Description Vitaliy Stulski 2005-05-06 14:41:52 EDT

Eclipse SWT Tree control does not include its visible children when computing
the control size. When a tree control is inside a section part and the tree node
is expanded the section part is not being resized properly. What happens after
tree node expansion - layout calls computeSize for the tree and computeSize for
the tree does not take into account newly expanded tree node(s). I attached an
interim fix for the problem we did in our application.


===============================================================================
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Tree;

public class SAPTree extends Tree {

    static boolean useBugFix = true;

    public SAPTree(Composite parent, int style) {
        super(parent, style);
    }

    public Point computeSize(int wHint, int hHint, boolean changed) {
        if (useBugFix) {
            try {
                checkWidget();
                return OSSAPTree.computeSize(this, wHint, hHint, changed);
            } catch (Throwable ignore) {
                useBugFix = false;
            }
        }
        return super.computeSize(wHint, hHint, changed);
    }
}
===============================================================================
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Tree;

import org.eclipse.swt.internal.win32.OS;
import org.eclipse.swt.internal.win32.RECT;

public class OSSAPTree {

    public OSSAPTree() {
        super();
    }

    /**
     * Recursivelly computes the size of the give item and it's visible children
     * 
     * @param hItem
     * @return
     */
    static Point internalComputeSize(Tree tree,int hItem) {
        int width = 0, height = 0;
        RECT rect = new RECT();
        Point childSize;
        while (hItem != 0) {
            rect.left = hItem;
            if (OS.SendMessage(tree.handle, OS.TVM_GETITEMRECT, 1, rect) != 0) {
                width = Math.max(width, rect.right);
                height += rect.bottom - rect.top;

                // compute children size
                int hChild = OS.SendMessage(tree.handle, OS.TVM_GETNEXTITEM,
OS.TVGN_CHILD, hItem);
                if (hChild != 0) {
                    childSize = internalComputeSize(tree, hChild);
                    width = Math.max(width, childSize.x);
                    height += childSize.y;
                }
            }
            hItem = OS.SendMessage(tree.handle, OS.TVM_GETNEXTITEM,
OS.TVGN_NEXT, hItem);
        }

        return new Point(width, height);
    }

    /* (non-Javadoc)
     * @see org.eclipse.swt.widgets.Control#computeSize(int, int, boolean)
     */
    static Point computeSize(Tree tree, int wHint, int hHint, boolean changed) {
        int width = 0, height = 0;
        int hItem = OS.SendMessage(tree.handle, OS.TVM_GETNEXTITEM,
OS.TVGN_ROOT, 0);

        // Compute the size of the root item and all visible children
        Point p = internalComputeSize(tree,  hItem);
        
        width = p.x;
        height = p.y;
        if (width == 0)
            width = 64;
        if (height == 0)
            height = 64;
        if (wHint != SWT.DEFAULT)
            width = wHint;
        if (hHint != SWT.DEFAULT)
            height = hHint;
        int border = tree.getBorderWidth();
        width += border * 2;
        height += border * 2;
        if ((tree.getStyle() & SWT.V_SCROLL) != 0) {
            width += OS.GetSystemMetrics(OS.SM_CXVSCROLL);
        }
        if ((tree.getStyle() & SWT.H_SCROLL) != 0) {
            height += OS.GetSystemMetrics(OS.SM_CYHSCROLL);
        }
        return new Point(width, height);
    }
}
===============================================================================