case-study/jdt-after/ui/org/eclipse/jdt/internal/ui/util/SWTUtil.java

   1 /*******************************************************************************
   2  * Copyright (c) 2000, 2011 IBM Corporation and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Eclipse Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/epl-v10.html
   7  *
   8  * Contributors:
   9  *     IBM Corporation - initial API and implementation
  10  *******************************************************************************/
  11 package org.eclipse.jdt.internal.ui.util;
  12
  13 import org.eclipse.swt.SWT;
  14 import org.eclipse.swt.accessibility.ACC;
  15 import org.eclipse.swt.accessibility.AccessibleAdapter;
  16 import org.eclipse.swt.accessibility.AccessibleEvent;
  17 import org.eclipse.swt.dnd.DragSource;
  18 import org.eclipse.swt.dnd.DropTarget;
  19 import org.eclipse.swt.layout.GridData;
  20 import org.eclipse.swt.layout.GridLayout;
  21 import org.eclipse.swt.widgets.Button;
  22 import org.eclipse.swt.widgets.Caret;
  23 import org.eclipse.swt.widgets.Combo;
  24 import org.eclipse.swt.widgets.Control;
  25 import org.eclipse.swt.widgets.Menu;
  26 import org.eclipse.swt.widgets.ScrollBar;
  27 import org.eclipse.swt.widgets.Shell;
  28 import org.eclipse.swt.widgets.Table;
  29 import org.eclipse.swt.widgets.Widget;
  30
  31 import org.eclipse.core.runtime.Assert;
  32
  33 import org.eclipse.jface.dialogs.IDialogConstants;
  34 import org.eclipse.jface.layout.PixelConverter;
  35 import org.eclipse.jface.resource.JFaceResources;
  36
  37
  38 /**
  39  * Utility class to simplify access to some SWT resources.
  40  */
  41 public class SWTUtil {
  42
  43         /**
  44          * The default visible item count for {@link Combo}s.
  45          * Workaround for https://bugs.eclipse.org/bugs/show_bug.cgi?id=245569 .
  46          *
  47          * @see Combo#setVisibleItemCount(int)
  48          *
  49          * @since 3.5
  50          */
  51         public static final int COMBO_VISIBLE_ITEM_COUNT= 30;
  52
  53         /**
  54          * Returns the shell for the given widget. If the widget doesn't represent
  55          * a SWT object that manage a shell, <code>null</code> is returned.
  56          * @param widget the widget
  57          *
  58          * @return the shell for the given widget
  59          */
  60         public static Shell getShell(Widget widget) {
  61                 if (widget instanceof Control)
  62                         return ((Control)widget).getShell();
  63                 if (widget instanceof Caret)
  64                         return ((Caret)widget).getParent().getShell();
  65                 if (widget instanceof DragSource)
  66                         return ((DragSource)widget).getControl().getShell();
  67                 if (widget instanceof DropTarget)
  68                         return ((DropTarget)widget).getControl().getShell();
  69                 if (widget instanceof Menu)
  70                         return ((Menu)widget).getParent().getShell();
  71                 if (widget instanceof ScrollBar)
  72                         return ((ScrollBar)widget).getParent().getShell();
  73
  74                 return null;
  75         }
  76
  77
  78         /**
  79          * Returns a width hint for a button control.
  80          * @param button the button
  81          * @return the width hint
  82          */
  83         public static int getButtonWidthHint(Button button) {
  84                 button.setFont(JFaceResources.getDialogFont());
  85                 PixelConverter converter= new PixelConverter(button);
  86                 int widthHint= converter.convertHorizontalDLUsToPixels(IDialogConstants.BUTTON_WIDTH);
  87                 return Math.max(widthHint, button.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).x);
  88         }
  89
  90         /**
  91          * Sets width and height hint for the button control.
  92          * <b>Note:</b> This is a NOP if the button's layout data is not
  93          * an instance of <code>GridData</code>.
  94          *
  95          * @param button        the button for which to set the dimension hint
  96          */
  97         public static void setButtonDimensionHint(Button button) {
  98                 Assert.isNotNull(button);
  99                 Object gd= button.getLayoutData();
 100                 if (gd instanceof GridData) {
 101                         ((GridData)gd).widthHint= getButtonWidthHint(button);
 102                         ((GridData)gd).horizontalAlignment = GridData.FILL;
 103                 }
 104         }
 105
 106         public static int getTableHeightHint(Table table, int rows) {
 107                 if (table.getFont().equals(JFaceResources.getDefaultFont()))
 108                         table.setFont(JFaceResources.getDialogFont());
 109                 int result= table.getItemHeight() * rows + table.getHeaderHeight();
 110                 if (table.getLinesVisible())
 111                         result+= table.getGridLineWidth() * (rows - 1);
 112                 return result;
 113         }
 114
 115         /**
 116          * Adds an accessibility listener returning the given fixed name.
 117          *
 118          * @param control the control to add the accessibility support to
 119          * @param text the name
 120          */
 121         public static void setAccessibilityText(Control control, final String text) {
 122                 control.getAccessible().addAccessibleListener(new AccessibleAdapter() {
 123                         @Override
 124                         public void getName(AccessibleEvent e) {
 125                                 if (e.childID == ACC.CHILDID_SELF) {
 126                                         e.result= text;
 127                                 }
 128                         }
 129                 });
 130         }
 131
 132         /**
 133          * Sets the default visible item count for {@link Combo}s.
 134          * Workaround for https://bugs.eclipse.org/bugs/show_bug.cgi?id=7845 .
 135          *
 136          * @param combo the combo
 137          *
 138          * @see Combo#setVisibleItemCount(int)
 139          * @see #COMBO_VISIBLE_ITEM_COUNT
 140          *
 141          * @since 3.5
 142          */
 143         public static void setDefaultVisibleItemCount(Combo combo) {
 144                 combo.setVisibleItemCount(COMBO_VISIBLE_ITEM_COUNT);
 145         }
 146
 147         public static GridLayout newLayoutNoMargins(int columns) {
 148                 GridLayout layout= new GridLayout(columns, false);
 149                 layout.marginWidth= 0;
 150                 layout.marginHeight= 0;
 151                 return layout;
 152         }
 153
 154
 155 }