如何使用 SynthLookAndFeel 更改“禁用图标”样式？

Question

I'm currently designing a Swing app with a custom "yellow on black" Look and Feel, and it seems SynthLookAndFeel is the way to go.

All my buttons consist of an ImageIcon (no text), for example:

When buttons are disabled, I would like the icons to turn to a faded yellow:

However, the default disabled icons are just greyscale versions of the "enabled" ones, and that breaks the yellow feel:

I read in this answer that disabled icons are generated internally by getDisabledIcon() , but I find no place to control it from synth's XML file.

I also read about SynthLookAndFeel's SynthPainter class , but it doesn't seem to address the question of disabled icons.

Is there a way to control that "getDisabledIcon" behaviour using SynthLookAndFeel, or am I asking too much? In the latter case, what would be the best suited look and feel to use or extend for easy definition of button backgrounds, shapes, etc?

Any hint is welcome.

Answer 1

OK, I think I found a clean way.

I was hesitating between finding a way with SynthLookAndFeel or subclassing another L&F... But didn't think of subclassing SynthLookAndFeel itself:-)

I've now got an implementation of SynthLookAndFeel that does exactly what I want, meaning the "disabled" icon is not a greyscale one, it's a desaturated, dimmed, color version:

Here we go for the full code:

import javax.swing.*;
import javax.swing.plaf.synth.SynthLookAndFeel;
import java.awt.*;
import java.awt.image.FilteredImageSource;
import java.awt.image.ImageProducer;
import java.awt.image.RGBImageFilter;

public class MySynthLookAndFeel extends SynthLookAndFeel {
    @Override
    public Icon getDisabledIcon(JComponent component, Icon icon) {
        if (icon instanceof ImageIcon) {
            return new ImageIcon(createDisabledImage(((ImageIcon)icon).getImage()));
        }
        return null;
    }

    private static Image createDisabledImage(Image i) {
        ImageProducer prod = new FilteredImageSource(i.getSource(), new RGBImageFilter() {
            public int filterRGB(int x, int y, int rgb) {
                // extract alpha mask
                int alphamask = rgb & 0xFF000000;

                // convert to HSB
                float[] hsb = Color.RGBtoHSB((rgb >> 16) & 0xff, (rgb >> 8) & 0xff, rgb & 0xff, null);
                // desaturate (half saturation)
                hsb[1] *= 0.5;
                // dim (half brightness)
                hsb[2] *= 0.5;
                // convert back to RGB
                int rgbval = Color.HSBtoRGB(hsb[0], hsb[1], hsb[2]);

                // reapply alpha
                rgbval = rgbval & 0x00FFFFFF | alphamask;
                return rgbval;
            }
        });
        return Toolkit.getDefaultToolkit().createImage(prod);
    }
}

Much simpler than I thought, in the end.