我有一个定义为坐标系的矩形，如下图所示。我想绘制点（-7.224,1002），但是我无法创建公式来绘制对应于该值的公式。参考代码：
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Stroke;
import java.awt.geom.AffineTransform;
import java.awt.geom.Ellipse2D;
import java.awt.geom.NoninvertibleTransformException;
import java.awt.geom.Point2D;
import java.io.BufferedReader;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.DoubleSummaryStatistics;
import java.util.stream.Collectors;
import javax.swing.JComponent;
class PlotComponent extends JComponent {
private ArrayList<Point> points = new ArrayList<Point>();
int sum=0,count=0,count1=0;
int val=0,val1=0;
private Color gridColor=new Color(200,200,200,200);
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
int x_start_point=(int)(getWidth()*0.1);
int x_end_point=(int)(getWidth()*0.8);
int y_start_point=(int)(getHeight()*0.1);
int y_end_point=(int)(getHeight()*0.8);
int y_line=y_end_point+y_start_point;
int x_line=x_end_point+x_start_point;
int div_x=(x_end_point-x_start_point)/13;
int div_y=(y_end_point-y_start_point)/13;
Rectangle shape=new Rectangle(x_start_point,y_start_point,x_end_point,y_end_point);
g2.setColor(Color.WHITE);
g2.fill(shape);
g2.setColor(Color.BLUE);
g2.drawRect(x_start_point,y_start_point,x_end_point,y_end_point);
int count=-2, count1=0;;
for(int i=0;i<15;i++)
{
g2.drawLine(x_start_point+(div_x*i),y_line,x_start_point+(div_x*i),(int)(y_line*1.02));
g2.drawString(Integer.toString(count), (int)(x_start_point+(div_x*i)-3.5),(int)(y_line*1.07));
count+=2;
g2.drawLine(x_start_point,y_line-(div_y*i),(int)(x_start_point*0.85),y_line-(div_y*i));
g2.drawString(Integer.toString(count1),7,(int)(y_line-(div_y*i)));
count1+=500;
}
}
public void addPoint(Point p) {
points.add(p);
}
}
现在，我已经基于一些偏移量值定义了一个矩形，因此在这种情况下，将根据偏移量和取自除法的值来绘制点，但我无法针对相同的点给出解决方案。请帮忙
答案 0 :(得分：0)
查看代码中的更改以及解释它们的注释：
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class SwingTest extends JFrame {
public SwingTest() {
setDefaultCloseOperation(EXIT_ON_CLOSE);
add(new PlotComponent());
pack();
setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(()-> new SwingTest());
}
}
class PlotComponent extends JComponent {
private final ArrayList<Point2D> points = new ArrayList<>();
//use constants for better readability
private static final int X_MARKS = 13, X_START = -8, X_INCREMENT = 2,Y_MARKS = 13,
Y_START = 0, Y_INCREMENT = 500, POINT_SIZE = 1;
public PlotComponent() {
setPreferredSize(new Dimension( 600, 500));
addPoint(new Point2D.Double(-7.224, 1002)); //add test point
}
@Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
//you need to use doubles to avoid rounding error and have use non integer coordinates
double x_start_point = xStart();
double y_start_point = yStart();
double y_end_point = yEnd();
double width = xEnd() - xStart();
double hight = yEnd() - yStart();
double div_x= width/X_MARKS; //this is also the scale: number of pixles per
double div_y= hight/Y_MARKS; //mark. used to scale points when painting
double xOrigin = x_start_point - div_x *(X_START/X_INCREMENT); //location of
double yOrigin = y_end_point + div_y *(Y_START/Y_INCREMENT); // 0,0
Rectangle2D shape=new Rectangle2D.Double(x_start_point,y_start_point,width,hight);
g2.setColor(Color.WHITE);
g2.fill(shape);
g2.setColor(Color.BLUE);
g2.draw(shape);
int xMarkValue= X_START;
for(int i=0; i <= X_MARKS;i++){
Shape xMark = new Line2D.Double(x_start_point+div_x*i, y_end_point,
x_start_point+ div_x*i,y_end_point*1.02);
g2.draw(xMark);
g2.drawString(Integer.toString(xMarkValue), (float) (x_start_point+div_x*i-3.5),
(float)(y_end_point*1.07));
xMarkValue+=X_INCREMENT;
}
int yMarkValue=Y_START;
for(int i=0; i<= Y_MARKS;i++){
Shape yMark = new Line2D.Double(x_start_point,y_end_point-div_y*i,
x_start_point*0.85,y_end_point-div_y*i);
g2.draw(yMark);
g2.drawString(Integer.toString(yMarkValue),7,(float) (y_end_point-div_y*i));
yMarkValue+=Y_INCREMENT;
}
g2.translate(xOrigin, yOrigin); // move the canvas origin to 0,0
g2.setColor(Color.RED);
for( Point2D p : points){
//scale point coordinates. also change y direction
Shape point = new Ellipse2D.Double(p.getX()/div_x, - p.getY()/div_y, POINT_SIZE, POINT_SIZE);
g2.draw(point);
}
}
private double xStart() {
return (int)(getWidth()*0.1);
}
private double xEnd() {
return (int)(getWidth()*0.8);
}
private double yStart() {
return (int)(getHeight()*0.1);
}
private double yEnd() {
return (int)(getHeight()*0.8);
}
public void addPoint(Point2D p) {
points.add(p);
}
}