/*******************************************************************************
* Copyright (c) 2005, 2015 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* Stefan Xenos <sxenos@gmail.com> - Bug 474061
*******************************************************************************/
package org.eclipse.jface.layout;
import org.eclipse.jface.util.Geometry;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Layout;
import org.eclipse.swt.widgets.Link;
import org.eclipse.swt.widgets.Scrollable;
/* package */class LayoutGenerator {
/**
* Default size for controls with varying contents
*/
private static final Point defaultSize = new Point(150, 150);
/**
* Default wrapping size for wrapped labels
*/
private static final int wrapSize = 350;
private static final GridDataFactory nonWrappingLabelData = GridDataFactory.fillDefaults().align(SWT.BEGINNING, SWT.CENTER).grab(false, false);
private static boolean hasStyle(Control c, int style) {
return (c.getStyle() & style) != 0;
}
/**
* Generates a GridLayout for the given composite by examining its child
* controls and attaching layout data to any immediate children that do not
* already have layout data.
*
* @param toGenerate
* composite to generate a layout for
*/
public static void generateLayout(Composite toGenerate) {
Control[] children = toGenerate.getChildren();
for (Control control : children) {
// Skip any children that already have layout data
if (control.getLayoutData() != null) {
continue;
}
applyLayoutDataTo(control);
}
}
private static void applyLayoutDataTo(Control control) {
defaultsFor(control).applyTo(control);
}
/**
* Creates default factory for this control types:
* <ul>
* <li>{@link Button} with {@link SWT#CHECK}</li>
* <li>{@link Button}</li>
* <li>{@link Composite}</li>
* </ul>
* @param control the control the factory is search for
* @return a default factory for the control
*/
public static GridDataFactory defaultsFor(Control control) {
if (control instanceof Button) {
Button button = (Button) control;
if (hasStyle(button, SWT.CHECK)) {
return nonWrappingLabelData.copy();
}
return GridDataFactory.fillDefaults().align(SWT.FILL, SWT.CENTER).hint(Geometry.max(button.computeSize(SWT.DEFAULT, SWT.DEFAULT, true), LayoutConstants.getMinButtonSize()));
}
if (control instanceof Scrollable) {
Scrollable scrollable = (Scrollable) control;
if (scrollable instanceof Composite) {
Composite composite = (Composite) control;
Layout theLayout = composite.getLayout();
if (theLayout instanceof GridLayout) {
boolean growsHorizontally = false;
boolean growsVertically = false;
Control[] children = composite.getChildren();
for (Control child : children) {
GridData data = (GridData) child.getLayoutData();
if (data != null) {
if (data.grabExcessHorizontalSpace) {
growsHorizontally = true;
}
if (data.grabExcessVerticalSpace) {
growsVertically = true;
}
}
}
return GridDataFactory.fillDefaults().grab(growsHorizontally, growsVertically);
}
}
}
boolean wrapping = hasStyle(control, SWT.WRAP);
// Links are always wrapping, even though they don't use the SWT.WRAP
// flag
if (control instanceof Link) {
wrapping = true;
}
// Assume any control with the H_SCROLL or V_SCROLL flags are
// horizontally or vertically
// scrollable, respectively.
boolean hScroll = hasStyle(control, SWT.H_SCROLL);
boolean vScroll = hasStyle(control, SWT.V_SCROLL);
boolean containsText = hasMethod(control, "setText", new Class<?>[] { String.class}); //$NON-NLS-1$
// If the control has a setText method, an addModifyListener method, and
// does not have
// the SWT.READ_ONLY flag, assume it contains user-editable text.
boolean userEditable = !hasStyle(control, SWT.READ_ONLY) && containsText && hasMethod(control, "addModifyListener", new Class<?>[] { ModifyListener.class }); //$NON-NLS-1$
// For controls containing user-editable text...
if (userEditable) {
if (hasStyle(control, SWT.MULTI)) {
vScroll = true;
}
if (!wrapping) {
hScroll = true;
}
}
// Compute the horizontal hint
int hHint = SWT.DEFAULT;
boolean grabHorizontal = hScroll;
// For horizontally-scrollable controls, override their horizontal
// preferred size
// with a constant
if (hScroll) {
hHint = defaultSize.x;
} else {
// For wrapping controls, there are two cases.
// 1. For controls that contain text (like wrapping labels,
// read-only text boxes,
// etc.) override their preferred size with the preferred wrapping
// point and
// make them grab horizontal space.
// 2. For non-text controls (like wrapping toolbars), assume that
// their non-wrapped
// size is best.
if (wrapping) {
if (containsText) {
hHint = wrapSize;
grabHorizontal = true;
}
}
}
int vAlign = SWT.FILL;
// Heuristic for labels: Controls that contain non-wrapping read-only
// text should be
// center-aligned rather than fill-aligned
if (!vScroll && !wrapping && !userEditable && containsText) {
vAlign = SWT.CENTER;
}
return GridDataFactory.fillDefaults().grab(grabHorizontal, vScroll).align(SWT.FILL, vAlign).hint(hHint, vScroll ? defaultSize.y : SWT.DEFAULT);
}
private static boolean hasMethod(Control control, String name, Class<?>[] parameterTypes) {
Class<? extends Control> c = control.getClass();
try {
return c.getMethod(name, parameterTypes) != null;
} catch (SecurityException e) {
return false;
} catch (NoSuchMethodException e) {
return false;
}
}
}