/*******************************************************************************
* Copyright (c) 2004, 2010 David Green 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:
* David Green - initial API and implementation
*******************************************************************************/
package org.eclipse.mylyn.internal.tasks.ui.editors;
import org.eclipse.core.runtime.Platform;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.CTabFolder;
import org.eclipse.swt.custom.ScrolledComposite;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Layout;
import org.eclipse.swt.widgets.ScrollBar;
import org.eclipse.ui.forms.widgets.ILayoutExtension;
import org.eclipse.ui.forms.widgets.Section;
/**
* A layout that uses the width hint or client area of a composite to recommend the width of its children, allowing
* children to fill the width and specify their preferred height for a given width. Intended for use with a composite
* that contains a single child that should fill available horizontal space.
*
* @author David Green
*/
class FillWidthLayout extends Layout implements ILayoutExtension {
private final int marginLeft;
private final int marginRight;
private final int marginTop;
private final int marginBottom;
private final int widthHintMargin;
private Composite layoutAdvisor;
private int lastWidthHint;
private Point lastComputedSize;
/**
* create with 0 margins
*/
public FillWidthLayout() {
this(0, 0, 0, 0);
}
/**
* create while specifying margins
*
* @param marginLeft
* the left margin in pixels, or 0 if there should be none
* @param marginRight
* the right margin in pixels, or 0 if there should be none
* @param marginTop
* the top margin in pixels, or 0 if there should be none
* @param marginBottom
* the bottom margin in pixels, or 0 if there should be none
*/
public FillWidthLayout(int marginLeft, int marginRight, int marginTop, int marginBottom) {
this(null, marginLeft, marginRight, marginTop, marginBottom);
}
/**
* create specifying margins and a {@link #getLayoutAdvisor() layout advisor}.
*
* @param layoutAdvisor
* the composite that is used to advise on layout based on its {@link Composite#getClientArea() client
* area}.
* @param marginLeft
* the left margin in pixels, or 0 if there should be none
* @param marginRight
* the right margin in pixels, or 0 if there should be none
* @param marginTop
* the top margin in pixels, or 0 if there should be none
* @param marginBottom
* the bottom margin in pixels, or 0 if there should be none
*/
public FillWidthLayout(Composite layoutAdvisor, int marginLeft, int marginRight, int marginTop, int marginBottom) {
this.layoutAdvisor = layoutAdvisor;
this.marginLeft = marginLeft;
this.marginRight = marginRight;
this.marginTop = marginTop;
this.marginBottom = marginBottom;
if (Platform.OS_MACOSX.equals(Platform.getOS())) {
this.widthHintMargin = 15;
} else {
this.widthHintMargin = 18;
}
}
/**
* calculate the client area of the given container, accomodating for insets and margins.
*/
private int calculateWidthHint(Composite container) {
return calculateWidthHint(container, layoutAdvisor == null);
}
/**
* calculate the client area of the given container, accomodating for insets and margins.
*/
private int calculateWidthHint(Composite container, boolean layoutAdvisorHit) {
if (container == layoutAdvisor) {
layoutAdvisorHit = true;
}
Rectangle clientArea = container.getClientArea();
int horizontalMargin = 0;
if (clientArea.width <= 1 || !layoutAdvisorHit) { // sometimes client area is incorrectly reported as 1
clientArea.width = calculateWidthHint(container.getParent(), layoutAdvisorHit);
}
Layout bodyLayout = container.getLayout();
if (bodyLayout instanceof GridLayout) {
GridLayout gridLayout = (GridLayout) bodyLayout;
horizontalMargin = (gridLayout.marginWidth * 2) + gridLayout.marginLeft + gridLayout.marginRight;
} else if (bodyLayout instanceof FillLayout) {
FillLayout fillLayout = (FillLayout) bodyLayout;
horizontalMargin = fillLayout.marginWidth * 2;
} else if (container instanceof Section) {
horizontalMargin = ((Section) container).marginWidth * 2;
} else if (container instanceof CTabFolder) {
CTabFolder folder = (CTabFolder) container;
horizontalMargin = folder.marginWidth * 2;
}
if (container instanceof ScrolledComposite) {
ScrolledComposite composite = (ScrolledComposite) container;
ScrollBar verticalBar = composite.getVerticalBar();
if (verticalBar != null) {
int verticalBarWidth = verticalBar.getSize().x;
horizontalMargin += Math.max(15, verticalBarWidth);
}
}
return clientArea.width - horizontalMargin;
}
@Override
protected Point computeSize(Composite composite, int widthHint, int heightHint, boolean flushCache) {
Control[] children = composite.getChildren();
if (children.length == 0) {
return new Point(0, 0);
}
if (widthHint <= 0) {
widthHint = calculateWidthHint(composite);
widthHint -= widthHintMargin;
}
int horizontalMargin = marginLeft + marginRight;
if (widthHint < horizontalMargin) {
widthHint = horizontalMargin;
}
if (lastComputedSize == null || widthHint != lastWidthHint) {
int resultX = 1;
int resultY = 1;
int controlWidthHint = Math.max(horizontalMargin, widthHint - horizontalMargin - 2);
for (Control control : children) {
Point sz = control.computeSize(controlWidthHint, -1, true);
resultX = Math.max(resultX, sz.x);
resultY = Math.max(resultY, sz.y);
}
lastWidthHint = widthHint;
lastComputedSize = new Point(resultX + horizontalMargin, resultY + marginTop + marginBottom);
}
return new Point(lastComputedSize.x, lastComputedSize.y + 1);
}
@Override
protected void layout(Composite composite, boolean flushCache) {
Rectangle area = composite.getClientArea();
if (area.width == 0) {
area.width = calculateWidthHint(composite);
}
// account for margins
area.x += marginLeft;
area.y += marginTop;
area.width -= (marginRight + marginLeft);
area.height -= (marginBottom + marginTop);
Control[] children = composite.getChildren();
for (Control control : children) {
control.setBounds(area);
}
}
/**
* the composite that is used to advise on layout based on its {@link Composite#getClientArea() client area}.
*
* @return the layout advisor, or null if there is none
*/
public Composite getLayoutAdvisor() {
return layoutAdvisor;
}
/**
* the composite that is used to advise on layout based on its {@link Composite#getClientArea() client area}.
*
* @param layoutAdvisor
* the layout advisor, or null if there is none
*/
public void setLayoutAdvisor(Composite layoutAdvisor) {
this.layoutAdvisor = layoutAdvisor;
}
/**
* Flushes all cached information about control sizes.
*/
public void flush() {
lastComputedSize = null;
}
public int computeMaximumWidth(Composite parent, boolean changed) {
int width = marginLeft + marginRight;
Control[] children = parent.getChildren();
for (Control control : children) {
width = Math.max(control.computeSize(SWT.DEFAULT, 0, changed).x + marginLeft + marginRight, width);
}
return width;
}
public int computeMinimumWidth(Composite parent, boolean changed) {
int width = marginLeft + marginRight;
// Control[] children = parent.getChildren();
// for (Control control : children) {
// width = Math.max(control.computeSize(0, SWT.DEFAULT, changed).x + marginLeft + marginRight, width);
// }
return width;
}
}