FastIncrementer.java

/**
 * Copyright (c) 2014 - 2017 Frank Appel
 * 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:
 *   Frank Appel - initial API and implementation
 */
package com.codeaffine.eclipse.swt.widget.scrollbar;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Display;

import com.codeaffine.eclipse.swt.widget.scrollbar.ClickControl.ClickAction;

class FastIncrementer implements ClickAction {

  private final FlatScrollBar scrollBar;

  private Point mouse;

  FastIncrementer( FlatScrollBar scrollBar ) {
    this.scrollBar = scrollBar;
  }

  @Override
  public void run() {
    Rectangle drag = getDragBounds();
    if( mouse.x > drag.x + drag.width || mouse.y > drag.y + drag.height ) {
      int selection = scrollBar.getSelection() + scrollBar.getPageIncrement();
      scrollBar.setSelectionInternal( selection, SWT.PAGE_DOWN );
    }
  }

  @Override
  public void setCoordinates( int x, int y ) {
    mouse = getMouseLocation( x, y );
  }

  private Point getMouseLocation(int x, int y) {
    return Display.getCurrent().map( scrollBar.downFast.getControl(), null, x, y );
  }

  private Rectangle getDragBounds() {
    Rectangle dragBounds = scrollBar.drag.getControl().getBounds();
    return Display.getCurrent().map( scrollBar, null, dragBounds );
  }
}