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/*******************************************************************************
* 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.layout;
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
/**
* <code>FillLayout</code> is the simplest layout class. It lays out
* controls in a single row or column, forcing them to be the same size.
* <p>
* Initially, the controls will all be as tall as the tallest control,
* and as wide as the widest. <code>FillLayout</code> does not wrap,
* but you can specify margins and spacing. You might use it to
* lay out buttons in a task bar or tool bar, or to stack checkboxes
* in a <code>Group</code>. <code>FillLayout</code> can also be used
* when a <code>Composite</code> only has one child. For example,
* if a <code>Shell</code> has a single <code>Group</code> child,
* <code>FillLayout</code> will cause the <code>Group</code> to
* completely fill the <code>Shell</code> (if margins are 0).
* </p>
* <p>
* Example code: first a <code>FillLayout</code> is created and
* its type field is set, and then the layout is set into the
* <code>Composite</code>. Note that in a <code>FillLayout</code>,
* children are always the same size, and they fill all available space.
* </p>
* <pre>
* FillLayout fillLayout = new FillLayout();
* fillLayout.type = SWT.VERTICAL;
* shell.setLayout(fillLayout);
* </pre>
*
* @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: LayoutExample</a>
* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
*/
public final class FillLayout extends Layout {
/**
* type specifies how controls will be positioned
* within the layout.
*
* The default value is HORIZONTAL.
*
* Possible values are: <ul>
* <li>HORIZONTAL: Position the controls horizontally from left to right</li>
* <li>VERTICAL: Position the controls vertically from top to bottom</li>
* </ul>
*/
public int type = SWT.HORIZONTAL;
/**
* marginWidth specifies the number of points of horizontal margin
* that will be placed along the left and right edges of the layout.
*
* The default value is 0.
*
* @since 3.0
*/
public int marginWidth = 0;
/**
* marginHeight specifies the number of points of vertical margin
* that will be placed along the top and bottom edges of the layout.
*
* The default value is 0.
*
* @since 3.0
*/
public int marginHeight = 0;
/**
* spacing specifies the number of points between the edge of one cell
* and the edge of its neighbouring cell.
*
* The default value is 0.
*
* @since 3.0
*/
public int spacing = 0;
/**
* Constructs a new instance of this class.
*/
public FillLayout () {
}
/**
* Constructs a new instance of this class given the type.
*
* @param type the type of fill layout
*
* @since 2.0
*/
public FillLayout (int type) {
this.type = type;
}
@Override
protected Point computeSize (Composite composite, int wHint, int hHint, boolean flushCache) {
Control [] children = composite.getChildren ();
int count = children.length;
int maxWidth = 0, maxHeight = 0;
for (int i=0; i<count; i++) {
Control child = children [i];
int w = wHint, h = hHint;
if (count > 0) {
if (type == SWT.HORIZONTAL && wHint != SWT.DEFAULT) {
w = Math.max (0, (wHint - (count - 1) * spacing) / count);
}
if (type == SWT.VERTICAL && hHint != SWT.DEFAULT) {
h = Math.max (0, (hHint - (count - 1) * spacing) / count);
}
}
Point size = computeChildSize (child, w, h, flushCache);
maxWidth = Math.max (maxWidth, size.x);
maxHeight = Math.max (maxHeight, size.y);
}
int width = 0, height = 0;
if (type == SWT.HORIZONTAL) {
width = count * maxWidth;
if (count != 0) width += (count - 1) * spacing;
height = maxHeight;
} else {
width = maxWidth;
height = count * maxHeight;
if (count != 0) height += (count - 1) * spacing;
}
width += marginWidth * 2;
height += marginHeight * 2;
if (wHint != SWT.DEFAULT) width = wHint;
if (hHint != SWT.DEFAULT) height = hHint;
return new Point (width, height);
}
Point computeChildSize (Control control, int wHint, int hHint, boolean flushCache) {
FillData data = (FillData)control.getLayoutData ();
if (data == null) {
data = new FillData ();
control.setLayoutData (data);
}
Point size = null;
if (wHint == SWT.DEFAULT && hHint == SWT.DEFAULT) {
size = data.computeSize (control, wHint, hHint, flushCache);
} else {
// TEMPORARY CODE
int trimX, trimY;
if (control instanceof Scrollable) {
Rectangle rect = ((Scrollable) control).computeTrim (0, 0, 0, 0);
trimX = rect.width;
trimY = rect.height;
} else {
trimX = trimY = control.getBorderWidth () * 2;
}
int w = wHint == SWT.DEFAULT ? wHint : Math.max (0, wHint - trimX);
int h = hHint == SWT.DEFAULT ? hHint : Math.max (0, hHint - trimY);
size = data.computeSize (control, w, h, flushCache);
}
return size;
}
@Override
protected boolean flushCache (Control control) {
Object data = control.getLayoutData();
if (data != null) ((FillData)data).flushCache();
return true;
}
String getName () {
String string = getClass ().getName ();
int index = string.lastIndexOf ('.');
if (index == -1) return string;
return string.substring (index + 1, string.length ());
}
@Override
protected void layout (Composite composite, boolean flushCache) {
Rectangle rect = composite.getClientArea ();
Control [] children = composite.getChildren ();
int count = children.length;
if (count == 0) return;
int width = rect.width - marginWidth * 2;
int height = rect.height - marginHeight * 2;
if (type == SWT.HORIZONTAL) {
width -= (count - 1) * spacing;
int x = rect.x + marginWidth, extra = width % count;
int y = rect.y + marginHeight, cellWidth = width / count;
for (int i=0; i<count; i++) {
Control child = children [i];
int childWidth = cellWidth;
if (i == 0) {
childWidth += extra / 2;
} else {
if (i == count - 1) childWidth += (extra + 1) / 2;
}
child.setBounds (x, y, childWidth, height);
x += childWidth + spacing;
}
} else {
height -= (count - 1) * spacing;
int x = rect.x + marginWidth, cellHeight = height / count;
int y = rect.y + marginHeight, extra = height % count;
for (int i=0; i<count; i++) {
Control child = children [i];
int childHeight = cellHeight;
if (i == 0) {
childHeight += extra / 2;
} else {
if (i == count - 1) childHeight += (extra + 1) / 2;
}
child.setBounds (x, y, width, childHeight);
y += childHeight + spacing;
}
}
}
/**
* Returns a string containing a concise, human-readable
* description of the receiver.
*
* @return a string representation of the layout
*/
@Override
public String toString () {
String string = getName ()+" {";
string += "type="+((type == SWT.VERTICAL) ? "SWT.VERTICAL" : "SWT.HORIZONTAL")+" ";
if (marginWidth != 0) string += "marginWidth="+marginWidth+" ";
if (marginHeight != 0) string += "marginHeight="+marginHeight+" ";
if (spacing != 0) string += "spacing="+spacing+" ";
string = string.trim();
string += "}";
return string;
}
}
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