How to turn ImageIcon to gray on Swing

Question

I would like to know if there is some way in Swing to turn an ImageIcon to gray scale in a way like:

component.setIcon(greyed(imageIcon));

Thyestes

Answer 1

One limitation of GrayFilter.createDisabledImage() is that it is designed to create a disabled appearance for icons across diverse Look & Feel implementations. Using this ColorConvertOp example, the following images contrast the effect:

GrayFilter.createDisabledImage(): com.apple.laf.AquaLookAndFeel

ColorConvertOp#filter(): com.apple.laf.AquaLookAndFeel

GrayFilter.createDisabledImage(): com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel

ColorConvertOp#filter(): com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel

/**
 * @see https://mcmap.net/q/969127/-how-to-turn-imageicon-to-gray-on-swing/230513
 * @see https://mcmap.net/q/1014434/-program-not-accessing-method-paintcomponent-of-extended-jpanel-class
 */
private Icon getGray(Icon icon) {
    final int w = icon.getIconWidth();
    final int h = icon.getIconHeight();
    GraphicsEnvironment ge =
        GraphicsEnvironment.getLocalGraphicsEnvironment();
    GraphicsDevice gd = ge.getDefaultScreenDevice();
    GraphicsConfiguration gc = gd.getDefaultConfiguration();
    BufferedImage image = gc.createCompatibleImage(w, h);
    Graphics2D g2d = image.createGraphics();
    icon.paintIcon(null, g2d, 0, 0);
    Image gray = GrayFilter.createDisabledImage(image);
    return new ImageIcon(gray);
}

Quoin

I currently just needed it for disabled icons, but your answer is way better mine, so I'll choose that one. Thank you for the great answer. – Thyestes

You are welcome, and thank you. I won't say better, just complementary. :-) – Quoin

Small enhancement to the code above: use gc.createCompatibleImage(w, h, Transparency.TRANSLUCENT); instead of gc.createCompatibleImage(w, h); to keep the original icons translucency. – Molybdous

Answer 2

You can use the following:

ImageIcon icon = new ImageIcon("yourFile.gif");
Image normalImage = icon.getImage();
Image grayImage = GrayFilter.createDisabledImage(normalImage);

Thyestes

@DavidKroukamp Asking and answering your question is encouraged on the Stack Exchange network, see - meta.stackexchange.com/a/17847/140951 (and I have other references if you want them) for more. – Drone