Develop Reference

Scaling an image on a button which is resized

I'm working on an application which allows a used to place controls, move, resize, etc. But I'm trying to add icon images to a button control. When placed and instanced, it resizes the icon image per the code below.
But when I resize the control using user features and it calls this routing again, it fails to resize the image and it remains the original icon size. I've tried using "this.", passing the control to itself, I've done prints to ensure it's seeing the new size and width... what I am missing?
Also, when I create a 2nd control (or 3rd, etc), it uses the 1st image's initial size.
Thanks!
protected void sizeIcon () {
try {
File f2 = new File("media\\button.gif");
BufferedImage inputImage = ImageIO.read(f2);
BufferedImage img = new BufferedImage(this.getWidth(), this.getHeight(), inputImage.getType());
Graphics2D g = img.createGraphics();
g.drawImage(inputImage, 7, 0, this.getWidth(), this.getHeight(), null);
ImageIO.write(img, "gif", new File("test.gif"));
this.setIcon(new ImageIcon("test.gif"));
g.dispose();
} catch(Exception e) {System.out.println(e);}

Sorry, got it, appears the old file was not being replaces.
-MH

Is there a function that converts any image into a circle of 150x150 pixels-java?

I need a function/method that can mold(crop and resize) an imported (.png format) image into a circle of exact 150x150 pixels and it should keep transparency. I have searched all over internet, also I have my own code but I think its completely useless. I need this function for a code I am using to make GUI of a social-media app database.
private ImageIcon logo = new ImageIcon(getClass().getResource("/test/test200x200.png"));
toCircle(logo);
I need the code for the following function:
public ImageIcon toCircle(ImageIcon icon)
{
//code
return icon;
}
This function should convert this picture:
To this:

Create a new transparent image
Get a Graphics object from the image.
Set a clip for the graphics object.
Paint the PNG format image.
See also this answer that uses a clipped region.

An alternative approach, that might be more straight-forward to implement for this use case, is:
Create a transparent BufferedImage the size of your icon
Create Graphics2D from image, set hints for antialias
Fill a circle the size of your background circle
Draw the image on top of your circle, using AlphaComposite.SrcIn
Something like:
public Icon toCircle(ImageIcon logo) {
BufferedImage image = new BufferedImage(150, 150); // Assuming logo 150x150
Graphics2D g = image.createGraphics();
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g.fillOval(1, 1, 148, 148); // Leaving some room for antialiasing if needed
g.setComposite(AlphaComposite.SrcIn);
g.drawImage(logo.getImage(), 0, 0, null);
g.dispose();
return new ImageIcon(image);
}

Java GUI image size

So I have an assignment where I need to create a catalog.
The catalog needs to have a list, an image and a description.
My entire code works, so I have no issue with the coding as such.
I do have an issue with the image size.
How do I take care of images on a java gui program to make them all into one size when it is running.
Please let me know :D

When you read in an image, create a new BufferedImage that is the exact size that you desire, get it's Graphics object via getGraphics(), draw the original image into the new image using Graphics#drawImage(Image img, int x, int y, int width, int height, ImageObserver observer) where x and y are 0 and width and height are from the dimensions of the new image, dispose() of the Graphics object, and then display the new Image as an ImageIcon in a JLabel. Make sure though that the original image is the same size or larger than the new one, else your images will look gawd-awful.
For example, and note that this code may not be exactly correct since I don't have my IDE up:
BufferedImage originalImage = ImageIO.read(something); // read in original image
// create new empty image of desired size
BufferedImage newImage = new BufferedImage(desiredWidth, desiredHeight, BufferedImage.TYPE_INT_ARGB);
Graphics g = newImage.getGraphics(); // get its graphics object
// draw old image into new image
g.drawImage(originalImage, 0, 0, desiredWidth, desiredHeight, null);
g.dispose(); // get rid of Graphics object
// create ImageIcon and put in JLabel to display
Icon newIcon = new ImageIcon(newImage);
myJLabel.setIcon(newIcon);

I would propably create a JPanel to draw on one Image, and then work with the method:
myPanel.setSize(new Dimension(x,y))
or
myPanel.setPreferredSize(new Dimension....)

There is a method (image = imgobj.getScaledInstance(width, height, hints)) in awt.Image class which provides re-sizing capabilities very nicely, I always use this to re-size my images when I need. Please see here some examples :-), I hope it will work for you, it is the most convenient way to scale images I have ever seen. create a method pass the image to the method and size of the image you want and return the image back in return to reuse the code ;)

Resizing image to fit in JLabel

I am trying to load an image from directory and place it as an icon in JLabel. But when the image size is big it doesn't fit completely in the label. I tried resizing the image to fit in the label but its not working. May I know where I am going wrong?
JFileChooser choose=new JFileChooser();
choose.showOpenDialog(null);
File f=choose.getSelectedFile();
String filename=f.getAbsolutePath();
path.setText(filename);
ImageIcon icon=new ImageIcon(filename);
Image img=icon.getImage();
BufferedImage bi = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_INT_ARGB);
Graphics g = bi.createGraphics();
g.drawImage(img,500, 500, null);
ImageIcon newIcon = new ImageIcon(bi);
image_label.setIcon(newIcon);

BufferedImage img = ImageIO.read(...);
Image scaled = img.getScaledInstance(500, 500, Image.SCALE_SMOOTH);
ImageIcon icon = new ImageIcon(scaled);
Beware, that this will scale the image so that it is square. Take a look at Java: maintaining aspect ratio of JPanel background image which discusses maintaining the aspect ratio of the image when scaled.
Also, you should read The Perils of Image.getScaledInstance() and have a look at Scale the ImageIcon automatically to label size which uses a divide and conqure scaling algorithim and Quality of Image after resize very low -- Java which demonstrates the issues of doing a one step scale...

Java2D/Swing: Rendering a component with text anti aliasing to a BufferedImage

I would like to render a Java Swing component, e.g. a JButton, which I also put on a JFrame, to a BufferedImage. This works in general, but with a major drawback: Text anti aliasing, especially "LCD" anti aliasing mode, is not working when rendering to a BufferedImage.
I've put some example code together to demonstrate the problem, but first my system information:
OS: Windows 7 64 Bit
JVM: 1.6.0_26-b03 (32 Bit)
The following example code will create a simple JFrame, put a JButton on it and then renders the JButton to a file "test.png":
public class TextAntiAliasingTest
{
public TextAntiAliasingTest() throws IOException
{
// Create Test-Button which will be rendered to an image
JButton button = new JButton( "The Test-Button" );
button.setSize( 200, 70 );
button.setLocation( 200, 150 );
// Create JFrame
final JFrame frame = new JFrame();
frame.setSize( 800, 600 );
frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
frame.setLayout( null );
frame.setLocationRelativeTo( null );
frame.add( button );
// Show JFrame
SwingUtilities.invokeLater( new Runnable() {
#Override public void run() {
frame.setVisible( true );
}
});
// Render JButton to an BufferedImage
BufferedImage image = new BufferedImage( 800, 600, BufferedImage.TYPE_INT_ARGB );
Graphics2D g2d = (Graphics2D)image.getGraphics();
button.paint( g2d );
// Write BufferedImage to a PNG file
ImageIO.write( image, "PNG", new File( "test.png" ) );
}
public static void main( String[] args ) throws Exception
{
UIManager.setLookAndFeel( "com.sun.java.swing.plaf.windows.WindowsLookAndFeel" );
System.setProperty( "awt.useSystemAAFontSettings", "lcd" );
new TextAntiAliasingTest();
}
}
The following image shows the difference between the JButton in the JFrame on screen, and the same rendered JButton in the image file:
Actually there is some text anti aliasing in the image, but not the LCD optimized anti aliasing which is shown on screen in the JFrame (this problem occurs also with the default LookAndFeel, not only with the "WindowsLookAndFeel").
I already tried to explicitely set the RenderingHint for text anti aliasing on the "g2d", the Graphics2D context of the BufferedImage like so:
g2d.setRenderingHint( RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_LCD_HRGB );
But it had no effect at all.
I urgently need to render the JButton to an image file like it is rendered on screen (this is just an example, actually I need to render some more complex components, which all suffer from that anti aliasing problem) and I hope there is a real solution without any nasty workaround like taking a screenshot or something.
I really appreciate any help - thanks a lot!

This is a JVM bug
I have encountered the same problem as you. And I have concluded that the problem is indeed with drawing to a translucent bitmap. I'm fairly certain that we're hitting: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6749069
Workaround
For now I draw into an opaque bitmap and blit it into my destination bitmap. If the background color behind your text is plain, this should work:
private void drawString(String text, int x, int y, Graphics2D g, Color bg){
// Prepare an off-screen image to draw the string to
Rectangle2D bounds = g.getFontMetrics().getStringBounds(text, g);
BufferedImage image = configuration.createCompatibleImage(
(int)(bounds.getWidth() + 1.0f),
(int)(bounds.getHeight() + 1.0f),
Transparency.OPAQUE);
Graphics2D ig = image.createGraphics();
// Fill the background color
ig.setColor(bg);
ig.fillRect(0, 0, image.getWidth(), image.getHeight());
// Draw the string
int x0 = 0;
int y0 = ig.getFontMetrics().getAscent();
ig.setColor(g.getColor());
ig.setRenderingHints(g.getRenderingHints());
ig.setFont(g.getFont());
ig.drawString(text, x0, y0);
ig.dispose();
// Blit the image to the destination
g.drawImage(image, x-x0, y-y0, null);
}
If your background is not a plain color, you'll have to render the text as white on black to a bitmap, A. Then fill another bitmap with your text color C. Then blit that to your destination image, D as: D += A*C or D = D*(1-A)+A*C or some other suitable blending function.

It's probably too late anyway. The problem could be related to a translucent BufferedImage image you're using. The following seems to work Ok:
BufferedImage image = new BufferedImage( 800, 600, BufferedImage.TYPE_INT_RGB);
Graphics2D g2d = (Graphics2D)image.getGraphics();
g2d.setRenderingHint( RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_LCD_HRGB);
While looking around I have found similar complains.

Either you want (a) your translucent BufferedImage to look as good as your JButton, or (b) you want your JButton and BufferedImage to look the same.
If (b), can you have a translucent JButton? Will it look the same as your translucent BufferedImage?
If (a) then a hard way to do it is, you could maybe paint the JButton to a non-translucent BufferedImage (if Java has a greyscale BufferedImage, use this). This will end up being the negative of your final BufferedImage's alpha channel (a black pixel becomes fully opaque, white fully transparent.) To get the colour for the pixels in the BufferedImage, you'll need to set any pixel that isn't transparent to black - the pixel's transparency should make it come out to be the grey you want.