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在Java Swing中从原始图像生成HiDPI ImageIcon

javaswinghidpi
6
我有一个应用程序，会使用带有32x32图标大小的ImageIcon的JLabel。
我现在想要使用64x64图像，如果是低DPI，则加载并将其调整大小为32x32，否则将其用作高DPI图像。
调整大小很容易，例如可以使用以下技巧：
ImageIcon icon = ...
Image lowRes = icon.getImage().getScaledInstance(32, 32, Image.SCALE_SMOOTH);
return new ImageIcon(lowRes);

然而，我无法找到一种方法将ImageIcon设置为高DPI图像。

我尝试过使用MultiResolutionImage进行调整，但没有成功。

编辑：尝试使用天真的方式使用MultiResolutionImage：

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);
}

堆栈跟踪:

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)
“我尝试过使用MultiResolutionImage进行实验，但没有成功。”请展示一下你的代码。当你尝试时发生了什么？ - VGR
我找不到一种方法来设置ImageIcon被视为高DPI图像 - 我不知道这是什么意思。您也可以将图像调整为更大的尺寸，但质量会受到影响。 - camickr
@VGR 我只是将图像的高分辨率和低分辨率版本创建为BaseMultiResolutionImage，然后将其提供给ImageIcon。但是我从中得到了一个运行时错误。 - Nuoji
在UIKit中，以图像为例，一个图像具有缩放因子和大小。因此，您可以创建一个缩放因子为2且大小为32x32的图像。该图像的实际像素大小为64x64。然后，您可以将该图像复制到64x64 /比例因子1或16x16 /比例因子4。 - Nuoji
请在您的问题中添加运行时错误的完整堆栈跟踪，以及导致该错误的代码。 - VGR
显示剩余3条评论
2个回答
6
这是一个示例，演示如何将SVG图标转换为适用于高分辨率屏幕的多分辨率图像。此前的评论提到了这一点。
  // Create a multi-resolution image with all 0.25 scaling steps up to 3x
  final int size = ...; // base size = 16, 24, 32 etc.

  // Create all resolution variants that Windows 10 offers by default
  // Could probably drop some, e.g. 1.25 = 2.50 / 2 (Swing should handle that...)
  final List< Integer > sizes = ImmutableList.of(
      (int) ( size * 1.00 ), // Base image
      (int) ( size * 1.25 ),
      (int) ( size * 1.50 ),
      (int) ( size * 1.75 ),
      (int) ( size * 2.00 ),
      (int) ( size * 2.25 ),
      (int) ( size * 2.50 ),
      (int) ( size * 2.75 ),
      (int) ( size * 3.00 ) );

  final byte[] rawSvgBytes = ...; // Read bytes from SVG file

  Image[] images = new Image[ sizes.size() ];
  for ( int isize = 0; isize < sizes.size(); isize++ )
  {
    // Create a PNG transcoder
    PNGTranscoder t = new PNGTranscoder();

    // Set the transcoding hints
    t.addTranscodingHint( SVGAbstractTranscoder.KEY_WIDTH, Float.valueOf( sizes.get( isize ) ) );
    t.addTranscodingHint( SVGAbstractTranscoder.KEY_HEIGHT, Float.valueOf( sizes.get( isize ) ) );

    // Create the transcoder input
    TranscoderInput input = new TranscoderInput();
    input.setInputStream( new ByteArrayInputStream( rawSvgBytes ) );
    // Create the transcoder output
    ByteArrayOutputStream ostream = new ByteArrayOutputStream();
    TranscoderOutput output = new TranscoderOutput( ostream );

    // Transcode the image
    t.transcode( input, output );

    // Create an image and ensure its size is initialised
    Image image = Toolkit.getDefaultToolkit().createImage( ostream.toByteArray() );
    while ( image.getWidth( null ) == -1 )
    {
      // HACK! Wait for the image to be loaded, else icons may not render at the correct
      // location as the width and height returned to Swing are -1
    }
    images[ isize ] = image;
  }
  return new ImageIcon( new BaseMultiResolutionImage( images ) ); // First image always the base image
哦，这是一个非常有帮助的答案 - 感谢你！想法：也许你可以在 while 循环中包含 Thread.yield()？ - Luke Usherwood
3

好的，问题如下：

ImageIcon创建的图像（以及ImageIcon上的getScaledInstance）是ToolkitImage类型。这些不是Swing期望的BufferedImage。

一个可行的解决方案是将图像转换为两个BufferedImage实例。以下是对上述代码进行修改的简单解决方案：

Original Answer翻译成"最初的回答"

  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);
1
这是一种非常迂回的方式来实现 ImageIO.read(MyApplication.class.getResource("res/icons/toolbar/" + iconName)) 的功能。 - VGR
1
我得出了同样的结论。巧合的是，今天我正在实现非常相似的东西，只不过我是加载SVG文件然后渲染到多个分辨率，而不是使用更大的光栅图像。我没有遇到“无效的图像变体”，因为使用Apache Batik将SVG光栅化会产生多个ToolkitImage实例，每个实例都由BufferedImage支持。我需要注意的一个怪癖是等待图像完成加载，否则getWidth可能会返回-1给Swing，导致它在错误的位置呈现。我会发布代码。 - nicktalbot
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