TextPrinterExample.java Source code

Introduction

Here is the source code for TextPrinterExample.java

Source

//Send questions, comments, bug reports, etc. to the authors:

//Rob Warner (rwarner@interspatial.com)
//Robert Harris (rbrt_harris@yahoo.com)

import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.printing.*;
import org.eclipse.swt.widgets.*;

import java.io.*;

/**
 * This class demonstrates printing text
 */
public class TextPrinterExample {
    /**
     * Runs the application
     */
    public void run() {
        Display display = new Display();
        Shell shell = new Shell(display);

        // Get the file to print
        FileDialog fileChooser = new FileDialog(shell, SWT.OPEN);
        String fileName = fileChooser.open();
        if (fileName != null) {
            // Have user select a printer
            PrintDialog dialog = new PrintDialog(shell);
            PrinterData printerData = dialog.open();
            if (printerData != null) {
                // Create the printer
                Printer printer = new Printer(printerData);

                try {
                    // Print the contents of the file
                    new WrappingPrinter(printer, fileName, getFileContents(fileName)).print();
                } catch (Exception e) {
                    MessageBox mb = new MessageBox(shell, SWT.ICON_ERROR | SWT.OK);
                    mb.setMessage(e.getMessage());
                    mb.open();
                }

                // Dispose the printer
                printer.dispose();
            }
        }
        display.dispose();
    }

    /**
     * Read in the file and return its contents
     * @param fileName
     * @return
     * @throws FileNotFoundException
     * @throws IOException
     */
    private String getFileContents(String fileName) throws FileNotFoundException, IOException {
        StringBuffer contents = new StringBuffer();
        BufferedReader reader = null;
        try {
            // Read in the file
            reader = new BufferedReader(new FileReader(fileName));
            while (reader.ready()) {
                contents.append(reader.readLine());
                contents.append("\n"); // Throw away LF chars, and just replace CR
            }
        } finally {
            if (reader != null)
                try {
                    reader.close();
                } catch (IOException e) {
                }
        }
        return contents.toString();
    }

    /**
     * The application entry point
     * 
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new TextPrinterExample().run();
    }
}

/**
 * This class performs the printing, wrapping text as necessary
 */
class WrappingPrinter {
    private Printer printer; // The printer
    private String fileName; // The name of the file to print
    private String contents; // The contents of the file to print
    private GC gc; // The GC to print on
    private int xPos, yPos; // The current x and y locations for print
    private Rectangle bounds; // The boundaries for the print
    private StringBuffer buf; // Holds a word at a time
    private int lineHeight; // The height of a line of text

    /**
     * WrappingPrinter constructor
     * @param printer the printer
     * @param fileName the fileName
     * @param contents the contents
     */
    WrappingPrinter(Printer printer, String fileName, String contents) {
        this.printer = printer;
        this.fileName = fileName;
        this.contents = contents;
    }

    /**
     * Prints the file
     */
    void print() {
        // Start the print job
        if (printer.startJob(fileName)) {
            // Determine print area, with margins
            bounds = computePrintArea(printer);
            xPos = bounds.x;
            yPos = bounds.y;

            // Create the GC
            gc = new GC(printer);

            // Determine line height
            lineHeight = gc.getFontMetrics().getHeight();

            // Determine tab width--use three spaces for tabs
            int tabWidth = gc.stringExtent("   ").x;

            // Print the text
            printer.startPage();
            buf = new StringBuffer();
            char c;
            for (int i = 0, n = contents.length(); i < n; i++) {
                // Get the next character
                c = contents.charAt(i);

                // Check for newline
                if (c == '\n') {
                    printBuffer();
                    printNewline();
                }
                // Check for tab
                else if (c == '\t') {
                    xPos += tabWidth;
                } else {
                    buf.append(c);
                    // Check for space
                    if (Character.isWhitespace(c)) {
                        printBuffer();
                    }
                }
            }
            printer.endPage();
            printer.endJob();
            gc.dispose();
        }
    }

    /**
     * Prints the contents of the buffer
     */
    void printBuffer() {
        // Get the width of the rendered buffer
        int width = gc.stringExtent(buf.toString()).x;

        // Determine if it fits
        if (xPos + width > bounds.x + bounds.width) {
            // Doesn't fit--wrap
            printNewline();
        }

        // Print the buffer
        gc.drawString(buf.toString(), xPos, yPos, false);
        xPos += width;
        buf.setLength(0);
    }

    /**
     * Prints a newline
     */
    void printNewline() {
        // Reset x and y locations to next line
        xPos = bounds.x;
        yPos += lineHeight;

        // Have we gone to the next page?
        if (yPos > bounds.y + bounds.height) {
            yPos = bounds.y;
            printer.endPage();
            printer.startPage();
        }
    }

    /**
     * Computes the print area, including margins
     * @param printer the printer
     * @return Rectangle
     */
    Rectangle computePrintArea(Printer printer) {
        // Get the printable area
        Rectangle rect = printer.getClientArea();

        // Compute the trim
        Rectangle trim = printer.computeTrim(0, 0, 0, 0);

        // Get the printer's DPI
        Point dpi = printer.getDPI();

        // Calculate the printable area, using 1 inch margins
        int left = trim.x + dpi.x;
        if (left < rect.x)
            left = rect.x;

        int right = (rect.width + trim.x + trim.width) - dpi.x;
        if (right > rect.width)
            right = rect.width;

        int top = trim.y + dpi.y;
        if (top < rect.y)
            top = rect.y;

        int bottom = (rect.height + trim.y + trim.height) - dpi.y;
        if (bottom > rect.height)
            bottom = rect.height;

        return new Rectangle(left, top, right - left, bottom - top);
    }
}