76 lines
2.3 KiB
Java
76 lines
2.3 KiB
Java
//: swt/SineWave.java
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// ©2015 MindView LLC: see Copyright.txt
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// SWT translation of Swing SineWave.java.
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import swt.util.*;
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import org.eclipse.swt.*;
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import org.eclipse.swt.widgets.*;
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import org.eclipse.swt.events.*;
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import org.eclipse.swt.layout.*;
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class SineDraw extends Canvas {
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private static final int SCALEFACTOR = 200;
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private int cycles;
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private int points;
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private double[] sines;
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private int[] pts;
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public SineDraw(Composite parent, int style) {
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super(parent, style);
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addPaintListener(new PaintListener() {
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public void paintControl(PaintEvent e) {
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int maxWidth = getSize().x;
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double hstep = (double)maxWidth / (double)points;
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int maxHeight = getSize().y;
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pts = new int[points];
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for(int i = 0; i < points; i++)
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pts[i] = (int)((sines[i] * maxHeight / 2 * .95)
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+ (maxHeight / 2));
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e.gc.setForeground(
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e.display.getSystemColor(SWT.COLOR_RED));
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for(int i = 1; i < points; i++) {
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int x1 = (int)((i - 1) * hstep);
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int x2 = (int)(i * hstep);
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int y1 = pts[i - 1];
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int y2 = pts[i];
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e.gc.drawLine(x1, y1, x2, y2);
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}
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}
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});
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setCycles(5);
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}
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public void setCycles(int newCycles) {
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cycles = newCycles;
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points = SCALEFACTOR * cycles * 2;
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sines = new double[points];
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for(int i = 0; i < points; i++) {
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double radians = (Math.PI / SCALEFACTOR) * i;
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sines[i] = Math.sin(radians);
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}
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redraw();
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}
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}
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public class SineWave implements SWTApplication {
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private SineDraw sines;
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private Slider slider;
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@Override
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public void createContents(Composite parent) {
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parent.setLayout(new GridLayout(1, true));
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sines = new SineDraw(parent, SWT.NONE);
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sines.setLayoutData(
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new GridData(SWT.FILL, SWT.FILL, true, true));
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sines.setFocus();
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slider = new Slider(parent, SWT.HORIZONTAL);
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slider.setValues(5, 1, 30, 1, 1, 1);
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slider.setLayoutData(
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new GridData(SWT.FILL, SWT.DEFAULT, true, false));
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slider.addSelectionListener(new SelectionAdapter() {
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public void widgetSelected(SelectionEvent event) {
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sines.setCycles(slider.getSelection());
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}
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});
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}
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public static void main(String[] args) {
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SWTConsole.run(new SineWave(), 700, 400);
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}
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} ///:~
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