sinewave.java

think in java 最新版本的源码

//: swt/SineWave.java
// SWT translation of Swing SineWave.java.
import swt.util.*;
import org.eclipse.swt.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.layout.*;

class SineDraw extends Canvas {
  private static final int SCALEFACTOR = 200;
  private int cycles;
  private int points;
  private double[] sines;
  private int[] pts;
  public SineDraw(Composite parent, int style) {
    super(parent, style);
    addPaintListener(new PaintListener() {
      public void paintControl(PaintEvent e) {
        int maxWidth = getSize().x;
        double hstep = (double)maxWidth / (double)points;
        int maxHeight = getSize().y;
        pts = new int[points];
        for(int i = 0; i < points; i++)
          pts[i] = (int)((sines[i] * maxHeight / 2 * .95)
            + (maxHeight / 2));
        e.gc.setForeground(
          e.display.getSystemColor(SWT.COLOR_RED));
        for(int i = 1; i < points; i++) {
          int x1 = (int)((i - 1) * hstep);
          int x2 = (int)(i * hstep);
          int y1 = pts[i - 1];
          int y2 = pts[i];
          e.gc.drawLine(x1, y1, x2, y2);
        }
      }
    });
    setCycles(5);
  }
  public void setCycles(int newCycles) {
    cycles = newCycles;
    points = SCALEFACTOR * cycles * 2;
    sines = new double[points];
    for(int i = 0; i < points; i++) {
      double radians = (Math.PI / SCALEFACTOR) * i;
      sines[i] = Math.sin(radians);
    }
    redraw();
  }
}

public class SineWave implements SWTApplication {
  private SineDraw sines;
  private Slider slider;
  public void createContents(Composite parent) {
    parent.setLayout(new GridLayout(1, true));
    sines = new SineDraw(parent, SWT.NONE);
    sines.setLayoutData(
      new GridData(SWT.FILL, SWT.FILL, true, true));
    sines.setFocus();
    slider = new Slider(parent, SWT.HORIZONTAL);
    slider.setValues(5, 1, 30, 1, 1, 1);
    slider.setLayoutData(
      new GridData(SWT.FILL, SWT.DEFAULT, true, false));
    slider.addSelectionListener(new SelectionAdapter() {
      public void widgetSelected(SelectionEvent event) {
        sines.setCycles(slider.getSelection());
      }
    });
  }
  public static void main(String[] args) {
    SWTConsole.run(new SineWave(), 700, 400);
  }
} ///:~