content: /*
   * Copyright 2019 FormDev Software GmbH
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package themeengine.include.com.formdev.flatlaf.ui;
  
  import static themeengine.include.com.formdev.flatlaf.util.UIScale.scale2;
  import java.awt.Insets;
  import java.beans.PropertyChangeListener;
  import java.util.function.Function;
  import javax.swing.JComponent;
  
  /**
   * Support for MigLayout visual paddings.
   *
   * Visual paddings are used by MigLayout to ignore the usually invisible space
   * around some components (e.g. buttons) that is used to paint a focus border.
   *
   * @author Karl Tauber
   */
  public class MigLayoutVisualPadding
  {
  	/**
  	 * Key of visual padding client property.
  	 * Value must be either an integer array of size 4, or java.awt.Insets.
  	 *
  	 * Same as themeengine.include.net.miginfocom.layout.PlatformDefaults.VISUAL_PADDING_PROPERTY,
  	 * but we don't want to depend on miglayout library.
  	 */
  	public static String VISUAL_PADDING_PROPERTY = "visualPadding";
  
  	private static final FlatMigInsets ZERO = new FlatMigInsets( 0, 0, 0, 0 );
  	private static final boolean migLayoutAvailable;
  
  	static {
  		// check whether MigLayout is available
  		boolean available = false;
  		try {
  			Class.forName( "themeengine.include.net.miginfocom.swing.MigLayout" );
  			available = true;
  		} catch( ClassNotFoundException ex ) {
  			// ignore
  		}
  		migLayoutAvailable = available;
  	}
  
  	/**
  	 * Sets the client property to the given insets.
  	 */
  	public static void install( JComponent c, Insets insets ) {
  		if( !migLayoutAvailable )
  			return;
  
  		setVisualPadding( c, insets );
  	}
  
  	/**
  	 * Convenience method that checks whether component border is a FlatBorder.
  	 */
  	public static void install( JComponent c ) {
  		if( !migLayoutAvailable )
  			return;
  
  		install( c, c2 -> {
  			FlatBorder border = FlatUIUtils.getOutsideFlatBorder( c2 );
  			if( border != null ) {
  				int focusWidth = border.getFocusWidth( c2 );
  				return new Insets( focusWidth, focusWidth, focusWidth, focusWidth );
  			} else
  				return null;
  		}, "border" );
  	}
  
  	/**
  	 * Invokes the given function to retrieve the actual visual paddings and sets
  	 * the client property. Also adds property change listener to component and
  	 * re-invokes the function if one of the given properties have changed.
  	 */
  	public static void install( JComponent c, Function<JComponent, Insets> getPaddingFunction, String... propertyNames ) {
  		if( !migLayoutAvailable )
  			return;
  
  		// set client property
  		setVisualPadding( c, getPaddingFunction.apply( c ) );
  
  		// add listener
  		c.addPropertyChangeListener( (FlatMigListener) e -> {
  			String propertyName = e.getPropertyName();
  			for( String name : propertyNames ) {
  				if( name == propertyName ) {
  					setVisualPadding( c, getPaddingFunction.apply( c ) );
  					break;
  				}
  			}
  		} );
  	}
  
  	private static void setVisualPadding( JComponent c, Insets visualPadding ) {
  		Object oldPadding = c.getClientProperty( VISUAL_PADDING_PROPERTY );
  		if( oldPadding == null || oldPadding instanceof FlatMigInsets ) {
  			FlatMigInsets flatVisualPadding = (visualPadding != null)
  				? new FlatMigInsets( scale2( visualPadding.top ), scale2( visualPadding.left ),
  					scale2( visualPadding.bottom ), scale2( visualPadding.right ) )
  				: ZERO;
  
  			c.putClientProperty( VISUAL_PADDING_PROPERTY, flatVisualPadding );
  		}
  	}
  
  	/**
  	 * Removes listeners and restores client property.
  	 */
  	public static void uninstall( JComponent c ) {
  		if( !migLayoutAvailable )
  			return;
  
  		// remove listener
  		for( PropertyChangeListener l : c.getPropertyChangeListeners() ) {
  			if( l instanceof FlatMigListener ) {
  				c.removePropertyChangeListener( l );
  				break;
  			}
  		}
  
  		// remove client property
  		if( c.getClientProperty( VISUAL_PADDING_PROPERTY ) instanceof FlatMigInsets )
  			c.putClientProperty( VISUAL_PADDING_PROPERTY, null );
  	}
  
  	//---- class FlatMigInsets ------------------------------------------------
  
  	/**
  	 * Marker class to identify our visual paddings and leaf paddings,
  	 * which were set from outside, untouched.
  	 */
  	private static class FlatMigInsets
  		extends Insets
  	{
  		FlatMigInsets( int top, int left, int bottom, int right ) {
  			super( top, left, bottom, right );
  		}
  	}
  
  	//---- class FlatMigListener ----------------------------------------------
  
  	/**
  	 * Marker interface needed for listener removal.
  	 */
  	private interface FlatMigListener
  		extends PropertyChangeListener
  	{
  	}
  }
  