用Java递归绘制图形
对于这个程序,我需要递归地绘制一个“宝塔”,它是一系列递减的矩形,中心对齐,堆叠在一起。我想我已经了解了实际图形背后的逻辑,但我很难弄清楚如何用图形2D将图形绘制成矩形。我试图把它塞进一个基本的图形绘制程序中,却找不到如何在其中使用递归 这是我到目前为止编写的代码,没有考虑图形:用Java递归绘制图形,java,recursion,graphics,graphics2d,Java,Recursion,Graphics,Graphics2d,对于这个程序,我需要递归地绘制一个“宝塔”,它是一系列递减的矩形,中心对齐,堆叠在一起。我想我已经了解了实际图形背后的逻辑,但我很难弄清楚如何用图形2D将图形绘制成矩形。我试图把它塞进一个基本的图形绘制程序中,却找不到如何在其中使用递归 这是我到目前为止编写的代码,没有考虑图形: import java.awt.Rectangle; public class PagodaDrawer { private int initialY; //Top of the bottom rectangle
import java.awt.Rectangle;
public class PagodaDrawer
{
private int initialY; //Top of the bottom rectangle
private int initialHeight; //Height for the bottom rectangle
private double scale; //Amount to reduce each layer
public PagodaDrawer(int initialY, int initialHeight, double scaleFactor)
{
this.initialY = initialY;
this.initialHeight = initialHeight;
scale = scaleFactor;
}
public void drawPagoda()
{
drawLayer(0, initialY, 2 * initialHeight, initialHeight);
}
public void drawLayer(double x, double y, double width, double height)
{
if(y < 0 || height < 5) //If off the top of the screen, or less than 5 tall
{
return;
}
drawLayer(x - (((1 - scale)* x) / 2), y + (y * scale), width * scale, height * scale );
Rectangle r = new Rectangle((int)x, (int)y, (int)(2 * height), (int)height);
//Draw r?
}
}
编写一个递归的
createRectangle()
,将每个新的Rectangle
实例添加到列表中,而不是使drawLayer()递归。在Java AWT和Swing中,在您的实现中呈现列表,如图所示。使用图形
/图形2D
方法绘制。
示例:graphics.fillRect(x,y,w,h)代码>
您应该从要绘制的组件(通常是主框架或某个组件)获取图形(?:2d)
对象
在框架的paintComponent()
中调用图形应该可以像这样工作:
以下是Java6文档:
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.util.ArrayList;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class PagodaDrawer extends JPanel
{
private int initialX;
private int initialY; //Top of the bottom rectangle
private int initialHeight; //Height for the bottom rectangle
private double scale; //Amount to reduce each layer
private boolean isRenderable;
private ArrayList<Rectangle> recs;
public PagodaDrawer(int initialX, int initialY, int initialHeight, double scaleFactor)
{
this.initialX = initialX;
this.initialY = initialY;
this.initialHeight = initialHeight;
scale = scaleFactor;
isRenderable = false;
recs = new ArrayList<Rectangle>();
}
public void drawPagoda()
{
drawLayer(initialX, initialY, 2 * initialHeight, initialHeight);
}
public void drawLayer(double x, double y, double width, double height)
{
if(y < 0 || height < 5) //If off the top of the screen, or less than 5 tall
{
isRenderable = true;
return;
}
drawLayer(x + .5 * (width - (width * scale)), y - (height * scale), width * scale, height * scale );
Rectangle r = new Rectangle((int)x, (int)y, (int)(2 * height), (int)height);
recs.add(r);
}
public void paintComponent(Graphics g)
{
if(!isRenderable)
return;
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
for(int i = 0; i < recs.size(); i++)
{
g2.draw(recs.get(i));
System.out.println(recs.get(i));
}
}
}
import javax.swing.JFrame;
import javax.swing.JPanel;
public class DisplayComponent extends JFrame
{
private static final long serialVersionUID = -4279682826771265863L;
private static final int FRAME_WIDTH = 500;
private static final int FRAME_HEIGHT = 500;
private JPanel panel;
private PagodaDrawer p;
public DisplayComponent(int initialHeight, double scaleFactor)
{
p = new PagodaDrawer(FRAME_WIDTH / 2, FRAME_HEIGHT, initialHeight, scaleFactor);
panel = new JPanel();
p.drawPagoda();
add(p);
pack();
setSize(FRAME_WIDTH, FRAME_HEIGHT);
setVisible(true);
}
}