Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2018 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.*; import org.eclipse.swt.internal.win32.*; /** * Instances of this class provide an etched border * with an optional title. * <p> * Shadow styles are hints and may not be honoured * by the platform. To create a group with the * default shadow style for the platform, do not * specify a shadow style. * <dl> * <dt><b>Styles:</b></dt> * <dd>SHADOW_ETCHED_IN, SHADOW_ETCHED_OUT, SHADOW_IN, SHADOW_OUT, SHADOW_NONE</dd> * <dt><b>Events:</b></dt> * <dd>(none)</dd> * </dl> * <p> * Note: Only one of the above styles may be specified. * </p><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</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 Group extends Composite { String text = ""; static final int CLIENT_INSET = 3; static final long GroupProc; static final TCHAR GroupClass = new TCHAR(0, "SWT_GROUP", true); static { /* * Feature in Windows. The group box window class * uses the CS_HREDRAW and CS_VREDRAW style bits to * force a full redraw of the control and all children * when resized. This causes flashing. The fix is to * register a new window class without these bits and * implement special code that damages only the control. */ WNDCLASS lpWndClass = new WNDCLASS(); TCHAR WC_BUTTON = new TCHAR(0, "BUTTON", true); OS.GetClassInfo(0, WC_BUTTON, lpWndClass); GroupProc = lpWndClass.lpfnWndProc; long hInstance = OS.GetModuleHandle(null); if (!OS.GetClassInfo(hInstance, GroupClass, lpWndClass)) { lpWndClass.hInstance = hInstance; lpWndClass.style &= ~(OS.CS_HREDRAW | OS.CS_VREDRAW); OS.RegisterClass(GroupClass, lpWndClass); } } /** * 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 composite control which will be the parent of the new instance (cannot be null) * @param style the style of control 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> * * @see SWT#SHADOW_ETCHED_IN * @see SWT#SHADOW_ETCHED_OUT * @see SWT#SHADOW_IN * @see SWT#SHADOW_OUT * @see SWT#SHADOW_NONE * @see Widget#checkSubclass * @see Widget#getStyle */ public Group(Composite parent, int style) { super(parent, checkStyle(style)); } @Override long callWindowProc(long hwnd, int msg, long wParam, long lParam) { if (handle == 0) return 0; /* * Feature in Windows. When the user clicks on the group * box label, the group box takes focus. This is unwanted. * The fix is to avoid calling the group box window proc. */ switch (msg) { case OS.WM_LBUTTONDOWN: case OS.WM_LBUTTONDBLCLK: return OS.DefWindowProc(hwnd, msg, wParam, lParam); } return OS.CallWindowProc(GroupProc, hwnd, msg, wParam, lParam); } static int checkStyle(int style) { style |= SWT.NO_FOCUS; /* * Even though it is legal to create this widget * with scroll bars, they serve no useful purpose * because they do not automatically scroll the * widget's client area. The fix is to clear * the SWT style. */ return style & ~(SWT.H_SCROLL | SWT.V_SCROLL); } @Override protected void checkSubclass() { if (!isValidSubclass()) error(SWT.ERROR_INVALID_SUBCLASS); } @Override Point computeSizeInPixels(int wHint, int hHint, boolean changed) { checkWidget(); Point size = super.computeSizeInPixels(wHint, hHint, changed); int length = text.length(); if (length != 0) { String string = fixText(false); /* * If the group has text, and the text is wider than the * client area, pad the width so the text is not clipped. */ char[] buffer = (string == null ? text : string).toCharArray(); long newFont, oldFont = 0; long hDC = OS.GetDC(handle); newFont = OS.SendMessage(handle, OS.WM_GETFONT, 0, 0); if (newFont != 0) oldFont = OS.SelectObject(hDC, newFont); RECT rect = new RECT(); int flags = OS.DT_CALCRECT | OS.DT_SINGLELINE; OS.DrawText(hDC, buffer, buffer.length, rect, flags); if (newFont != 0) OS.SelectObject(hDC, oldFont); OS.ReleaseDC(handle, hDC); int offsetY = OS.IsAppThemed() ? 0 : 1; size.x = Math.max(size.x, rect.right - rect.left + CLIENT_INSET * 6 + offsetY); } return size; } @Override Rectangle computeTrimInPixels(int x, int y, int width, int height) { checkWidget(); Rectangle trim = super.computeTrimInPixels(x, y, width, height); long newFont, oldFont = 0; long hDC = OS.GetDC(handle); newFont = OS.SendMessage(handle, OS.WM_GETFONT, 0, 0); if (newFont != 0) oldFont = OS.SelectObject(hDC, newFont); TEXTMETRIC tm = new TEXTMETRIC(); OS.GetTextMetrics(hDC, tm); if (newFont != 0) OS.SelectObject(hDC, oldFont); OS.ReleaseDC(handle, hDC); int offsetY = OS.IsAppThemed() ? 0 : 1; trim.x -= CLIENT_INSET; trim.y -= tm.tmHeight + offsetY; trim.width += CLIENT_INSET * 2; trim.height += tm.tmHeight + CLIENT_INSET + offsetY; return trim; } @Override void createHandle() { /* * Feature in Windows. When a button is created, * it clears the UI state for all controls in the * shell by sending WM_CHANGEUISTATE with UIS_SET, * UISF_HIDEACCEL and UISF_HIDEFOCUS to the parent. * This is undocumented and unexpected. The fix * is to ignore the WM_CHANGEUISTATE, when sent * from CreateWindowEx(). */ parent.state |= IGNORE_WM_CHANGEUISTATE; super.createHandle(); parent.state &= ~IGNORE_WM_CHANGEUISTATE; state |= DRAW_BACKGROUND; state &= ~CANVAS; } @Override void enableWidget(boolean enabled) { super.enableWidget(enabled); /* * Bug in Windows. When a group control is right-to-left and * is disabled, the first pixel of the text is clipped. The * fix is to add a space to both sides of the text. */ String string = fixText(enabled); if (string != null) { TCHAR buffer = new TCHAR(getCodePage(), string, true); OS.SetWindowText(handle, buffer); } if (enabled && hasCustomForeground()) { OS.InvalidateRect(handle, null, true); } } String fixText(boolean enabled) { /* * Bug in Windows. When a group control is right-to-left and * is disabled, the first pixel of the text is clipped. The * fix is to add a space to both sides of the text. */ if (text.length() == 0) return null; if ((style & SWT.RIGHT_TO_LEFT) != 0) { String string = null; if (!enabled && !OS.IsAppThemed()) { string = " " + text + " "; } return (style & SWT.FLIP_TEXT_DIRECTION) == 0 ? string : string != null ? LRE + string : LRE + text; } else if ((style & SWT.FLIP_TEXT_DIRECTION) != 0) { return RLE + text; } return null; } @Override Rectangle getClientAreaInPixels() { checkWidget(); forceResize(); RECT rect = new RECT(); OS.GetClientRect(handle, rect); long newFont, oldFont = 0; long hDC = OS.GetDC(handle); newFont = OS.SendMessage(handle, OS.WM_GETFONT, 0, 0); if (newFont != 0) oldFont = OS.SelectObject(hDC, newFont); TEXTMETRIC tm = new TEXTMETRIC(); OS.GetTextMetrics(hDC, tm); if (newFont != 0) OS.SelectObject(hDC, oldFont); OS.ReleaseDC(handle, hDC); int offsetY = OS.IsAppThemed() ? 0 : 1; int x = CLIENT_INSET, y = tm.tmHeight + offsetY; int width = Math.max(0, rect.right - CLIENT_INSET * 2); int height = Math.max(0, rect.bottom - y - CLIENT_INSET); return new Rectangle(x, y, width, height); } @Override String getNameText() { return getText(); } /** * Returns the receiver's text, which is the string that the * is used as the <em>title</em>. If the text has not previously * been set, returns an empty string. * * @return the text * * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public String getText() { checkWidget(); return text; } @Override boolean mnemonicHit(char key) { return setFocus(); } @Override boolean mnemonicMatch(char key) { char mnemonic = findMnemonic(getText()); if (mnemonic == '\0') return false; return Character.toUpperCase(key) == Character.toUpperCase(mnemonic); } @Override void printWidget(long hwnd, long hdc, GC gc) { /* * Bug in Windows. For some reason, PrintWindow() * returns success but does nothing when it is called * on a printer. The fix is to just go directly to * WM_PRINT in this case. */ boolean success = false; if (!(OS.GetDeviceCaps(gc.handle, OS.TECHNOLOGY) == OS.DT_RASPRINTER)) { int bits = OS.GetWindowLong(hwnd, OS.GWL_STYLE); if ((bits & OS.WS_VISIBLE) == 0) { OS.ShowWindow(hwnd, OS.SW_SHOW); } success = OS.PrintWindow(hwnd, hdc, 0); if ((bits & OS.WS_VISIBLE) == 0) { OS.ShowWindow(hwnd, OS.SW_HIDE); } } /* * Bug in Windows. For some reason, PrintWindow() fails * when it is called on a push button. The fix is to * detect the failure and use WM_PRINT instead. Note * that WM_PRINT cannot be used all the time because it * fails for browser controls when the browser has focus. */ if (!success) { /* * Bug in Windows. For some reason, WM_PRINT when called * with PRF_CHILDREN will not draw the tool bar divider * for tool bar children that do not have CCS_NODIVIDER. * The fix is to draw the group box and iterate through * the children, drawing each one. */ int flags = OS.PRF_CLIENT | OS.PRF_NONCLIENT | OS.PRF_ERASEBKGND; OS.SendMessage(hwnd, OS.WM_PRINT, hdc, flags); int nSavedDC = OS.SaveDC(hdc); Control[] children = _getChildren(); Rectangle rect = getBoundsInPixels(); OS.IntersectClipRect(hdc, 0, 0, rect.width, rect.height); for (int i = children.length - 1; i >= 0; --i) { Point location = children[i].getLocationInPixels(); int graphicsMode = OS.GetGraphicsMode(hdc); if (graphicsMode == OS.GM_ADVANCED) { float[] lpXform = { 1, 0, 0, 1, location.x, location.y }; OS.ModifyWorldTransform(hdc, lpXform, OS.MWT_LEFTMULTIPLY); } else { OS.SetWindowOrgEx(hdc, -location.x, -location.y, null); } long topHandle = children[i].topHandle(); int bits = OS.GetWindowLong(topHandle, OS.GWL_STYLE); if ((bits & OS.WS_VISIBLE) != 0) { children[i].printWidget(topHandle, hdc, gc); } if (graphicsMode == OS.GM_ADVANCED) { float[] lpXform = { 1, 0, 0, 1, -location.x, -location.y }; OS.ModifyWorldTransform(hdc, lpXform, OS.MWT_LEFTMULTIPLY); } } OS.RestoreDC(hdc, nSavedDC); } } @Override void releaseWidget() { super.releaseWidget(); text = null; } @Override int resolveTextDirection() { return BidiUtil.resolveTextDirection(text); } @Override public void setFont(Font font) { checkWidget(); Rectangle oldRect = getClientAreaInPixels(); super.setFont(font); Rectangle newRect = getClientAreaInPixels(); if (!oldRect.equals(newRect)) sendResize(); } /** * Sets the receiver's text, which is the string that will * be displayed as the receiver's <em>title</em>, to the argument, * which may not be null. The string may include the mnemonic character. * <p> * Mnemonics are indicated by an '&' that causes the next * character to be the mnemonic. When the user presses a * key sequence that matches the mnemonic, focus is assigned * to the first child of the group. On most platforms, the * mnemonic appears underlined but may be emphasised in a * platform specific manner. The mnemonic indicator character * '&' can be escaped by doubling it in the string, causing * a single '&' to be displayed. * </p><p> * Note: If control characters like '\n', '\t' etc. are used * in the string, then the behavior is platform dependent. * </p> * @param string the new text * * @exception IllegalArgumentException <ul> * <li>ERROR_NULL_ARGUMENT - if the text is null</li> * </ul> * @exception SWTException <ul> * <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li> * <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li> * </ul> */ public void setText(String string) { checkWidget(); if (string == null) error(SWT.ERROR_NULL_ARGUMENT); text = string; if ((state & HAS_AUTO_DIRECTION) == 0 || !updateTextDirection(AUTO_TEXT_DIRECTION)) { string = fixText(OS.IsWindowEnabled(handle)); TCHAR buffer = new TCHAR(getCodePage(), string == null ? text : string, true); OS.SetWindowText(handle, buffer); } } @Override boolean updateTextDirection(int textDirection) { if (super.updateTextDirection(textDirection)) { String string = fixText(OS.IsWindowEnabled(handle)); TCHAR buffer = new TCHAR(getCodePage(), string == null ? text : string, true); OS.SetWindowText(handle, buffer); return true; } return false; } @Override int widgetStyle() { /* * Bug in Windows. When GetDCEx() is called with DCX_INTERSECTUPDATE, * the HDC that is returned does not include the current update region. * This was confirmed under DEBUG Windows when GetDCEx() complained about * invalid flags. Therefore, it is not easily possible to get an HDC from * outside of WM_PAINT that includes the current damage and clips children. * Because the receiver has children and draws a frame and label, it is * necessary that the receiver always draw clipped, in the current damaged * area. The fix is to force the receiver to be fully clipped by including * WS_CLIPCHILDREN and WS_CLIPSIBLINGS in the default style bits. */ return super.widgetStyle() | OS.BS_GROUPBOX | OS.WS_CLIPCHILDREN | OS.WS_CLIPSIBLINGS; } @Override TCHAR windowClass() { return GroupClass; } @Override long windowProc() { return GroupProc; } @Override LRESULT WM_ERASEBKGND(long wParam, long lParam) { LRESULT result = super.WM_ERASEBKGND(wParam, lParam); if (result != null) return result; /* * Feature in Windows. Group boxes do not erase * the background before drawing. The fix is to * fill the background. */ drawBackground(wParam); return LRESULT.ONE; } @Override LRESULT WM_NCHITTEST(long wParam, long lParam) { LRESULT result = super.WM_NCHITTEST(wParam, lParam); if (result != null) return result; /* * Feature in Windows. The window proc for the group box * returns HTTRANSPARENT indicating that mouse messages * should not be delivered to the receiver and any children. * Normally, group boxes in Windows do not have children and * this is the correct behavior for this case. Because we * allow children, answer HTCLIENT to allow mouse messages * to be delivered to the children. */ long code = callWindowProc(handle, OS.WM_NCHITTEST, wParam, lParam); if (code == OS.HTTRANSPARENT) code = OS.HTCLIENT; return new LRESULT(code); } @Override LRESULT WM_MOUSEMOVE(long wParam, long lParam) { LRESULT result = super.WM_MOUSEMOVE(wParam, lParam); if (result != null) return result; /* * Feature in Windows. In version 6.00 of COMCTL32.DLL, * every time the mouse moves, the group title redraws. * This only happens when WM_NCHITTEST returns HTCLIENT. * The fix is to avoid calling the group window proc. */ return LRESULT.ZERO; } @Override LRESULT WM_PAINT(long wParam, long lParam) { LRESULT result = super.WM_PAINT(wParam, lParam); if (hasCustomForeground() && text.length() != 0) { String string = fixText(false); char[] buffer = (string == null ? text : string).toCharArray(); // We cannot use BeginPaint and EndPaint, because that removes the group border long hDC = OS.GetDC(handle); RECT rect = new RECT(); OS.GetClientRect(handle, rect); rect.left += 3 * CLIENT_INSET; long newFont, oldFont = 0; newFont = OS.SendMessage(handle, OS.WM_GETFONT, 0, 0); if (newFont != 0) oldFont = OS.SelectObject(hDC, newFont); OS.DrawText(hDC, buffer, buffer.length, rect, OS.DT_SINGLELINE | OS.DT_LEFT | OS.DT_TOP | OS.DT_CALCRECT); // The calculated rectangle is a little bit too small. Italic fonts would show some small part in the default color. rect.right += CLIENT_INSET; drawBackground(hDC, rect); OS.SetBkMode(hDC, OS.TRANSPARENT); OS.SetTextColor(hDC, getForegroundPixel()); OS.DrawText(hDC, buffer, buffer.length, rect, OS.DT_SINGLELINE | OS.DT_LEFT | OS.DT_TOP); if (newFont != 0) OS.SelectObject(hDC, oldFont); OS.ReleaseDC(handle, hDC); // Without validating the drawn area it would be overdrawn by windows OS.ValidateRect(handle, rect); } return result; } @Override LRESULT WM_PRINTCLIENT(long wParam, long lParam) { LRESULT result = super.WM_PRINTCLIENT(wParam, lParam); if (result != null) return result; /* * Feature in Windows. In version 6.00 of COMCTL32.DLL, * when WM_PRINTCLIENT is sent from a child BS_GROUP * control to a parent BS_GROUP, the parent BS_GROUP * clears the font from the HDC. Normally, group boxes * in Windows do not have children so this behavior is * undefined. When the parent of a BS_GROUP is not a * BS_GROUP, there is no problem. The fix is to save * and restore the current font. */ if (OS.IsAppThemed()) { int nSavedDC = OS.SaveDC(wParam); long code = callWindowProc(handle, OS.WM_PRINTCLIENT, wParam, lParam); OS.RestoreDC(wParam, nSavedDC); return new LRESULT(code); } return result; } @Override LRESULT WM_UPDATEUISTATE(long wParam, long lParam) { LRESULT result = super.WM_UPDATEUISTATE(wParam, lParam); if (result != null) return result; /* * Feature in Windows. When WM_UPDATEUISTATE is sent to * a group, it sends WM_CTLCOLORBTN to get the foreground * and background. If drawing happens in WM_CTLCOLORBTN, * it will overwrite the contents of the control. The * fix is draw the group without drawing the background * and avoid the group window proc. */ boolean redraw = findImageControl() != null; if (!redraw) { if ((state & THEME_BACKGROUND) != 0) { if (OS.IsAppThemed()) { redraw = findThemeControl() != null; } } if (!redraw) redraw = findBackgroundControl() != null; } if (redraw) { OS.InvalidateRect(handle, null, false); long code = OS.DefWindowProc(handle, OS.WM_UPDATEUISTATE, wParam, lParam); return new LRESULT(code); } return result; } @Override LRESULT WM_WINDOWPOSCHANGING(long wParam, long lParam) { LRESULT result = super.WM_WINDOWPOSCHANGING(wParam, lParam); if (result != null) return result; /* * Invalidate the portion of the group widget that needs to * be redrawn. Note that for some reason, invalidating the * group from inside WM_SIZE causes pixel corruption for * radio button children. */ if (!OS.IsWindowVisible(handle)) return result; WINDOWPOS lpwp = new WINDOWPOS(); OS.MoveMemory(lpwp, lParam, WINDOWPOS.sizeof); if ((lpwp.flags & (OS.SWP_NOSIZE | OS.SWP_NOREDRAW)) != 0) { return result; } RECT rect = new RECT(); OS.SetRect(rect, 0, 0, lpwp.cx, lpwp.cy); OS.SendMessage(handle, OS.WM_NCCALCSIZE, 0, rect); int newWidth = rect.right - rect.left; int newHeight = rect.bottom - rect.top; OS.GetClientRect(handle, rect); int oldWidth = rect.right - rect.left; int oldHeight = rect.bottom - rect.top; if (newWidth == oldWidth && newHeight == oldHeight) { return result; } if (newWidth != oldWidth) { int left = oldWidth; if (newWidth < oldWidth) left = newWidth; OS.SetRect(rect, left - CLIENT_INSET, 0, newWidth, newHeight); OS.InvalidateRect(handle, rect, true); } if (newHeight != oldHeight) { int bottom = oldHeight; if (newHeight < oldHeight) bottom = newHeight; if (newWidth < oldWidth) oldWidth -= CLIENT_INSET; OS.SetRect(rect, 0, bottom - CLIENT_INSET, oldWidth, newHeight); OS.InvalidateRect(handle, rect, true); } return result; } }