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How to have recursive maze generator draw each step?

I finished writing a program that creates a maze recursively but have not been able to figure out how to have it draw the maze after each step. Any changes to the maze happen before the next recursive call. The maze is prerendered onto a JPanel as a grid of squares, and I have attempted to have the program render each step, by using JPanel.repaint before the next recursive call (I have comments within my generate method where I have previously tried to repaint. No matter what I try, the maze just simply renders the finished product (maze with all of the paths, walls, etc) all at once at the end. Attached is my recursive generate method.
private static boolean generate(int x, int y) {
System.out.println("xcord: " + x + ", ycord: " + y);
//panel.repaint(); when i have repaint here, it renders the entire maze at the end
a[x][y].visited = true;
if (unvisitedCells == 0) { // if you have visited all of the cells, maze is done generating
System.out.println("done");
return true;
}
int movesTried = 0; // keeps track of which directions have been tried
int currentMove = (int) (Math.random() * 4); // try moving a random direction first (0 = north, 1 = east, etc.)
while (movesTried < 4) { // continue as long as all four moves havent been tried
// north move
if (a[x][y].northCell != null && a[x][y].northCell.visited != true && currentMove == 0) {
a[x][y].northCell.visited = true;
a[x][y].northWall = false;
a[x][y].northCell.southWall = false;
unvisitedCells -= 1;
// tried repainting here, but had no effect
if (generate(x, y - 1)) {
return true; // move successful
}
}
// east move
if (a[x][y].eastCell != null && a[x][y].eastCell.visited != true && currentMove == 1) {
a[x][y].eastCell.visited = true;
a[x][y].eastWall = false;
a[x][y].eastCell.westWall = false;
unvisitedCells -= 1;
// tried repainting here, but had no effect
if (generate(x + 1, y)) {
return true; // move successful
}
}
// south move
if (a[x][y].southCell != null && a[x][y].southCell.visited != true && currentMove == 2) {
a[x][y].southCell.visited = true;
a[x][y].southWall = false;
a[x][y].southCell.northWall = false;
unvisitedCells -= 1;
// tried repainting here, but had no effect
if (generate(x, y + 1)) {
return true; // move successful
}
}
// west move
if (a[x][y].westCell != null && a[x][y].westCell.visited != true && currentMove == 3) {
a[x][y].westCell.visited = true;
a[x][y].westWall = false;
a[x][y].westCell.eastWall = false;
unvisitedCells -= 1;
// tried repainting here, but had no effect
if (generate(x - 1, y)) {
return true; // move successful
}
}
movesTried++; // another move has been tried
if (currentMove == 3 && movesTried < 4) {
currentMove = 0; // wraps back to north move if maze started at a move greater than 0, and you
// have more moves to try
} else {
currentMove++;
}
}
// at this point, all 4 moves have been tried, and there are no possible moves
// from the current maze cell
return false;
}
Each cell is rendered individually onto a JPanel, using information kept in a MazeCell class.
public class MazeCell {
public boolean northWall = true;
public boolean eastWall = true;
public boolean southWall = true;
public boolean westWall = true;
public MazeCell northCell = null;
public MazeCell eastCell = null;
public MazeCell southCell = null;
public MazeCell westCell = null;
public boolean visited = false;
}
Here I have set up a JPanel which draws each cell individually, based on whether there is a wall in each of 4 directions.
panel = new JPanel() {
private static final long serialVersionUID = 1L;
public void paintComponent(Graphics g) {
super.paintComponent(g);
a[0][0].northWall = false;
a[mazeSize - 1][mazeSize - 1].southWall = false;
for (int y = 0; y < mazeSize; y++) {
for (int x = 0; x < mazeSize; x++) {
if (a[x][y].northWall) {
g.drawLine(100 + (x * 25), 100 + (y * 25), 100 + (x * 25) + 25, 100 + (y * 25));
}
if (a[x][y].eastWall) {
g.drawLine(100 + (x * 25) + 25, 100 + (y * 25), 100 + (x * 25) + 25, 100 + (y * 25) + 25);
}
if (a[x][y].southWall) {
g.drawLine(100 + (x * 25), 100 + (y * 25) + 25, 100 + (x * 25) + 25, 100 + (y * 25) + 25);
}
if (a[x][y].westWall) {
g.drawLine(100 + (x * 25), 100 + (y * 25), 100 + (x * 25), 100 + (y * 25) + 25);
}
}
}
}
};

Warp the long process (generate(int x, int y)) with a SwingWorker, and let it update the GUI. Here is an example:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingWorker;
public class RecursiveGuiUpdate extends JFrame {
private final int SIZE = 4;
JLabel[][] grid = new JLabel[SIZE][SIZE];
RecursiveGuiUpdate() {
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
add(getGrid(), BorderLayout.NORTH);
JButton paint = new JButton("Paint");
paint.addActionListener(a -> updateGui());
add(paint, BorderLayout.SOUTH);
pack();
setVisible(true);
}
private void updateGui() {
new Task().execute();
}
private Component getGrid() {
JPanel panel = new JPanel(new GridLayout(SIZE, SIZE));
for(int i=0; i<=(SIZE-1); i++) {
for(int j=0; j<=(SIZE-1); j++) {
JLabel l = new JLabel(i+"-"+j, JLabel.CENTER);
l.setOpaque(true);
panel.add(l);
grid[i][j] = l;
}
}
return panel;
}
class Task extends SwingWorker<Void,Void> {
#Override
public Void doInBackground() {
updateGui(0, 0);
return null;
}
#Override
public void done() { }
//recursively set labels background
void updateGui(int i, int j) {
System.out.println(i+"-"+j);
//set random, background color
grid[i][j].setBackground(new Color((int)(Math.random() * 0x1000000)));
try {
Thread.sleep(500); //simulate long process
} catch (InterruptedException ex) { ex.printStackTrace();}
if((i==(SIZE-1))&&(j==(SIZE-1))) { return; }
if(i<(SIZE-1)) {
updateGui(++i, j);
}else {
i=0;
updateGui(i, ++j);
}
}
}
public static void main(String[] args) {
new RecursiveGuiUpdate();
}
}
If needed, you can override process(java.util.List) to get and process interim results.
If you need help with adapting such solution to your code, please post another question with mcve.

Cannot get sprite to collide with map images (java)

I am creating a 2D game which the zombie moves with WASD keys and is supposed to collide with the walls and not enter them, as well as collide with the brains and removes them. Every type of code I have used does not create collision. I am using a zombie sprite sheet i found on google as well as 2 backgroundless images for walls and brains.
After I figure out collision, I then then to implement a autorun sequence to where it bounces around like a screensaver and does the same thing just automatically until all brains are collected.
The EZ is just a library that is utilized by UH Manoa, that can be found here: EZ Graphics
Main
import java.awt.Color;
import java.io.FileReader;
import java.util.Scanner;
public class ZombieMain {
static EZImage[] walls = new EZImage[500];
static EZImage[] sideWalls = new EZImage[500];
static EZImage[] brains = new EZImage[50];
static int wallsCount = 0;
static int sideWallsCount = 0;
static int brainsCount = 0;
/*public static void addWall(EZImage wall) {
walls[wallsCount] = wall;
wallsCount++;
}
public static void addCoin(EZImage brain) {
brains[brainsCount] = brain;
brainsCount++;
}*/
/*public static void CollisingCoin(EZImage me) {
int x = me.getXCenter();
int y = me.getYCenter();
for (int i = 0; i < brainsCount; i++) {
if ((brains[i].isPointInElement(me.getXCenter() - 30, me.getYCenter() - 30))
|| (brains[i].isPointInElement(me.getXCenter() + 30, me.getYCenter() - 30))
|| (brains[i].isPointInElement(me.getXCenter() - 30, me.getYCenter() + 30))
|| (brains[i].isPointInElement(me.getXCenter() + 30, me.getYCenter() + 30))) {
brains[i].translateTo(-20, -20);
System.out.println("You ate a brain!");
}
}
}*/
public static void main(String[] args) throws java.io.IOException {
//initialize scanner
Scanner fScanner = new Scanner(new FileReader("boundaries.txt"));
int w = fScanner.nextInt();
int h = fScanner.nextInt();
String inputText = fScanner.nextLine();
//create backdrop
EZ.initialize(w*33,h*32);
EZ.setBackgroundColor(new Color(0, 0,0));
Zombie me = new Zombie("zombieSheet.png", 650, 450, 65, 63, 10);
//set reading parameters and establish results of case readings
int row = 0;
while(fScanner.hasNext()) {
inputText = fScanner.nextLine();
for (int column = 0; column < inputText.length(); column++){
char ch = inputText.charAt(column);
switch(ch){
case 'W':
walls[wallsCount] = EZ.addImage("barbwire.jpg", column*32, row*32);
wallsCount++;
break;
case 'M':
sideWalls[wallsCount] = EZ.addImage("barb.jpg", column*32, row*32);
wallsCount++;
break;
case 'B':
brains[brainsCount] = EZ.addImage("brains.png", column*32, row*32);
brainsCount++;
break;
default:
// Do nothing
break;
}
//printed count of walls, side walls, and brains
System.out.println("W = " + wallsCount);
System.out.println("M = " + sideWallsCount);
System.out.println("B = " + brainsCount);
}
row++;
}
fScanner.close();
while (true) {
// check if going to collide with wall
// we want to check this before we actually move
// otherwise, we get "stuck" in a situation where we can't move
// if no collision, we can move
/*if (EZInteraction.isKeyDown('a')) {
if (!isCollisingWall(me, -2, 0)) {
me.translateBy(-2, 0);
}
} else if (EZInteraction.isKeyDown('d')) {
if (!isCollisingWall(me, 2, 0)) {
me.translateBy(2, 0);
}
} else if (EZInteraction.isKeyDown('w')) {
if (!isCollisingWall(me, 0, -2)) {
me.translateBy(0, -2);
}
} else if (EZInteraction.isKeyDown('s')) {
if (!isCollisingWall(me, 0, 2)) {
me.translateBy(0, 2);
}
}*/
me.go();
EZ.refreshScreen();
}
}
}
Sprite
public class Zombie {
EZImage zombieSheet;
int x = 0; // Position of Sprite
int y = 0;
int zombieWidth; // Width of each sprite
int zombieHeight; // Height of each sprite
int direction = 0; // Direction character is walking in
int walkSequence = 0; // Walk sequence counter
int cycleSteps; // Number of steps before cycling to next animation step
int counter = 0; // Cycle counter
Zombie(String imgFile, int startX, int startY, int width, int height, int steps) {
x = startX; // position of the sprite character on the screen
y = startY;
zombieWidth = width; // Width of the sprite character
zombieHeight = height; // Height of the sprite character
cycleSteps = steps; // How many pixel movement steps to move before changing the sprite graphic
zombieSheet = EZ.addImage(imgFile, x, y);
setImagePosition();
}
private void setImagePosition() {
// Move the entire sprite sheet
zombieSheet.translateTo(x, y);
// Show only a portion of the sprite sheet.
// Portion is determined by setFocus which takes 4 parameters:
// The 1st two numbers is the top left hand corner of the focus region.
// The 2nd two numbers is the bottom right hand corner of the focus region.
zombieSheet.setFocus(walkSequence * zombieWidth, direction, walkSequence * zombieWidth + zombieWidth, direction + zombieHeight);
}
public void moveDown(int stepSize) {
y = y + stepSize;
direction = 0;
if ((counter % cycleSteps) == 0) {
walkSequence++;
if (walkSequence > 6)
walkSequence = 0;
}
counter++;
setImagePosition();
}
public void moveLeft(int stepSize) {
x = x - stepSize;
direction = zombieHeight * 2;
if ((counter % cycleSteps) == 0) {
walkSequence--;
if (walkSequence < 0)
walkSequence = 6;
}
counter++;
setImagePosition();
}
public void moveRight(int stepSize) {
x = x + stepSize;
direction = zombieHeight;
if ((counter % cycleSteps) == 0) {
walkSequence++;
if (walkSequence > 6)
walkSequence = 0;
}
counter++;
setImagePosition();
}
public void moveUp(int stepSize) {
y = y - stepSize;
direction = zombieHeight * 3;
if ((counter % cycleSteps) == 0) {
walkSequence--;
if (walkSequence < 0)
walkSequence = 6;
}
setImagePosition();
counter++;
}
// Keyboard controls for moving the character.
public void go() {
if (EZInteraction.isKeyDown('w')) {
moveUp(2);
} else if (EZInteraction.isKeyDown('a')) {
moveLeft(2);
} else if (EZInteraction.isKeyDown('s')) {
moveDown(2);
} else if (EZInteraction.isKeyDown('d')) {
moveRight(2);
}
}
public void translateBy(int i, int j) {
// TODO Auto-generated method stub
}
public int getXCenter() {
// TODO Auto-generated method stub
return x;
}
public int getYCenter() {
// TODO Auto-generated method stub
return y;
}
public int getWidth() {
// TODO Auto-generated method stub
return 0;
}
public int getHeight() {
// TODO Auto-generated method stub
return 0;
}
}

EZElement provides a getBounds property, which returns a java.awt.Shape object; why is this important? Because the Java 2D Graphics API already provides some hit detection.
From this, we then need to determine the player shape's intersection with any other shapes. To do this, we need to wrap both shapes in a Area and use it to make the final determinations.
Area meArea = new Area(me.getBounds());
Area checkArea = new Area(elementToCheck.getBounds());
checkArea(meArea);
if (!checkArea.isEmpty()) {
//... We have collision
}
Obviously, this should all be wrapped up in some kind of method to handle the core functionality, but you could have a helper method which simply took two EZElements and return true/false if the collide
For brevity and testing, I stripped back your example, but the basic idea should continue to work
import java.awt.Color;
import java.awt.Shape;
import java.awt.geom.Area;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class Test {
private List<EZImage> brains = new ArrayList<>(25);
private Zombie me;
public static void main(String[] args) throws java.io.IOException {
new Test();
}
public Test() {
int w = 10;
int h = 10;
//create backdrop
EZ.initialize(w * 33, h * 32);
EZ.setBackgroundColor(new Color(0, 0, 0));
me = new Zombie("Zombie.png", 0, 0);
brains.add(EZ.addImage("Brains.png", (w * 33) / 2, (h * 32 / 2)));
while (true) {
detectCollision();
// check if going to collide with wall
// we want to check this before we actually move
// otherwise, we get "stuck" in a situation where we can't move
// if no collision, we can move
/*if (EZInteraction.isKeyDown('a')) {
if (!isCollisingWall(me, -2, 0)) {
me.translateBy(-2, 0);
}
} else if (EZInteraction.isKeyDown('d')) {
if (!isCollisingWall(me, 2, 0)) {
me.translateBy(2, 0);
}
} else if (EZInteraction.isKeyDown('w')) {
if (!isCollisingWall(me, 0, -2)) {
me.translateBy(0, -2);
}
} else if (EZInteraction.isKeyDown('s')) {
if (!isCollisingWall(me, 0, 2)) {
me.translateBy(0, 2);
}
}*/
me.go();
EZ.refreshScreen();
}
}
public boolean doesCollide(EZElement element, EZElement with) {
Area a = new Area(element.getBounds());
Area b = new Area(with.getBounds());
a.intersect(b);
return !a.isEmpty();
}
public void detectCollision() {
Iterator<EZImage> obstacles = brains.iterator();
while (obstacles.hasNext()) {
EZElement next = obstacles.next();
if (doesCollide(me.zombieSheet, next)) {
System.out.println("Me = " + me.getBounds().getBounds());
System.out.println("next = " + next.getBounds().getBounds());
EZ.removeEZElement(next);
obstacles.remove();
}
}
}
public class Zombie {
EZImage zombieSheet;
int x = 0; // Position of Sprite
int y = 0;
Zombie(String imgFile, int startX, int startY) {
x = startX; // position of the sprite character on the screen
y = startY;
zombieSheet = EZ.addImage(imgFile, x, y);
setImagePosition();
}
public Shape getBounds() {
return zombieSheet.getBounds();
}
private void setImagePosition() {
// Move the entire sprite sheet
zombieSheet.translateTo(x, y);
}
public void moveDown(int stepSize) {
y = y + stepSize;
setImagePosition();
}
public void moveLeft(int stepSize) {
x = x - stepSize;
setImagePosition();
}
public void moveRight(int stepSize) {
x = x + stepSize;
setImagePosition();
}
public void moveUp(int stepSize) {
y = y - stepSize;
setImagePosition();
}
// Keyboard controls for moving the character.
public void go() {
if (EZInteraction.isKeyDown('w')) {
moveUp(2);
} else if (EZInteraction.isKeyDown('a')) {
moveLeft(2);
} else if (EZInteraction.isKeyDown('s')) {
moveDown(2);
} else if (EZInteraction.isKeyDown('d')) {
moveRight(2);
}
}
}
}

I would recommend that you give each entity (and block/tile) a collision box, then test if a specific entity's bounding box collided with another entity's bounding box, then make it so that the entities can't move in that direction until there isn't a bounding box in a direction, if that made any since.
Do the same for testing for the brains, though I recommend making an ArrayList of brains, and removing specific ones if that brain had been touched.

java.lang.NullPointerException Can't Find Source

I'm in the process of programming a java rpg game, and have reached an impass. My code currently has sprite animation, a random map generation with perlin noise and collision detection. The map is tiled base, so i'm currently trying to convert the perlin noise to tiles. The perlin functions generate a array, and im each number of that array to a tile png. This is where the problem comes: RUNTIME ERROR: Java.Lang.NullPointerException.
The probleme is my compiler (netbeans) does not show me where the error occurs, but instead only gives me this error code. With a process of exclusion I managed to locate the error, which occurs at line 364. If this site doesnt support lines, it is at the loadTile() method, at "if(perlinIsland[x][y] <= 0.05)blockImg[x][y] = TILE[0];". I believe all the variables are correctly initialized, but I can't manage to find a solution. Please excuse the long code, but I included everything for the sake of information. Thanks you in advance for you help!
package java4k;
import java.awt.*;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;
import java.awt.image.*;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.Random;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import java.math.*;
import java.util.*;
/**
*
* #author Christophe
*/
public class Main extends JFrame implements Runnable{
public Image dbImage;
public Graphics dbGraphics;
//Image + Array size
final static int listWidth = 500, listHeight = 500;
//Move Variables
int playerX = 320, playerY = 240, xDirection, yDirection;
//Sprites
BufferedImage spriteSheet;
//Lists for sprite sheet: 1 = STILL; 2 = MOVING_1; 3 = MOVING_2
BufferedImage[] ARCHER_NORTH = new BufferedImage[4];
BufferedImage[] ARCHER_SOUTH = new BufferedImage[4];
BufferedImage[] ARCHER_EAST = new BufferedImage[4];
BufferedImage[] ARCHER_WEST = new BufferedImage[4];
Image[] TILE = new Image[8];
//Animation Variables
int currentFrame = 0, framePeriod = 150;
long frameTicker = 0l;
Boolean still = true;
Boolean MOVING_NORTH = false, MOVING_SOUTH = false, MOVING_EAST = false, MOVING_WEST = false;
BufferedImage player = ARCHER_SOUTH[0];
//World Tile Variables
//20 X 15 = 300 tiles
Rectangle[][] blocks = new Rectangle[listWidth][listHeight];
Image[][] blockImg = new Image[listWidth][listHeight];
Image[][] blockImgTrans = new Image[listWidth][listHeight];
Boolean[][] isSolid = new Boolean[listWidth][listHeight];
int tileX = 0, tileY = 0;
Random r = new Random();
Rectangle playerRect = new Rectangle(playerX + 4,playerY+20,32,20);
//Map Navigation
static final byte PAN_UP = 0, PAN_DOWN = 1, PAN_LEFT = 2, PAN_RIGHT = 3;
//Perlin noise variables:
Color test = new Color(0, 0, 0);
static float[][] perlinNoise = new float[listWidth][listHeight];
static float[][] gradiantNoise = new float[listWidth][listHeight];
static float[][] perlinIsland = new float[listWidth][listHeight];
static float[][] biome = new float[listWidth][listHeight];
//Saved as png
static BufferedImage perlinImage;
public Main(){
this.setTitle("JAVA4K");
this.setSize(640,505);
this.setResizable(false);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
addKeyListener(new AL());
TILE[0] = new ImageIcon("C:/Users/Christophe/Documents/NetBeansProjects/Java4k/src/java4k/TILE_GRASS_1.png").getImage();
TILE[1] = new ImageIcon("C:/Users/Christophe/Documents/NetBeansProjects/Java4k/src/java4k/TILE_GRASS_2.png").getImage();
TILE[2] = new ImageIcon("C:/Users/Christophe/Documents/NetBeansProjects/Java4k/src/java4k/TILE_GRASS_3.png").getImage();
TILE[3] = new ImageIcon("C:/Users/Christophe/Documents/NetBeansProjects/Java4k/src/java4k/TILE_WATER_1.png").getImage();
TILE[4] = new ImageIcon("C:/Users/Christophe/Documents/NetBeansProjects/Java4k/src/java4k/TILE_TREE_1_BOT.png").getImage();
TILE[5] = new ImageIcon("C:/Users/Christophe/Documents/NetBeansProjects/Java4k/src/java4k/TILE_TREE_1_TOP.png").getImage();
TILE[6] = new ImageIcon("C:/Users/Christophe/Documents/NetBeansProjects/Java4k/src/java4k/TILE_TREE_2_BOT.png").getImage();
TILE[7] = new ImageIcon("C:/Users/Christophe/Documents/NetBeansProjects/Java4k/src/java4k/TILE_TREE_2_TOP.png").getImage();
loadTiles();
init();
}
//Step 1: Generates array of random number 0 < n < 1
public static float[][] GenerateWhiteNoise(int width, int height){
Random r = new Random();
Random random = new Random(r.nextInt(1000000000)); //Seed to 0 for testing
float[][] noise = new float[width][height];
for (int i = 0; i < width; i++)
{
for (int j = 0; j < height; j++)
{
noise[i][j] = (float)random.nextDouble() % 1;
}
}
return noise;
}
//Step 2: Smooths out random numbers
public static float[][] GenerateSmoothNoise(float[][] baseNoise, int octave){
int width = baseNoise.length;
int height = baseNoise.length;
float[][] smoothNoise = new float[width][height];
int samplePeriod = 1 << octave; // calculates 2 ^ k
float sampleFrequency = 1.0f / samplePeriod;
for (int i = 0; i < width; i++)
{
//calculate the horizontal sampling indices
int sample_i0 = (i / samplePeriod) * samplePeriod;
int sample_i1 = (sample_i0 + samplePeriod) % width; //wrap around
float horizontal_blend = (i - sample_i0) * sampleFrequency;
for (int j = 0; j < height; j++)
{
//calculate the vertical sampling indices
int sample_j0 = (j / samplePeriod) * samplePeriod;
int sample_j1 = (sample_j0 + samplePeriod) % height; //wrap around
float vertical_blend = (j - sample_j0) * sampleFrequency;
//blend the top two corners
float top = Interpolate(baseNoise[sample_i0][sample_j0],
baseNoise[sample_i1][sample_j0], horizontal_blend);
//blend the bottom two corners
float bottom = Interpolate(baseNoise[sample_i0][sample_j1],
baseNoise[sample_i1][sample_j1], horizontal_blend);
//final blend
smoothNoise[i][j] = Interpolate(top, bottom, vertical_blend);
}
}
return smoothNoise;
}
//Used in GeneratePerlinNoise() to derivate functions
public static float Interpolate(float x0, float x1, float alpha)
{
float ft = alpha * 3.1415927f;
float f = (float) (1 - Math.cos(ft)) * .5f;
return x0*(1-f) + x1*f;
}
//Step 3: Combines arrays together to generate final perlin noise
public static float[][] GeneratePerlinNoise(float[][] baseNoise, int octaveCount)
{
int width = baseNoise.length;
int height = baseNoise[0].length;
float[][][] smoothNoise = new float[octaveCount][][]; //an array of 2D arrays containing
float persistance = 0.5f;
//generate smooth noise
for (int i = 0; i < octaveCount; i++)
{
smoothNoise[i] = GenerateSmoothNoise(baseNoise, i);
}
float[][] perlinNoise = new float[width][height];
float amplitude = 1.0f;
float totalAmplitude = 0.0f;
//blend noise together
for (int octave = octaveCount - 1; octave >= 0; octave--)
{
amplitude *= persistance;
totalAmplitude += amplitude;
for (int i = 0; i < width; i++)
{
for (int j = 0; j < height; j++)
{
perlinNoise[i][j] += smoothNoise[octave][i][j] * amplitude;
}
}
}
//normalisation
for (int i = 0; i < width; i++)
{
for (int j = 0; j < height; j++)
{
perlinNoise[i][j] /= totalAmplitude;
}
}
return perlinNoise;
}
//Step 4: Generate circular gradiant: center = 0, outside = 1
public static float[][] GenerateCircularGradiant(float[][] base, int size, int centerX, int centerY){
base = new float[size][size];
for (int x = 0; x < base.length; x++) {
for (int y = 0; y < base.length; y++) {
//Simple squaring, you can use whatever math libraries are available to you to make this more readable
//The cool thing about squaring is that it will always give you a positive distance! (-10 * -10 = 100)
float distanceX = (centerX - x) * (centerX - x);
float distanceY = (centerY - y) * (centerY - y);
float distanceToCenter = (float) Math.sqrt(distanceX + distanceY);
//Make sure this value ends up as a float and not an integer
//If you're not outputting this to an image, get the correct 1.0 white on the furthest edges by dividing by half the map size, in this case 64. You will get higher than 1.0 values, so clamp them!
float mapSize = base.length/2;
//mapSize = 500;
distanceToCenter = distanceToCenter / mapSize;
base[x][y] = distanceToCenter - 0.2f;
}
}
return base;
}
//step 5: Combine perlin noise with circular gradiant to create island
public static float[][] GenerateIsland(float[][] baseCircle, float[][] baseNoise){
float[][] baseIsland = new float[baseNoise.length][baseNoise.length];
for(int x = 0; x < baseNoise.length; x++){
for(int y = 0; y < baseNoise.length; y++){
baseIsland[x][y] = baseNoise[x][y] - baseCircle[x][y];
}
}
return baseIsland;
}
//Method for optional paramater = float[][] biome
public static void GreyWriteImage(float[][] data, String filename){
float[][] temp = null;
GreyWriteImage(data, temp, filename);
}
//Converts array data to png image
public static void GreyWriteImage(float[][] data, float[][] biome, String fileName){
//this takes and array of doubles between 0 and 1 and generates a grey scale image from them
BufferedImage image = new BufferedImage(data.length,data[0].length, BufferedImage.TYPE_INT_RGB);
for (int y = 0; y < data[0].length; y++)
{
for (int x = 0; x < data.length; x++)
{
if (data[x][y]>1){
data[x][y]=1;
}
if (data[x][y]<0){
data[x][y]=0;
}
Color col;
//Deep Water 0 - 0.05
if(data[x][y] <= 0.05) col = new Color(0, 0, 255);
//Shallow Water 0.05 - 0.08
else if(data[x][y] <= 0.08) col = new Color(100, 100, 255);
//Beach 0.08 - 0.2
else if(data[x][y]<=0.15) col = new Color(255, 255, 0);
//Forest 0.2 - 0.6 + 0 0 0.7
else if(data[x][y]<=0.6 && biome != null && (biome[x][y] < 0.6 || biome[x][y] > 0.9)){
//Forest
if(biome[x][y] < 0.6) col = new Color(0, 150, 0);
//Desert
else col = new Color(200, 200, 0);
}
//Plains 0.2 - 0.6
else if(data[x][y] <= 0.6) col = new Color(0, 255, 0);
//Rocky Mountains 0.6 - 0.8
else if(data[x][y] <= 0.65) col = new Color(100, 100, 100);
//Snowy Mountains 0.6 - 1
else col = new Color(255, 255, 255);
image.setRGB(x, y, col.getRGB());
}
}
try {
// retrieve image
File outputfile = new File(fileName);
outputfile.createNewFile();
ImageIO.write(image, "png", outputfile);
} catch (IOException e) {
System.out.println("GREY WRITE IMAGE ERROR 303: " + e);
}
}
//First called to store image tiles in blockImg[][] and tile rectangles in blocks[][]
private void loadTiles(){
//Primary Perlin Noise Generation
perlinNoise = GenerateWhiteNoise(listWidth, listHeight);
GreyWriteImage(perlinNoise, "perlinNoise.png");
perlinNoise = GenerateSmoothNoise(perlinNoise, 7);
GreyWriteImage(perlinNoise, "smoothNoise.png");
perlinNoise = GeneratePerlinNoise(perlinNoise, 5);
GreyWriteImage(perlinNoise, "finalPerlin.png");
gradiantNoise = GenerateCircularGradiant(gradiantNoise, listWidth, listWidth/2 - 1, listHeight/2 - 1);
GreyWriteImage(gradiantNoise, "gradiantNoise.png");
perlinIsland = GenerateIsland(gradiantNoise, perlinNoise);
GreyWriteImage(perlinIsland, "perlinIsland.png");
//Biome Perlin Noise Generation
biome = GenerateWhiteNoise(listWidth, listHeight);
biome = GenerateSmoothNoise(biome, 6);
biome = GeneratePerlinNoise(biome, 5);
GreyWriteImage(perlinIsland, biome, "biome.png");
for(int y = 0; y < listHeight; y++){
for(int x = 0; x < listWidth; x++){
//Sets boundaries: 0 < perlinIsland[x][y] < 1
if (perlinIsland[x][y]>1) perlinIsland[x][y]=1;
if (perlinIsland[x][y]<0) perlinIsland[x][y]=0;
//Deep Water 0 - 0.05
if(perlinIsland[x][y] <= 0.05)blockImg[x][y] = TILE[0];
//Shallow Water 0.05 - 0.08
else if(perlinIsland[x][y] <= 0.08) blockImg[x][y] = TILE[3];
//Beach 0.08 - 0.2
else if(perlinIsland[x][y]<=0.15) blockImg[x][y] = TILE[4];
//Forest 0.2 - 0.6 + 0 0 0.7
else if(perlinIsland[x][y]<=0.6 && biome != null && (biome[x][y] < 0.6 || biome[x][y] > 0.9)){
//Forest
if(biome[x][y] < 0.6) blockImg[x][y] = TILE[5];
//Desert
else blockImg[x][y] = TILE[3];
}
//Plains 0.2 - 0.6
else if(perlinIsland[x][y] <= 0.6) blockImg[x][y] = TILE[2];
//Rocky Mountains 0.6 - 0.8
else if(perlinIsland[x][y] <= 0.65) blockImg[x][y] = TILE[3];
//Snowy Mountains 0.6 - 1
else blockImg[x][y] = TILE[1];
blocks[x][y] = new Rectangle(x*32, y*32, 32, 32);
}
}
}
//collision detection
public boolean collide(Rectangle in)
{
if(blocks[0][0] != null){
for (int y = (int)((playerRect.y - blocks[0][0].y) / 32)-1; y <= (int)((playerRect.y+playerRect.height - blocks[0][0].y) / 32)+1; y++){
for (int x = (int)((playerRect.x - blocks[0][0].x) / 32)-1; x <= (int)((playerRect.x+playerRect.width - blocks[0][0].x) / 32) + 1; x++){
if (x >= 0 && y >= 0 && x < 32 && y < 32){
if (blockImg[x][y] != null)
{
if (in.intersects(blocks[x][y]) && isSolid[x][y] == true){
{
return true;
}
}
}
}
}
}
}
return false;
}
//Key Listener
public class AL extends KeyAdapter{
public void keyPressed(KeyEvent e){
int keyInput = e.getKeyCode();
still = false;
if(keyInput == e.VK_LEFT){
navigateMap(PAN_RIGHT);
MOVING_WEST = true;
}if(keyInput == e.VK_RIGHT){
navigateMap(PAN_LEFT);
MOVING_EAST = true;
}if(keyInput == e.VK_UP){
navigateMap(PAN_DOWN);
MOVING_NORTH = true;
}if(keyInput == e.VK_DOWN){
navigateMap(PAN_UP);
MOVING_SOUTH = true;
}
}
public void keyReleased(KeyEvent e){
int keyInput = e.getKeyCode();
setYDirection(0);
setXDirection(0);
if(keyInput == e.VK_LEFT){
MOVING_WEST = false;
player = ARCHER_WEST[0];
}if(keyInput == e.VK_RIGHT){
MOVING_EAST = false;
player = ARCHER_EAST[0];
}if(keyInput == e.VK_UP){
MOVING_NORTH = false;
player = ARCHER_NORTH[0];
}if(keyInput == e.VK_DOWN){
MOVING_SOUTH = false;
player = ARCHER_SOUTH[0];
}
if( MOVING_SOUTH == MOVING_NORTH == MOVING_EAST == MOVING_WEST == false){
still = true;
}
}
}
public void moveMap(){
for(int a = 0; a < 30; a++){
for(int b = 0; b < 30; b++){
if(blocks[a][b] != null){
blocks[a][b].x += xDirection;
blocks[a][b].y += yDirection;
}
}
}
if(collide(playerRect) && blocks[0][0]!= null){
for(int a = 0; a < 30; a++){
for(int b = 0; b < 30; b++){
blocks[a][b].x -= xDirection;
blocks[a][b].y -= yDirection;
}
}
}
}
public void navigateMap(byte pan){
switch(pan){
default:
System.out.println("Unrecognized pan!");
break;
case PAN_UP:
setYDirection(-1);
break;
case PAN_DOWN:
setYDirection(+1);
break;
case PAN_LEFT:
setXDirection(-1);
break;
case PAN_RIGHT:
setXDirection(+1);
break;
}
}
//Animation Update
public void update(long gameTime) {
if (gameTime > frameTicker + framePeriod) {
frameTicker = gameTime;
currentFrame++;
if (currentFrame >= 4) {
currentFrame = 0;
}
}
if(MOVING_NORTH) player = ARCHER_NORTH[currentFrame];
if(MOVING_SOUTH) player = ARCHER_SOUTH[currentFrame];
if(MOVING_EAST) player = ARCHER_EAST[currentFrame];
if(MOVING_WEST) player = ARCHER_WEST[currentFrame];
}
public void setXDirection(int xdir){
xDirection = xdir;
}
public void setYDirection(int ydir){
yDirection = ydir;
}
//Method to get sprites
public BufferedImage grabSprite(int x, int y, int width, int height){
BufferedImage sprite = spriteSheet.getSubimage(x, y, width, height);
return sprite;
}
private void init(){
spriteSheet = null;
try {
spriteSheet = loadImage("ARCHER_SPRITESHEET.png");
} catch (IOException ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
for(int i = 0; i <= 3; i++){
ARCHER_NORTH[i] = grabSprite(i*16, 16, 16,16);
ARCHER_SOUTH[i] = grabSprite(i*16, 0, 16, 16);
ARCHER_EAST[i] = grabSprite(i*16, 32, 16, 16);
ARCHER_WEST[i] = grabSprite(i*16, 48, 16, 16);
}
}
public BufferedImage loadImage(String pathRelativeToThis) throws IOException{
URL url = this.getClass().getResource(pathRelativeToThis);
BufferedImage img = ImageIO.read(url);
return img;
}
public void paint(Graphics g){
dbImage = createImage(getWidth(), getHeight());
dbGraphics = dbImage.getGraphics();
paintComponent(dbGraphics);
g.drawImage(dbImage, 0, 25, this);
}
public void paintComponent(Graphics g){
requestFocus();
/**
//Draws tiles and rectangular boundaries for debugging
for(int a = 200; a < 230; a++){
for(int b = 200; b < 230; b++){
if(blockImg[a][b] != null && blocks[a][b] != null){
g.drawImage(blockImg[a][b], Math.round(blocks[a][b].x), Math.round(blocks[a][b].y), 32, 32, null);
}
}
}
//Draw player and rectangular boundary for collision detection
g.drawImage(player, playerX, playerY, 40, 40, null);
repaint();
//Draws transparent tiles
for(int a = 0; a < 20; a++){
for(int b = 0; b < 15; b++){
if(blockImgTrans[a][b] != null && blocks[a][b] != null){
g.drawImage(blockImgTrans[a][b], blocks[a][b].x, blocks[a][b].y, 32, 32, null);
}
}
}
**/
}
public void run(){
try{
while(true){
moveMap();
if(!still) update(System.currentTimeMillis());
Thread.sleep(13);
}
}catch(Exception e){
System.out.println("RUNTIME ERROR: " + e);
}
}
public static void main(String[] args) {
Main main = new Main();
//Threads
Thread thread1 = new Thread(main);
thread1.start();
}
}

Your limited catch block code hampers your ability to find your nulls.
For instance, these lines of code:
try {
while (true) {
moveMap();
if (!still)
update(System.currentTimeMillis());
Thread.sleep(13);
}
} catch (Exception e) {
System.out.println("RUNTIME ERROR: " + e);
}
Will only print
RUNTIME ERROR: java.lang.NullPointerException
without line numbers or stack trace when this code runs into an NPE.
First off, you should not be trapping for plain Exception but rather for explicit Exceptions. Next you should use a more informative catch block, for instance one that at least prints out the stack trace via e.printStackTrace().
The block above should really be written:
public void run() {
while (true) {
moveMap();
if (!still)
update(System.currentTimeMillis());
try {
Thread.sleep(13);
// only catch the explicit exception and in localized code if possible.
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
Do this, and you'll see that the NPE occurs here:
if (in.intersects(blocks[x][y]) && isSolid[x][y] == true) {
Then you can stuff code in front of that line to see which variable is causing the problem:
e.g.,
if (blockImg[x][y] != null) {
System.out.println("in is null: " + (in == null));
System.out.println("blocks[x][y] is null: "
+ (blocks[x][y] == null));
System.out.println("isSolid is null: "
+ (isSolid == null));
System.out.println("isSolid[x][y] is null: "
+ (isSolid[x][y] == null));
if (in.intersects(blocks[x][y]) && isSolid[x][y] == true) {
{
return true;
}
}
}
And you'll see the problem is that isSolid[x][y] is null:
in is null: false
blocks[x][y] is null: false
isSolid is null: false
isSolid[x][y] is null: true
in is null: false
blocks[x][y] is null: false
isSolid is null: false
isSolid[x][y] is null: true
in is null: false
blocks[x][y] is null: false
isSolid is null: false
isSolid[x][y] is null: true
Exception in thread "Thread-3" java.lang.NullPointerException
at pkg.Main.collide(Main.java:465)
at pkg.Main.moveMap(Main.java:557)
at pkg.Main.run(Main.java:693)
at java.lang.Thread.run(Unknown Source)
in is null: false
blocks[x][y] is null: false
isSolid is null: false
isSolid[x][y] is null: true
in is null: false
blocks[x][y] is null: false
isSolid is null: false
isSolid[x][y] is null: true
in is null: false
blocks[x][y] is null: false
isSolid is null: false
isSolid[x][y] is null: true
And why is that? It's an array of Booleans, not booleans, so it is not initialized to Boolean.FALSE but rather it defaults to null. Solution: either use boolean[][] array or initialize your array explicitly.
Most important: use informative catch blocks and don't catch for general Exceptions.
Edit note that as an aside, in order for me to get your code to run, I had to disable your use of images and sprite sheets, since these are resources that are unavailable to me. This effort should be yours though since you are the one seeking in the future. I ask that in the future, you limit your code to the smallest code that we can test and run, that demonstrates your problem, but that has no code unrelated to your problem, and that does not rely on outside resources such as images, databases, etc..., an sscce.

zoom in/out graph using AWT on Applet

I am newbie to the java....working on a piece of applet code...............as I am still going through the OOPs concepts and java understanding and need to develop below mentioned functionality.
The piece of code I have works like this :
First it reads all parameters from HTML tags and stores in global variables. Then it sends query to CGI to read graph data. Then it converts data for plotting and draws graph. There is a option for user to select 1-24 hours. Based on the selection graph will be plotted by plotting only selected data. Every 30 sec it sends query to CGI for collecting data.
The code uses following library and uses java 1.5 environment and i cannot change it due to embeded requirements :
I need to enchance it by implementing zoom in zoom out feature with x-y axis granuality changing with zoom in .
My worry is how to do that?I know its Frustrating question ...but i am here to get suggestion from the java experts so that I can quickly learn and implement this stuff.
import java.awt.*;
import java.awt.image.*;
import java.awt.event.*;
import java.applet.*;
import java.net.*;
import java.io.*;
import java.util.*;
import java.text.*;
/******************************************************************************
*
* Class - Graph
*
* This is the entry point.
* This class extends Applet class and implements Runnable.
*
*****************************************************************************/
public class GraphPerf extends Applet implements Runnable,ItemListener,MouseMotionListener
{
//Global variables
int MAX_DATA_X ;
int SIZE_X= 480;
int SIZE_Y= 250;
int SIZE_Y1= 240;
int MIN_ERROR = -1;
int MAX_LOG10_ERROR_COUNT = 1001;
int MAX_ERROR_COUNT = 101;
int SIZE_Y_EXTENDED_BOTTOM = 20;
int MAX_DISP_PARMS = 16;
int MAX_NUM_INTERVELL_PER_DAY = 96;
int MAX_DISP_PARMS_STD = 7;
int refreshTime;
String serverAddress,hostAddr;
Color plotColor1,plotColor8;
float graphData[][];
float graph_data_rf_east,graph_data_rf_west;
int xOffset = 50;
int yOffset = 40;
int Y1_MAX_VALUE = 100;
int Y2_MAX_VALUE = 3;
float RANGE2;
Thread graphThread;
Image Buffer;
Graphics plot;
Choice timeChoice, modeChoice, seloptChoice;
int duration=1, viewMode=1, line_type = 0,viewOpt = 1;
Label valueLabel1, valueLabel2,valueLabel3,valueLabel4,valueLabel5;
boolean GraphBottomExtendFlag=true;
/******************************************************************************
*
* method - init
*
* This is the method called first after applet loaded in to browser.
* This function reads configurable parameters from HTML tag and updates
* global variables.
*****************************************************************************/
public void init()
{
MAX_DATA_X = 672;//Integer.parseInt(getParameter("max_data_x"));
//refreshTime = 30;//Integer.parseInt(getParameter("refresh_sec"));
/*URL url = getDocumentBase();
String host = url.getHost();
try
{
InetAddress addr = InetAddress.getByName(host);
hostAddr=addr.getHostAddress();
}catch (UnknownHostException ex) {
ex.printStackTrace();
}
*/
//serverAddress = new String ( getParameter("access_str")+ hostAddr + getParameter("data_server"));
graphData = new float[MAX_DISP_PARMS][MAX_DATA_X+1];
/*initialize the array with -1 not with 0(0 also valid for graph data) */
int i =0,j = 0;
for( j=0; j<MAX_DISP_PARMS; j++)
{
for( i=0; i<MAX_DATA_X+1; i++)
{
graphData[j][i] = -1;
}
}
graph_data_rf_east = -1;
graph_data_rf_west = -1;
plotColor1 = Color.orange;
plotColor2 = Color.black;
plotColor8 = Color.red;
plotColor9 = Color.green;
setBackground(Color.white);
setLayout(null);
timeChoice = new Choice();
timeChoice.add("1");
timeChoice.add("2");
timeChoice.add("3");
timeChoice.add("4");
timeChoice.add("5");
timeChoice.add("6");
timeChoice.add("7");
add(timeChoice);
timeChoice.setBounds(190,340,40,23);
timeChoice.addItemListener(this);
Label timeLabel1 = new Label("View graph for last");
Label timeLabel2 = new Label("day(s)");
add(timeLabel1);
timeLabel1.setBounds(xOffset+30,340,160,23);
add(timeLabel2);
timeLabel2.setBounds(240,340,50,23);
valueLabel1 = new Label();
add(valueLabel1);
valueLabel1.setBounds(300,340,50,23);
valueLabel2 = new Label();
add(valueLabel2);
valueLabel2.setBounds(370,340,70,23);
valueLabel3 = new Label();
add(valueLabel3);
valueLabel3.setBounds(440,340,70,23);
valueLabel4 = new Label();
add(valueLabel4);
valueLabel4.setBounds(500,340,70,23);
valueLabel5 = new Label();
add(valueLabel5);
valueLabel5.setBounds(370,370,80,25);
modeChoice = new Choice();
modeChoice.add("East");
modeChoice.add("West");
/* Display this only for Protected and East-West Mode */
if(2/*Integer.parseInt(getParameter("mode"))*/ == 2)
{
add(modeChoice);
}
else
{
viewOpt = 1;
}
modeChoice.setBounds(xOffset+SIZE_X-55, 0, 60, 25);
modeChoice.addItemListener(this);
addMouseMotionListener(this);
}
public void start()
{
graphThread = new Thread(this);
graphThread.start();
}
public void stop()
{
graphThread = null;
}
/******************************************************************************
*
* This method will be called after starting the thread. This is a
* infinite loop which will call query method for every 30 sec to read data
* from CGI. Then it plots graph by calling plotGraph method
* the thread.
*****************************************************************************/
public void run()
{
/*while (false)
{
try
{//getData(serverAddress);
int sizeY = SIZE_Y;
if(GraphBottomExtendFlag)
{
sizeY += SIZE_Y_EXTENDED_BOTTOM;
}
repaint(xOffset+1,yOffset+1,SIZE_X-1,sizeY-1);
//graphThread.sleep(refreshTime*1000);
}catch (Exception e) { System.out.println(e); }
}*/
}
/******************************************************************************
*
* method - paint
*
* This method displays the graph plotted by plotGraph method
* in the screen. Then it draws axis for the graph
*
*****************************************************************************/
public void paint(Graphics g1)
{
int sizeY = SIZE_Y;
/*If Graph Bottom is to be Etended
*soo that zero is displayed properly
*/
if(GraphBottomExtendFlag)
{
sizeY += SIZE_Y_EXTENDED_BOTTOM;
}
if( duration <= 5 )
{
Buffer = createImage(SIZE_X, sizeY);
plot = Buffer.getGraphics();
plotGraph(plot);
g1.drawImage (Buffer,xOffset,yOffset,this);
}
else
{
Buffer = createImage(MAX_DATA_X*duration/7,sizeY);
plot = Buffer.getGraphics();
plotGraph(plot);
g1.drawImage (Buffer,xOffset,yOffset,SIZE_X,sizeY,this);
}
g1.setColor(Color.black);
g1.drawRect(70,150,270,80);
/*Dram Graph boarder */
g1.drawRect(xOffset,yOffset,SIZE_X,sizeY);
g1.drawRect(xOffset-1,yOffset-1,SIZE_X+2,sizeY+2);
/*Plot X axis*/
int max_x_marks = 8;
int temp = 1,cnt_graph = 0;
int float_temp,float_temp2;
/*max 8 plots on x axis*/
for(int x=max_x_marks; x>0; x--)
{
float_temp = (int)((MAX_NUM_INTERVELL_PER_DAY*duration)/max_x_marks)*((max_x_marks+1)-x);
float_temp2 = SIZE_X-(60*cnt_graph);
g1.drawString(String.valueOf(float_temp),(float_temp2-20) ,SIZE_Y+yOffset+35);
cnt_graph++;
}
/*Plot Y1 AXIS*/
temp = Y1_MAX_VALUE;
for(int x = 0; x <= SIZE_Y; x+= 25)
{
g1.drawString(String.valueOf(temp), 25, x + yOffset+10);
temp -= (Y1_MAX_VALUE - 0)/10;
}
temp = 1000;
/*Plot Y2 AXIS*/
int index_log = 1;
for(int x = 0; x <= SIZE_Y1; x+= 80)
{
if(x== 240)
index_log--;
if(temp>=1)
{
g1.drawString(String.valueOf(temp), 550, x+yOffset+8-index_log);
g1.drawLine(530,x+yOffset+5-index_log, 540, x+yOffset+5-index_log);
}
temp = temp/10;
}
Font thisFont = new Font("Times New Roman", Font.BOLD, 14);
g1.setFont(thisFont);
g1.drawString("Y2", 550, 160);
g1.drawString("Y1",5, 160);
}
/******************************************************************************
*
* method - plotGraph
*
* Depending on the mode, "East", "West" or "Combined", it plots
* single or two graphs in the same applet.
*
* Inputs :
* g - Graphics object
*****************************************************************************/
public void plotGraph(Graphics g)
{
g.setColor(new Color(255,255,220));
/*If Error-Sec-Count Graph
*Then extend the lower portion
*soo that zero is displayed properly
*/
if(GraphBottomExtendFlag)
{
g.fillRect(0,0,MAX_DATA_X,SIZE_Y + SIZE_Y_EXTENDED_BOTTOM);
}
else
{
g.fillRect(0,0,MAX_DATA_X,SIZE_Y);
}
switch(viewMode)
{
case 1 :
plot1(g);
plot_timeelapsed_east(g);
break;
case 2 :
plot8(g);
plot_timeelapsed_west(g);
break;
}
}
/******************************************************************************
*
* method - plot1
*
* This method uses graphData[0][] global variable and plots series of lines
* in the applet
*
* Inputs :
* g - Graphics object
*****************************************************************************/
void plot1(Graphics g)
{
int end = MAX_DATA_X;
int localPlotBuffer[];
localPlotBuffer = new int[2];
g.setColor(plotColor1);
if(duration > 5)
{
for(int x=(duration*MAX_NUM_INTERVELL_PER_DAY); x > 0 ; x--)
{
/*if data is valid data then plot else ignore*/
if((graphData[0][end]>MIN_ERROR)&&(graphData[0][end-1]<MAX_LOG10_ERROR_COUNT)&&(graphData[0][end-1]>MIN_ERROR)&&(graphData[0][end]<MAX_LOG10_ERROR_COUNT))
{
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[0][end] == 0)
{
localPlotBuffer[0] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[0][end]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[0][end])/(float)Y2_MAX_VALUE));
}
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[0][end-1] == 0)
{
localPlotBuffer[1] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[0][end-1]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[1] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[0][end-1])/(float)Y2_MAX_VALUE));
}
g.drawLine(x-1,(localPlotBuffer[0]+5), x-2,(localPlotBuffer[1]+5));
g.drawLine(x,(localPlotBuffer[0]+5), x-1,(localPlotBuffer[1]+5));
}
end--;
}
}
else
{
float temp = SIZE_X;
for(int x=(duration*MAX_NUM_INTERVELL_PER_DAY) ; x > 0 ; x--)
{
float LocalTemp1 = temp;
float LocalTemp2 = (int)(temp-(double)5/(double)duration);
/*Normalise the pixcel positions */
/*Normalise the pixcel positions */
if(duration == 1)
{
if(LocalTemp1>(SIZE_X-3))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-3))
LocalTemp2 = SIZE_X;
}
/*Normalise the pixcel positions */
else if(duration == 2)
{
if(LocalTemp1>(SIZE_X-2))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-2))
LocalTemp2 = SIZE_X;
}
/*Normalise the pixcel positions */
else if(duration == 3)
{
if(LocalTemp1>(SIZE_X-1))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-1))
LocalTemp2 = SIZE_X;
}
/*if data is valid data then plot else ignore*/
if((graphData[0][end]>MIN_ERROR)&&(graphData[0][end-1]<MAX_LOG10_ERROR_COUNT)&&(graphData[0][end-1]>MIN_ERROR)&&(graphData[0][end]<MAX_LOG10_ERROR_COUNT))
{
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[0][end] == 0)
{
localPlotBuffer[0] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[0][end]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[0][end])/(float)Y2_MAX_VALUE));
}
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[0][end-1] == 0)
{
localPlotBuffer[1] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[0][end-1]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[1] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[0][end-1])/(float)Y2_MAX_VALUE));
}
g.drawLine((int)LocalTemp1,(localPlotBuffer[0]+5), (int)LocalTemp2,(localPlotBuffer[1]+5));
}
temp-=(double)5/(double)duration;
end--;
}
}
}
/******************************************************************************
*
* method - plot8
*
* This method uses graphData[7][] global variable and plots series of lines
* in the applet
*
* Inputs :
* g - Graphics object
*****************************************************************************/
void plot8(Graphics g)
{
int end = MAX_DATA_X;
int localPlotBuffer[];
localPlotBuffer = new int[2];
g.setColor(plotColor1);
if(duration > 5)
{
for(int x=(duration*MAX_NUM_INTERVELL_PER_DAY); x > 0 ;x-- )
{
/*if data is valid data then plot else ignore*/
if((graphData[8][end]>MIN_ERROR)&&(graphData[8][end-1]<MAX_LOG10_ERROR_COUNT)&&(graphData[8][end-1]>MIN_ERROR)&&(graphData[8][end]<MAX_LOG10_ERROR_COUNT))
{
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[8][end] == 0)
{
localPlotBuffer[0] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[8][end]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[8][end])/(float)Y2_MAX_VALUE));
}
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[8][end-1]== 0)
{
localPlotBuffer[1] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[8][end-1]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[1] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[8][end-1])/(float)Y2_MAX_VALUE));
}
g.drawLine(x-1,(localPlotBuffer[0]+5), x-2,(localPlotBuffer[1]+5));
g.drawLine(x,(localPlotBuffer[0]+5), x-1,(localPlotBuffer[1]+5));
}
end--;
}
}
else
{
float temp = SIZE_X;
for(int x=(duration*MAX_NUM_INTERVELL_PER_DAY) ; x > 0 ; x--)
{
float LocalTemp1 = temp;
float LocalTemp2 = (int)(temp-(double)5/(double)duration);
/*Normalise the pixcel positions */
if(duration == 1)
{
if(LocalTemp1>(SIZE_X-3))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-3))
LocalTemp2 = SIZE_X;
}
/*Normalise the pixcel positions */
else if(duration == 2)
{
if(LocalTemp1>(SIZE_X-2))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-2))
LocalTemp2 = SIZE_X;
}
/*Normalise the pixcel positions */
else if(duration == 3)
{
if(LocalTemp1>(SIZE_X-1))
LocalTemp1 = SIZE_X;
if(LocalTemp2>(SIZE_X-1))
LocalTemp2 = SIZE_X;
}
/*if data is valid data then plot else ignore*/
if((graphData[8][end]>MIN_ERROR)&&(graphData[8][end-1]<MAX_LOG10_ERROR_COUNT)&&(graphData[8][end-1]>MIN_ERROR)&&(graphData[8][end]<MAX_LOG10_ERROR_COUNT))
{
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[8][end] == 0)
{
localPlotBuffer[0] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[8][end]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[8][end])/(float)Y2_MAX_VALUE));
}
/*if data present is 0, log10(0) is not define so then plot this graph in normal scale */
if(graphData[8][end-1]== 0)
{
localPlotBuffer[1] = (int)((float)(SIZE_Y )*(float)(1 - (float)graphData[8][end-1]/(float)Y1_MAX_VALUE)) ;
}
else
{
localPlotBuffer[1] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graphData[8][end-1])/(float)Y2_MAX_VALUE));
}
g.drawLine((int)LocalTemp1,(localPlotBuffer[0]+5), (int)LocalTemp2,(localPlotBuffer[1]+5));
}
temp-=(double)5/(double)duration;
end--;
}
}
}
/******************************************************************************
*
* method - plot_timeelapsed_east
*
* This method uses graph_data_rf_east global variable and plots series of lines
* in the applet
*****************************************************************************/
void plot_timeelapsed_east(Graphics g)
{
int end = MAX_DATA_X;
int localPlotBuffer[];
int x= 0;
localPlotBuffer = new int[2];
x= (duration*MAX_NUM_INTERVELL_PER_DAY);
g.setColor(plotColor9);
/*if data is valid data then plot else ignore*/
if((graph_data_rf_east>0)&&(graph_data_rf_east<MAX_LOG10_ERROR_COUNT))
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graph_data_rf_east)/(float)Y2_MAX_VALUE));
if(duration>5)
g.drawLine(x-1,SIZE_Y+5, x-2,(localPlotBuffer[0]+5));
else
g.drawLine(SIZE_X,SIZE_Y+5, 474+duration,(localPlotBuffer[0]+5));
}
}/*End for plot_timeelapsed_east() */
/******************************************************************************
*
* method - plot_timeelapsed_west
*
* This method uses graph_data_rf_east global variable and plots series of lines
* in the applet
*****************************************************************************/
void plot_timeelapsed_west(Graphics g)
{
int end = MAX_DATA_X;
int localPlotBuffer[];
int x= 0;
localPlotBuffer = new int[2];
x= (duration*MAX_NUM_INTERVELL_PER_DAY);
g.setColor(plotColor9);
/*if data is valid data then plot else ignore*/
if((graph_data_rf_east>MIN_ERROR)&&(graph_data_rf_east<MAX_LOG10_ERROR_COUNT))
{
localPlotBuffer[0] = (int)((float)(SIZE_Y1 )*(float)(1 - (float)Math.log10(graph_data_rf_west)/(float)Y2_MAX_VALUE));
if(duration>5)
g.drawLine(x-1,SIZE_Y+5, x-2,(localPlotBuffer[0]+5));
else
g.drawLine(SIZE_X,SIZE_Y+5, 474+duration,(localPlotBuffer[0]+5));
}
}
/******************************************************************************
*
* method - getData
*
* This method sends query to CGI to collect data. Then it converts the
* data for applet area then updates global variable.
*
* Inputs :
* serverAddress - server CGI path
*****************************************************************************/
public void getData(String serverAddress)
{
URL addr;
BufferedReader in;
String inputLine;
int count = 0;
int i=0,j = 0;
try
{
addr = new URL(serverAddress);
URLConnection connection = addr.openConnection();
in = new BufferedReader(new InputStreamReader(addr.openStream()));
/*Read data for first link */
for( j=0; j<MAX_DISP_PARMS_STD; j++)
{
for( i=0; i<MAX_DATA_X+1; i++)
{
inputLine = in.readLine();
graphData[j][i] = Integer.parseInt(inputLine);
}
}
for( i=0; i<MAX_DATA_X; i++)
{
inputLine = in.readLine();
graphData[7][i] = Integer.parseInt(inputLine);
if(graphData[7][i] == 1)
graphData[7][i] = 10;
}
inputLine = in.readLine();
graph_data_rf_east = Integer.parseInt(inputLine);
/*Reading data for second link */
if(Integer.parseInt(getParameter("mode")) == 2)
{
for( j=8; j<15; j++)
{
for( i=0; i<MAX_DATA_X+1; i++)
{
inputLine = in.readLine();
graphData[j][i] = Integer.parseInt(inputLine);
}
}
for( i=0; i<MAX_DATA_X; i++)
{
inputLine = in.readLine();
graphData[15][i] = Integer.parseInt(inputLine);
if(graphData[15][i] == 1)
graphData[15][i] = 10;
}
inputLine = in.readLine();
graph_data_rf_west = Integer.parseInt(inputLine);
}
in.close();
}catch (Exception e) { System.out.println("Server Data Read Error:"+e); }
}
/******************************************************************************
*
* method - itemStateChanged
*
* This method will be called whenever event occured on this choice.
* it read the current status and changes scale accordingly.
* *****************************************************************************/
public void itemStateChanged(ItemEvent evt)
{
if( evt.getSource() == timeChoice )
duration = Integer.parseInt(timeChoice.getSelectedItem());
else
viewMode = modeChoice.getSelectedIndex()+1;
repaint();
}
/******************************************************************************
*
* method - mouseMoved
*
* This method will be called whenever mouse cursor is moved over the
* applet. Depending on the cursor position, it will display Actual
* X and Y values of the graph.
*****************************************************************************/
public void mouseMoved(MouseEvent evt)
{
int x = evt.getX()-xOffset;
int y = evt.getY()-yOffset-5;
int a = evt.getX();
int b = evt.getY();
int duration = Integer.parseInt(timeChoice.getSelectedItem());
if( (x>=0) && (x<=SIZE_X) && (y>=0) && (y<=SIZE_Y) )
{
valueLabel1.setText("X ");
valueLabel2.setText("Y1 ");
valueLabel3.setText("Y2 ");
try
{
int x_max_value = ((SIZE_X*duration)/5);
int x1 = (int)((float)((float)((float)(SIZE_X*duration))/5) * ((float)((float)(SIZE_X - x))/((float)SIZE_X)));
/*For Durations less than 16 scale starts with 1*/
int y1 = (int)((float)Y1_MAX_VALUE * (((float)SIZE_Y - (float)y)/((float)SIZE_Y)));
int y2 = (int) Math.pow(10,((float)(3 * ((float)(1 - (float)y/((float)SIZE_Y1))))));
valueLabel1.setText("X="+x1);
valueLabel2.setText("X pix="+a);
valueLabel3.setText("Y="+y1);
valueLabel4.setText("Y pix="+b);
valueLabel5.setText("Y2="+y2);
}
catch(Exception e) {System.out.println("Mouse Moved Error" + e);}
}
else
{
valueLabel1.setText(" ");
valueLabel2.setText(" ");
valueLabel3.setText(" ");
}
}
public void mouseDragged(MouseEvent evt) { }
}

There are many ways to do this. Here are two:
You can simply scale the values: Multiply every coordinate with the zoom factor.
Use Java2D and AffineTransform:
AffineTransform transformer = new AffineTransform();
transformer.scale(zoom, zoom);
Graphics2D g2d = (Graphics2D)g;
g2d.setTransform(transformer);
// draw to g2d.
[EDIT] If you want to do everything yourself, see this page for a refresh of basic linear algebra: 2D Transformations
Don't mind the 3D example at the top; the rest of the page is about 2D.

I used JCC kit for my target platform and it's less than 100kb library. You need to understand the library and after that you can play without worrying about size. :)
Good library to use in embedded systems whether size is always the issue. it has inbuilt function o transform coordinates into screen coordinates and vice-verse.

resize required to view images in java applet

I'm working with java images for the first time and having a problem viewing them when the applet loads. If I resize the window they display fine. I feel like this is a common first-timer error. Has anyone else encountered this? Any idea what the fix could be? What I believe to be the pertinent parts of the code are listed below. Thanks for any and all help with this...
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;
import java.util.*;
public class example extends JApplet implements Runnable
{
boolean updating;
Thread thread;
private int width, height;
Table aTable; //used to create and store values
private AudioClip[] sounds = new AudioClip[4]; //array to hold audio clips
private int counter = 0; //counter for audio clip array
private Image GameImage;
private Graphics GameGraphics;
public example() //set up applet gui
{
this.resize(new Dimension(600, 500));
//setup table
aTable = new Table(50, 50, 50, 50, 16, 16, getImage("images/FLY.gif", Color.white),
getImage("images/FlySwatter.gif", Color.white)); //Table must be square or flyswatter wont move straight
//add cordTxtFlds to bottom of screen
//this.add(cordTxtFlds, BorderLayout.SOUTH);
super.resize(800, 600);
repaint();
}
public void init()
{
width = getSize().width;
height = getSize().height;
GameImage = createImage(width, height);
GameGraphics = GameImage.getGraphics();
// Automatic in some systems, not in others
GameGraphics.setColor(Color.black);
repaint();
validate();
//show the greeting
ImageIcon icon = new ImageIcon("images/FLY.gif",
"a fly");
repaint();
validate();
}
/** Description of paint(Graphics g)
*
* Function draws table and sets the table color
* #param g graphics object used to draw table
* #return void
*/
public void paint(Graphics g)
{
GameGraphics.clearRect(0, 0, getWidth(), getHeight());
aTable.draw(GameGraphics);
g.drawImage(GameImage, 0, 0, this);
}
public void update(Graphics g)
{
paint(g);
validate();
}
public void start()
{
thread = new Thread(this);
thread.start();
}
public void stop()
{
updating = false;
}
public void run()
{
while(updating)
{
aTable.update();
}
}
//returns a transparent image.
//color is made transparent
private Image getImage(String imgPath, final Color color)
{
Image img = Toolkit.getDefaultToolkit().getImage(imgPath);
ImageFilter filter = new RGBImageFilter() {
// the color we are looking for... Alpha bits are set to opaque
public int markerRGB = color.getRGB() | 0xFFFFFF;
public final int filterRGB(int x, int y, int rgb) {
if ( ( rgb | 0xFF000000 ) == markerRGB ) {
// Mark the alpha bits as zero - transparent
return 0x00FFFFFF & rgb;
}
else {
// nothing to do
return rgb;
}
}
};
ImageProducer ip = new FilteredImageSource(img.getSource(), filter);
img = Toolkit.getDefaultToolkit().createImage(ip);
return img;
}
}
and the class which handles the drawing (in drawValues())
import java.awt.*;
import java.util.Random;
public class Table extends Panel
{
private char[][]values = new char[10][10]; //probably better to use array of integer values(0 or 1)
private Point[]coordLoc;// = new Point[100]; //stores the x & y coordinates of points on the grid
private boolean[]itemMarker; //stores the truth value of wether or not an item
// is located at the coresponding point in cordLoc array
private int [][]coords;// = new int [100][2];
Image itemImg; // stores the item image
private int Rows; // stores number of rows
private int Columns; // stores number of columns
private int BoxWidth ; // stores the width of a box
private int BoxHeight; // stores the height of a box
public Point Pos = new Point(); // creates a new point to draw from
private int tableHeight; // stores the height of the table
private int tableWidth; // stores the width of the table
private int numOfGridLocs;
/** Description of public Table( x, y, width, height, col, rows, X, O)
*
* Constructor function
* #param x contains an x-coordinate of the table
* #param y contains a y-coordinate of the table
* #param width contains the width of a box in the table
* #param height contains the height of a box in the table
* #param col contains the number of columns in the table
* #param rows contains the number of rows in the table
* #param itemImg contains the "target" image ie: ant, fly, ... unicorn
* #return none
*/
public Table(int x, int y, int width, int height, int col, int rows, Image itemImg, Image swatterImg)
{
/*set values*/
numOfGridLocs = (col - 1) * (rows - 1);
//initialize arrays
coordLoc = new Point[numOfGridLocs];
for(int i = 0; i < numOfGridLocs; i++)
coordLoc[i] = new Point();
Rows = rows;
Columns = col;
BoxWidth = width;
BoxHeight = height;
Pos.x = x;
Pos.y = y;
this.itemImg = itemImg;
tableHeight = Rows*BoxHeight;
tableWidth = Columns*BoxWidth;
itemMarker = new boolean[numOfGridLocs];
coords = new int [numOfGridLocs][2];
this.setValues();
mapGrid();
}
/** Description of draw(Graphics g)
*
* Function draws the lines used in the table
* #param g object used to draw the table
* #return none
*/
public void draw(Graphics g)
{
Graphics2D g2=(Graphics2D)g;
//draw flyswatter
drawValues(g2); //draw values
//draw vertical table lines
for (int i = 0 ; i <= Columns ; i++)
{
//make center line thicker
if(i == Rows/2)
g2.setStroke(new BasicStroke(2));
else
g2.setStroke(new BasicStroke(1));
g2.drawLine(i*BoxWidth + Pos.x, Pos.y, i*BoxWidth + Pos.x, tableHeight+Pos.y);
}
//draw horizontal table line
for(int i = 0 ; i <= Rows ; i++)
{
//make center line thicker
if(i == Rows/2)
g2.setStroke(new BasicStroke(2));
else
g2.setStroke(new BasicStroke(1));
g2.drawLine(Pos.x, i*BoxHeight + Pos.y, tableWidth+Pos.x, i*BoxHeight + Pos.y);
}
drawLables(g);
}
/** Description of drawLables(Graphics g)
*
* Function draws the Lables of the Table
* #param g object used to draw the table
* #return none
*/
private void drawLables(Graphics g)
{
String Lable;
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
Font font = new Font("Serif", Font.PLAIN, 10);
g2.setFont(font);
int xLabel = this.Columns/2 * -1;
int yLabel = this.Rows/2;
//draw Row lables
for (int i = 0 ; i <= Rows ; i++)
{
Lable = "" + yLabel;
g2.drawString(Lable, Pos.x - 25, Pos.y + BoxHeight*i);
yLabel--;
}
//draw Column lables
for (int i = 0 ; i <= Columns ; i++)
{
Lable = "" + xLabel;
g2.drawString(Lable, Pos.x + BoxWidth*i - 5, Pos.y - 20 );
xLabel++;
}
}
/** Description of randomChangeFunc()
*
* Function randomly determines which table value to change
* #param none
* #return void
*/
public int getX(int XCordinate)
{
int x = XCordinate+Columns/2;
if(x < 0) x *= -1; //x must be positive
x *= BoxWidth;
x += Pos.x;
return x-BoxWidth/2;
}
//returns Position of Y-cordinate
public int getY(int YCordinate)
{
int y = YCordinate -Rows/2;
if (y < 0) y *= -1; //y must be positive
y *= BoxHeight;
y += Pos.y;
return y-BoxHeight/2;
}
/** Description of getValue( col, row )
*
* Function draws the lines used in the table
* #param col contains a column coordinate
* #param row contains a row coordinate
* #return returns table coordinates
*/
public char getValue(int col, int row)
{
return values[row][col];
}
/** Description of isDrawable( x, y )
*
* Function returns true if (x,y) is a point in the table
* #param x contains a table column
* #param y contains a table row
* #return boolean if (x,y) is a point in the table
*/
public boolean isDrawable(int x, int y)
{
if((this.getRow(y)!=-1)||(this.getColumn(x)!=-1))
return true;
else
return false;
}
private void drawValues(Graphics g)
{
for(int i = 0; i < numOfGridLocs; i++)
if(itemMarker[i])
g.drawImage(itemImg,coordLoc[i].x+1, coordLoc[i].y+1, BoxWidth-1, BoxHeight-1, null);
g.setColor(Color.black); // set color of table to black
}
//sets the randomized boolean values in itemMarker array
private void setValues()
{
double probOfItem = .25;
for(int count = 0; count < numOfGridLocs; count++){
itemMarker[count] = randomBool(probOfItem);
if(itemMarker[count])
System.out.println("true");
else
System.out.println("false");
}
}
//returns random boolean value, p is prob of 'true'
private boolean randomBool(double p)
{
return (Math.random() < p);
}
public int getColumn(int x)
{
x += (BoxWidth/2); //aTable.getX/Y returns in the middle of squares not at upper left point
int offsetx=0;
for (int i = 0 ; i < Columns*2 ; i++)
{
offsetx = i*BoxWidth;
if((x>=Pos.x+offsetx)&& (x<Pos.x+offsetx+BoxWidth))
return i-Columns;
}
return -100;
}
public int getRow(int y)
{
int offsety=0;
y += (BoxHeight/2); //aTable.getX/Y returns in the middle of squares not at upper left point
for (int i = 0 ; i < Rows*2 ; i++) {
offsety = i * BoxHeight;
if((y >= (offsety+Pos.y))&& (y < (offsety+BoxHeight+Pos.y)))
{
return ((i)*-1)+Rows;
}
}
return -100;
}
public boolean isValidGuess(int x, int y)
{
if ((x > Columns/2) || (x < Columns/2*-1) || (y > Rows/2) || (y < Rows/2*-1))
return false;
return true;
}
/** Description of randomChangeFunc()
*
* Function randomly determines which table value to change
* #param none
* #return void
*/
public void randomChangeFunc()
{
//get random row and column
Random rand=new Random();
int randRow = rand.nextInt(Rows); // gets and holds a random column
int randCol = rand.nextInt(Columns); // gets and holds a random column
System.out.println("randRow = " + randRow + " randCol = " + randCol);
if(values[randRow][randCol] == 'X')
values[randRow][randCol] = 'O';
else if(values[randRow][randCol] == 'O')
values[randRow][randCol] = 'X';
else
System.out.println("ERROR SWAPPING SQUARE VALUE"); // error message
}
private void mapGrid() //set values for coordLoc array
{
//set counter variables
int count = 0;
int index = 0;
//loop through all points, assigning them to the coordLoc array
for (int r=0; r < Rows-1; r++)
for (int c=0; c < Columns-1; c++) {
//the width/height / 2 places the points on grid line intersections, not the boxes they create
coordLoc[count].x = Pos.x + (BoxWidth) * c + (BoxWidth/2); // record x-point
coordLoc[count].y = Pos.y + (BoxHeight) * r + (BoxHeight/2); // record y-point
System.out.println(coordLoc[count].getX() + ", " + coordLoc[count].getY());
count++;
} //end inner for
//set positive x coord values for coords array
int y_axisBeginingIndex = (Rows - 2)/2;
for(int greaterIndex = 0; greaterIndex < ((Rows) / 2); greaterIndex++){
for(int minorIndex = 0; minorIndex < (Rows - 1); minorIndex++){
index = y_axisBeginingIndex + greaterIndex + ((Rows - 1) * minorIndex);
coords[index][0] = greaterIndex;
}
}
//set negative x coord values for coords array
for(int greaterIndex = -1; greaterIndex > (0-((Rows) / 2)); greaterIndex--){
for(int minorIndex = 0; minorIndex < (Rows - 1); minorIndex++){
index = y_axisBeginingIndex + greaterIndex + ((Rows - 1) * minorIndex);
coords[index][0] = greaterIndex;
}
}
//set positive y values for coords array
int x_axisBeginingIndex = (Rows - 1) * ((Rows / 2) - 1);
for(int greaterIndex = 0; greaterIndex < ((Rows) / 2); greaterIndex++){
for(int minorIndex = 0; minorIndex < (Rows - 1); minorIndex++){
index = x_axisBeginingIndex + minorIndex;
coords[index][1] = greaterIndex;
}
x_axisBeginingIndex -= (Rows - 1);
}
//set negative y values for coords array
x_axisBeginingIndex = (Rows - 1) * ((Rows / 2) - 1) + (Rows - 1);
for(int greaterIndex = -1; greaterIndex > (0-((Rows) / 2)); greaterIndex--){
for(int minorIndex = 0; minorIndex < (Rows - 1); minorIndex++){
index = x_axisBeginingIndex + minorIndex;
coords[index][1] = greaterIndex;
}
x_axisBeginingIndex += (Rows - 1);
}
//print out the x and y coords
for(int i = 0; i < numOfGridLocs; i++){
System.out.println("[" + i + "] -> x = " + coords[i][0] + " y = " + coords[i][1]);
}
}
public boolean thereIsAnItemAt(int index){
return itemMarker[index];
}
public boolean bugsLeft(){
boolean thereAreBugsLeft = false;
for(int i = 0; i < numOfGridLocs; i++)
if(itemMarker[i])
thereAreBugsLeft = true;
return thereAreBugsLeft;
}
void update()
{
this.repaint();
}
}
Been stumped on this for weeks. Thanks again...

What I believe to be the pertinent
parts of the code are listed below.
By definition when you have a problem you don't know what part of the code is (or isn't) relevant. That is why you need to post a SSCCE that demonstrates the problem so we can see what you are doing.
The fact that is work "after" a resize means the problem is not with the painting. The problem could be that the images aren't loaded in which case you should be using:
drawImage(...., this);
The "this" instead of "null" notifies the panel to repaint the image when the image gets fully loaded.
Or maybe, you added the panel to the frame after the frame was visible and forgot to use
panel.revalidate().
By resizing the frame you force a revalidation.
The point is we are guessing. So save us time and post a SSCCE next time.

Sorry still too much code.
You need to read the article on Painting in AWT and Swing. Your code is a mixture of both.
Basically, as you where told in your last posting custom painting is done by overriding the paintComponent(...) method of JPanel. So you do the custom painting and then add the JPanel to the JApplet. I gave you a link to the Swing tutorial in your last posting and it also contains a section on how to write an Applet.
You should be extending JPanel, not Panel.
Also, you should NOT be overriding the paint() and upated() method of JApplet, this is old AWT code and should NOT be used with Swing.
Read the article and fix the problems first.

The answer is changing the draw() method in the class that extends JPanel to paintComponent() and switching the last parameter in the call to drawImage() to 'this' instead of 'null'. Worked instantly and perfectly!