我想说（希望这样做会带来更好的性能），也许，如果您愿意采用这种
Image方法，则最好创建一个尺寸为1x1像素的图像，然后转换其创建的图形以匹配所请求的图形点。并将此图像重新用于相同
Component（甚至
GraphicsConfiguration）的后续采样。
我通过创建以下方法进行了一些性能测试：
- 所谓的一种方法，
getColorAtClipped
它设置的创建剪辑Graphics
的的Image
要绘制所以并不是所有操作都有。 - 一种称为的方法
getColorAtRelocation
，该方法将组件的位置临时设置在需要采样的位置，然后（实际上使其更快）创建尺寸为1x1的图像并在其上绘制父对象。尽管此方法对于Swing而言并不是真正的线程安全方法，因为它需要设置Component
来回的位置。它还要求printAll
父级Container
，这意味着Component
要绘制更多。 - 然后调用一种方法
getColorAtTranslation
，该方法创建一个1x1图像并转换其Graphics
实例，以便所需的位置实际上将绘制在（0,0）处，这是图像中真正的唯一像素。事实证明，对于这前三种方法，该方法是最快的。 - 那么，为什么不为以后的样本重用相同的资源呢？…这导致我进入最终方法：一个包含所有参与样本的必需资源的类：
ComponentColorSampler
在以下代码中调用的一个类
测试代码：
本节中的代码用于测试上述方法的性能。如果不正确，请在评论中让我知道，但是请注意，我对每种方法进行了大约300万次采样，以期避免附带的延迟。测试方法的每百万个样本中，我会打印一些时间，然后重新启动该过程以测试另外一百万个，最多3个。
import java.awt.Color;import java.awt.Component;import java.awt.Dimension;import java.awt.Graphics;import java.awt.Graphics2D;import java.awt.Point;import java.awt.image.BufferedImage;import java.lang.reflect.InvocationTargetException;import java.util.Objects;import java.util.function.IntBinaryOperator;import java.util.function.Supplier;import javax.swing.Jframe;import javax.swing.JPanel;import javax.swing.SwingUtilities;public class Main { public static Color getColorAtClipped(final Component comp, final Point p) { final BufferedImage bimg = comp.getGraphicsConfiguration().createCompatibleImage(comp.getWidth(), comp.getHeight()); final Graphics2D g2d = (Graphics2D) bimg.createGraphics(); g2d.setClip(p.x, p.y, 1, 1); comp.printAll(g2d); g2d.dispose(); final Color c = new Color(bimg.getRGB(p.x, p.y), true); bimg.flush(); return c; } public static Color getColorAtRelocation(final Component comp, final Point p) { final Point loc = comp.getLocation(); final BufferedImage bimg = comp.getGraphicsConfiguration().createCompatibleImage(1, 1); comp.setLocation(loc.x - p.x, loc.y - p.y); final Graphics2D g2d = (Graphics2D) bimg.createGraphics(); //g2d.setClip(0, 0, 1, 1); comp.getParent().printAll(g2d); comp.setLocation(loc); g2d.dispose(); final Color c = new Color(bimg.getRGB(0, 0), true); bimg.flush(); return c; } public static Color getColorAtTranslation(final Component comp, final Point p) { final BufferedImage bimg = comp.getGraphicsConfiguration().createCompatibleImage(1, 1); final Graphics2D g2d = (Graphics2D) bimg.createGraphics(); g2d.translate(-p.x, -p.y); //g2d.setClip(0, 0, 1, 1); comp.printAll(g2d); g2d.dispose(); final Color c = new Color(bimg.getRGB(0, 0), true); bimg.flush(); return c; } public static class ComponentColorSampler<C extends Component> implements AutoCloseable, IntBinaryOperator, Supplier<C> { private final C comp; private final BufferedImage bimg; private final Graphics2D g2d; private int x, y; public ComponentColorSampler(final C comp) { this.comp = Objects.requireNonNull(comp); bimg = comp.getGraphicsConfiguration().createCompatibleImage(1, 1); g2d = bimg.createGraphics(); //g2d.setClip(0, 0, 1, 1); x = y = 0; } @Override public C get() { return comp; } @Override public int applyAsInt(final int x, final int y) { g2d.clearRect(0, 0, 1, 1); g2d.translate(this.x - x, this.y - y); this.x = x; this.y = y; comp.printAll(g2d); return bimg.getRGB(0, 0); } public Color sample(final int x, final int y) { return new Color(applyAsInt(x, y), true); } @Override public void close() { g2d.dispose(); bimg.flush(); } } public static class DrawPanel extends JPanel { private final int x, y; private Color c; public DrawPanel(final int x, final int y) { this.x = x; this.y = y; c = Color.BLUE; } @Override protected void paintComponent(final Graphics g) { super.paintComponent(g); g.setColor(c); g.fillRect(x, y, 1, 1); } public void setColor(final Color c) { this.c = Objects.requireNonNull(c); paintImmediately(0, 0, getWidth(), getHeight()); //Not sure yet. repaint(); //Just to be sure now. } } //@SuppressWarnings("SleepWhileInLoop") public static boolean checkValid(final DrawPanel dp, final Supplier<Color> sampler) throws InterruptedException, InvocationTargetException { for (final Color c: new Color[]{Color.BLUE, Color.RED, Color.BLACK, Color.WHITE, Color.BLACK, Color.CYAN}) { SwingUtilities.invokeAndWait(() -> dp.setColor(c)); Thread.sleep(250); //Let it some time to change (not sure if needed). if (!Objects.equals(c, sampler.get())) return false; } return true; } public static long checkTime(final Supplier<Color> sampler) { final long start = System.currentTimeMillis(); for (int i = 0; i < 1000000; ++i) sampler.get(); return System.currentTimeMillis() - start; } public static void main(final String[] args) throws InterruptedException, InvocationTargetException { final Point p = new Point(100, 100); final DrawPanel contents = new DrawPanel(p.x, p.y); contents.setPreferredSize(new Dimension(200, 200)); final Jframe frame = new Jframe("Printed!"); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); frame.getContentPane().add(contents); frame.pack(); frame.setLocationRelativeTo(null); frame.setResizable(false); frame.setVisible(true); final ComponentColorSampler<Component> sampler = new ComponentColorSampler<>(contents); final Supplier<Color> clipped = () -> getColorAtClipped(contents, p), relocation = () -> getColorAtRelocation(contents, p), translation = () -> getColorAtTranslation(contents, p), samplerSampler = () -> sampler.sample(p.x, p.y); System.out.println("#### Validity checks..."); for (int i = 0; i < 3; ++i) { System.out.println("Batch " + (i + 1) + ':'); System.out.println("> Clipped: " + checkValid(contents, clipped) + '.'); System.out.println("> Relocation: " + checkValid(contents, relocation) + '.'); System.out.println("> Translation: " + checkValid(contents, translation) + '.'); System.out.println("> Sampler: " + checkValid(contents, samplerSampler) + '.'); } System.out.println("#### Timings..."); for (int i = 0; i < 3; ++i) { System.out.println("Batch " + (i + 1) + ':'); System.out.println("> Clipped: " + checkTime(clipped) + "ms."); System.out.println("> Relocation: " + checkTime(relocation) + "ms."); System.out.println("> Translation: " + checkTime(translation) + "ms."); System.out.println("> Sampler: " + checkTime(samplerSampler) + "ms."); } System.out.println("#### Done."); }}结果：
程序输出：
#### Validity checks...Batch 1:> Clipped: true.> Relocation: true.> Translation: true.> Sampler: true.Batch 2:> Clipped: true.> Relocation: true.> Translation: true.> Sampler: true.Batch 3:> Clipped: true.> Relocation: true.> Translation: true.> Sampler: true.#### Timings...Batch 1:> Clipped: 34668ms.> Relocation: 22737ms.> Translation: 5416ms.> Sampler: 1152ms.Batch 2:> Clipped: 38521ms.> Relocation: 22805ms.> Translation: 5451ms.> Sampler: 1156ms.Batch 3:> Clipped: 38275ms.> Relocation: 22864ms.> Translation: 5415ms.> Sampler: 1163ms.#### Done.
因此，对于一百万个样本，第一种方法大约需要37秒，第二种方法大约需要22秒，第三种方法大约需要5秒，最后一种方法恰好超过1秒（对于一百万个样本）。
ComponentColorSampler在这些测试中最快的实现也是如此（每毫秒约865个样本），并且可以在任何测试上运行
Component。有效性检查只是为了稍微验证所采样的颜色是否具有正确的值。
注意 ：这些测试不是Swing /线程安全的，但是指出了正确使用它们（例如，在事件调度线程上执行采样）的性能。
