Java tutorial
//package com.java2s; /* * 11/14/2003 * * RPrintUtilities.java - A collection of static methods useful for printing * text from Swing text components. * * This library is distributed under a modified BSD license. See the included * RSyntaxTextArea.License.txt file for details. */ import javax.swing.text.BadLocationException; import javax.swing.text.Document; import javax.swing.text.Element; import java.awt.Color; import java.awt.Font; import java.awt.FontMetrics; import java.awt.Graphics; import java.awt.print.*; public class Main { private static int currentDocLineNumber; private static int numDocLines; private static Element rootElement; private static final char[] breakChars = { ' ', '\t', ',', '.', ';', '?', '!' }; private static int xOffset; private static int tabSizeInSpaces; private static FontMetrics fm; /** * Prints a <code>Document</code> using a monospaced font, word wrapping on * the characters ' ', '\t', '\n', ',', '.', and ';'. This method is * expected to be called from Printable 'print(Graphics g)' functions. * * @param g The graphics context to write to. * @param doc The <code>javax.swing.text.Document</code> to print. * @param fontSize the point size to use for the monospaced font. * @param pageIndex The page number to print. * @param pageFormat The format to print the page with. * @param tabSize The number of spaces to expand tabs to. * * @see #printDocumentMonospaced */ public static int printDocumentMonospacedWordWrap(Graphics g, Document doc, int fontSize, int pageIndex, PageFormat pageFormat, int tabSize) { g.setColor(Color.BLACK); g.setFont(new Font("Monospaced", Font.PLAIN, fontSize)); // Initialize our static variables (these are used by our tab expander below). tabSizeInSpaces = tabSize; fm = g.getFontMetrics(); // Create our tab expander. //RPrintTabExpander tabExpander = new RPrintTabExpander(); // Get width and height of characters in this monospaced font. int fontWidth = fm.charWidth('w'); // Any character will do here, since font is monospaced. int fontHeight = fm.getHeight(); int MAX_CHARS_PER_LINE = (int) pageFormat.getImageableWidth() / fontWidth; int MAX_LINES_PER_PAGE = (int) pageFormat.getImageableHeight() / fontHeight; final int STARTING_LINE_NUMBER = MAX_LINES_PER_PAGE * pageIndex; // The (x,y) coordinate to print at (in pixels, not characters). // Since y is the baseline of where we'll start printing (not the top-left // corner), we offset it by the font's ascent ( + 1 just for good measure). xOffset = (int) pageFormat.getImageableX(); int y = (int) pageFormat.getImageableY() + fm.getAscent() + 1; // A counter to keep track of the number of lines that WOULD HAVE been // printed if we were printing all lines. int numPrintedLines = 0; // Keep going while there are more lines in the document. currentDocLineNumber = 0; // The line number of the document we're currently on. rootElement = doc.getDefaultRootElement(); // To shorten accesses in our loop. numDocLines = rootElement.getElementCount(); // The number of lines in our document. while (currentDocLineNumber < numDocLines) { // Get the line we are going to print. String curLineString; Element currentLine = rootElement.getElement(currentDocLineNumber); int startOffs = currentLine.getStartOffset(); try { curLineString = doc.getText(startOffs, currentLine.getEndOffset() - startOffs); } catch (BadLocationException ble) { // Never happens ble.printStackTrace(); return Printable.NO_SUCH_PAGE; } // Remove newlines, because they end up as boxes if you don't; this is a monospaced font. curLineString = curLineString.replaceAll("\n", ""); // Replace tabs with how many spaces they should be. if (tabSizeInSpaces == 0) { curLineString = curLineString.replaceAll("\t", ""); } else { int tabIndex = curLineString.indexOf('\t'); while (tabIndex > -1) { int spacesNeeded = tabSizeInSpaces - (tabIndex % tabSizeInSpaces); String replacementString = ""; for (int i = 0; i < spacesNeeded; i++) replacementString += ' '; // Note that "\t" is actually a regex for this method. curLineString = curLineString.replaceFirst("\t", replacementString); tabIndex = curLineString.indexOf('\t'); } } // If this document line is too long to fit on one printed line on the page, // break it up into multpile lines. while (curLineString.length() > MAX_CHARS_PER_LINE) { int breakPoint = getLineBreakPoint(curLineString, MAX_CHARS_PER_LINE) + 1; numPrintedLines++; if (numPrintedLines > STARTING_LINE_NUMBER) { g.drawString(curLineString.substring(0, breakPoint), xOffset, y); y += fontHeight; if (numPrintedLines == STARTING_LINE_NUMBER + MAX_LINES_PER_PAGE) return Printable.PAGE_EXISTS; } curLineString = curLineString.substring(breakPoint, curLineString.length()); } currentDocLineNumber += 1; // We have printed one more line from the document. numPrintedLines++; if (numPrintedLines > STARTING_LINE_NUMBER) { g.drawString(curLineString, xOffset, y); y += fontHeight; if (numPrintedLines == STARTING_LINE_NUMBER + MAX_LINES_PER_PAGE) return Printable.PAGE_EXISTS; } } // Now, the whole document has been "printed." Decide if this page had any text on it or not. if (numPrintedLines > STARTING_LINE_NUMBER) return Printable.PAGE_EXISTS; return Printable.NO_SUCH_PAGE; } /** * Returns the position closest to, but before, position <code>maxCharsPerLine</code> in * <code>line</code> of one of the chars in <code>breakChars</code>, or simply returns * <code>maxCharsPerLine-1</code> if none of the <code>breakChars</code> comes before * that position. This position represents the logical line break for this <code>java.lang.String</code> * if it is being printed in a monospaced font when lines can only be <code>maxCharsPerLine</code> * characters long. * * @param line The text being printed. * @param maxCharsPerLine Only up-to this many characters from * <code>line</code> can be printed on one line. * @return The logical position at which to stop printing <code>line</code> * to simulate word wrap. */ private static int getLineBreakPoint(String line, final int maxCharsPerLine) { int breakPoint = -1; for (int i = 0; i < breakChars.length; i++) { int breakCharPos = line.lastIndexOf(breakChars[i], maxCharsPerLine - 1); if (breakCharPos > breakPoint) breakPoint = breakCharPos; } return (breakPoint == -1 ? maxCharsPerLine - 1 : breakPoint); } }