I have an app which would use JLabel with an ImageIcon with an icon size of 32x32.
I'd now like to use a 64x64 image, load it and resize it to 32x32 if low DPI, otherwise use it as a high DPI image.
Resizing is easy, this trick works for example:
ImageIcon icon = ...
Image lowRes = icon.getImage().getScaledInstance(32, 32, Image.SCALE_SMOOTH);
return new ImageIcon(lowRes);
However, I fail to find a way to set the ImageIcon to be treated as a high DPI image.
I've tried playing around with MultiResolutionImage but with no success.
EDIT: Attempt using MultiResolutionImage in a naive way:
private ImageIcon loadIcon(String iconName)
{
ImageIcon icon = new ImageIcon(getClass().getClassLoader()
.getResource("res/icons/toolbar/" + iconName));
BaseMultiResolutionImage baseMultiResolutionImage = new BaseMultiResolutionImage(
icon.getImage().getScaledInstance(32, 32, Image.SCALE_SMOOTH),
icon.getImage()
);
return new ImageIcon(baseMultiResolutionImage);
}
Stacktrace:
2019-06-11 14:00:45,962 ERROR [AWT-EventQueue-0] Catch.all - Uncaught exception on [AWT-EventQueue-0]: Invalid Image variant
java.lang.IllegalArgumentException: Invalid Image variant
at java.desktop/sun.awt.image.SurfaceManager.getManager(SurfaceManager.java:82)
at java.desktop/sun.java2d.SurfaceData.getSourceSurfaceData(SurfaceData.java:218)
at java.desktop/sun.java2d.pipe.DrawImage.renderImageCopy(DrawImage.java:572)
at java.desktop/sun.java2d.pipe.DrawImage.copyImage(DrawImage.java:67)
at java.desktop/sun.java2d.pipe.DrawImage.copyImage(DrawImage.java:1027)
at java.desktop/sun.java2d.SunGraphics2D.drawImage(SunGraphics2D.java:3415)
at java.desktop/sun.java2d.SunGraphics2D.drawImage(SunGraphics2D.java:3391)
at java.desktop/javax.swing.ImageIcon.paintIcon(ImageIcon.java:425)
at java.desktop/com.apple.laf.AquaButtonUI.paintIcon(AquaButtonUI.java:395)
at java.desktop/com.apple.laf.AquaButtonUI.paint(AquaButtonUI.java:304)
at java.desktop/javax.swing.plaf.ComponentUI.update(ComponentUI.java:161)
at java.desktop/javax.swing.JComponent.paintComponent(JComponent.java:797)
at java.desktop/javax.swing.JComponent.paint(JComponent.java:1074)
at java.desktop/javax.swing.JComponent.paintChildren(JComponent.java:907)
at java.desktop/javax.swing.JComponent.paint(JComponent.java:1083)
at java.desktop/javax.swing.JComponent.paintChildren(JComponent.java:907)
at java.desktop/javax.swing.JComponent.paint(JComponent.java:1083)
at java.desktop/javax.swing.JComponent.paintChildren(JComponent.java:907)
at java.desktop/javax.swing.JComponent.paint(JComponent.java:1083)
at java.desktop/javax.swing.JComponent.paintChildren(JComponent.java:907)
at java.desktop/javax.swing.JComponent.paint(JComponent.java:1083)
at java.desktop/javax.swing.JLayeredPane.paint(JLayeredPane.java:590)
at java.desktop/javax.swing.JComponent.paintChildren(JComponent.java:907)
at java.desktop/javax.swing.JComponent.paintToOffscreen(JComponent.java:5262)
at java.desktop/javax.swing.RepaintManager$PaintManager.paintDoubleBufferedImpl(RepaintManager.java:1643)
at java.desktop/javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(RepaintManager.java:1618)
at java.desktop/javax.swing.RepaintManager$PaintManager.paint(RepaintManager.java:1556)
at java.desktop/javax.swing.RepaintManager.paint(RepaintManager.java:1323)
at java.desktop/javax.swing.JComponent.paint(JComponent.java:1060)
at java.desktop/java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:39)
at java.desktop/sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:78)
at java.desktop/sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:115)
at java.desktop/java.awt.Container.paint(Container.java:2002)
at java.desktop/java.awt.Window.paint(Window.java:3926)
at java.desktop/javax.swing.RepaintManager$4.run(RepaintManager.java:876)
at java.desktop/javax.swing.RepaintManager$4.run(RepaintManager.java:848)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:389)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
at java.desktop/javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:848)
at java.desktop/javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:823)
at java.desktop/javax.swing.RepaintManager.prePaintDirtyRegions(RepaintManager.java:772)
at java.desktop/javax.swing.RepaintManager$ProcessingRunnable.run(RepaintManager.java:1884)
Ok, so the problem is as follows:
The image created by ImageIcon (and getScaledInstance on ImageIcon) are of the type ToolkitImage. These are not the BufferedImage that are expected by Swing.
One working solution is to take the images and then convert them to two BufferedImage instances. Here is an ugly solution to hack the code above:
ImageIcon icon = new ImageIcon(getClass().getClassLoader().getResource("res/icons/toolbar/" + iconName));
BufferedImage ax = new BufferedImage(32, 32, BufferedImage.TYPE_INT_ARGB);
BufferedImage bx = new BufferedImage(64, 64, BufferedImage.TYPE_INT_ARGB);
Graphics g = ax.createGraphics();
new ImageIcon(icon.getImage().getScaledInstance(32, 32, Image.SCALE_SMOOTH)).paintIcon(null, g, 0, 0);
g.dispose();
g = bx.createGraphics();
icon.paintIcon(null, g, 0, 0);
g.dispose();
BaseMultiResolutionImage baseMultiResolutionImage = new BaseMultiResolutionImage(ax, bx);
return new ImageIcon(baseMultiResolutionImage);