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Rotating Coordinate Plane for Data and Text in Java
This issue deals with challenges in plotting data points and rotating labels on the y-axis of a data plot. The provided code defines basic structures for plotting data and labels, but it encounters two difficulties:
Resolving the Issues
To address these issues, let's focus on the following modifications:
1. Rotating the Coordinate Plane
We can rotate the coordinate plane to align with the new origin (bottom-left corner of the blue rectangle) and invert the y-axis using the following code:
<code class="java">g2d.translate(leftStartPlotWindow, blueTop);//translate origin to bottom-left corner of blue rectangle g2d.scale(1, -1);//invert the y-axis</code>
2. Plotting Data
We adjust the data to fit the rotated coordinate plane by multiplying it by a scalar:
<code class="java">double Scalar = blueWidth/maxPlot; ArrayList<Double> scaledDiffs = new ArrayList<>(); for(int e = 0;e<myDiffs.size();e++){scaledDiffs.add(myDiffs.get(e)*Scalar);}</code>
3. Rotating Text for Y-Axis Labels
To rotate labels on the y-axis, we use the following code:
<code class="java">g2d.rotate(Math.toRadians(-90), 0, 0);//rotate text 90 degrees counter-clockwise g.drawString(yString, -(height/2)-(yStrWidth/2), yStrHeight); g2d.rotate(Math.toRadians(+90), 0, 0);//rotate text 90 degrees clockwise</code>
Complete Code
The modified code with these adjustments should resolve the issues:
DataGUI.java
<code class="java">//... Previous code omitted for brevity import java.awt.geom.AffineTransform; import java.text.DecimalFormat; import java.text.NumberFormat; import java.util.ArrayList; import java.util.List; class DataGUI extends JFrame{ //... Previous code omitted for brevity @Override public void paint(Graphics g) { // ... Previous code omitted for brevity int height = getHeight(); int width = getWidth(); ins = getInsets(); // Obtain data about graphics environment and text Graphics2D g2d = (Graphics2D) g; FontMetrics fontMetrics = g2d.getFontMetrics(); String xString = "x-axis Label"; int xStrWidth = fontMetrics.stringWidth(xString); int xStrHeight = fontMetrics.getHeight(); // Set parameters for the inner rectangle int hPad = 10; int vPad = 6; int testLeftStartPlotWindow = ins.left + 5 + (3 * yStrHeight); int testInnerWidth = width - testLeftStartPlotWindow - ins.right - hPad; // Find minimum and maximum values getMaxMinDiffs(); getMaxPlotVal(); // Determine the maximum number of ticks for the axes double increment = 5.0; int numTicks = (int) (maxPlot / increment); int remainder = testInnerWidth % numTicks; int leftStartPlotWindow = testLeftStartPlotWindow - remainder; // Calculate the bottom padding and blue rectangle dimensions int bottomPad = (3 * xStrHeight) - vPad; int blueTop = ins.bottom + (vPad / 2) + titleStrHeight; int blueHeight = height - bottomPad - blueTop; int blueWidth = blueHeight; int blueBottom = blueHeight + blueTop; // Start drawing // ... Previous code omitted for brevity // Scale the diffs to fit the window double Scalar = blueWidth / maxPlot; List<Double> scaledDiffs = new ArrayList<>(); for (Double myDiff : myDiffs) { scaledDiffs.add(myDiff * Scalar); } // Rotate the graphics context for plotting data AffineTransform at = g2d.getTransform(); g2d.translate(leftStartPlotWindow, blueTop); g2d.scale(1, -1); // Plot the scaled diffs for (int w = 0; w < scaledDiffs.size(); w++) { if (w > 0) { double prior = scaledDiffs.get(w - 1); int priorInt = (int) prior; double current = scaledDiffs.get(w); int currentInt = (int) current; g2d.drawOval(priorInt, currentInt, 4, 4); } } // Restore the transform for conventional rendering g2d.setTransform(at); // ... Rest of the code omitted for brevity } // ... Previous code omitted for brevity }</code>
DataPanel.java
<code class="java">//... Previous code omitted for brevity @Override protected void paintComponent(Graphics g) { //... Previous code omitted for brevity int blueTop = ins.bottom+(vPad/2)+titleStrHeight; int blueHeight = height-bottomPad-blueTop; int blueWidth = blueHeight; int blueBottom = blueHeight+blueTop; //... Previous code omitted for brevity // Rotate the graphics context for y-axis labels g2d.rotate(Math.toRadians(-90), 0, 0); g.drawString(yString, -(height/2)-(yStrWidth/2), yStrHeight); // Restore the graphics context for normal rendering g2d.rotate(Math.toRadians(+90), 0, 0); //... Previous code omitted for brevity }</code>
Additional Resource
For further information on graphics transformations, refer to:
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