Hi i am a beginner in java, here I have my program, however, when I try resizing the panel my text just disappears?
Moreover, how can i draw a thick green line under my text which will stay under the text even when resizing, I am very clueless?
import javax.swing.*;
import java.awt.*;
import java.awt.geom.AffineTransform;
public class Groovy
{
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame= new JFrame("Shearing Word Demo");
frame.setResizable(true);
frame.setSize(new Dimension(500,250));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Toolkit it=Toolkit.getDefaultToolkit();
Dimension d=it.getScreenSize();
int w=frame.getWidth(), h=frame.getHeight();
frame.setLocation(d.width/2-w/2, d.height/2-h/2);
frame.add(new JComponent(){
#Override public void paintComponent(Graphics g){
Graphics2D g2=(Graphics2D) g;
g2.setColor(Color.magenta);
g2.setFont(new Font("Comic Sans MS",Font.BOLD,44));
g2.drawString("Feeling Groovy!", 110,125 );
}
});
frame.setVisible(true);
}
});
}
}
how can i draw a thick green line under my text which will stay under the text even when resizing, I
If you do custom painting then the basic steps you need to follow would be something like:
get the FontMetrics of the Graphics object using the getFonTMetrics() method
get the rectangle of text using the getStringBounds(...) method
use the setStroke(...) method of the Graphics2D object to set the thickness of the line to paint
use the drawLine(...) method Graphics2D object to paint the line based on the location of the text and the information of the Rectangle from the string bounds
An easier solution for displaying text is to use a JLabel. Then you can set the Border of the label. Read the section from the Swing tutorial on How to Use Borders for more information.
Note when doing custom painting with a JComponent you are also responsible for clearing the background of the component. So the first painting in the method should be:
g2.setColor( getBackground() );
g2.fillRect(0, 0, getWidth(), getHeight());
Most people use a JPanel for custom painting then you can just use:
super.paintComponent(g);
to make sure the background is cleared.
Related
I'm making a game and I want to add a JTextField to a JPanel that has Paint Component. I repaint the JPanel every 16 milliseconds.
I add() the textfield to the panel but it show up only for a single frame when i click on it.
Then I tried to repaint() the textfield but now it is flashing.
public class Screen extends JPanel {
public Screen() {
JTextField txt = new JTextField();
txt.setBounds(10, 10, 300, 50);
this.add(txt);
}
#Override
public void paint(Graphics g) {
Graphics2D g2D = (Graphics2D) g;
g2D.setColor(Color.BLACK);
g2D.fillRect(0, 0, this.getWidth(), this.getHeight());
g2D.setColor(Color.WHITE);
g2D.fillRect(0, 0, this.getWidth(), 20);
txt.repaint();
}
}
I want to show the textfield on the top of the panel
JTextField txt = new JTextField();
When you create a JTextField you should use code like:
JTextField txt = new JTextField(10);
Now the text field can calculate its own preferred size.
//txt.setBounds(10, 10, 300, 50);
Don't use setBounds() to give a component a size. Again each Swing component is responsible for determining its own preferred size. Then the layout manager will set the size/location of the component on the panel.
//public void paint(Graphics g) {
public void paintComponent(Graphics g)
{
super.paintComponent(g);
// add custom painting here
}
Don't override paint(). Custom painting is done by overriding the paintComponent() method. And the first statement in the method should be super.paintComopnent(g)
//g2D.setColor(Color.BLACK);
//g2D.fillRect(0, 0, this.getWidth(), this.getHeight());
Don't paint the background of the panel. That is the job of the panel and that is why you need to super.paintComponent(), to make sure the background is painted.
Then in the constructor of your JPanel class you simply use setBackground( Color.BLACK )
//txt.repaint();
Don't ever invoke repaint() on any component in a painting method.
Read the section from the Swing tutorial on Custom Painting for working examples to get you started. Use the demo code as the starting point for you program. Then you simply add a JTextField to the panel, so it will be a single line of code that is needed to display the text field.
It seems like you want to have a JTextField on a black panel. You don't need to set the colour of the panel every time in paint() method. Instead add this to the constructor:
public Screen() {
setOpaque(true);
setBackground(Color.BLACK);
//...
}
and remove paint() method.
Also, if you want to use absolute positioning with setBounds() method then you should set the layout to null setLayout(null) in constructor. If you use absolute positioning you will also need to specify the size of the panel explicitly. However, I would still suggest you use a layout manager that takes care of panel sizing as well.
See this post for more information about absolute positioning.
I have the following program. It is supposed to print red text on a green ground. When the program opens, I only see the green background but not the red text on it. Once the window is resized and by this recalculated, the red text appears.
It works properly if I use a JPanel within the window and add a component there. If the colors are set in paintComponent then, everything works fine.
So where is the problem, if I draw on the JFrame directly. Am I missing a first "update" or something? It looks like there is some information missing on first draw of the window (the additional text) of which the program only becomes aware once the window is recalculated and redrawn.
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;
public class PaintAWT extends JFrame {
PaintAWT() {
this.setSize(600, 400);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setVisible(true);
}
#Override
public void paint(Graphics g) {
super.paint(g);
// Set background color:
// If you don't paint the background, one can see the red text.
// If I use setBackground I only see a green window, until it is
// resized, then the red text appears on green ground
this.getContentPane().setBackground(new Color(0,255,0));
// Set color of text
g.setColor(new Color(255,0,0));
// Paint string
g.drawString("Test", 50, 50);
}
public static void main(String[] args) {
new PaintAWT();
}
}
You should NOT be setting properties of a component in a painting method. Painting methods are for painting only. Don't use setBackground().
You should be setting the background of the content pane when you create the frame.
Whenever you do custom painting you should also be overriding the getPreferredSize() method to return the size of the component.
You should also not be extending JFrame. You only extend a class when you add functionality to the class.
Start by reading the section from the Swing tutorial on Custom Painting fore more information and working examples. The examples will show you how to better structure your code to follow Swing conventions.
You should move setBackground to constructor. Setting of background in paint method is a bad approach.
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class PaintAWT extends JFrame {
PaintAWT() {
this.setSize(600, 400);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Set background color:
// If you don't paint the background, one can see the red text.
// If I use setBackground I only see a green window, until it is
// resized, then the red text appears on green ground
this.getContentPane().setBackground(new Color(0,255,0));
this.setVisible(true);
}
#Override
public void paint(Graphics g) {
super.paint(g);
// Set color of text
g.setColor(new Color(255,0,0));
// Paint string
g.drawString("Test", 50, 50);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new PaintAWT();
}
});
}
}
Helo guys,
my problem is that sometimes if my Rectangle2D gets a big width or height its bottom,left border splits and no longer makes a continous border and if I even make it wider the border goes smaller and smaller, like if there were a limitation of how long a rectangles border can be... It is really confusing and so far I have not found the solution :S I put there a link to a picture so you can see for yourself.
new Rectangle2D.Double(mojrectangle.getUpperleftPointmojRectangle().getX(), mojrectangle.getUpperleftPointmojRectangle().getY(),1000,1000)
repaint();
thanks for your help..
BTW I have the same problem with Arc2D if it gets really big
UPDATE: I removed from the function the setStroke command and now it draws it correctly, but in the future I will need to set the Rectangles stroke so it leaves me sad.
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2=(Graphics2D)g;
//g2.setStroke(stroke);
g2.draw(rectangle);
}
Here I put an example code of my project, please try it with g2.setStroke(selectedstroke)- it wont work, and without it...I hope I explained myself clear .
package com.awtgraphicsdemo;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.JComboBox;
public class AWTgraphicsdemo extends Frame {
final float dash[] = {10.0f};
final float solid[] = {1000.0f}; // these must be in an Array
float lineWidth[]={2.0f,4.0f,6.0f,8.0f,10.0f}; // width of the drawing line
String[] lineWidthString={"2.0","4.0","6.0","8.0","10.0"};
JComboBox strokecombobox=new JComboBox(lineWidthString);
BasicStroke selectedStroke = new BasicStroke(lineWidth[0],BasicStroke.CAP_BUTT,BasicStroke.JOIN_MITER, 10.0f, solid, 0.0f);
public AWTgraphicsdemo(){
super("Java AWT Examples");
prepareGUI();
}
public static void main(String[] args){
AWTgraphicsdemo awtGraphicsDemo = new AWTgraphicsdemo();
awtGraphicsDemo.setVisible(true);
}
private void prepareGUI(){
setSize(400,400);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent windowEvent){
System.exit(0);
}
});
}
#Override
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.setStroke(selectedStroke);
g2.draw (new Rectangle2D.Double(10, 10, 1000, 900));
Font font = new Font("Serif", Font.PLAIN, 24);
g2.setFont(font);
g.drawString("Welcome to TutorialsPoint", 50, 70);
g2.drawString("Rectangle2D.Rectangle", 100, 120);
}
}
Helo again,
I figured out my problem, it was in the properties of stroke,so after some lenght of the compoment the stroke got activated which made changed to the drawn shape.By modifying the strokes solid array I was able the get the result I wanted.
Thank you for your help and suggestions :)
Take Care
Better to:
Not override paint(...) in top level windows (as MadProgrammer states) since this also changes painting of borders and child components -- a dangerous thing to do.
Instead override paintComponent(...) of a JPanel (again as MadProgrammer states) and place that JPanel into your top level window.
Don't set the Stroke of the Graphics object passed into your painting method, but rather a copy of the Graphics object so not to have side effects down the road.
e.g.,
public class MyPanel extends JPanel {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g.create();
g2.setStroke(....);
// do drawing with g2 here
g2.dispose();
}
}
I have a problem with put drawn circle into middle of Frame by using methods getWidth() and getHeight(). I tried something with Image package but no idea where to implement this methods:
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Frame;
import java.awt.Image;
public class Circle extends Frame {
public Circle() {
setSize(400,400);
setLocationRelativeTo(null);
setVisible(true);
}
public Color() {
}
public void paint(Graphics g) {
g.setColor(Color.ORANGE);
g.fillOval(200, 200, 200, 200);
}
public static void main(String[] args) {
Circle c = new Circle();
c.paint(null);
}
}
Then I have to use method setColor(Color) and Color class constructor to make random color of this circle (after every run of this program). I opened Color constructor but there is an error :/
Better to extract all the paint functionality to a JComponent here to take full advantage of Swing's optimized paint model using paintComponent.
The Circle is actually a JFrame. Inside in its constructor, a new component is created which handles the painting of the circle. The Color constructor has been removed as this is invalid syntax.
The circle co-ordinates are start in the top left-hand corner and take the full available width & height for drawing.
Also would recommend using lightweight Swing components over old-style AWT component.
public class Circle extends JFrame {
public Circle() {
setSize(400, 400);
add(new CirclePanel());
setLocationRelativeTo(null);
setVisible(true);
}
public static void main(String[] args) {
Circle c = new Circle();
}
}
class CirclePanel extends JComponent {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.ORANGE);
g.fillOval(0, 0, getWidth(), getHeight());
}
}
See: Painting in AWT and Swing
Simply call getWidth() and getHeight() from within the paint(...) method and use the results returned for your fillOval(...) parameters.
But having said that, it's a better idea to draw in a Canvas that is added to the Frame. And having said that, it's much better still to draw in the paintComponent(...) method of a JPanel that is added to the contentPane of a JFrame in a Swing application.
I created a new JApplet form in NetBeans:
public class UI extends javax.swing.JApplet {
//generated code...
}
And a JPanel in design mode named panou:
// Variables declaration - do not modify
private javax.swing.JPanel panou;
How do I get to draw a line on panou? I've been searching for this for 5 hours now so a code snippet and where to place it would be great. Using Graphics2D preferably.
Go to design mode
Right Click on the panel "panou"
Click "Costumize code"
In the dialog select in the first combobox "costum creation"
add after = new javax.swing.JPanel() this, so you see this:
panou = new javax.swing.JPanel(){
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g); // Do the original draw
g.drawLine(10, 10, 60, 60); // Write here your coordinates
}
};
Make sure you import java.awt.Graphics.
The line that you will see is always one pixel thick. You can make it more "line" by doing the following:
Create this method:
public static final void setAntiAliasing(Graphics g, boolean yesno)
{
Object obj = yesno ? RenderingHints.VALUE_ANTIALIAS_ON
: RenderingHints.VALUE_ANTIALIAS_OFF;
((Graphics2D) g).setRenderingHint(RenderingHints.KEY_ANTIALIASING, obj);
}
And add after super.paintComponent(g); (in your costum creation) this:
setAntiAlias(g, true);
Edit:
What you are doing wrong is: you paint the line once (by creating the frame).
When you paint the line the frame is also invisible. The first draw is happening when the frame becomes visible. The frame will be Repainted, so everything from the previous paint will disappear.
Always you resize the frame, everything will be repainted. So you have to make sure each time the panel is painted, the line also is painted.
To do custom painting in a JPanel, one would need to make a subclass of a JPanel, and then overload the paintComponent method:
class MyPanel extends JPanel {
public void paintComponent(Graphics g) {
// Perform custom painting here.
}
}
In the example above, the MyPanel class is a subclass of JPanel, which will perform whatever custom painting is written in the paintComponent method.
For more information on how to do custom painting in Swing components, Lesson: Performing Custom Painting from The Java Tutorials have some examples.
If one wants to do painting with Java2D (i.e. using Graphics2D) then one could do some painting on a BufferedImage first, then draw the contents of the BufferedImage onto the JPanel:
class MyPanel extends JPanel {
BufferedImage image;
public MyPanel() {
Graphics2D g = image.createGraphics();
// Do Java2D painting onto the BufferedImage.
}
public void paintComponent(Graphics g) {
// Draw the contents of the BufferedImage onto the panel.
g.drawImage(image, 0, 0, null);
}
}
Further reading:
Painting in AWT and Swing
Trail: 2D Graphics