向基本的Java矩形添加发光 [英] Add glow to a basic Java rectangle
问题描述
我有一个非常基本的矩形绘图面板,但是我想知道是否有一种简单的方法可以向矩形添加某种发光效果.
I've got a very basic rectangle drawing panel, but I would like to know if there is a simple way to add some sort of glow to the rectangles.
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);
}
}
}
推荐答案
根据您要实现的目标,有点涉及发光"效果的产生.
Generating a "glow" effect is a little bit involved, depending on what you want to achieve.
我使用这种方法为透明/非矩形形状生成发光效果(例如,用于生成阴影的伟大效果).
I use this approach to generate glow effects for transparent/non-rectangular shapes (great for generating drop shadows for example).
此示例基本上创建了一个表示辉光"的BufferedImage
,然后生成了一个遮罩",该遮罩将其中的原始BufferedImage
切掉了.我这样做是因为它允许我在透明/半透明图像下方绘制发光".就您而言,您可以跳过掩盖"过程,但这取决于您.
This example basically creates a BufferedImage
which represents the "glow", it then generates a "mask" which cuts the original BufferedImage
out of it. I do it this way, as it allows me to draw the "glow" beneath transparent/translucent images. In your case, you could skip the "masking" process, but that's up to you.
您还需要一个 JHLab,图像过滤器的副本.不用担心自己制作模糊滤镜
You will also need a copy of the JHLabs, Image Filters, as I can't be bothered making my own blur filter
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;
}
}
基本工作流程如下:
- 创建一个
BufferedImage
,它代表要向其应用辉光的形状(这是不透明的图像) - 基于
size
参数创建一个蒙版"图像,该图像比要在其周围产生发光效果的图像大,但其原始图像绘制在中间. - 使用蒙版"图像生成模糊"图像
- 使用原始图像,将其蒙版为模糊"图像,以便从模糊"图像中切出"原始图像.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(发光效果比原始形状大,因此我们需要调整其位置)
- 在所需位置绘制矩形
- Create a
BufferedImage
which represents the shape you want to apply a glow to (this is a opaque image) - Create a "mask" image, which is larger then the image you want to generate a glow effect around, based on the
size
parameter, but which has the original image painted to it in the center - Use the "mask" image to generate a "blur" image
- Using the original image, mask it to the "blur" image, so that the original image is "cut out" of the "blur" image. This becomes the bases for our glow effect
- Paint the "glow/blur" image, adjusting the x/y position accordingly (the glow effect is larger then the original shape, so we need to adjust it's position)
- Paint the rectangle at the desired location
您需要查看合成图形有关屏蔽过程如何工作的更多详细信息.
You'll want to have a look at Compositing Graphics for more details about how the masking process works.
I use this kind of idea to generate drop shadows for transparent/no-rectangular shapes, for example, example and example
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