PrintOperation.java

/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.draw2d;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.printing.Printer;

import org.eclipse.draw2d.geometry.Insets;
import org.eclipse.draw2d.geometry.Rectangle;

/**
 * Implementation of draw2d's printing capabilities. 
 *  
 * @author Dan Lee
 * @author Eric Bordeau
 */
public abstract class PrintOperation {

private GC printerGC;  // Note: Only one GC instance should be created per print job
private Insets printMargin = new Insets(0, 0, 0, 0);
private Printer printer;
private PrinterGraphics printerGraphics;
private SWTGraphics g;

/**
 * Creates a new PrintOperation
 */
public PrintOperation() { }

/**
 * Creates a new PrintOperation on Printer p
 * @param p The printer to print on
 */
public PrintOperation(Printer p) {
	setPrinter(p);
}

/**
 * Disposes the PrinterGraphics and GC objects associated with this PrintOperation. 
 */
protected void cleanup() {
	if (g != null) {
		printerGraphics.dispose();
		g.dispose();
	}
	if (printerGC != null)
		printerGC.dispose();
}		

/**
 * Returns a new PrinterGraphics setup for the Printer associated with this
 * PrintOperation.
 * 
 * @return PrinterGraphics The new PrinterGraphics
 */
protected PrinterGraphics getFreshPrinterGraphics() {
	if (printerGraphics != null) {
		printerGraphics.dispose();
		g.dispose();
		printerGraphics = null;
		g = null;
	}
	g = new SWTGraphics(printerGC);
	printerGraphics = new PrinterGraphics(g, printer);
	setupGraphicsForPage(printerGraphics);
	return printerGraphics;
}

/**
 * This method is invoked by the {@link #run(String)} method to determine the orientation
 * of the GC to be used for printing.  This default implementation always returns
 * SWT.LEFT_TO_RIGHT.
 * @return SWT.LEFT_TO_RIGHT or SWT.RIGHT_TO_LEFT
 * @since 3.1
 * @TODO Make protected post-3.1
 */
int getGraphicsOrientation() {
	return SWT.LEFT_TO_RIGHT;
}

/**
 * Returns the printer.
 * @return Printer
 */
public Printer getPrinter() {
	return printer;
}

/**
 * Returns a Rectangle that represents the region that can be printed to. The x, y,
 * height, and width values are using the printers coordinates.
 * @return the print region
 */
public Rectangle getPrintRegion() {
	org.eclipse.swt.graphics.Rectangle trim = printer.computeTrim(0, 0, 0, 0);
	org.eclipse.swt.graphics.Point printerDPI = printer.getDPI();
	Insets notAvailable = new Insets(-trim.y, -trim.x,
			trim.height + trim.y, trim.width + trim.x);
	Insets userPreferred = new Insets(
			(printMargin.top * printerDPI.x) / 72,
			(printMargin.left * printerDPI.x) / 72,
			(printMargin.bottom * printerDPI.x) / 72,
			(printMargin.right * printerDPI.x) / 72);
	Rectangle paperBounds = new Rectangle(printer.getBounds());	
	Rectangle printRegion = paperBounds.getCropped(notAvailable);
	printRegion.intersect(paperBounds.getCropped(userPreferred));
	printRegion.translate(trim.x, trim.y);
	return printRegion;
}

/**
 * This method contains all operations performed to sourceFigure prior to being printed.
 */
protected void preparePrintSource() { }

/**
 * This method is responsible for printing pages. (A page is printed by calling
 * Printer.startPage(), followed by painting to the PrinterGraphics object, and then
 * calling Printer.endPage()).
 */
protected abstract void printPages();

/**
 * This method contains all operations performed to
 * sourceFigure after being printed.
 */
protected void restorePrintSource() { }

/**
 * Sets the print job into motion. 
 * 
 * @param jobName A String representing the name of the print job
 */
public void run(String jobName) {
	preparePrintSource();
	if (printer.startJob(jobName)) {
		printerGC = new GC(getPrinter(), getGraphicsOrientation());
		printPages();
		printer.endJob();
	}
	restorePrintSource();
	cleanup();
}

/**
 * Sets the printer.
 * @param printer The printer to set
 */
public void setPrinter(Printer printer) {
	this.printer = printer;
}

/**
 * Sets the page margin in pels (logical pixels) to the passed Insets.(72 pels == 1 inch)
 * 
 * @param margin The margin to set on the page 
 */
public void setPrintMargin(Insets margin) {
	printMargin = margin;
}

/**
 * Manipulates the PrinterGraphics to position it to paint in the desired region of the
 * page. (Default is the top left corner of the page).
 * 
 * @param pg The PrinterGraphics to setup
 */
protected void setupGraphicsForPage(PrinterGraphics pg) {
	Rectangle printRegion = getPrintRegion();
	pg.clipRect(printRegion);
	pg.translate(printRegion.getTopLeft());
}

}