HorizontalSelectionComputer.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.scrollable;

import static java.lang.Math.max;
import static java.lang.Math.min;

import com.codeaffine.eclipse.swt.widget.scrollable.context.AdaptionContext;

class HorizontalSelectionComputer {

  int compute( AdaptionContext<?> context ) {
    return min( selection( context ), availableSpaceForSelection( context ) );
  }

  private static int availableSpaceForSelection( AdaptionContext<?> context ) {
    int scrollableWidth = context.getScrollable().getSize().x;
    return max( 0, scrollableWidth - context.getAdapter().getClientArea().width - context.getVerticalBarOffset() );
  }

  private static int selection( AdaptionContext<?> context ) {
    if( context.isScrollableReplacedByAdapter() ) {
      return context.getHorizontalAdapterSelection();
    }
    return 0;
  }
}