Class GWindow

public class GWindow

The GWindow class defines a simple graphics window. The default size is 400 by 400 pixels. A "pixel" is one "dot" on the screen. It is the smallest unit that can be displayed on a window. The coordinate system is x and y, where x and y are offsets from the upper left corner of the window. (Note the Y coordinate grows positively in the downward direction -- which is different from the traditional Cartesian coordinate system.)

The GWindow supports two modes of displaying objects. In the first, a GWindow maintains a collection of Shape objects. Shape objects may be added or removed from the GWindow's container. When the GWindow paints itself, it paints each of its shape objects, in the order in which they are added.

In the second, (via the display()) method), the GWindow keeps a list of objects to be displayed. The next time the window repaints itself, all objects in the list are displayed, and then discarded. This mode is often useful for animations.

Shapes obscure other shapes, depending upon the order of their addition (and their position).

Version:

$Id: GWindow.java,v 1.13 2001/05/18 02:52:46 administrator Exp $

Author:

Ben Dugan

See Also:

Serialized Form

Constructor Detail

GWindow

public GWindow()

Create a new window, with default name and size.

GWindow

public GWindow(java.lang.String name)

Create a new window of the default size.

Parameters:

name - the title of the window

GWindow

public GWindow(java.lang.String name,
               int width,
               int height)

Create a new window of the given dimensions.

Parameters:

name - the title of the window

width - the width of the window, in pixels

height - the height of the window, in pixels

Method Detail

version

public double version()

Answer the version number.

paint

public void paint(java.awt.Graphics g)

Do a paint operation. Clients will almost never call this method. It is called by repaint(), or by update() by the window management system.

Overrides:

paint in class java.awt.Container

Parameters:

g - a graphics context.

update

public void update(java.awt.Graphics g)

When we update the window, we just do a paint(g).

Overrides:

update in class java.awt.Container

erase

public void erase()

Discards all of the shape objects and clears the screen.

add

public boolean add(Shape s)

Add the given shape and paint it onto the screen.

Parameters:

s - a shape object (Rectangle, etc)

Returns:

true if the shape was actually added (a shape is only added if it hasn't already been added)

display

public void display(Shape s)

Simply adds this shape to the to-be-displayed queue.

remove

public boolean remove(Shape s)

Remove the given shape and repaint the screen.

Parameters:

s - a shape object (Rectangle, etc)

Returns:

true if the shape was actually removed, false if not

translate

public void translate(int x,
                      int y)

Translate the position of every object by the given deltas, and repaint the screen.

Parameters:

x - the deltaX

y - the deltaY

readInt

public int readInt(java.lang.String prompt)

Use a dialog box to prompt the user for an integer. If the user doesn't provide us with an integer, they will be reprompted until they do.

readDouble

public double readDouble(java.lang.String prompt)

Use a dialog box to prompt the user for a double. If the user doesn't provide us with an double, they will be reprompted until they do.

readChar

public char readChar(java.lang.String prompt)

Use a dialog box to prompt the user for a character. If the user doesn't provide us with an character, they will be reprompted until they do.

readString

public java.lang.String readString(java.lang.String prompt)

Use a dialog box to prompt the user for a String. Essentially the entire line that the user types is returned.

print

public void print(java.lang.String msg)

picture

public static void picture()

Draws a poor approximation of Russian constructivist art :)

showColorTable

public static void showColorTable()

Opens a color picker application. Click on the color in the window and the console will show the color you have chosen.

main

public static void main(java.lang.String[] args)