将辉光添加到基本Java矩形

我有一个非常基本的矩形绘图面板，但我想知道是否有一种简单的方法可以为矩形添加某种发光。 

public class Blocks extends JPanel { public void paintComponent(Graphics g) { super.paintComponent(g); this.setBackground(Color.BLACK); for (int i = 1; i <= totalSteps; i++) { g.setColor(Color.WHITE); g.fillRect(100 + i*60, 260, 50, 50); } } }

根据您想要实现的目标，产生“发光”效果有点牵扯。

我使用这种方法为透明/非矩形形状生成发光效果（例如，非常适合生成阴影）。

这个例子基本上创建了一个表示“发光”的BufferedImage ，然后生成一个“掩码”，从而将原始的BufferedImage剪切掉。 我这样做，因为它允许我在透明/半透明图像下绘制“发光”。 在您的情况下，您可以跳过“屏蔽”过程，但这取决于您。

您还需要一份JHLabs，图像filter ，因为我不能打扰我自己的模糊filter

发光效果 

 import com.jhlabs.image.GaussianFilter; import java.awt.AlphaComposite; import java.awt.Color; import java.awt.Dimension; import java.awt.EventQueue; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.GraphicsConfiguration; import java.awt.GraphicsEnvironment; import java.awt.Transparency; import java.awt.image.BufferedImage; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.UIManager; import javax.swing.UnsupportedLookAndFeelException; public class GlowEffect { public static void main(String[] args) { new GlowEffect(); } public GlowEffect() { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { ex.printStackTrace(); } JFrame frame = new JFrame("Testing"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.add(new TestPane()); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } }); } public class TestPane extends JPanel { public TestPane() { } @Override public Dimension getPreferredSize() { return new Dimension(200, 200); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2d = (Graphics2D) g.create(); int width = 50; int height = 50; int x = (getWidth() - width) / 2; int y = (getHeight() - height) / 2; BufferedImage img = generateGlow(width, height, 20, Color.YELLOW, 1f); g2d.drawImage(img, x - ((img.getWidth() - width) / 2), y - ((img.getHeight() - height) / 2), this); g2d.setColor(Color.WHITE); g2d.fillRect(x, y, width, height); g2d.dispose(); } } public static BufferedImage generateGlow(int width, int height, int size, Color glow, float alpha) { BufferedImage source = createCompatibleImage(width, height); Graphics2D g2d = source.createGraphics(); g2d.setColor(Color.WHITE); g2d.fillRect(0, 0, width, height); g2d.dispose(); return generateGlow(source, size, glow, alpha); } public static BufferedImage generateGlow(BufferedImage imgSource, int size, Color color, float alpha) { int imgWidth = (int)Math.round(imgSource.getWidth() + (size * 2.5)); int imgHeight = (int)Math.round(imgSource.getHeight() + (size * 2.5)); BufferedImage imgMask = createCompatibleImage(imgWidth, imgHeight); Graphics2D g2 = imgMask.createGraphics(); int x = Math.round((imgWidth - imgSource.getWidth()) / 2f); int y = Math.round((imgHeight - imgSource.getHeight()) / 2f); g2.drawImage(imgSource, x, y, null); g2.dispose(); BufferedImage imgGlow = generateBlur(imgMask, size, color, alpha); imgGlow = applyMask(imgGlow, imgMask, AlphaComposite.DST_OUT); return imgGlow; } public static BufferedImage generateBlur(BufferedImage imgSource, int size, Color color, float alpha) { GaussianFilter filter = new GaussianFilter(size); int imgWidth = imgSource.getWidth(); int imgHeight = imgSource.getHeight(); BufferedImage imgBlur = createCompatibleImage(imgWidth, imgHeight); Graphics2D g2 = imgBlur.createGraphics(); g2.drawImage(imgSource, 0, 0, null); g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_IN, alpha)); g2.setColor(color); g2.fillRect(0, 0, imgSource.getWidth(), imgSource.getHeight()); g2.dispose(); imgBlur = filter.filter(imgBlur, null); return imgBlur; } public static BufferedImage createCompatibleImage(int width, int height) { return createCompatibleImage(width, height, Transparency.TRANSLUCENT); } public static BufferedImage createCompatibleImage(int width, int height, int transparency) { BufferedImage image = getGraphicsConfiguration().createCompatibleImage(width, height, transparency); image.coerceData(true); return image; } public static GraphicsConfiguration getGraphicsConfiguration() { return GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration(); } public static BufferedImage applyMask(BufferedImage sourceImage, BufferedImage maskImage, int method) { BufferedImage maskedImage = null; if (sourceImage != null) { int width = maskImage.getWidth(null); int height = maskImage.getHeight(null); maskedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB); Graphics2D mg = maskedImage.createGraphics(); int x = (width - sourceImage.getWidth(null)) / 2; int y = (height - sourceImage.getHeight(null)) / 2; mg.drawImage(sourceImage, x, y, null); mg.setComposite(AlphaComposite.getInstance(method)); mg.drawImage(maskImage, 0, 0, null); mg.dispose(); } return maskedImage; } }

基本工作流程遵循以下内容：

  • 创建一个BufferedImage ，表示要应用辉光的形状（这是一个不透明的图像）
  • 根据size参数创建一个“蒙版”图像，该图像比想要生成光晕效果的图像大，但是在中心绘制了原始图像
  • 使用“蒙版”图像生成“模糊”图像
  • 使用原始图像，将其遮盖到“模糊”图像，以便原始图像“剪切”出“模糊”图像。 这成为我们发光效果的基础
  • 绘制“发光/模糊”图像，相应地调整x / y位置（发光效果大于原始形状，因此我们需要调整它的位置）
  • 在所需位置绘制矩形

您将需要查看合成图形，以获取有关屏蔽过程如何工作的更多详细信息。

我使用这种想法为透明/无矩形形状生成阴影， 例如 ， 示例和示例

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