Colour

Dr Andy Evans

[Fullscreen]

Background

• You can change the background colour of any container with:

  	
  someObject.setBackground(someColor);
  
  

• Here someColor is a object of type java.awt.Color.
• Note the US spelling.

Color

• Comes with static types you can use:

  	
  setBackground(Color.RED);
  
  

• Or you can set them up with RGB (red, green, blue) values between 0 and 255:

  	
  Color red = new Color(255,0,0);
  setBackground(red);
  
  

• There's actually also a transparency (alpha: RGBA) level you can set, but anything other than 0 (clear) and 255 (opaque) is poorly supported.

  	
  Color red = new Color(255,0,0,255);
  
  

• There are also options for using hue, saturation, brightness (HSB) instead.

Common colours

• 	
  new Color (255,0,0)		// Red
  new Color (0,255,0)		// Green
  new Color (0,0,255)		// Blue
  new Color (0,0,0)		// Black
  new Color (127,127,127)	// Medium grey
  new Color (255,255,255)	// White
  
  

• Note that whenever the values are the same, you get greyscale.

Color methods

• If we get a Color object, e.g. from an image, we can find out the RGB values thus:

  	
  int r = ourColor.getRed();
  int g = ourColor.getGreen();
  int b = ourColor.getBlue();