printer.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.printing;


import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.internal.win32.*;

/**
 * Instances of this class are used to print to a printer.
 * Applications create a GC on a printer using <code>new GC(printer)</code>
 * and then draw on the printer GC using the usual graphics calls.
 * <p>
 * A <code>Printer</code> object may be constructed by providing
 * a <code>PrinterData</code> object which identifies the printer.
 * A <code>PrintDialog</code> presents a print dialog to the user
 * and returns an initialized instance of <code>PrinterData</code>.
 * Alternatively, calling <code>new Printer()</code> will construct a
 * printer object for the user's default printer.
 * </p><p>
 * Application code must explicitly invoke the <code>Printer.dispose()</code> 
 * method to release the operating system resources managed by each instance
 * when those instances are no longer required.
 * </p>
 *
 * @see PrinterData
 * @see PrintDialog
 */
public final class Printer extends Device {
	/**
	 * the handle to the printer DC
	 * (Warning: This field is platform dependent)
	 */
	public int handle;

	/**
	 * the printer data describing this printer
	 */
	PrinterData data;

	/**
	 * whether or not a GC was created for this printer
	 */
	boolean isGCCreated = false;

	/**
	 * strings used to access the Windows registry
	 * (Warning: These fields are platform dependent)
	 */
	static TCHAR profile;
	static TCHAR appName;
	static TCHAR keyName;
	static {
		profile = new TCHAR(0, "PrinterPorts", true); //$NON-NLS-1$
		appName = new TCHAR(0, "windows", true); //$NON-NLS-1$
		keyName = new TCHAR(0, "device", true); //$NON-NLS-1$
	}
	
/**
 * Returns an array of <code>PrinterData</code> objects
 * representing all available printers.
 *
 * @return the list of available printers
 */
public static PrinterData[] getPrinterList() {
	int length = 1024;
	/* Use the character encoding for the default locale */
	TCHAR buf = new TCHAR(0, length);
	TCHAR nullBuf = new TCHAR(0, 1);
	int n = OS.GetProfileString(profile, null, nullBuf, buf, length);
	if (n == 0) return new PrinterData[0];
	String[] deviceNames = new String[5];
	int nameCount = 0;
	int index = 0;
	for (int i = 0; i < n; i++) {
		if (buf.tcharAt(i) == 0) {
			if (nameCount == deviceNames.length) {
				String[] newNames = new String[deviceNames.length + 5];
				System.arraycopy(deviceNames, 0, newNames, 0, deviceNames.length);
				deviceNames = newNames;
			}
			deviceNames[nameCount] = buf.toString(index, i - index);
			nameCount++;
			index = i + 1;
		}
	}
	PrinterData printerList[] = new PrinterData[nameCount];
	for (int p = 0; p < nameCount; p++) {
		String device = deviceNames[p];
		String driver = ""; //$NON-NLS-1$
		if (OS.GetProfileString(profile, new TCHAR(0, device, true), nullBuf, buf, length) > 0) {
			int commaIndex = 0;
			while (buf.tcharAt(commaIndex) != ',' && commaIndex < length) commaIndex++;
			if (commaIndex < length) {
				driver = buf.toString(0, commaIndex);
			}
		}
		printerList[p] = new PrinterData(driver, device);
	}
	return printerList;
}

/**
 * Returns a <code>PrinterData</code> object representing
 * the default printer or <code>null</code> if there is no 
 * printer available on the System.
 *
 * @return the default printer data or null
 * 
 * @since 2.1
 */
public static PrinterData getDefaultPrinterData() {
	String deviceName = null;
	int length = 1024;
	/* Use the character encoding for the default locale */
	TCHAR buf = new TCHAR(0, length);
	TCHAR nullBuf = new TCHAR(0, 1);
	int n = OS.GetProfileString(appName, keyName, nullBuf, buf, length);
	if (n == 0) return null;
	int commaIndex = 0;
	while(buf.tcharAt(commaIndex) != ',' && commaIndex < length) commaIndex++;
	if (commaIndex < length) {
		deviceName = buf.toString(0, commaIndex);		
	}
	String driver = ""; //$NON-NLS-1$
	if (OS.GetProfileString(profile, new TCHAR(0, deviceName, true), nullBuf, buf, length) > 0) {
		commaIndex = 0;
		while (buf.tcharAt(commaIndex) != ',' && commaIndex < length) commaIndex++;
		if (commaIndex < length) {
			driver = buf.toString(0, commaIndex);	
		}
	}
	return new PrinterData(driver, deviceName);
}

static DeviceData checkNull (PrinterData data) {
	if (data == null) data = new PrinterData();
	if (data.driver == null || data.name == null) {
		PrinterData defaultPrinter = getDefaultPrinterData();
		if (defaultPrinter == null) SWT.error(SWT.ERROR_NO_HANDLES);
		data.driver = defaultPrinter.driver;
		data.name = defaultPrinter.name;		
	}
	return data;
}

/**
 * Constructs a new printer representing the default printer.
 * <p>
 * You must dispose the printer when it is no longer required. 
 * </p>
 *
 * @exception SWTError <ul>
 *    <li>ERROR_NO_HANDLES - if there are no valid printers
 * </ul>
 *
 * @see Device#dispose
 */
public Printer() {
	this(null);
}

/**
 * Constructs a new printer given a <code>PrinterData</code>
 * object representing the desired printer.
 * <p>
 * You must dispose the printer when it is no longer required. 
 * </p>
 *
 * @param data the printer data for the specified printer
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the specified printer data does not represent a valid printer
 * </ul>
 * @exception SWTError <ul>
 *    <li>ERROR_NO_HANDLES - if there are no valid printers
 * </ul>
 *
 * @see Device#dispose
 */
public Printer(PrinterData data) {
	super(checkNull(data));
}

/**	 
 * Creates the printer handle.
 * This method is called internally by the instance creation
 * mechanism of the <code>Device</code> class.
 */
protected void create(DeviceData deviceData) {
	data = (PrinterData)deviceData;
	/* Use the character encoding for the default locale */
	TCHAR driver = new TCHAR(0, data.driver, true);
	TCHAR device = new TCHAR(0, data.name, true);
	int lpInitData = 0;
	byte buffer [] = data.otherData;
	int hHeap = OS.GetProcessHeap();
	if (buffer != null && buffer.length != 0) {
		lpInitData = OS.HeapAlloc(hHeap, OS.HEAP_ZERO_MEMORY, buffer.length);
		OS.MoveMemory(lpInitData, buffer, buffer.length);
	}
	handle = OS.CreateDC(driver, device, 0, lpInitData);
	if (lpInitData != 0) OS.HeapFree(hHeap, 0, lpInitData);
	if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES);
}

/**	 
 * Invokes platform specific functionality to allocate a new GC handle.
 * <p>
 * <b>IMPORTANT:</b> This method is <em>not</em> part of the public
 * API for <code>Printer</code>. It is marked public only so that it
 * can be shared within the packages provided by SWT. It is not
 * available on all platforms, and should never be called from
 * application code.
 * </p>
 *
 * @param data the platform specific GC data 
 * @return the platform specific GC handle
 */
public int internal_new_GC(GCData data) {
	if (handle == 0) SWT.error(SWT.ERROR_NO_HANDLES);
	if (data != null) {
		if (isGCCreated) SWT.error(SWT.ERROR_INVALID_ARGUMENT);
		int mask = SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT;
		if ((data.style & mask) != 0) {
			data.layout = (data.style & SWT.RIGHT_TO_LEFT) != 0 ? OS.LAYOUT_RTL : 0;
		} else {
			data.style |= SWT.LEFT_TO_RIGHT;
		}
		data.device = this;
		data.hFont = OS.GetCurrentObject(handle, OS.OBJ_FONT);
		isGCCreated = true;
	}
	return handle;
}

/**	 
 * Invokes platform specific functionality to dispose a GC handle.
 * <p>
 * <b>IMPORTANT:</b> This method is <em>not</em> part of the public
 * API for <code>Printer</code>. It is marked public only so that it
 * can be shared within the packages provided by SWT. It is not
 * available on all platforms, and should never be called from
 * application code.
 * </p>
 *
 * @param hDC the platform specific GC handle
 * @param data the platform specific GC data 
 */
public void internal_dispose_GC(int hDC, GCData data) {
	if (data != null) isGCCreated = false;
}

/**
 * Starts a print job and returns true if the job started successfully