Java tutorial
/******************************************************************************* * Copyright (c) 2006, 2016 IBM Corporation and others. * * This program and the accompanying materials * are made available under the terms of the Eclipse Public License 2.0 * which accompanies this distribution, and is available at * https://www.eclipse.org/legal/epl-2.0/ * * SPDX-License-Identifier: EPL-2.0 * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.swt.examples.graphics; import org.eclipse.swt.SWT; import org.eclipse.swt.graphics.Device; import org.eclipse.swt.graphics.Font; import org.eclipse.swt.graphics.GC; import org.eclipse.swt.graphics.Path; import org.eclipse.swt.graphics.Point; import org.eclipse.swt.graphics.Transform; import org.eclipse.swt.layout.GridLayout; import org.eclipse.swt.widgets.Combo; import org.eclipse.swt.widgets.Composite; import org.eclipse.swt.widgets.Label; import org.eclipse.swt.widgets.Spinner; /** * This tab presents a count down from 5 to 1, then displays SWT. * */ public class CountDownTab extends AnimatedGraphicsTab { final int startNumber = 5; // number at which to start the countdown int nextNumber = startNumber; // next number to be displayed int angle = -90; // angle used to rotate the bar Spinner lineWidthSpinner; // spinner for line width Combo aliasCombo, lineCapCombo; // combo for alias type and line cap int antialias, lineCap; // antialias and linecap values int[] capValues = { SWT.CAP_FLAT, SWT.CAP_SQUARE, SWT.CAP_ROUND }; int[] aliasValues = { SWT.DEFAULT, SWT.OFF, SWT.ON }; /** * Constructor * * @param example * A GraphicsExample */ public CountDownTab(GraphicsExample example) { super(example); } /** * This method creates the controls specific to the tab. The call to the * createControlPanel method in the super class create the controls that are * defined in the super class. * * @param parent * The parent composite */ @Override public void createControlPanel(Composite parent) { super.createControlPanel(parent); if (nextNumber < 1) nextNumber = startNumber; // add selection listener to reset nextNumber after // the sequence has completed playItem.addListener(SWT.Selection, event -> { if (nextNumber < 1) nextNumber = startNumber; }); Composite comp; GridLayout gridLayout = new GridLayout(2, false); // create spinner for line width comp = new Composite(parent, SWT.NONE); comp.setLayout(gridLayout); new Label(comp, SWT.CENTER).setText(GraphicsExample.getResourceString("LineWidth")); //$NON-NLS-1$ lineWidthSpinner = new Spinner(comp, SWT.BORDER | SWT.WRAP); lineWidthSpinner.setSelection(20); lineWidthSpinner.setMinimum(1); lineWidthSpinner.setMaximum(100); lineWidthSpinner.addListener(SWT.Selection, event -> { if (!pauseItem.isEnabled()) { example.redraw(); } }); // create drop down combo for antialiasing comp = new Composite(parent, SWT.NONE); comp.setLayout(gridLayout); new Label(comp, SWT.CENTER).setText(GraphicsExample.getResourceString("Antialiasing")); //$NON-NLS-1$ aliasCombo = new Combo(comp, SWT.DROP_DOWN); aliasCombo.add("DEFAULT"); aliasCombo.add("OFF"); aliasCombo.add("ON"); aliasCombo.select(0); antialias = aliasValues[0]; aliasCombo.addListener(SWT.Selection, event -> { antialias = aliasValues[aliasCombo.getSelectionIndex()]; if (!pauseItem.isEnabled()) { example.redraw(); } }); // create drop down combo for line cap comp = new Composite(parent, SWT.NONE); comp.setLayout(gridLayout); new Label(comp, SWT.CENTER).setText(GraphicsExample.getResourceString("LineCap")); //$NON-NLS-1$ lineCapCombo = new Combo(comp, SWT.DROP_DOWN); lineCapCombo.add("FLAT"); lineCapCombo.add("SQUARE"); lineCapCombo.add("ROUND"); lineCapCombo.select(0); lineCap = capValues[0]; lineCapCombo.addListener(SWT.Selection, event -> { lineCap = capValues[lineCapCombo.getSelectionIndex()]; if (!pauseItem.isEnabled()) { example.redraw(); } }); } @Override public String getCategory() { return GraphicsExample.getResourceString("Misc"); //$NON-NLS-1$ } @Override public String getText() { return GraphicsExample.getResourceString("Countdown"); //$NON-NLS-1$ } @Override public String getDescription() { return GraphicsExample.getResourceString("CountdownDescription"); //$NON-NLS-1$ } @Override public int getInitialAnimationTime() { return 28; } @Override public void next(int width, int height) { if (angle == 270) { nextNumber--; if (nextNumber < 1) { // stop animation setAnimation(false); } angle = -90; } angle += 10; } @Override public void paint(GC gc, int width, int height) { if (!example.checkAdvancedGraphics()) return; Device device = gc.getDevice(); // diameter of the circle in pixels int diameter = ((width < height) ? width - 25 : height - 25); if (!getAnimation() && nextNumber == 0) { Font font = new Font(device, getPlatformFontFace(1), diameter / 2, SWT.NONE); gc.setFont(font); // display "SWT" gc.setForeground(device.getSystemColor(SWT.COLOR_DARK_BLUE)); gc.setTextAntialias(SWT.ON); // determine the dimensions of the word String text = GraphicsExample.getResourceString("SWT"); Point point = gc.stringExtent(text); int textWidth = point.x; int textHeight = point.y; gc.drawString(text, (width - textWidth) / 2, (height - textHeight) / 2, true); font.dispose(); } else { Font font = new Font(device, getPlatformFontFace(0), 6 * diameter / 10, SWT.NONE); gc.setFont(font); // set attributes from controls gc.setLineWidth(lineWidthSpinner.getSelection()); gc.setLineCap(lineCap); // round line ends gc.setAntialias(antialias); // smooth jagged edges gc.setTextAntialias(antialias); // smooth jagged edges // draw the circles Path path = new Path(device); path.addArc((width - diameter) / 2, (height - diameter) / 2, diameter, diameter, 0, 360); path.addArc((width - diameter + 50) / 2, (height - diameter + 50) / 2, diameter - 50, diameter - 50, 0, 360); gc.drawPath(path); gc.setBackground(device.getSystemColor(SWT.COLOR_RED)); gc.fillPath(path); path.dispose(); Point point = gc.stringExtent(Integer.valueOf(nextNumber).toString()); int textWidth = point.x; int textHeight = point.y; // draw the number gc.drawString(Integer.valueOf(nextNumber).toString(), (width - textWidth) / 2, (height - textHeight) / 2, true); // draw the rotating arm Transform transform = new Transform(device); transform.translate(width / 2, height / 2); transform.rotate(angle); gc.setTransform(transform); gc.setForeground(device.getSystemColor(SWT.COLOR_RED)); gc.drawLine(0, 0, diameter / 2, 0); transform.dispose(); font.dispose(); } } /** * Returns the name of a valid font for the resident platform. * * @param index * index is used to determine the appropriate font face */ static String getPlatformFontFace(int index) { if (SWT.getPlatform() == "win32") { return new String[] { "Courier", "Impact" }[index]; } else if (SWT.getPlatform() == "gtk") { return new String[] { "Courier", "Baekmuk Headline" }[index]; } else { return new String[] { "Courier", "Verdana" }[index]; } } }