1 - Using the mouse.

A Window class object, in addition to a Keyboard class instance, also provides one of the Mouse class. To access this object , use the following procedure:

Mouse mouse = window.getMouse();  

Like the keyboard, the mouse buttons also have behaviors that, if necessary, can be changed. But it is not possible to add or remove buttons.

2 - Standard mouse buttons

The standard buttons are as follows: BUTTON_LEFT, BUTTON_MIDDLE and BUTTON_RIGHT. To access the code for these buttons do: Mouse.BUTTON_RIGHT, for the right button, for example.

All the standard buttons have the DETECT_INITAL_PRESS_ONLY behavior.

3 - Changing the behavior of a button.

To change the behavior of a button use the method:

public void setBehavior(int numberBotton, int behavior);

The parameters to be passed are: the button code to be changed and the desired behavior.

Example: Changing the behavior of the right button:

 mouse.setBehavior(Mouse.BUTTON_RIGHT, Mouse.DETECT_EVERY_PRESS);

Now, while the right button is pressed, the method boolean isRightButtonPressed(), described below, will return true.

4 - Pressed buttons

To find out if a button is pressed, use the following methods of the Mouse class:

 
								//Returns true if the left button is pressed, otherwise, returns false.
								public boolean isLeftButtonPressed();
								
								//Returns true if the scroll is pressed, otherwise, returns false.
								public boolean isMiddleButtonPressed(); 
								
								//Returns true if the right button is pressed, otherwise, returns false.
								public boolean isRightButtonPressed ();
							

5 - Retrieving the mouse position

To retrieve the position (x,y) of the mouse on the screen use the method below, present in the Mouse class:

public Point getPosition();

Example: Point mousePosition = mouse.getPosition();

The Point class, that exists in Java, serves to store the (x,y) values returned by getPosition() method. The values are accessed as follows: ‘mousePosition.x ‘ and ‘mousePosition.y’.

6 - Mouse over some object of the game.

To determine whether the mouse is over some object of the game, use the method present in the Mouse class:

								//Returns true if the mouse is over the object passed as parameter,
								//otherwise, returns false.												
								public boolean isOverObject(GameObject obj);								
							

The object passed as parameter can be one of the following objects: GameObject, GameImage, Animation or Sprite.

Example:

								Mouse mouse = window.getMouse();
								Sprite car = new Sprite("car.png");
								if (mouse.isOverObject(carro))
									System.out.println("mouse is over the car!");
								else
									System.out.println("mouse is NOT over the car!"); 
							

7 - Mouse over a given area

To determine whether the mouse is over a determined of the screen use the method present in the Mouse class:

								//Returns true if the mouse is over the area, returns false otherwise.
								public boolean isOverArea(Point start, Point end);

Beside, an area is represented with 45 pixels of height and 237 pixels of width.

Their minimum and maximum points are (0,0) and (45,237).

To determine whether the mouse is over an area, use the following procedure:

								Point minimumPoint = new Point(0,0);
								Point maximumPoint = new Point(45,237);
								if (mouse. isOverArea(maximumPoint, minimumPoint))
									print("Mouse is over the area"); 
								else
									print("Is not over the area!") 
							

Instead of boolean isOverArea(Point start, Point end) we could have used the following method, which still would have the same result:

public boolean isOverArea (int minX, int minY, int maxX, int maxY); 

Using the boolean method isOverArea (int minX, int minY, int maxX, int maxY), we would have:

								if (mouse. isOverArea(0, 0, 45, 257 ))
									print("Mouse is over the area"); 
							

Example: By clicking with the mouse the image changes its position.

								package Mouse001;

								import java.awt.Point;
								import jplay.GameImage;
								import jplay.Keyboard;
								import jplay.Mouse;
								import jplay.Window;

								 /**
								  * @author Gefersom Cardoso Lima
								  * Federal Fluminense University - UFF - Brazil
								  * Computer Science
								  */

								public class Mouse001
								{
									public static void main(String[] args)
									{
										Window window = new Window(800,600);
										Keyboard keyboard = window.getKeyboard();
										Mouse mouse = window.getMouse();

										GameImage backGround = new GameImage("background.png");
										GameImage image = new GameImage("megaMan.png");

										boolean running = true;
										while(running)
										{
												backGround.draw();
												image.draw();
												window.update();

												//If the left button clicked the image will appear where there was the click.
												if (mouse.isLeftButtonPressed() == true)
												{
													Point position = mouse.getPosition();
													image.x = position.x;
													image.y = position.y;
												}

												if (keyboard.keyDown(Keyboard.ESCAPE_KEY) == true)
													running = false;
										}
										window.exit();
									}
								}
							

Note: The order in which images are draw is important. If we draw first the 'image' and then the background, the 'image' will be overlaid.