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Is there a way to generate an icon from Graphics?

Working in Java Swing I would like to be able to dynamically change the icon
of the JFrame as events happen in the code without having any .pngs. Is there any way to draw the image internally and have it then used as the icon, so that I can do something like the below?
public void Icon(Graphics g){
ImageIcon img = g.getImageIcon();
myFrame.setIconImage(img.getImage());
}

Thanks to input from Gilbert Le Blanc, Andrew Thompson I was able to find a way to code this by using buffed image and Graphics2D
public void Icon(){
BufferedImage icon = new BufferedImage(32, 32, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = icon.createGraphics();
generateImage(g);
myFrame.setIconImage(icon);
}
Where generateImage is some function or another to paint the graphics onto g.

Updating an image in Java Swing shows strange behaviour

I want to update an image in Java Swing and tried two different methods of rendering these images.
Define a JLabel and set the icon of it
Override the paintComponent(Graphics g) function in a custom JPanel and call g.drawImage(img, 0, 0, null)
Rendering the first image works as expected in both ways, but if I'm trying to update the image, it doesn't replace but renders one layer above which is a problem, because the images I want to render are semi-transparent, so you can see the others through.
I'm already using the repaint() method.
Method 1
public void setImage(Image img) {
this.backgroundLabel.setIcon(new ImageIcon(img));
this.repaint();
}
Method 2
public void setImage(Image img) {
this.img = img;
this.repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(img, 0, 0, null);
}
I'm thankful for any tips! <3

The first thing line in paintComponent(Graphics g) should be
super.paintComponent(g);
This clears the panel, does any background painting if necessary, and any other support functions from the overridden paintComponent method. Otherwise, you will keep drawing images over the previous ones without first clearing them.

For anyone in the future with the same problem, here is the answer I came up with.
I didn't repainted the full frame, but only the JPanel.
I had to add
frame.repaint();
in setImage().

Java (re)painting mechanism [duplicate]

In java awt or swing when you want to change painting of some component you usually have to override the method paint(Graphics g) (in awt) or paintComponent(Graphics g) (in swing).
This is usually (maybe allways - I'm not sure) done when you are creating the component for example:
JPanel jPanel = new JPanel() {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
//... my implementation of paint, some transfromations, rotation, etc
}
};
Imagine that you have container of components which could for example consists of some JLabels, some JTextFields, some image. Which will be all put on one component.
By container I mean you have some list or map with ids or some similar structure in which are all components you will put on one JFrame.
The question is if I can change the painting method after creating with all of the components which are in this list in the moment when all of them are already created. For example I want do the rotation action (rotate), which is defined in Graphisc2D, with all of them.
So basicaly what I want is that I throught the list of componets I have and say:
"All of you (components) which are in the list will be rotated by some angle". Is that possible? If yes how?
Edit:
This is my not correctly working solution:
graphicalDisplayPanel = new JPanel() {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g2d = (Graphics2D) g;
g2d.rotate(Math.PI, anchorx, anchory);
}
#Override
public void paintChildren(Graphics g) {
super.paintChildren(g);
Graphics2D g2d2 = (Graphics2D) g;
g2d2.rotate(Math.PI, anchorx, anchory);
}
};
JFrame jFrame = JFrame();
// ... setting dimension, position, visible etc for JFrame, it works correctly nonrotated
jFrame.setContentPane(graphicalDisplayPanel);

I have not tested this, but it seems like it would work. A JComponent's paint() method calls:
paintComponent(co);
paintBorder(co);
paintChildren(co);
where co is a Graphics object. In theory you create an image, retrieve the graphics object and then pass that into paintChildren(). you will have to call paintComponent() and paintBorder() yourself, if you do this. Then, just rotate the image and draw it into your component. You may have to crop the image or resize your component accordingly for this to work. It might look something like this:
BufferedImage myImage;
#Override
public void paint(Graphics g){
myImage = new BufferedImage(getWidth(), getHeight(), BufferedImage.TRANSLUCENT);
//using a transparent BufferedImage might not be efficient in your case
Graphics myGraphics = myImage.getGraphics();
super.paintComponent(g);
super.paintBorder(g);
super.paintChildren(myGraphics);
//rotation code here
// ...
//draw children onto your component
g.drawImage(myImage, 0, 0,getWidth(), getHeight(), null);
}
I hope I didn't make any mistakes, please let me know if this works.

So basicaly what I want is that I throught the list of componets I have and say: "All of you (components) which are in the list will be rotated by some angle".
If you want to rotate panel and therefore all the components on the panel as a single using then you need to do the custom painting in the paintComponent() method.
If you want to rotate, for example, individual images that each have a different angle of rotation then you can again do this in the paintComponent(...) method and change the angle for each component.
Or, in this second case you can use the Rotated Icon class. In this case the Icon is just added to a JLabel. Then you can change the degrees of rotation and repaint the label, so there is no custom painting (except in the Icon itself).

Overlay images Java

I'm trying to overlay a background picture with a .png sample, and I don't know how it works.
I tried to create 2 JPanels, but didn't find out how to overlay them, then I tried to create 2 JLabels and once again, they just stay separated.
Have you any idea ?
Thanks !

You can use one jPanel.Override paint or paintComponent method and draw your picture with graphic object.
public class MyCustomPanel extends JPanel{
private Image img;
public MyCustomPanel(// use constructor to get img or load it directly from below){
//load image
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
// Draws the img to the BackgroundPanel.
g.drawImage(img, 0, 0, this);
}
}
Then you can go to your main class and use this JPanel
MyCustomPanel mcp=new MyCustomPanel(//img path);
mcp.add(new JLabel("Hello"),BorderLayout.CENTER);
add(mcp),BorderLayout.CENTER);
//etc
I hope you understand
Next time post some code if you want to have answr faster and more complex/better suited for your case.

Setting a background image in a simple java game

I'm making my first simple game, that looks like Space Invaders.
I have used paint for drawing my hero on my JPanel. Now I guess if it's possible, in a simple way, to add a background image on my JPanel.
ImageIcon img = new ImageIcon(this.getClass().getResource("back.gif"));
Image image = img.getImage();
setDoubleBuffered(true);
hero = new Hero("hbarrel.gif",350,500);
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2d = (Graphics2D)g;
g2d.drawImage(hero.getImage(), hero.getX(), hero.getY(), this);
g2d.drawImage(image,0,0,this);
// Toolkit.getDefaultToolkit().sync();
g.dispose();
}
So, this is it: I tried to use my background img as hero img, and it works! but when I use the code above it only paints my hero img.... so it isn't a resource position issue.

Override paintComponent(Graphics) method and use Graphics.drawImage() to do that in your own custom component.

Well, try to paint the background image first and then the hero so that you have hero above background image