Java开发GUI之图形绘制

在Java的GUI组件中，每一个视图都有一个paint方法，这个方法负责组件的绘制，其中会传入Graphics对象参数，开发者可以在paint方法中操作这个对象进行自定义图形的绘制。示例如下：

class DrawPanel extends Panel{

private static final long serialVersionUID = 1L;

public DrawPanel() {

 super();

}

@Override

public void paint(Graphics g) {

 // TODO Auto-generated method stub

 super.paint(g);

 Color bg = Color.WHITE;

 Color fg = Color.RED;

 //绘制背景

 g.setColor(bg);

 g.draw3DRect(50, 50, 699, 140, true);

 g.draw3DRect(53, 53, 692, 133, true);

 g.setColor(fg);

 //绘制线

 g.drawLine(60, 60, 140, 60);

 //绘制矩形

 g.drawRect(150, 60, 80, 50);

 //绘制圆角矩形

 g.drawRoundRect(240, 60, 80, 50, 25, 25);

 //绘制椭圆

 g.drawOval(330, 60, 80, 50);

 //绘制弧线

 g.drawArc(420, 60, 50, 50, 0, 90);

 //绘制闭合折线

 Polygon polygon = new Polygon();

 polygon.addPoint(510, 60);

 polygon.addPoint(550, 60);

 polygon.addPoint(550, 110);

 polygon.addPoint(590, 110);

 g.drawPolygon(polygon);

 //填充矩形

 g.fillRect(600, 60, 80, 50);

 //填充3D矩形

 g.fill3DRect(60, 120, 80, 50, true);

 //填充圆角矩形

 g.fillRoundRect(150, 120, 80, 50, 25, 25);

 //填充椭圆

 g.fillOval(240, 120, 80, 50);

 //填充弧线

 g.fillArc(330, 120, 50, 50, 0, 90);

 //填充闭合折线

 Polygon polygon2 = new Polygon();

 polygon2.addPoint(390, 120);

 polygon2.addPoint(440, 120);

 polygon2.addPoint(440, 180);

 polygon2.addPoint(490, 180);

 g.fillPolygon(polygon2);

 //绘制文字

 g.drawString("finish draw test!", 500, 150);

}

}

效果如下图：