Rect.java

import java.awt.Graphics;
import java.awt.Color;

/**
 * A rectangle that can be manipulated and that draws itself on a canvas.
 *
 * @author  Michael Kölling and David J. Barnes and Brian Dahlem
 * @version 2018.11.26
 */

public class Rect
{
    private int xPosition;
    private int yPosition;
    private int xSize;
    private int ySize;
    private Color color;
    private boolean isVisible;

    /**
     * Create a new rectangle at default position with default color.
     */
    public Rect()
    {
        xSize = 60;
        ySize = 60;
        xPosition = 310;
        yPosition = 120;
        color = Canvas.getColor("red");
        isVisible = false;
    }

    /**
     * Make this rectangle visible. If it was already visible, do nothing.
     */
    public void makeVisible()
    {
        if (!isVisible) {
            isVisible = true;
            add();
        }
    }

    /**
     * Make this rectangle invisible. If it was already invisible, do nothing.
     */
    public void makeInvisible()
    {
        if (isVisible){
            remove();
            isVisible = false;
        }
    }

    /**
     * Move the rectangle a few pixels to the right.
     */
    public void moveRight()
    {
        moveHorizontal(20);
    }

    /**
     * Move the rectangle a few pixels to the left.
     */
    public void moveLeft()
    {
        moveHorizontal(-20);
    }

    /**
     * Move the rectangle a few pixels up.
     */
    public void moveUp()
    {
        moveVertical(-20);
    }

    /**
     * Move the rectangle a few pixels down.
     */
    public void moveDown()
    {
        moveVertical(20);
    }

    /**
     * Move the rectangle horizontally by 'distance' pixels.
     * @param distance the distance to move the rectangle along the x axis, 
     *                  positive to the right
     */
    public void moveHorizontal(int distance)
    {
        xPosition += distance;
    }

    /**
     * Move the rectangle vertically by 'distance' pixels.
     * @param distance the distance to move the rectangle along the y axis, 
     *                  positive down
     */
    public void moveVertical(int distance)
    {
        yPosition += distance;
    }

    /**
     * Change the size to the new size (in pixels). Size must be >= 0.
     * @param newSize the new width and height of the square
     */
    public void changeSize(int newSize)
    {
        xSize = newSize;
        ySize = newSize;
    }

    /**
     * Change the size of the rectangle to a new, non-square size.  newHeight and newWidth must be >= 0.
     * @param newHeight the new length of the rectangle along the y axis
     * @param newWidth the new width of the rectangle along the x axis
     */
    public void changeSize(int newHeight, int newWidth)
    {
        xSize = newWidth;
        ySize = newHeight;
    }

    /**
     * Change the color. Valid colors are "red", "yellow", "blue", "green",
     * "magenta", "cyan", "brown", "white", and "black", or rgb hex strings
     * "#rrggbb" where rr, gg, bb are 2-hexit values for red, green, and
     * blue levels.
     * @param newColor a string naming the new color for the rectangle
     */
    public void changeColor(String newColor)
    {
        color = Canvas.getColor(newColor);
    }

    /**
     * Draw a rectangle with current specifications on screen.
     */
    private void add()
    {
        if(isVisible) {
            Canvas canvas = Canvas.getCanvas();
            canvas.add(this, (g) -> {g.setColor(color);
                                     g.fillRect(xPosition, yPosition,
                                                xSize, ySize);});
        }
    }

    /**
     * Remove the rectangle from the screen.
     */
    private void remove()
    {
        if(isVisible) {
            Canvas canvas = Canvas.getCanvas();
            canvas.remove(this);
        }
    }

    /**
     * Get a text description of the rectangle.
     */
    public String toString() {
        String visibility;
        if (isVisible) {
            visibility = "Visible";
        }
        else {
            visibility = "Invisible";
        }

        return visibility + " Rectangle" +
            " with width " + this.xSize + 
            " height  " + this.ySize +
            " at (" + this.xPosition + ", " + this.yPosition + ")" +
            " with color " + this.color;
    }
}