Bug 74786

Description Arnaud 2004-09-23 11:38:48 EDT

Horizontal scroll bar doesn't receive mouse wheel's scroll event if vertical 
bar can't scroll (vertical bar is created but doesn't allow any scroll).
The only way HBar have to receive MWheel is to not create SWT.V_SCROLL
(but it's too bad for me, be cause I need both scroll bar, but sometimes only 
one is usefull, and this is know at run time, not canvas creation time).

Here there are a class to reproduce:
package canvas;

import org.eclipse.swt.events.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.SWT;

public class ACanvas 
{
  public static void main(String v[] )
  {
    Display d = Display.getDefault();
    Shell s = new Shell( d );
    //use this one and horizontal bar receive mouse wheel's scroll
    //Canvas c = new Canvas( s, SWT.H_SCROLL );//|SWT.V_SCROLL );
    Canvas c = new Canvas( s, SWT.H_SCROLL|SWT.V_SCROLL );
    s.setLayout(new FillLayout());
    c.addKeyListener( new KeyAdapter(){} );
    c.setFocus();
    
    if( c.getVerticalBar()!=null ) //if haven't V_SCROLL
    {
      c.getVerticalBar().setValues( 0, 0, 0,1,1,2);  //cnat' scroll 
      c.getVerticalBar().addSelectionListener(  new SelectionListener() {
        public void widgetSelected( SelectionEvent evt) 
        {
          System.out.println("| Vertical Scrollbar  selected"); 
        }
        public void widgetDefaultSelected( SelectionEvent e ) 
        {
          System.out.println("| Vertical Scrollbar  default selected"); 
        }
      });
    }
    
    c.getHorizontalBar().setValues( 0, 0, 100,10,1,10);
    c.getHorizontalBar().addSelectionListener(  new SelectionListener() {
          public void widgetSelected( SelectionEvent evt) 
          {
            System.out.println("- Horizontal Scrollbar  selected"); 
          }
          public void widgetDefaultSelected( SelectionEvent e ) 
          {
            System.out.println("- Horizontal Scrollbar  default selected"); 
          }
    });
    
    s.setSize( 400, 400 );
    s.open ();
    while (!s.isDisposed ()) {
      if (!d.readAndDispatch ()) 
        d.sleep ();
    }
    d.dispose ();
  }
}