Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2014 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.widgets; import org.eclipse.swt.*; import org.eclipse.swt.graphics.*; import org.eclipse.swt.internal.win32.*; /** * Instances of this class allow the user to select a font * from all available fonts in the system. * <dl> * <dt><b>Styles:</b></dt> * <dd>(none)</dd> * <dt><b>Events:</b></dt> * <dd>(none)</dd> * </dl> * <p> * IMPORTANT: This class is <em>not</em> intended to be subclassed. * </p> * * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample, Dialog tab</a> * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a> * @noextend This class is not intended to be subclassed by clients. */ public class FontDialog extends Dialog { FontData fontData; RGB rgb; boolean effectsVisible = true; /** * Constructs a new instance of this class given only its parent. * * @param parent a shell which will be the parent of the new instance * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the parent is null</li> * </ul> * @exception SWTException <ul> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li> * <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li> * </ul> */ public FontDialog(Shell parent) { this(parent, SWT.APPLICATION_MODAL); } /** * Constructs a new instance of this class given its parent * and a style value describing its behavior and appearance. * <p> * The style value is either one of the style constants defined in * class <code>SWT</code> which is applicable to instances of this * class, or must be built by <em>bitwise OR</em>'ing together * (that is, using the <code>int</code> "|" operator) two or more * of those <code>SWT</code> style constants. The class description * lists the style constants that are applicable to the class. * Style bits are also inherited from superclasses. * </p> * * @param parent a shell which will be the parent of the new instance * @param style the style of dialog to construct * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the parent is null</li> * </ul> * @exception SWTException <ul> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li> * <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li> * </ul> */ public FontDialog(Shell parent, int style) { super(parent, checkStyle(parent, style)); checkSubclass(); } /** * Returns <code>true</code> if the dialog's effects selection controls * are visible, and <code>false</code> otherwise. * <p> * If the platform's font dialog does not have any effects selection controls, * then this method always returns false. * </p> * * @return <code>true</code> if the dialog's effects selection controls * are visible and <code>false</code> otherwise * * @since 3.8 */ public boolean getEffectsVisible() { return effectsVisible; } /** * Returns a FontData object describing the font that was * selected in the dialog, or null if none is available. * * @return the FontData for the selected font, or null * @deprecated use #getFontList () */ @Deprecated public FontData getFontData() { return fontData; } /** * Returns a FontData set describing the font that was * selected in the dialog, or null if none is available. * * @return the FontData for the selected font, or null * @since 2.1.1 */ public FontData[] getFontList() { if (fontData == null) return null; FontData[] result = new FontData[1]; result[0] = fontData; return result; } /** * Returns an RGB describing the color that was selected * in the dialog, or null if none is available. * * @return the RGB value for the selected color, or null * * @see PaletteData#getRGBs * * @since 2.1 */ public RGB getRGB() { return rgb; } /** * Makes the dialog visible and brings it to the front * of the display. * * @return a FontData object describing the font that was selected, * or null if the dialog was cancelled or an error occurred * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the dialog has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the dialog</li> * </ul> */ public FontData open() { /* Get the owner HWND for the dialog */ long hwndOwner = parent.handle; long hwndParent = parent.handle; /* * Feature in Windows. There is no API to set the orientation of a * font dialog. It is always inherited from the parent. The fix is * to create a hidden parent and set the orientation in the hidden * parent for the dialog to inherit. */ boolean enabled = false; int dialogOrientation = style & (SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT); int parentOrientation = parent.style & (SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT); if (dialogOrientation != parentOrientation) { int exStyle = OS.WS_EX_NOINHERITLAYOUT; if (dialogOrientation == SWT.RIGHT_TO_LEFT) exStyle |= OS.WS_EX_LAYOUTRTL; hwndOwner = OS.CreateWindowEx(exStyle, Shell.DialogClass, null, 0, OS.CW_USEDEFAULT, 0, OS.CW_USEDEFAULT, 0, hwndParent, 0, OS.GetModuleHandle(null), null); enabled = OS.IsWindowEnabled(hwndParent); if (enabled) OS.EnableWindow(hwndParent, false); } /* Open the dialog */ long hHeap = OS.GetProcessHeap(); CHOOSEFONT lpcf = new CHOOSEFONT(); lpcf.lStructSize = CHOOSEFONT.sizeof; lpcf.hwndOwner = hwndOwner; lpcf.Flags = OS.CF_SCREENFONTS; if (effectsVisible) { lpcf.Flags |= OS.CF_EFFECTS; } long lpLogFont = OS.HeapAlloc(hHeap, OS.HEAP_ZERO_MEMORY, LOGFONT.sizeof); if (fontData != null && fontData.data != null) { LOGFONT logFont = fontData.data; int lfHeight = logFont.lfHeight; long hDC = OS.GetDC(0); int pixels = -(int) (0.5f + (fontData.height * OS.GetDeviceCaps(hDC, OS.LOGPIXELSY) / 72)); OS.ReleaseDC(0, hDC); logFont.lfHeight = pixels; lpcf.Flags |= OS.CF_INITTOLOGFONTSTRUCT; OS.MoveMemory(lpLogFont, logFont, LOGFONT.sizeof); logFont.lfHeight = lfHeight; } lpcf.lpLogFont = lpLogFont; if (rgb != null) { int red = rgb.red & 0xFF; int green = (rgb.green << 8) & 0xFF00; int blue = (rgb.blue << 16) & 0xFF0000; lpcf.rgbColors = red | green | blue; } /* Make the parent shell be temporary modal */ Dialog oldModal = null; Display display = parent.getDisplay(); if ((style & (SWT.APPLICATION_MODAL | SWT.SYSTEM_MODAL)) != 0) { oldModal = display.getModalDialog(); display.setModalDialog(this); } display.sendPreExternalEventDispatchEvent(); /* Open the dialog */ boolean success = OS.ChooseFont(lpcf); display.sendPostExternalEventDispatchEvent(); /* Clear the temporary dialog modal parent */ if ((style & (SWT.APPLICATION_MODAL | SWT.SYSTEM_MODAL)) != 0) { display.setModalDialog(oldModal); } /* Compute the result */ if (success) { LOGFONT logFont = new LOGFONT(); OS.MoveMemory(logFont, lpLogFont, LOGFONT.sizeof); /* * This will not work on multiple screens or * for printing. Should use DC for the proper device. */ long hDC = OS.GetDC(0); int logPixelsY = OS.GetDeviceCaps(hDC, OS.LOGPIXELSY); int pixels = 0; if (logFont.lfHeight > 0) { /* * Feature in Windows. If the lfHeight of the LOGFONT structure * is positive, the lfHeight measures the height of the entire * cell, including internal leading, in logical units. Since the * height of a font in points does not include the internal leading, * we must subtract the internal leading, which requires a TEXTMETRIC, * which in turn requires font creation. */ long hFont = OS.CreateFontIndirect(logFont); long oldFont = OS.SelectObject(hDC, hFont); TEXTMETRIC lptm = new TEXTMETRIC(); OS.GetTextMetrics(hDC, lptm); OS.SelectObject(hDC, oldFont); OS.DeleteObject(hFont); pixels = logFont.lfHeight - lptm.tmInternalLeading; } else { pixels = -logFont.lfHeight; } OS.ReleaseDC(0, hDC); float points = pixels * 72f / logPixelsY; fontData = FontData.win32_new(logFont, points); if (effectsVisible) { int red = lpcf.rgbColors & 0xFF; int green = (lpcf.rgbColors >> 8) & 0xFF; int blue = (lpcf.rgbColors >> 16) & 0xFF; rgb = new RGB(red, green, blue); } } /* Free the OS memory */ if (lpLogFont != 0) OS.HeapFree(hHeap, 0, lpLogFont); /* Destroy the BIDI orientation window */ if (hwndParent != hwndOwner) { if (enabled) OS.EnableWindow(hwndParent, true); OS.SetActiveWindow(hwndParent); OS.DestroyWindow(hwndOwner); } /* * This code is intentionally commented. On some * platforms, the owner window is repainted right * away when a dialog window exits. This behavior * is currently unspecified. */ // if (hwndOwner != 0) OS.UpdateWindow (hwndOwner); if (!success) return null; return fontData; } /** * Sets the effects selection controls in the dialog visible if the * argument is <code>true</code>, and invisible otherwise. * <p> * By default the effects selection controls are displayed if the * platform font dialog supports effects selection. * </p> * * @param visible whether or not the dialog will show the effects selection controls * * @since 3.8 */ public void setEffectsVisible(boolean visible) { effectsVisible = visible; } /** * Sets a FontData object describing the font to be * selected by default in the dialog, or null to let * the platform choose one. * * @param fontData the FontData to use initially, or null * @deprecated use #setFontList (FontData []) */ @Deprecated public void setFontData(FontData fontData) { this.fontData = fontData; } /** * Sets the set of FontData objects describing the font to * be selected by default in the dialog, or null to let * the platform choose one. * * @param fontData the set of FontData objects to use initially, or null * to let the platform select a default when open() is called * * @see Font#getFontData * * @since 2.1.1 */ public void setFontList(FontData[] fontData) { if (fontData != null && fontData.length > 0) { this.fontData = fontData[0]; } else { this.fontData = null; } } /** * Sets the RGB describing the color to be selected by default * in the dialog, or null to let the platform choose one. * * @param rgb the RGB value to use initially, or null to let * the platform select a default when open() is called * * @see PaletteData#getRGBs * * @since 2.1 */ public void setRGB(RGB rgb) { this.rgb = rgb; } }