Java：在图像上创建阴影效果

我正在尝试在图像上创建阴影效果（使用java）。

我已经看到了多个相关问题，我已经实现了几个建议的解决方案。 不幸的是，我总是遇到同样的问题：阴影效果以灰色（即阴影颜色）重新绘制整个图像 – 因此原始图像不再可见。

我测试的代码示例（基于JIDE免费库）：

ShadowFactory sf = new ShadowFactory(2, 0.5f, Color.black); ImageIO.write(sf.createShadow(ImageIO.read(new File("c:\\out2.png"))), "png", new File("c:\\out3.png")); 

不需要说我用多个源文件（out2.png）测试了这个。

我很无能为力：任何暗示/帮助都会受到高度赞赏。

Answer 1

整个理论很简单。 基本上，您需要生成图像的蒙版（使用AlphaComposite并使用您想要的颜色填充生成的图像（也使用AlphaComposite 。当然，这些都适用于图像的Alpha通道…

一旦你有了这个面具，你需要将两个图像组合在一起（将原始图像与蒙面图像重叠）

这个例子利用JHLabsfilter来提供模糊…

 public class TestImageDropShadow { public static void main(String[] args) { new TestImageDropShadow(); } public TestImageDropShadow() { EventQueue.invokeLater(new Runnable() { @Override public void run() { try { UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { } JFrame frame = new JFrame("Testing"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setLayout(new BorderLayout()); frame.add(new ImagePane()); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } }); } public class ImagePane extends JPanel { private BufferedImage background; public ImagePane() { try { BufferedImage master = ImageIO.read(getClass().getResource("/Scaled.png")); background = applyShadow(master, 5, Color.BLACK, 0.5f); } catch (IOException ex) { Logger.getLogger(TestImageDropShadow.class.getName()).log(Level.SEVERE, null, ex); } } @Override public Dimension getPreferredSize() { return background == null ? super.getPreferredSize() : new Dimension(background.getWidth(), background.getHeight()); } @Override protected void paintComponent(Graphics g) { super.paintComponent(g); if (background != null) { int x = (getWidth() - background.getWidth()) / 2; int y = (getHeight() - background.getHeight()) / 2; g.drawImage(background, x, y, this); } } } public static void applyQualityRenderingHints(Graphics2D g2d) { g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY); g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY); g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE); g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON); g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR); g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); g2d.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE); } 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 BufferedImage createCompatibleImage(BufferedImage image) { return createCompatibleImage(image, image.getWidth(), image.getHeight()); } public static BufferedImage createCompatibleImage(BufferedImage image, int width, int height) { return getGraphicsConfiguration().createCompatibleImage(width, height, image.getTransparency()); } public static GraphicsConfiguration getGraphicsConfiguration() { return GraphicsEnvironment.getLocalGraphicsEnvironment().getDefaultScreenDevice().getDefaultConfiguration(); } public static BufferedImage generateMask(BufferedImage imgSource, Color color, float alpha) { int imgWidth = imgSource.getWidth(); int imgHeight = imgSource.getHeight(); BufferedImage imgBlur = createCompatibleImage(imgWidth, imgHeight); Graphics2D g2 = imgBlur.createGraphics(); applyQualityRenderingHints(g2); 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(); return imgBlur; } 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(); applyQualityRenderingHints(g2); 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 applyShadow(BufferedImage imgSource, int size, Color color, float alpha) { BufferedImage result = createCompatibleImage(imgSource, imgSource.getWidth() + (size * 2), imgSource.getHeight() + (size * 2)); Graphics2D g2d = result.createGraphics(); g2d.drawImage(generateShadow(imgSource, size, color, alpha), size, size, null); g2d.drawImage(imgSource, 0, 0, null); g2d.dispose(); return result; } public static BufferedImage generateShadow(BufferedImage imgSource, int size, Color color, float alpha) { int imgWidth = imgSource.getWidth() + (size * 2); int imgHeight = imgSource.getHeight() + (size * 2); BufferedImage imgMask = createCompatibleImage(imgWidth, imgHeight); Graphics2D g2 = imgMask.createGraphics(); applyQualityRenderingHints(g2); int x = Math.round((imgWidth - imgSource.getWidth()) / 2f); int y = Math.round((imgHeight - imgSource.getHeight()) / 2f); g2.drawImage(imgSource, x, y, null); g2.dispose(); // ---- Blur here --- BufferedImage imgGlow = generateBlur(imgMask, (size * 2), color, alpha); return imgGlow; } public static Image applyMask(BufferedImage sourceImage, BufferedImage maskImage) { return applyMask(sourceImage, maskImage, AlphaComposite.DST_IN); } 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; } } 

Answer 2

这是我的版本：

 private static Image dropShadow(BufferedImage img) { // a filter which converts all colors except 0 to black ImageProducer prod = new FilteredImageSource(img.getSource(), new RGBImageFilter() { @Override public int filterRGB(int x, int y, int rgb) { if (rgb == 0) return 0; else return 0xff000000; } }); // create whe black image Image shadow = Toolkit.getDefaultToolkit().createImage(prod); // result BufferedImage result = new BufferedImage(img.getWidth(), img.getHeight(), img.getType()); Graphics2D g = (Graphics2D) result.getGraphics(); // draw shadow with offset g.drawImage(shadow, 10, 0, null); // draw original image g.drawImage(img, 0, 0, null); return result; }