.setColor( Color.red );
> p.show();

> pixel.setColor( new Color( 12, 253, 47 ) );
> p.show();

> p.getPixel(320,240).setColor( Color.black );
> p.getPixel(320,241).setColor( Color.black );
> p.getPixel(320,242).setColor( Color.black );
> p.getPixel(320,243).setColor( Color.black );
> p.getPixel(320,244).setColor( Color.black );
> p.getPixel(320,245).setColor( Color.black );
> p.getPixel(320,246).setColor( Color.black );
> p.getPixel(320,247).setColor( Color.black );
> p.getPixel(320,248).setColor( Color.black );
> p.getPixel(320,249).setColor( Color.black );
> p.show();

> for (int y = 240; y < 250; y++)
      p.getPixel(320, y).setColor( Color.white );
> p.show();

// Are you surprised to see the white line?  Recall the colors
// of the original pixel: red=188 green=128 blue=154

============================== a longer black line...

> p = new Picture( "/Users/wallingf/Desktop/wheaties-box.jpg" );
> p.show();
> for (int y = 240; y < 250; y++)
      p.getPixel(320, y).setColor( Color.black );
> p.show();
> for (int y = 240; y < 340; y++)
      p.getPixel(320, y).setColor( Color.black );
> p.show();

// ***   HOW do we grow the line in the opposite direction?
// ***   HOW do we draw the line horizontally?

============================== for-loops *over PixelArrays*

// LOOK AT clearBlue() in Picture
// LOOK AT negate() in Picture

Picture wheatiesBox =
  new Picture( "/Users/wallingf/Desktop/wheaties-box.jpg" );
> wheatiesBox.show();
> wheatiesBox.clearBlue();
> wheatiesBox.show();

> Pixel[] pixels = wheatiesBox.getPixels();
> for (int i = 0; i < pixels.length; i++)
  {
    red = pixels[i].getRed();
    green = pixels[i].getGreen();
    pixels[i].setBlue( (red + green) / 2 );
  }
> wheatiesBox.write( "/Users/wallingf/Desktop/wheaties-box-unblued.jpg" );