我一直想设计一个龙曲线生成器。
(如果您想了解有关该问题的信息，请查看 this，但这对问题来说并不重要)
龙曲线是一个重复的数学构造。
我已经为 Canvas 应该绘制的内容编写了一个生成器，它的工作原理是返回一个由“r”或“l”组成的字符数组，表示接下来该线是否必须向左转或向右转。在此处的代码中，它是方法 input()。这部分工作完美。
问题是，每当我想在 Canvas 上绘制它(使用drawLine)时，它只会将前两行绘制为实际线条，其余的只是点。
这些点位于正确的位置，如果你把东西做得很大，你就无法再分辨出差异了，但尽管如此，那里应该有线条。
图片:
这是我使用的代码:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
/**
*
* Description
*
* @version 1.0 from 4/20/2016
* @author
*/
public class CurveGen extends JFrame {
// start attributes
private Canvas display = new Canvas();
private JButton startButton = new JButton();
private JLabel jLabel1 = new JLabel();
private JTextArea outText = new JTextArea("");
private JScrollPane outTextScrollPane = new JScrollPane(outText);
private JLabel jLabel2 = new JLabel();
private JSlider xSlider = new JSlider();
private JSlider ySlider = new JSlider();
private JNumberField iterationsNF = new JNumberField();
private JNumberField sizeNF = new JNumberField();
// end attributes
public CurveGen(String title) {
// Frame-Init
super(title);
setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
int frameWidth = 1022;
int frameHeight = 731;
setSize(frameWidth, frameHeight);
Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
int x = (d.width - getSize().width) / 2;
int y = (d.height - getSize().height) / 2;
setLocation(x, y);
setResizable(false);
Container cp = getContentPane();
cp.setLayout(null);
// start components
display.setBounds(16, 64, 601, 601);
cp.add(display);
startButton.setBounds(736, 464, 241, 129);
startButton.setText("START!");
startButton.setMargin(new Insets(2, 2, 2, 2));
startButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
startButton_ActionPerformed(evt);
}
});
startButton.setFont(new Font("Dialog", Font.BOLD, 36));
cp.add(startButton);
jLabel1.setBounds(760, 96, 75, 41);
jLabel1.setText("Iterations:");
cp.add(jLabel1);
outTextScrollPane.setBounds(728, 392, 257, 57);
cp.add(outTextScrollPane);
jLabel2.setBounds(768, 144, 67, 41);
jLabel2.setText("Size:");
cp.add(jLabel2);
xSlider.setBounds(0, 8, 633, 49);
xSlider.setMinorTickSpacing(25);
xSlider.setMajorTickSpacing(100);
xSlider.setPaintTicks(true);
xSlider.setPaintLabels(true);
xSlider.setToolTipText("Starting point y-coordinate");
xSlider.setMaximum(600);
xSlider.setValue(300);
cp.add(xSlider);
ySlider.setBounds(624, 56, 65, 625);
ySlider.setMinorTickSpacing(25);
ySlider.setMajorTickSpacing(100);
ySlider.setPaintTicks(true);
ySlider.setPaintLabels(true);
ySlider.setOrientation(SwingConstants.VERTICAL);
ySlider.setMaximum(600);
ySlider.setInverted(true);
ySlider.setValue(300);
ySlider.setToolTipText("Starting point x-coordinate");
cp.add(ySlider);
iterationsNF.setBounds(856, 96, 81, 41);
iterationsNF.setText("");
cp.add(iterationsNF);
sizeNF.setBounds(856, 144, 81, 41);
sizeNF.setText("");
cp.add(sizeNF);
// end components
setVisible(true);
} // end of public CurveGen
// start methods
public static void main(String[] args) {
new CurveGen("CurveGen");
} // end of main
public char[] input(int iter) {
char oldOut[] = new char[0];
for (int i=1;i<=iter;i++) {
char newOut[] = new char[((int)Math.pow(2, i))-1];
for (int n=0;n<oldOut.length;n++) {
newOut[n] = oldOut[n];
if (oldOut[n]=='r') {
newOut[newOut.length-n-1] = 'l';
}
if (oldOut[n]=='l') {
newOut[newOut.length-n-1] = 'r';
} // end of if
} // end of for
newOut[oldOut.length]='l';
oldOut = newOut;
} // end of for
return oldOut;
}
public void startButton_ActionPerformed(ActionEvent evt) {
int iterations = iterationsNF.getInt();
int size = sizeNF.getInt();
char com[] = input(iterations);
outText.setText(String.valueOf(com));
int dir = 0;
int newDir = 0;
int lastPos[] = {xSlider.getValue(),ySlider.getValue()-size};
int newPos[] = {0,0};
Graphics g = display.getGraphics();
g.clearRect(0,0,601,601);
g.drawLine(xSlider.getValue(),ySlider.getValue(),xSlider.getValue(),ySlider.getValue()-size);
for (int i=0;i<=com.length-1;i++) {
dir = newDir;
if (dir==0) {
if (com[i]=='l') {
newPos[0] = lastPos[0]-size;
newPos[1] = lastPos[1];
newDir = 3;
}
if (com[i]=='r') {
newPos[0] = lastPos[0]+size;
newPos[1] = lastPos[1];
newDir = 1;
}
}
if (dir==1) {
if (com[i]=='l') {
newPos[0] = lastPos[0];
newPos[1] = lastPos[1]-size;
newDir = 0;
}
if (com[i]=='r') {
newPos[0] = lastPos[0];
newPos[1] = lastPos[1]+size;
newDir = 2;
}
}
if (dir==2) {
if (com[i]=='l') {
newPos[0] = lastPos[0]+size;
newPos[1] = lastPos[1];
newDir = 1;
}
if (com[i]=='r') {
newPos[0] = lastPos[0]-size;
newPos[1] = lastPos[1];
newDir = 3;
}
}
if (dir==3) {
if (com[i]=='l') {
newPos[0] = lastPos[0];
newPos[1] = lastPos[1]+size;
newDir = 2;
}
if (com[i]=='r') {
newPos[0] = lastPos[0];
newPos[1] = lastPos[1]-size;
newDir = 0;
}
}
g.drawLine(lastPos[0],lastPos[1],newPos[0],newPos[1]);
lastPos=newPos;
} // end of for
} // end of startButton_ActionPerformed
// end methods
} // end of class CurveGen
最佳答案
好吧，我已经回顾了代码......
- 混合重量级 (
java.awt.Canvas) 和轻量级 (Swing) 组件是不可取的，因为它们可能会导致或各种绘画问题 getGraphics不是绘制的方式。相反，我会从自定义JPanel开始并覆盖其paintComponent。请参阅Painting in AWT and Swing和 Performing Custom Painting了解更多详情- 避免使用
null布局，像素完美布局是现代 UI 设计中的一种幻觉。影响组件个体尺寸的因素太多，您无法控制其中任何一个。 Swing 的设计目的是与核心的布局管理器一起工作，放弃这些将导致无休止的问题和问题，您将花费越来越多的时间来尝试纠正
我相信问题与此有关...
lastPos=newPos;
您所做的只是使 lastPos 指向内存中与 newPos 相同的位置，因此当您为 newPos 赋值时，lastPos 将具有相同的值，这就是您看到点的原因。
我首先要做的是将负责生成数据的部分与显示部分分开。
我将从某种模型开始(注意，您可以创建一个采用迭代并自行生成数据的模型，但我专注于解决最初的问题)
public class DragonModel {
private Point startPoint;
private int size;
private char[] values;
public DragonModel(Point startPoint, int size, char[] values) {
this.startPoint = startPoint;
this.size = size;
this.values = values;
}
public Point getStartPoint() {
return startPoint;
}
public int getSize() {
return size;
}
public char[] getValues() {
return values;
}
}
然后显示...
public class DragonPane extends JPanel {
private DragonModel model;
public void setModel(DragonModel model) {
this.model = model;
repaint();
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (model != null) {
Graphics2D g2d = (Graphics2D) g.create();
int size = model.getSize();
int dir = 0;
int newDir = 0;
Point lastPos = model.getStartPoint();
Point newPos = new Point(0, 0);
for (char value : model.values) {
if (dir == 0) {
if (value == 'l') {
newPos.x = lastPos.x - size;
newPos.y = lastPos.y;
newDir = 3;
}
if (value == 'r') {
newPos.x = lastPos.x + size;
newPos.y = lastPos.y;
newDir = 1;
}
}
if (dir == 1) {
if (value == 'l') {
newPos.x = lastPos.x;
newPos.y = lastPos.y - size;
newDir = 0;
}
if (value == 'r') {
newPos.x = lastPos.x;
newPos.y = lastPos.y + size;
newDir = 2;
}
}
if (dir == 2) {
if (value == 'l') {
newPos.x = lastPos.x + size;
newPos.y = lastPos.y;
newDir = 1;
}
if (value == 'r') {
newPos.x = lastPos.x - size;
newPos.y = lastPos.y;
newDir = 3;
}
}
if (dir == 3) {
if (value == 'l') {
newPos.x = lastPos.x;
newPos.y = lastPos.y + size;
newDir = 2;
}
if (value == 'r') {
newPos.x = lastPos.x;
newPos.y = lastPos.y - size;
newDir = 0;
}
}
g.drawLine(lastPos.x, lastPos.y, newPos.x, newPos.y);
dir = newDir;
lastPos = new Point(newPos);
}
}
}
}
这里的想法是尝试将责任稍微解耦，数据生成和显示的责任牢牢地位于两个不同的领域。
然后在您的 actionPerformed 方法中您可以简单地执行...
public void startButton_ActionPerformed(ActionEvent evt) {
int iterations = Integer.parseInt(iterationsNF.getText());
int size = Integer.parseInt(sizeNF.getText());
char com[] = input(iterations);
outText.setText(String.valueOf(com));
DragonModel model = new DragonModel(new Point(xSlider.getValue(), ySlider.getValue()), size, com);
display.setModel(model);
} // end of startButton_ActionPerformed
这可能会导致......
关于Java jFrame Canvas 绘制点而不是线，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36757704/