How to Rotate the Coordinate Plane in Java for Data Visualization?

Rotating Coordinate Plane for Data and Text in Java

When manipulating data and text in Java, it may be necessary to rotate the coordinate plane to gain a desired perspective. This can involve moving the origin and rotating the plane so that x-values progress rightward and y-values upward from a specified location. Additionally, it may be necessary to plot rotated labels for tic marks on the y-axis.

Moving the Origin and Rotating the Coordinate Plane

To move the origin and rotate the coordinate plane, consider the following steps:

1. Translate the Origin:

   • Use the translate() method from Graphics2D to shift the origin to the desired location. Specify the x and y coordinates of the new origin.

   • For example, to move the origin to the lower left corner of the plotted area:

     <code class="java">g2d.translate(leftStartPlotWindow, blueTop);</code>

2. Invert the Y-Axis:

   • Use the scale() method with a y-scale factor of -1 to invert the y-axis. This will reverse the direction of y-values, resulting in points plotted from bottom to top.

   • For example:

     <code class="java">g2d.scale(1, -1);</code>

Plotting Rotated Labels for Y-Axis Tic Marks

To plot rotated labels for y-axis tic marks, follow these steps:

1. Rotate the Text:

   • Use the rotate() method from Graphics2D to rotate the text counter-clockwise by 90 degrees. Specify the location at which to perform the rotation.

   • For example, to rotate the text for the y-axis labels:

     <code class="java">g2d.rotate(Math.toRadians(-90), 0, 0);</code>

2. Draw the Labels:

   • After rotating the text, use drawString() to draw the tic mark labels at the appropriate locations along the y-axis.

   • For example:

     <code class="java">g.drawString(yString, -(height / 2) - (yStrWidth / 2), yStrHeight);</code>

Code Implementation

Here is an updated version of the DataPanel class with the necessary modifications to rotate the coordinate plane and plot rotated y-axis labels:

<code class="java">import java.awt.*;
import java.awt.geom.AffineTransform;
import javax.swing.*;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.*;

class DataPanel extends JPanel {
    Insets ins; // holds the panel's insets
    ArrayList<Double> myDiffs;
    double maxDiff = Double.NEGATIVE_INFINITY;
    double minDiff = Double.POSITIVE_INFINITY;
    double maxPlot;

    DataPanel(ArrayList<Double> Diffs, int h, int w){
        setOpaque(true);// Ensure that panel is opaque.
        setPreferredSize(new Dimension(w, h));
        setMinimumSize(new Dimension(w, h));
        setMaximumSize(new Dimension(w, h));
        myDiffs = Diffs;
        repaint();
        this.setVisible(true);
    }

    protected void paintComponent(Graphics g){// Override paintComponent() method.
        super.paintComponent(g);
        //get data about plotting environment and about text
        int height = getHeight();
        int width = getWidth();
        ins = getInsets();
        Graphics2D g2d = (Graphics2D)g;
        FontMetrics fontMetrics = g2d.getFontMetrics();
        String xString = ("x-axis label");
        int xStrWidth = fontMetrics.stringWidth(xString);
        int xStrHeight = fontMetrics.getHeight();
        String yString = "y-axis label";
        int yStrWidth = fontMetrics.stringWidth(yString);
        int yStrHeight = fontMetrics.getHeight();</code>

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