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Custom java BarChart Scaling issues

i have been trying to make a custom BarChart in Java for a school project but for some reason it has some weird Scaling issues. Here is the Code.
static class BarChart extends JPanel
{
private int[] chartValues;
private String[] chartLabels;
private String chartTitle;
public BarChart(String title,int[] values,String[]labels)
{
this.chartTitle = title;
this.chartValues = values;
this.chartLabels = labels;
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Random r = new Random();
if(this.chartValues == null || this.chartValues.length==0)
{
return;
}
Dimension chartDimension = this.getSize();
int panelWidth = chartDimension.width;
int panelHeight = chartDimension.height;
int barWidth = panelWidth / this.chartValues.length;
int maxValue = this.chartValues[0];
int minValue = this.chartValues[0];
for(int tempValue:this.chartValues)
{
maxValue = Math.max(maxValue, tempValue);
minValue = Math.min(minValue, tempValue);
}
Font titleFont = new Font("Book Antiqua", Font.BOLD, 15);
FontMetrics titleFontMetrics = g.getFontMetrics(titleFont);
Font labelFont = new Font("Book Antiqua", Font.PLAIN, 14);
FontMetrics labelFontMetrics = g.getFontMetrics(labelFont);
int titleWidth = titleFontMetrics.stringWidth(this.chartTitle);
int stringHeight = titleFontMetrics.getAscent();
int stringWidth = (panelWidth - titleWidth) / 2;
g.setFont(titleFont);
g.drawString(this.chartTitle, stringWidth, stringHeight);
int top = titleFontMetrics.getHeight();
int bottom = labelFontMetrics.getHeight();
if(maxValue==minValue)
{
return;
}
double barScale = (panelHeight - top - bottom)/(maxValue - minValue);
stringHeight = panelHeight - labelFontMetrics.getDescent();
int xPos = 5;
g.setFont(labelFont);
for(int i=0; i<this.chartValues.length;i++)
{
int tempValue = this.chartValues[i];
int barHeight = (int) ( (double)tempValue * barScale);
int yPos = top;
if(tempValue>=0)
{
yPos += (int) ((maxValue - tempValue)* barScale);
}
else
{
yPos += (int) (maxValue * barScale);
barHeight = - barHeight;
}
g.setColor(new Color(r.nextInt(255),r.nextInt(255),r.nextInt(255)));
g.fillRect(xPos, yPos, barWidth, barHeight);
g.setColor(Color.BLUE);
g.drawRect(xPos, yPos, barWidth, barHeight);
xPos += barWidth;
}
g.setColor(Color.BLACK);
g.drawString("Xronos", stringWidth, stringHeight);
}
}
But when i run this with my main with values {1,5,4,7,120} i get this depending on the screen resolution.
Wrong image (the height between bars and label is too much).
Correct height between bars and label. I really apreciate any help. And sorry if this stupid is a question.

you are doing integer division here:
double barScale = (panelHeight - top - bottom)/(maxValue - minValue);
try
double barScale = (panelHeight - top - bottom)/(double)(maxValue - minValue);
instead

Why are JLabels being painted over higher components in a JLayeredPane?

I have a JLayeredPane that has four layers:
JPanel set as a background
Grid of JPanels each holding a JLabel
Grid of JPanels each holding several JLabels that are only set to visible if the label in the panel below is empty
A custom component that is only used to override the paintComponent() method to draw over everything below
For some reason if I change the background colour of the labels in layer 3 and then draw to layer 4, the labels in layer 3 are painted over the graphics painted in level 4. I have tried to set ignoreRepaint() on various components as well as playing around with the opacity and code structure but all to no avail.
Does anyone know how to prevent this from happening?
I won't attach the source code because the project is quite large but I've attached an example that runs as a stand alone program and demonstrates my problem when you hit the "add arrow" button.
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Polygon;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;
import javax.swing.border.LineBorder;
public class GraphicsTest {
#SuppressWarnings("serial")
class Painter extends JComponent {
public Painter(int x, int y) {
setBounds(0, 0, x, y);
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
}
}
private static final int CELL_SIZE = 40;
private static final int NOTE_SIZE = 20;
private JFrame frame;
private static JButton test;
private static JButton clear;
private static JLayeredPane pane = new JLayeredPane();
private static JPanel back = new JPanel();
private static JPanel[][] cellPanels = new JPanel[10][10];
private static JLabel[][] cells = new JLabel[10][10];
private static JPanel[][] notePanels = new JPanel[10][10];
private static JLabel[][][] notes = new JLabel[10][10][4];
private static Painter painter;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
GraphicsTest window = new GraphicsTest();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public GraphicsTest() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setSize(600, 700);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(null);
pane.setBounds(50, 50, 500, 500);
pane.setLayout(null);
frame.getContentPane().add(pane);
back.setBounds(0, 0, 500, 500);
back.setBackground(Color.BLACK);
pane.add(back, new Integer(100));
for (int i = 0; i < 10; i++) {
for (int k = 0; k < 10; k++) {
String text = "";
if ((i % 2) == 1 && (k % 2) == 1) text = (i + k) + "";
cellPanels[i][k] = new JPanel();
cellPanels[i][k].setBounds(k * CELL_SIZE, i * CELL_SIZE, CELL_SIZE, CELL_SIZE);
cellPanels[i][k].setBackground(Color.WHITE);
cellPanels[i][k].setBorder(new LineBorder(Color.BLACK, 1));
cells[i][k] = new JLabel(text);
cells[i][k].setBounds(0, 0, CELL_SIZE, CELL_SIZE);
cells[i][k].setOpaque(false);
cellPanels[i][k].add(cells[i][k]);
pane.add(cellPanels[i][k], new Integer(200));
}
}
boolean display;
for (int i = 0; i < 10; i++) {
for (int k = 0; k < 10; k++) {
if ((i % 2) == 0 && (k % 2) == 0) {
display = true;
} else {
display = false;
}
notePanels[i][k] = new JPanel();
notePanels[i][k].setBounds(k * CELL_SIZE, i * CELL_SIZE, CELL_SIZE, CELL_SIZE);
notePanels[i][k].setBackground(Color.WHITE);
notePanels[i][k].setBorder(new LineBorder(Color.BLACK, 1));
notePanels[i][k].setLayout(null);
for (int m = 0; m < 2; m++) {
for (int p = 0; p < 2; p++) {
notes[i][k][(m * 2) + p] = new JLabel(30 + "");
notes[i][k][(m * 2) + p].setBounds(m * NOTE_SIZE, p * NOTE_SIZE, NOTE_SIZE, NOTE_SIZE);
notes[i][k][(m * 2) + p].setOpaque(true);
notePanels[i][k].add(notes[i][k][(m * 2) + p]);
}
}
if (display) {
notePanels[i][k].setVisible(true);
} else {
notePanels[i][k].setVisible(false);
}
pane.add(notePanels[i][k], new Integer(300));
}
}
painter = new Painter(500, 500);
pane.add(painter, new Integer(400));
test = new JButton("Add Arrow");
test.setBounds(50, 600, 100, 25);
test.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
highlightNotes();
Arrow.drawArrow(painter.getGraphics(), 20, 20, 400, 400, 20, 30, 40, Color.BLACK, Color.GREEN);
}
});
frame.getContentPane().add(test);
clear = new JButton("Clear");
clear.setBounds(175, 600, 100, 25);
clear.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0) {
painter.repaint();
}
});
frame.getContentPane().add(clear);
}
private static void highlightNotes() {
for (int i = 0; i < 10; i++) {
for (int k = 0; k < 10; k++) {
for (int n = 0; n < 4; n++) {
notes[i][k][n].setBackground(Color.BLUE);
}
}
}
}
static class Arrow {
public static void drawArrow(Graphics g, int tailx, int taily, int headx, int heady,
int shaftw, int headw, int headh, Color outline, Color fill) {
if ((shaftw % 2) == 0) {
shaftw--;
}
if ((headw % 2) == 0) {
headw--;
}
if ((headh % 2) == 0) {
headh--;
}
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
double length = Math.sqrt((double) (((headx - tailx) * (headx - tailx))
+ ((heady - taily) * (heady - taily))));
int tailLength = (int) (length - headw) + 1;
double theta = Math.atan2(heady - taily, headx - tailx);
Point point1 = new Point(0, -(shaftw / 2));
point1 = getTransPoint(point1, theta);
point1.x += tailx;
point1.y += taily;
Point point2 = new Point(tailLength, -(shaftw / 2));
point2 = getTransPoint(point2, theta);
point2.x += tailx;
point2.y += taily;
Point point3 = new Point(tailLength, -(headw / 2));
point3 = getTransPoint(point3, theta);
point3.x += tailx;
point3.y += taily;
Point point4 = new Point((int) length, 0);
point4 = getTransPoint(point4, theta);
point4.x += tailx;
point4.y += taily;
Point point5 = new Point(tailLength, (headw / 2));
point5 = getTransPoint(point5, theta);
point5.x += tailx;
point5.y += taily;
Point point6 = new Point(tailLength, (shaftw / 2));
point6 = getTransPoint(point6, theta);
point6.x += tailx;
point6.y += taily;
Point point7 = new Point(0, (shaftw / 2));
point7 = getTransPoint(point7, theta);
point7.x += tailx;
point7.y += taily;
//Create arrow at tail coordinates passed in
Polygon arrow = new Polygon();
arrow.addPoint(point1.x, point1.y);
arrow.addPoint(point2.x, point2.y);
arrow.addPoint(point3.x, point3.y);
arrow.addPoint(point4.x, point4.y);
arrow.addPoint(point5.x, point5.y);
arrow.addPoint(point6.x, point6.y);
arrow.addPoint(point7.x, point7.y);
//Draw and fill the arrow
g2.setColor(fill);
g2.fillPolygon(arrow);
g2.setColor(outline);
g2.drawPolygon(arrow);
}
private static Point getTransPoint(Point point, double theta) {
int x = (int) ((point.x * Math.cos(theta)) - (point.y * Math.sin(theta)));
int y = (int) ((point.y * Math.cos(theta)) + (point.x * Math.sin(theta)));
return new Point(x, y);
}
}
}

Determine if circles intersect

I am working on a project where I have to draw 20 circles with random starting points and random sizes. Then I have to determine if any of the circles intersect. If a circle intersects with another, I have to color that circle green. And if the circle does not intersect with another, the color needs to be red. I have all of the code... I think... but when I run it, I still get some circles that should be green, but are red instead. Here is my code. Any help will be greatly appreciated.
import java.awt.Graphics;
import javax.swing.JPanel;
import java.util.Random;
import javax.swing.JFrame;
import java.awt.*;
public class IntersectingCircles extends JPanel
{
private int[] xAxis = new int [20]; // array to hold x axis points
private int[] yAxis = new int [20]; // array to hold y axis points
private int[] radius = new int [20]; // array to hold radius length
public static void main (String[] args)
{
JFrame frame = new JFrame("Random Circles");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add (new IntersectingCircles());
frame.pack();
frame.setVisible(true);
}
public IntersectingCircles()
{
setPreferredSize(new Dimension(1300, 800)); // set window size
Random random = new Random();
for (int i = 0; i < 20; i++)
{
xAxis[i] = random.nextInt(800) + 100;
yAxis[i] = random.nextInt(500) + 100;
radius[i] = random.nextInt(75) + 10;
}
}
public void paintComponent(Graphics g)
{
for (int i = 0; i < 20; i++)
{
int color = 0;
for (int h = 0; h < 20; h++)
{
if(i < h)
{
double x1 = 0, x2 = 0, y1 = 0, y2 = 0, d = 0;
x1 = (xAxis[i] + radius[i]);
y1 = (yAxis[i] + radius[i]);
x2 = (xAxis[h] + radius[h]);
y2 = (yAxis[h] + radius[h]);
d = (Math.sqrt(((x2 - x1) * (x2 - x1)) + ((y2 - y1)*(y2 - y1))));
if (d > radius[i] + radius[h] || d < (Math.abs(radius[i] - radius[h])))
{
color = 0;
}
else
{
color = 1;
break;
}
}
}
if (color == 0)
{
g.setColor(Color.RED);
g.drawOval(xAxis[i], yAxis[i], radius[i] * 2, radius[i] * 2);
}
else
{
g.setColor(Color.GREEN);
g.drawOval(xAxis[i], yAxis[i], radius[i] * 2, radius[i] * 2);
}
}
}
}

In the inside for loop, you are only comparing circles of i index with circles with h index, but only those with i < h, because of the condition:
for (int h = 0; h < 20; h++)
{
if(i < h)
{
...
So, instead you should compare every i circle with every h circle, except if they are the same. You want instead:
for (int h = 0; h < 20; h++)
{
if(i != h) //note the change here
{
...

How to render colours properly in Java Graphics

I was using this code placed here to generate bar-charts for my datasets. However, the colours were all the same (red in the code), so I decided to generate a colour ramp for this. I wrote the following code:
Color[] getColorRamp(int numColours)
{
Color[] colours = new Color[numColours];
int red_1 = 255;
int green_1 = 0;
int blue_1 = 0;
int red_2 = 0;
int green_2 = 0;
int blue_2 = 255;
int count = 0;
for (float t=0.0f;t<1.0f;t+=1.0/(float)numColours) {
colours[count] = new Color((int)(t*red_2 + (1-t)*red_1),
(int)(t*green_2 + (1-t)*green_1),
(int)(t*blue_2 + (1-t)*blue_1),34);
//System.out.print((int)(t*red_2 + (1-t)*red_1) +",");
//System.out.print((int)(t*green_2 + (1-t)*green_1) +",");
//System.out.println((int)(t*blue_2 + (1-t)*blue_1));
}
return colours;
}
It is here, where the problem starts. Only the first colour (pretty light blue) get rendered properly. Other colours are rendered as black! You can see that I have put System.out.println to verify the colours generated (commented in the code posted here). I saw that colours were generated as perfect RGB combinations.
The modified barchart function is posted here:
void drawBarChart(Graphics g, double[] values, String[] names, String title)
{
if (values == null || values.length == 0)
return;
double minValue = 0;
double maxValue = 0;
for (int i = 0; i < values.length; i++) {
if (minValue > values[i])
minValue = values[i];
if (maxValue < values[i])
maxValue = values[i];
}
//Graphics2D g = (Graphics2D)gg;
Dimension d = getSize();
int clientWidth = d.width;
int clientHeight = d.height;
int barWidth = clientWidth / values.length;
Font titleFont = new Font("SansSerif", Font.BOLD, 20);
FontMetrics titleFontMetrics = g.getFontMetrics(titleFont);
Font labelFont = new Font("SansSerif", Font.PLAIN, 10);
FontMetrics labelFontMetrics = g.getFontMetrics(labelFont);
int titleWidth = titleFontMetrics.stringWidth(title);
int y = titleFontMetrics.getAscent();
int x = (clientWidth - titleWidth) / 2;
g.setFont(titleFont);
g.drawString(title, x, y);
int top = titleFontMetrics.getHeight();
int bottom = labelFontMetrics.getHeight();
if (maxValue == minValue)
return;
double scale = (clientHeight - top - bottom) / (maxValue - minValue);
y = clientHeight - labelFontMetrics.getDescent();
g.setFont(labelFont);
Color[] colours = getColorRamp(values.length);
for (int i = 0; i < values.length; i++) {
int valueX = i * barWidth + 1;
int valueY = top;
int height = (int) (values[i] * scale);
if (values[i] >= 0)
valueY += (int) ((maxValue - values[i]) * scale);
else {
valueY += (int) (maxValue * scale);
height = -height;
}
g.setColor(colours[i]);
g.fillRect(valueX, valueY, barWidth - 2, height);
g.setColor(Color.black);
g.drawRect(valueX, valueY, barWidth - 2, height);
int labelWidth = labelFontMetrics.stringWidth(names[i]);
x = i * barWidth + (barWidth - labelWidth) / 2;
g.drawString(names[i], x, y);
}
//paintComponent(g);
}
I wish to know, what mistake I am making!

You're probably going to hit yourself on the head now. The reason it fails is that you forget to increase the variable count after setting the first colour, so you're constantly overwriting the first element of the Color array, and leaving all the other values in the array as their initial default (null).
Fixed code:
for (float t=0.0f;t<1.0f;t+=1.0/(float)numColours) {
colours[count++] = new Color((int)(t*red_2 + (1-t)*red_1),
(int)(t*green_2 + (1-t)*green_1),
(int)(t*blue_2 + (1-t)*blue_1),34);
}
(Notice the colours[count++])

Need to edit swing GUI code for bar chart

I wanted to make a bar chart using java and Swing. I had a look at the code at the link below -
http://www.java2s.com/Code/Java/2D-Graphics-GUI/Simplebarchart.htm
I want to increase the space between bars in this chart. How do I do it?
The code -
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class ChartPanel extends JPanel {
private double[] values;
private String[] names;
private String title;
public ChartPanel(double[] v, String[] n, String t) {
names = n;
values = v;
title = t;
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (values == null || values.length == 0)
return;
double minValue = 0;
double maxValue = 0;
for (int i = 0; i < values.length; i++) {
if (minValue > values[i])
minValue = values[i];
if (maxValue < values[i])
maxValue = values[i];
}
Dimension d = getSize();
int clientWidth = d.width;
int clientHeight = d.height;
int barWidth = clientWidth / values.length;
Font titleFont = new Font("SansSerif", Font.BOLD, 20);
FontMetrics titleFontMetrics = g.getFontMetrics(titleFont);
Font labelFont = new Font("SansSerif", Font.PLAIN, 10);
FontMetrics labelFontMetrics = g.getFontMetrics(labelFont);
int titleWidth = titleFontMetrics.stringWidth(title);
int y = titleFontMetrics.getAscent();
int x = (clientWidth - titleWidth) / 2;
g.setFont(titleFont);
g.drawString(title, x, y);
int top = titleFontMetrics.getHeight();
int bottom = labelFontMetrics.getHeight();
if (maxValue == minValue)
return;
double scale = (clientHeight - top - bottom) / (maxValue - minValue);
y = clientHeight - labelFontMetrics.getDescent();
g.setFont(labelFont);
for (int i = 0; i < values.length; i++) {
int valueX = i * barWidth + 1;
int valueY = top;
int height = (int) (values[i] * scale);
if (values[i] >= 0)
valueY += (int) ((maxValue - values[i]) * scale);
else {
valueY += (int) (maxValue * scale);
height = -height;
}
g.setColor(Color.red);
g.fillRect(valueX, valueY, barWidth - 2, height);
g.setColor(Color.black);
g.drawRect(valueX, valueY, barWidth - 2, height);
int labelWidth = labelFontMetrics.stringWidth(names[i]);
x = i * barWidth + (barWidth - labelWidth) / 2;
g.drawString(names[i], x, y);
}
}
public static void main(String[] argv) {
JFrame f = new JFrame();
f.setSize(400, 300);
double[] values = new double[3];
String[] names = new String[3];
values[0] = 1;
names[0] = "Item 1";
values[1] = 2;
names[1] = "Item 2";
values[2] = 4;
names[2] = "Item 3";
f.getContentPane().add(new ChartPanel(values, names, "title"));
WindowListener wndCloser = new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
};
f.addWindowListener(wndCloser);
f.setVisible(true);
}
}

Here is a line of code where you set X coordinates for the bars:
int valueX = i * barWidth + 1;
To shift each bar further you can change it to:
int valueX = i * (barWidth+20) + 1;
You can declare a separate class level variable for this:
int barSpace = 20;
...//later in paintComponent.
int valueX = i * (barWidth+space) + 1;
UPDATE: Here is a line of code with calculation of barWidth:
int barWidth = clientWidth / values.length;
To fit your chart in client area you can use the following code:
barWidth-= barSpace; //or barWidth-=20;
This way you will take some space from each bar