带有背景图像的JTextArea的内部填充
我的最终目标是拥有一个带有背景图像的JTextArea 。 我发现在线代码向我展示了如何做到这一点，但现在我遇到的问题是文本位于图像之上。
这就是我的意思：
有什么方法可以添加一种向内缩进，以便文本不与图像的边缘重叠？
这是原始评论气泡图像。
这是代码：
import java.awt.BorderLayout; import java.awt.Container; import java.awt.Graphics; import java.awt.Image; import javax.swing.GrayFilter; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTextArea; public class myBackgroundSample { String file; public myBackgroundSample(String i) { file = i; setItUp(); } public void setItUp() { final ImageIcon imageIcon = new ImageIcon(file); JTextArea textArea = new JTextArea() { Image image = imageIcon.getImage(); public void paint(Graphics g) { setOpaque(false); g.drawImage(image, 0, 0, this); super.paint(g); } }; JFrame frame = new JFrame("Background Example"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JScrollPane scrollPane = new JScrollPane(textArea); Container content = frame.getContentPane(); content.add(scrollPane, BorderLayout.CENTER); frame.setSize(400, 400); frame.setVisible(true); } public static void main(String[] args) { // TODO Auto-generated method stub String right = "chat1.jpg"; myBackgroundSample temp = new myBackgroundSample(right); } }
使用扩展AbstractBorder的自定义边框。 像这样的东西：
获得确切的形状和颜色留给读者练习。 🙂
import java.awt.*; import java.awt.geom.*; import javax.swing.*; import javax.swing.border.AbstractBorder; class TextBubbleBorder extends AbstractBorder { private Color color; private int thickness = 4; private int radii = 8; private int pointerSize = 7; private Insets insets = null; private BasicStroke stroke = null; private int strokePad; private int pointerPad = 4; RenderingHints hints; TextBubbleBorder( Color color) { new TextBubbleBorder(color, 4, 8, 7); } TextBubbleBorder( Color color, int thickness, int radii, int pointerSize) { this.thickness = thickness; this.radii = radii; this.pointerSize = pointerSize; this.color = color; stroke = new BasicStroke(thickness); strokePad = thickness/2; hints = new RenderingHints( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); int pad = radii + strokePad; int bottomPad = pad + pointerSize + strokePad; insets = new Insets(pad,pad,bottomPad,pad); } @Override public Insets getBorderInsets(Component c) { return insets; } @Override public Insets getBorderInsets(Component c, Insets insets) { return getBorderInsets(c); } @Override public void paintBorder( Component c, Graphics g, int x, int y, int width, int height) { Graphics2D g2 = (Graphics2D)g; int bottomLineY = height-thickness-pointerSize; RoundRectangle2D.Double bubble = new RoundRectangle2D.Double( 0+strokePad, 0+strokePad, width-thickness, bottomLineY, radii, radii ); Polygon pointer = new Polygon(); // left point pointer.addPoint( strokePad+radii+pointerPad, bottomLineY); // right point pointer.addPoint( strokePad+radii+pointerPad+pointerSize, bottomLineY); // bottom point pointer.addPoint( strokePad+radii+pointerPad+(pointerSize/2), height-strokePad); Area area = new Area(bubble); area.add(new Area(pointer)); g2.setRenderingHints(hints); Area spareSpace = new Area(new Rectangle(0,0,width,height)); spareSpace.subtract(area); g2.setClip(spareSpace); g2.clearRect(0,0,width,height); g2.setClip(null); g2.setColor(color); g2.setStroke(stroke); g2.draw(area); } public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { JLabel l = new JLabel( "The quick brown fox jumped over the lazy dog!"); l.setBorder(new TextBubbleBorder(Color.MAGENTA.darker(),2,4,0)); l.setOpaque(true); l.setBackground(Color.BLACK); JOptionPane.showMessageDialog(null, l); } }); } }
您应该使用Border ，更具体地说，您应该使用BorderFactory.createEmptyBorder(int top, int left, int bottom, int right) ：
textArea.setBorder(BorderFactory.createEmptyBorder(10,10,15,10));
您还应该覆盖paintComponent而不是paint 。 另外，使用setRows()和setColumns()来设置textArea的大小，然后可以使用pack()而不是setSize(400,400) ，这是不推荐的。 看这个例子：
import java.awt.BasicStroke; import java.awt.BorderLayout; import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import javax.swing.BorderFactory; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JTextArea; public class Test extends JFrame { class MyTextArea extends JTextArea { public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D)g; g2.setColor(Color.PINK); g2.setStroke(new BasicStroke(4)); g2.drawRoundRect(3, 3, getWidth()-7, getHeight()-7, 5, 5); } } public Test() { JPanel panel = new JPanel(new BorderLayout()); JTextArea textArea = new MyTextArea(); textArea.setRows(3); textArea.setColumns(25); textArea.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10)); panel.add(textArea, BorderLayout.NORTH); add(panel); pack(); setDefaultCloseOperation(EXIT_ON_CLOSE); setVisible(true); } public static void main(String[] args) { new Test(); } }
要发布代码 ，请将每行缩进四个空格。
我假设您正在为您的JTextArea重写paintComponent() *。 如果是，请通过添加确保它是透明的
setOpaque(false);
*如果你覆盖paint() ，这也有效，但是当trashgod正确陈述时，会干扰paintBorder() 。