--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwtx/draw2d/ScrollBarLayout.d	Sun Aug 03 00:52:14 2008 +0200
@@ -0,0 +1,201 @@
+/*******************************************************************************
+ * Copyright (c) 2000, 2005 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
+ * Port to the D programming language:
+ *     Frank Benoit <benoit@tionex.de>
+ *******************************************************************************/
+module dwtx.draw2d.ScrollBarLayout;
+
+import dwt.dwthelper.utils;
+
+import dwtx.draw2d.geometry.Dimension;
+import dwtx.draw2d.geometry.Insets;
+import dwtx.draw2d.geometry.Rectangle;
+import dwtx.draw2d.geometry.Transposer;
+
+import dwtx.draw2d.AbstractLayout;
+import dwtx.draw2d.IFigure;
+import dwtx.draw2d.ScrollBar;
+
+/**
+ * Lays out the Figures that make up a ScrollBar.
+ */
+public class ScrollBarLayout
+    : AbstractLayout
+{
+
+/** Used as a constraint for the up arrow figure. */
+public static final String UP_ARROW   = "up arrow";   //$NON-NLS-1$
+/** Used as a constraint for the down arrow figure. */
+public static final String DOWN_ARROW = "down arrow"; //$NON-NLS-1$
+/** Used as a constraint for the thumb figure. */
+public static final String THUMB      = "thumb";      //$NON-NLS-1$
+/** Used as a constraint for the page up figure. */
+public static final String PAGE_UP    = "page_up";    //$NON-NLS-1$
+/** Used as a constraint for the page down figure. */
+public static final String PAGE_DOWN  = "page_down";  //$NON-NLS-1$
+
+IFigure up, down, thumb, pageUp, pageDown;
+
+/**
+ * Transposes values if the ScrollBar is horizontally oriented. When used properly, the
+ * layout manager just needs to code for one case: vertical orientation.
+ */
+protected final Transposer transposer;
+
+/**
+ * Constructs a ScrollBarLayout. If the given Transposer is enabled, the Scrollbar will
+ * be horizontally oriented. Otherwise, the ScrollBar will be vertically oriented.
+ *
+ * @param t the Transposer
+ * @since 2.0
+ */
+public this(Transposer t) {
+    transposer = t;
+}
+
+/**
+ * @see AbstractLayout#setConstraint(IFigure, Object)
+ */
+public void setConstraint(IFigure figure, Object constraint_) {
+    String constraint = stringcast(constraint_);
+    if (constraint.equals(UP_ARROW))
+        up = figure;
+    else if (constraint.equals(DOWN_ARROW))
+        down = figure;
+    else if (constraint.equals(THUMB))
+        thumb = figure;
+    else if (constraint.equals(PAGE_UP))
+        pageUp = figure;
+    else if (constraint.equals(PAGE_DOWN))
+        pageDown = figure;
+}
+
+/**
+ * @see AbstractLayout#calculatePreferredSize(IFigure, int, int)
+ */
+protected Dimension calculatePreferredSize(IFigure parent, int w, int h) {
+    Insets insets = transposer.t(parent.getInsets());
+    Dimension d = new Dimension(16, 16 * 4);
+    d.expand(insets.getWidth(), insets.getHeight());
+    return transposer.t(d);
+}
+
+/**
+ * @see LayoutManager#layout(IFigure)
+ */
+public void layout(IFigure parent) {
+    ScrollBar scrollBar = cast(ScrollBar) parent;
+
+    Rectangle trackBounds = layoutButtons(scrollBar);
+
+    int extent = scrollBar.getExtent();
+    int max = scrollBar.getMaximum();
+    int min = scrollBar.getMinimum();
+    int totalRange =  max - min;
+    int valueRange = totalRange - extent;
+    if ((valueRange < 1) || (!scrollBar.isEnabled())) {
+        Rectangle boundsUpper = new Rectangle(trackBounds),
+                  boundsLower = new Rectangle(trackBounds);
+        boundsUpper.height /= 2;
+        boundsLower.y += boundsUpper.height;
+        boundsLower.height = trackBounds.height - boundsUpper.height;
+        if (pageUp !is null)
+            pageUp.setBounds(transposer.t(boundsUpper));
+        if (pageDown !is null)
+            pageDown.setBounds(transposer.t(boundsLower));
+        return;
+    }
+
+    if (totalRange is 0)
+        return;
+    int thumbHeight = Math.max(thumb is null ? 0 : thumb.getMinimumSize().height,
+                                trackBounds.height * extent / totalRange);
+
+    if (thumb !is null)
+        thumb.setVisible(trackBounds.height > thumbHeight);
+
+    int thumbY = trackBounds.y + (trackBounds.height - thumbHeight)
+                    * (scrollBar.getValue() - min) / valueRange;
+
+    Rectangle thumbBounds =  new Rectangle(
+        trackBounds.x,
+        thumbY,
+        trackBounds.width,
+        thumbHeight);
+
+    if (thumb !is null)
+        thumb.setBounds(transposer.t(thumbBounds));
+
+    if (pageUp !is null)
+        pageUp.setBounds(transposer.t(new Rectangle(
+            trackBounds.x,
+            trackBounds.y,
+            trackBounds.width,
+            thumbBounds.y - trackBounds.y)));
+
+    if (pageDown !is null)
+        pageDown.setBounds(transposer.t(new Rectangle(
+            trackBounds.x ,
+            thumbBounds.y + thumbHeight,
+            trackBounds.width,
+            trackBounds.bottom() - thumbBounds.bottom())));
+}
+
+/**
+ * Places the buttons and returns the Rectangle into which the track should be placed.
+ * The track consists of the pageup, pagedown, and thumb figures. The Rectangle returned
+ * should be transposed correctly, that is, it should be vertically oriented.  Users of
+ * the rectangle will re-transpose it for horizontal use.
+ *
+ * @param scrollBar the scrollbar whose buttons are being layed out
+ * @return the Rectangle into which the track should be placed
+ * @since 2.0
+ */
+protected Rectangle layoutButtons(ScrollBar scrollBar) {
+    Rectangle bounds = transposer.t(scrollBar.getClientArea());
+    Dimension buttonSize = new Dimension(
+        bounds.width,
+        Math.min(bounds.width, bounds.height / 2));
+
+    if (up !is null)
+        up.setBounds(transposer.t(
+            new Rectangle(bounds.getTopLeft(), buttonSize)));
+    if (down !is null) {
+        Rectangle r = new Rectangle (
+            bounds.x, bounds.bottom() - buttonSize.height,
+            buttonSize.width, buttonSize.height);
+        down.setBounds(transposer.t(r));
+    }
+
+    Rectangle trackBounds = bounds.getCropped(
+        new Insets(
+            (up   is null) ? 0 : buttonSize.height, 0,
+            (down is null) ? 0 : buttonSize.height, 0));
+
+    return trackBounds;
+}
+
+/**
+ * @see LayoutManager#remove(IFigure)
+ */
+public void remove(IFigure child) {
+    if (child is up) {
+        up = null;
+    } else if (child is down) {
+        down = null;
+    } else if (child is thumb) {
+        thumb = null;
+    } else if (child is pageUp) {
+        pageUp = null;
+    } else if (child is pageDown) {
+        pageDown = null;
+    }
+}
+}