Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2012 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 *******************************************************************************/ package org.eclipse.swt.graphics; import org.eclipse.swt.*; import org.eclipse.swt.internal.cocoa.*; /** * Instances of this class manage operating system resources that * define how text looks when it is displayed. Fonts may be constructed * by providing a device and either name, size and style information * or a <code>FontData</code> object which encapsulates this data. * <p> * Application code must explicitly invoke the <code>Font.dispose()</code> * method to release the operating system resources managed by each instance * when those instances are no longer required. * </p> * * @see FontData * @see <a href="http://www.eclipse.org/swt/snippets/#font">Font snippets</a> * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Examples: GraphicsExample, PaintExample</a> * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> */ public final class Font extends Resource { /** * the handle to the OS font resource * (Warning: This field is platform dependent) * <p> * <b>IMPORTANT:</b> This field is <em>not</em> part of the SWT * public API. 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 accessed from application code. * </p> * * @noreference This field is not intended to be referenced by clients. */ public NSFont handle; /** * the traits not supported to the OS font resource * (Warning: This field is platform dependent) * <p> * <b>IMPORTANT:</b> This field is <em>not</em> part of the SWT * public API. 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 accessed from application code. * </p> * * @noreference This field is not intended to be referenced by clients. */ public int extraTraits; /** * FontMetrics of this font. This has to be calculated by GC, so it's more * efficient to do it once and store it with the Font. */ FontMetrics metrics = null; static final double SYNTHETIC_BOLD = -2.5; static final double SYNTHETIC_ITALIC = 0.2; Font(Device device) { super(device); } /** * Constructs a new font given a device and font data * which describes the desired font's appearance. * <p> * You must dispose the font when it is no longer required. * </p> * * @param device the device to create the font on * @param fd the FontData that describes the desired font (must not be null) * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device</li> * <li>ERROR_NULL_ARGUMENT - if the fd argument is null</li> * </ul> * @exception SWTError <ul> * <li>ERROR_NO_HANDLES - if a font could not be created from the given font data</li> * </ul> * * @see #dispose() */ public Font(Device device, FontData fd) { super(device); if (fd == null) SWT.error(SWT.ERROR_NULL_ARGUMENT); NSAutoreleasePool pool = null; if (!NSThread.isMainThread()) pool = (NSAutoreleasePool) new NSAutoreleasePool().alloc().init(); try { init(fd.getName(), fd.getHeightF(), fd.getStyle(), fd.nsName); init(); } finally { if (pool != null) pool.release(); } } /** * Constructs a new font given a device and an array * of font data which describes the desired font's * appearance. * <p> * You must dispose the font when it is no longer required. * </p> * * @param device the device to create the font on * @param fds the array of FontData that describes the desired font (must not be null) * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device</li> * <li>ERROR_NULL_ARGUMENT - if the fds argument is null</li> * <li>ERROR_INVALID_ARGUMENT - if the length of fds is zero</li> * <li>ERROR_NULL_ARGUMENT - if any fd in the array is null</li> * </ul> * @exception SWTError <ul> * <li>ERROR_NO_HANDLES - if a font could not be created from the given font data</li> * </ul> * * @see #dispose() * * @since 2.1 */ public Font(Device device, FontData[] fds) { super(device); if (fds == null) SWT.error(SWT.ERROR_NULL_ARGUMENT); if (fds.length == 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT); for (int i = 0; i < fds.length; i++) { if (fds[i] == null) SWT.error(SWT.ERROR_INVALID_ARGUMENT); } NSAutoreleasePool pool = null; if (!NSThread.isMainThread()) pool = (NSAutoreleasePool) new NSAutoreleasePool().alloc().init(); try { FontData fd = fds[0]; init(fd.getName(), fd.getHeightF(), fd.getStyle(), fd.nsName); init(); } finally { if (pool != null) pool.release(); } } /** * Constructs a new font given a device, a font name, * the height of the desired font in points, and a font * style. * <p> * You must dispose the font when it is no longer required. * </p> * * @param device the device to create the font on * @param name the name of the font (must not be null) * @param height the font height in points * @param style a bit or combination of NORMAL, BOLD, ITALIC * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if device is null and there is no current device</li> * <li>ERROR_NULL_ARGUMENT - if the name argument is null</li> * <li>ERROR_INVALID_ARGUMENT - if the height is negative</li> * </ul> * @exception SWTError <ul> * <li>ERROR_NO_HANDLES - if a font could not be created from the given arguments</li> * </ul> * * @see #dispose() */ public Font(Device device, String name, int height, int style) { super(device); NSAutoreleasePool pool = null; if (!NSThread.isMainThread()) pool = (NSAutoreleasePool) new NSAutoreleasePool().alloc().init(); try { init(name, height, style, null); init(); } finally { if (pool != null) pool.release(); } } /*public*/ Font(Device device, String name, float height, int style) { super(device); init(name, height, style, null); init(); } void addTraits(NSMutableAttributedString attrStr, NSRange range) { if ((extraTraits & OS.NSBoldFontMask) != 0) { attrStr.addAttribute(OS.NSStrokeWidthAttributeName, NSNumber.numberWithDouble(SYNTHETIC_BOLD), range); } if ((extraTraits & OS.NSItalicFontMask) != 0) { attrStr.addAttribute(OS.NSObliquenessAttributeName, NSNumber.numberWithDouble(SYNTHETIC_ITALIC), range); } } void addTraits(NSMutableDictionary dict) { if ((extraTraits & OS.NSBoldFontMask) != 0) { dict.setObject(NSNumber.numberWithDouble(SYNTHETIC_BOLD), OS.NSStrokeWidthAttributeName); } if ((extraTraits & OS.NSItalicFontMask) != 0) { dict.setObject(NSNumber.numberWithDouble(SYNTHETIC_ITALIC), OS.NSObliquenessAttributeName); } } @Override void destroy() { handle.release(); handle = null; metrics = null; } /** * Compares the argument to the receiver, and returns true * if they represent the <em>same</em> object using a class * specific comparison. * * @param object the object to compare with this object * @return <code>true</code> if the object is the same as this object and <code>false</code> otherwise * * @see #hashCode */ @Override public boolean equals(Object object) { if (object == this) return true; if (!(object instanceof Font)) return false; Font font = (Font) object; return handle == font.handle; } /** * Returns an array of <code>FontData</code>s representing the receiver. * On Windows, only one FontData will be returned per font. On X however, * a <code>Font</code> object <em>may</em> be composed of multiple X * fonts. To support this case, we return an array of font data objects. * * @return an array of font data objects describing the receiver * * @exception SWTException <ul> * <li>ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed</li> * </ul> */ public FontData[] getFontData() { if (isDisposed()) SWT.error(SWT.ERROR_GRAPHIC_DISPOSED); NSAutoreleasePool pool = null; if (!NSThread.isMainThread()) pool = (NSAutoreleasePool) new NSAutoreleasePool().alloc().init(); try { NSString family = handle.familyName(); String name = family.getString(); NSString str = handle.fontName(); String nsName = str.getString(); NSFontManager manager = NSFontManager.sharedFontManager(); long traits = manager.traitsOfFont(handle); int style = SWT.NORMAL; if ((traits & OS.NSItalicFontMask) != 0) style |= SWT.ITALIC; if ((traits & OS.NSBoldFontMask) != 0) style |= SWT.BOLD; if ((extraTraits & OS.NSItalicFontMask) != 0) style |= SWT.ITALIC; if ((extraTraits & OS.NSBoldFontMask) != 0) style |= SWT.BOLD; Point dpi = device.dpi, screenDPI = device.getScreenDPI(); FontData data = new FontData(name, (float) handle.pointSize() * screenDPI.y / dpi.y, style); data.nsName = nsName; return new FontData[] { data }; } finally { if (pool != null) pool.release(); } } /** * Invokes platform specific functionality to allocate a new font. * <p> * <b>IMPORTANT:</b> This method is <em>not</em> part of the public * API for <code>Font</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 device the device on which to allocate the color * @param handle the handle for the font * * @noreference This method is not intended to be referenced by clients. */ public static Font cocoa_new(Device device, NSFont handle) { Font font = new Font(device); font.handle = handle; return font; } /** * Returns an integer hash code for the receiver. Any two * objects that return <code>true</code> when passed to * <code>equals</code> must return the same value for this * method. * * @return the receiver's hash * * @see #equals */ @Override public int hashCode() { return handle != null ? (int) handle.id : 0; } void init(String name, float height, int style, String nsName) { if (name == null) SWT.error(SWT.ERROR_NULL_ARGUMENT); if (height < 0) SWT.error(SWT.ERROR_INVALID_ARGUMENT); Point dpi = device.dpi, screenDPI = device.getScreenDPI(); float size = height * dpi.y / screenDPI.y; NSFont systemFont = NSFont.systemFontOfSize(size); NSFont boldSystemFont = NSFont.boldSystemFontOfSize(size); String systemFontName = systemFont.familyName().getString(); String boldSystemFontName = boldSystemFont.familyName().getString(); if (systemFontName.equals(name) || boldSystemFontName.equals(name)) { // Use system font to prevent baseline problems with bold text handle = ((style & SWT.BOLD) == 0 ? systemFont : boldSystemFont); } else if (nsName != null) { handle = NSFont.fontWithName(NSString.stringWith(nsName), size); } else { NSString family = NSString.stringWith(name); handle = NSFont.fontWithName(family, size); } initTraits(style, systemFont); handle.retain(); } private void initTraits(int style, NSFont systemFont) { NSFontManager manager = NSFontManager.sharedFontManager(); if (handle != null && (manager.traitsOfFont(handle) & OS.NSBoldFontMask) == 0 && ((style & SWT.BOLD) != 0)) { handle = manager.convertFont(handle, OS.NSBoldFontMask); } if (handle != null && (manager.traitsOfFont(handle) & OS.NSItalicFontMask) == 0 && ((style & SWT.ITALIC) != 0)) { handle = manager.convertFont(handle, OS.NSItalicFontMask); } if (handle == null) { handle = systemFont; } if ((style & SWT.ITALIC) != 0 && (manager.traitsOfFont(handle) & OS.NSItalicFontMask) == 0) { extraTraits |= OS.NSItalicFontMask; } if ((style & SWT.BOLD) != 0 && (manager.traitsOfFont(handle) & OS.NSBoldFontMask) == 0) { extraTraits |= OS.NSBoldFontMask; } } /** * Returns <code>true</code> if the font has been disposed, * and <code>false</code> otherwise. * <p> * This method gets the dispose state for the font. * When a font has been disposed, it is an error to * invoke any other method (except {@link #dispose()}) using the font. * * @return <code>true</code> when the font is disposed and <code>false</code> otherwise */ @Override public boolean isDisposed() { return handle == null; } /** * Returns a string containing a concise, human-readable * description of the receiver. * * @return a string representation of the receiver */ @Override public String toString() { if (isDisposed()) return "Font {*DISPOSED*}"; return "Font {" + handle + "}"; } }