Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2018 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 * Lars Vogel <Lars.Vogel@vogella.com> - Bug 502845 *******************************************************************************/ package org.eclipse.swt.snippets; /* * Printing example snippet: print text to printer, with word wrap and pagination * * For a list of all SWT example snippets see * http://www.eclipse.org/swt/snippets/ */ import static org.eclipse.swt.events.SelectionListener.*; import java.io.*; import org.eclipse.swt.*; import org.eclipse.swt.graphics.*; import org.eclipse.swt.layout.*; import org.eclipse.swt.printing.*; import org.eclipse.swt.widgets.*; public class Snippet133 { Display display; Shell shell; Text text; Font font; Color foregroundColor, backgroundColor; Printer printer; GC gc; FontData[] printerFontData; RGB printerForeground, printerBackground; int lineHeight = 0; int tabWidth = 0; int leftMargin, rightMargin, topMargin, bottomMargin; int x, y; int index, end; String textToPrint; String tabs; StringBuilder wordBuffer; public static void main(String[] args) { new Snippet133().open(); } void open() { display = new Display(); shell = new Shell(display); shell.setLayout(new FillLayout()); shell.setText("Print Text"); text = new Text(shell, SWT.BORDER | SWT.MULTI | SWT.V_SCROLL | SWT.H_SCROLL); Menu menuBar = new Menu(shell, SWT.BAR); shell.setMenuBar(menuBar); MenuItem item = new MenuItem(menuBar, SWT.CASCADE); item.setText("&File"); Menu fileMenu = new Menu(shell, SWT.DROP_DOWN); item.setMenu(fileMenu); item = new MenuItem(fileMenu, SWT.PUSH); item.setText("&Open..."); item.setAccelerator(SWT.CTRL + 'O'); item.addSelectionListener(widgetSelectedAdapter(e -> menuOpen())); item = new MenuItem(fileMenu, SWT.PUSH); item.setText("Font..."); item.addSelectionListener(widgetSelectedAdapter(e -> menuFont())); item = new MenuItem(fileMenu, SWT.PUSH); item.setText("Foreground Color..."); item.addSelectionListener(widgetSelectedAdapter(e -> menuForegroundColor())); item = new MenuItem(fileMenu, SWT.PUSH); item.setText("Background Color..."); item.addSelectionListener(widgetSelectedAdapter(e -> menuBackgroundColor())); item = new MenuItem(fileMenu, SWT.PUSH); item.setText("&Print..."); item.setAccelerator(SWT.CTRL + 'P'); item.addSelectionListener(widgetSelectedAdapter(e -> menuPrint())); new MenuItem(fileMenu, SWT.SEPARATOR); item = new MenuItem(fileMenu, SWT.PUSH); item.setText("E&xit"); item.addSelectionListener(widgetSelectedAdapter(e -> shell.dispose())); shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) display.sleep(); } if (font != null) font.dispose(); if (foregroundColor != null) foregroundColor.dispose(); if (backgroundColor != null) backgroundColor.dispose(); display.dispose(); } void menuOpen() { final String textString; FileDialog dialog = new FileDialog(shell, SWT.OPEN); dialog.setFilterExtensions(new String[] { "*.java", "*.*" }); String name = dialog.open(); if ((name == null) || (name.length() == 0)) return; File file = new File(name); try (FileInputStream stream = new FileInputStream(file.getPath())) { Reader in = new BufferedReader(new InputStreamReader(stream)); char[] readBuffer = new char[2048]; StringBuilder buffer = new StringBuilder((int) file.length()); int n; while ((n = in.read(readBuffer)) > 0) { buffer.append(readBuffer, 0, n); } textString = buffer.toString(); stream.close(); } catch (FileNotFoundException e) { MessageBox box = new MessageBox(shell, SWT.ICON_ERROR); box.setMessage("File not found:\n" + name); box.open(); return; } catch (IOException e) { MessageBox box = new MessageBox(shell, SWT.ICON_ERROR); box.setMessage("Error reading file:\n" + name); box.open(); return; } text.setText(textString); } void menuFont() { FontDialog fontDialog = new FontDialog(shell); fontDialog.setFontList(text.getFont().getFontData()); FontData fontData = fontDialog.open(); if (fontData != null) { if (font != null) font.dispose(); font = new Font(display, fontData); text.setFont(font); } } void menuForegroundColor() { ColorDialog colorDialog = new ColorDialog(shell); colorDialog.setRGB(text.getForeground().getRGB()); RGB rgb = colorDialog.open(); if (rgb != null) { if (foregroundColor != null) foregroundColor.dispose(); foregroundColor = new Color(display, rgb); text.setForeground(foregroundColor); } } void menuBackgroundColor() { ColorDialog colorDialog = new ColorDialog(shell); colorDialog.setRGB(text.getBackground().getRGB()); RGB rgb = colorDialog.open(); if (rgb != null) { if (backgroundColor != null) backgroundColor.dispose(); backgroundColor = new Color(display, rgb); text.setBackground(backgroundColor); } } void menuPrint() { PrintDialog dialog = new PrintDialog(shell, SWT.NONE); PrinterData data = dialog.open(); if (data == null) return; if (data.printToFile) { data.fileName = "print.out"; // you probably want to ask the user for a filename } /* Get the text to print from the Text widget (you could get it from anywhere, i.e. your java model) */ textToPrint = text.getText(); /* Get the font & foreground & background data. */ printerFontData = text.getFont().getFontData(); printerForeground = text.getForeground().getRGB(); printerBackground = text.getBackground().getRGB(); /* Do the printing in a background thread so that spooling does not freeze the UI. */ printer = new Printer(data); Thread printingThread = new Thread("Printing") { @Override public void run() { print(printer); printer.dispose(); } }; printingThread.start(); } void print(Printer printer) { if (printer.startJob("Text")) { // the string is the job name - shows up in the printer's job list Rectangle clientArea = printer.getClientArea(); Rectangle trim = printer.computeTrim(0, 0, 0, 0); Point dpi = printer.getDPI(); leftMargin = dpi.x + trim.x; // one inch from left side of paper rightMargin = clientArea.width - dpi.x + trim.x + trim.width; // one inch from right side of paper topMargin = dpi.y + trim.y; // one inch from top edge of paper bottomMargin = clientArea.height - dpi.y + trim.y + trim.height; // one inch from bottom edge of paper /* Create a buffer for computing tab width. */ int tabSize = 4; // is tab width a user setting in your UI? StringBuilder tabBuffer = new StringBuilder(tabSize); for (int i = 0; i < tabSize; i++) tabBuffer.append(' '); tabs = tabBuffer.toString(); /* Create printer GC, and create and set the printer font & foreground color. */ gc = new GC(printer); Font printerFont = new Font(printer, printerFontData); Color printerForegroundColor = new Color(printer, printerForeground); Color printerBackgroundColor = new Color(printer, printerBackground); gc.setFont(printerFont); gc.setForeground(printerForegroundColor); gc.setBackground(printerBackgroundColor); tabWidth = gc.stringExtent(tabs).x; lineHeight = gc.getFontMetrics().getHeight(); /* Print text to current gc using word wrap */ printText(); printer.endJob(); /* Cleanup graphics resources used in printing */ printerFont.dispose(); printerForegroundColor.dispose(); printerBackgroundColor.dispose(); gc.dispose(); } } void printText() { printer.startPage(); wordBuffer = new StringBuilder(); x = leftMargin; y = topMargin; index = 0; end = textToPrint.length(); while (index < end) { char c = textToPrint.charAt(index); index++; if (c != 0) { if (c == 0x0a || c == 0x0d) { if (c == 0x0d && index < end && textToPrint.charAt(index) == 0x0a) { index++; // if this is cr-lf, skip the lf } printWordBuffer(); newline(); } else { if (c != '\t') { wordBuffer.append(c); } if (Character.isWhitespace(c)) { printWordBuffer(); if (c == '\t') { x += tabWidth; } } } } } if (y + lineHeight <= bottomMargin) { printer.endPage(); } } void printWordBuffer() { if (wordBuffer.length() > 0) { String word = wordBuffer.toString(); int wordWidth = gc.stringExtent(word).x; if (x + wordWidth > rightMargin) { /* word doesn't fit on current line, so wrap */ newline(); } gc.drawString(word, x, y, false); x += wordWidth; wordBuffer = new StringBuilder(); } } void newline() { x = leftMargin; y += lineHeight; if (y + lineHeight > bottomMargin) { printer.endPage(); if (index + 1 < end) { y = topMargin; printer.startPage(); } } } }