How do you convert a JPanel to a File? My panel has a moving Image and I want to get individual frames.
You can create a BufferedImage of the panel at different points in time and then save the image to a file.
The basic logic for this would be:
BufferedImage image = new BufferedImage(panel.getWidth(), panel.getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = image.createGraphics();
panel.print( g2d );
g2d.dispose();
ImageIO.write(...);
Check out the Screen Image class for convenience methods that implement the above functionality.
Of course this won't be very efficient since you need a completely new image for each frame.
Related
I've made a code to draw on a Jpanel
frame1.add( new JPanel() {
public void paintComponent( Graphics g ) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setColor(Color.white);
g2.fillRect(0, 0, width, height);
//Drawnig Part
});
Every thing is OK
Now My question is how to save what I've drawn on my JPanel in a file a.PNG or any other type
I have spent a lot of time to write the Drawing Part, So it will be helpful if you can suggest a solution by changing the required parts of my code, instead of rewriting the whole code.
I suggest that you buffer your drawing operations with a BufferedImage, like so:
// This should not be done in the draw method, but rather when
// the frame is created. You should also make a new buffer image when
// the frame is resized. `frameWidth` and `frameHeight` are the
// frame's dimensions.
BufferedImage bufferImage = new BufferedImage(frameWidth, frameHeight,
BufferedImage.TYPE_INT_ARGB);
Graphics2D bufferGraphics = bufferImage.createGraphics();
// In your draw method, do the following steps:
// 1. Clear the buffer:
bufferGraphics.clearRect(0, 0, width, height);
// 2. Draw things to bufferGraphics...
// 3. Copy the buffer:
g2.drawImage(bufferImage, null, 0, 0);
// When you want to save your image presented in the frame, call the following:
ImageIO.write(bufferImage, "png", new File("frameImage.png"));
The Java Tutorial on Creating and Drawing to an Image, along with the ImageIO API reference might be helpful should you require more information.
Have a look at Writing/Saving an Image for more details, but essentially you can do something like...
BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = img.createGraphics();
// Draw what ever you want to to the graphics context
g2d.dispose();
ImageIO.write(img, "png", new File("My Awesome Drawing.png"));
If you can't separate the drawing logic from your panel, you could simply use the Graphics context from the BufferedImage to paint the the component with.
Have a look at Exporting a JPanel to an image and Print the whole program layout for examples
So I am trying to get a screen shot of my panel and the code below does perfect. I want to lower the starting point of the screenshot by like 200 pixels. If I do size.height-200 it raises the bottom . I will need to do that in the future but how do I lower the top too? Or will I need to do a different method?
System.out.println("Trying to screenshot");
Dimension size = getSize ();
BufferedImage img = new BufferedImage (size.width, size.height, BufferedImage.TYPE_3BYTE_BGR);
Graphics g = img.getGraphics ();
paint (g);
g.dispose ();
try
{
ImageIO.write (img, "png", new File ("screenshot1.png"));
}
catch (IOException ex)
{
ex.printStackTrace ();
}
Do you want to draw a component with an offset? If yes, then AffineTransformation is your friend. Try calling
Graphics2D g = img.createGraphics();
g.transform(AffineTransform.getTranslateInstance(0, -200));
paint(g);
g.dispose();
You can use the Screen Image class. It allows you to specify a Rectangle when creating an image of the panel.
If you don't want to use the class, then take at look at the code. For your requirement the key is to translate the graphics before you do the painting.
When I'm rendering a Swing component to an image the fonts are different then when the component is rendered on screen. Here is an image showing the difference:
And this is the code:
public static BufferedImage renderComponent(Component component) {
int width = component.getWidth();
int height = component.getHeight();
BufferedImage buffImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = (Graphics2D) buffImage.getGraphics();
g.setFont(component.getFont());
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
component.paint(g);
g.dispose();
return buffImage;
}
What should I change to make a perfect screen shot of a Swing component? (The app is running on Windows 7)
What should I change to make a perfect screen shot of a Swing component?
I would guess you should not be providing rendering hints.
I use the Screen Image class for this (it is basically your code with a few other features built in).
After comparing the ScreenImage class (suggested by camickr) I found the cause of the problem. If I create a BufferedImage with the type set to TYPE_INT_RGB instead of TYPE_INT_ARGB the fonts are fine.
Class Robot
public synchronized BufferedImage createScreenCapture(Rectangle screenRect)
?
Could someone provide an example of how to dynamically create an image in Java, draw lines et cetera on it, and then draw the image so that areas not painted will remain transparent in the drawing process?
One could use a BufferedImage with an image type that supports transparency such as BufferedImage.TYPE_INT_ARGB:
BufferedImage img = new BufferedImage(100, 100, BufferedImage.TYPE_INT_ARGB);
One can draw on the BufferedImage by calling BufferedImage.createGraphics to obtain a Graphics2D object, then perform some drawing:
BufferedImage img = new BufferedImage(100, 100, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = img.createGraphics();
g.drawLine(0, 0, 10, 10); // draw a line.
g.dispose();
Then, since BufferedImage is a subclass of Image that can be used to draw onto another Image using one of the Graphics.drawImage that accepts an Image.
I have loaded a jpg image in which I want to draw letters and circles, given a x,y coordinate.
I have been trying to figure out the paintIcon of the ImageIcon class
public void paintIcon(Component c,
Graphics g,
int x,
int y)
Does this method allow me to edit jpg images the way I want to? What are supposd to be the Component c and Graphics g paramethers? What would I add to its body to paint circles or letters?
I'm working on Netbeans 6.5, do I have anything builtin for this task (instead of ImageIcon)?
The pure-Java way is to use ImageIO to load the image as a BufferedImage. Then you can call createGraphics() to get a Graphics2D object; you can then draw whatever you want onto the image.
You can use an ImageIcon embedded in a JLabel to do the displaying, and you can add a MouseListener and/or a MouseMotionListener to the JLabel if you're trying to allow the user to edit the image.
Manipulating images in Java can be achieved by using the Graphics or Graphics2D contexts.
Loading images such as JPEG and PNG can be performed by using the ImageIO class. The ImageIO.read method takes in a File to read in and returns a BufferedImage, which can be used to manipulate the image via its Graphics2D (or the Graphics, its superclass) context.
The Graphics2D context can be used to perform many image drawing and manipulation tasks. For information and examples, the Trail: 2D Graphics of The Java Tutorials would be a very good start.
Following is a simplified example (untested) which will open a JPEG file, and draw some circles and lines (exceptions are ignored):
// Open a JPEG file, load into a BufferedImage.
BufferedImage img = ImageIO.read(new File("image.jpg"));
// Obtain the Graphics2D context associated with the BufferedImage.
Graphics2D g = img.createGraphics();
// Draw on the BufferedImage via the graphics context.
int x = 10;
int y = 10;
int width = 10;
int height = 10;
g.drawOval(x, y, width, height);
g.drawLine(0, 0, 50, 50);
// Clean up -- dispose the graphics context that was created.
g.dispose();
The above code will open an JPEG image, and draw an oval and a line. Once these operations are performed to manipulate the image, the BufferedImage can be handled like any other Image, as it is a subclass of Image.
For example, by creating an ImageIcon using the BufferedImage, one can embed the image into a JButton or JLabel:
JLabel l = new JLabel("Label with image", new ImageIcon(img));
JButton b = new JButton("Button with image", new ImageIcon(img));
The JLabel and JButton both have constructors which take in an ImageIcon, so that can be an easy way to add an image to a Swing component.
Use a library to do just that. One that you might try is JMagick.
I have used Java Advanced Imaging library (http://java.sun.com/products/java-media/jai/forDevelopers/jaifaq.html), but you can also look at ImageJ (http://rsbweb.nih.gov/ij/index.html)
I imagen you could use this method to overlay the elements you need every time the image is drawn in the UI (this would happen numerous times as you are not drawing ON the image data its self) but may be suitable to your purposes (and advantageous if the overlay changes over time).
Something like:
new ImageIcon("someUrl.png"){
public void paintIcon(Component c, Graphics g, int x, int y) {
super(c, g, x, y);
g.translate(x, y);
g.drawOval(0, 0, 10, 10);
...
g.translate(-x, -y);
}
};
Having said that, mmyers' answer is much better if you want to modify the image data.