ImageDisplay.java

import javax.swing.*;
import java.awt.*;
import java.awt.image.*;

/**
 * Class to display an image and the current location with a + sign
 * 
 * @author Barb Ericson ericson@cc.gatech.edu
 */
public class ImageDisplay extends JPanel implements Scrollable
{
 
 /////////////////////////// fields (attributes ///////////////////////////
 /** the image to draw */
 private Image image; 
 /** the preferred size of the display */
 private Dimension prefSize; 
 /** the current x index */
 private int currentX = 0; 
 /** the current y index */
 private int currentY = 0; 
 
 //////////////////////////// constructors /////////////////////////////////
 
 /**
 * Constructor that takes the image to display
 * @param theImage the image to display
 */
 public ImageDisplay(Image theImage)
 {
 image = theImage;
 prefSize = new Dimension(image.getWidth(this),image.getHeight(this));
 setPreferredSize(prefSize);
 revalidate();
 }
 
 /**
 * Constructor that takes the image and current x and y
 * @param theImage the image to display
 * @param x the current x value to use
 * @param y the current y value to use
 */
 public ImageDisplay(Image theImage, int x, int y)
 {
 this(theImage);
 currentX = x;
 currentY = y;
 }
 
 ////////////////////// methods /////////////////////////////////////////////
 
 /**
 * Method to get the image
 * @return the image
 */
 public Image getImage() { return image; }
 
 /**
 * Method to get the current x
 * @return the current x value
 */
 public int getCurrentX() { return currentX; }
 
 /**
 * Method to get the current y
 * @return the current y value
 */
 public int getCurrentY() { return currentY; }
 
 /**
 * Method to set the current x
 * @param x the x value to use
 */
 public void setCurrentX(int x) 
 {
 currentX = x;
 repaint();
 }
 
 /**
 * Method to set the current y
 * @param y the y value to use
 */
 public void setCurrentY(int y) 
 {
 currentY = y;
 repaint();
 }
 
 /**
 * Method to set the image
 * @param theImage the new image to use
 */
 public void setImage(Image theImage)
 {
 image = theImage;
 setPreferredSize(new Dimension(image.getWidth(this),image.getHeight(this)));
 repaint();
 }
 
 /**
 * Method to return the preferred size
 * @return the preferred size of this component
 */
 public Dimension getPreferredScrollableViewportSize()
 {
 return prefSize;
 }
 
 /**
 * Method to return the unit increment for scrolling
 * @param visibleRect the visible rectangle
 * @param orientation vertical or horizontal
 * @param direction neg is up or left and pos is right or down
 * @return the unit increment for arrow clicks
 */
 public int getScrollableUnitIncrement(Rectangle visibleRect, 
 int orientation, 
 int direction)
 { return 1; }
 
 /**
 * Method to return the block increment for scrolling
 * @param visibleRect the visible rectangle
 * @param orientation vertical or horizontal
 * @param direction neg is up or left and pos is right or down
 * @return the block increment for clicking in scroll area
 */
 public int getScrollableBlockIncrement(Rectangle visibleRect, 
 int orientation, 
 int direction)
 {
 return 10;
 }
 
 /**
 * Method to check if the viewport width is the source width
 * @return true if viewport and source have same width
 */
 public boolean getScrollableTracksViewportWidth()
 { return false; }
 
 /**
 * Method to check if the viewport height is the source height
 * @return true if viewport and source have same height
 */
 public boolean getScrollableTracksViewportHeight()
 { return false; }
 
 /**
 * Method to handle displaying this object
 * @param g the graphics object for drawing with
 */
 public void paintComponent(Graphics g)
 {
 super.paintComponent(g);
 int num = 3;
 int xStart = currentX - num;
 int xEnd = currentX + num;
 int yStart = currentY - num;
 int yEnd = currentY + num;
 int width = image.getWidth(this);
 int maxX = width - 1;
 int height = image.getHeight(this);
 int maxY = height - 1;
 
 // draw the image
 g.drawImage(image,0,0,this);
 
 // check if the current index is in the image
 if (currentX >= 0 && currentX < width &&
 currentY >= 0 && currentY < height)
 {
 
 // check that the start and end values are visible
 if (xStart < 0)
 xStart = 0;
 if (xEnd > maxX)
 xEnd = maxX;
 if (yStart < 0)
 yStart = 0;
 if (yEnd > maxY)
 yEnd = maxY;
 
 // draw a small cross at the current x and y in yellow
 g.setColor(Color.yellow);
 g.drawLine(xStart,currentY,xEnd,currentY);
 g.drawLine(currentX,yStart,currentX,yEnd);
 g.setColor(Color.black);
 
 // outline the cross in black so that it shows up better
 int leftX = currentX - 1;
 int rightX = currentX + 1;
 int upY = currentY - 1;
 int downY = currentY + 1; 
 if (xStart <= leftX && upY >= 0)
 g.drawLine(xStart,upY,leftX,upY);
 if (yStart <= upY && leftX >= 0)
 g.drawLine(leftX,yStart,leftX,upY);
 if (yStart <= upY && rightX <= maxX)
 g.drawLine(rightX,yStart,rightX,upY);
 if (upY >= 0 && rightX <= xEnd)
 g.drawLine(rightX,upY,xEnd,upY);
 if (downY < height && rightX <= xEnd)
 g.drawLine(rightX,downY,xEnd,downY);
 if (downY <= yEnd && rightX < width)
 g.drawLine(rightX,downY,rightX,yEnd);
 if (xStart <= leftX && downY < height)
 g.drawLine(xStart,downY,leftX,downY);
 if (leftX >= 0 && downY <= yEnd)
 g.drawLine(leftX,downY,leftX,yEnd);
 
 }
 }
 
}