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package TIJ4_code.swt;

//: 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);

}

} ///:~