src/com/googlecode/lanterna/gui2/BorderLayout.java

   1 /*
   2  * This file is part of lanterna (http://code.google.com/p/lanterna/).
   3  *
   4  * lanterna is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU Lesser General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  *
  17  * Copyright (C) 2010-2015 Martin
  18  */
  19 package com.googlecode.lanterna.gui2;
  20
  21 import com.googlecode.lanterna.TerminalPosition;
  22 import com.googlecode.lanterna.TerminalSize;
  23
  24 import java.util.*;
  25
  26 /**
  27  * BorderLayout imitates the BorderLayout class from AWT, allowing you to add a center component with optional
  28  * components around it in top, bottom, left and right locations. The edge components will be sized at their preferred
  29  * size and the center component will take up whatever remains.
  30  * @author martin
  31  */
  32 public class BorderLayout implements LayoutManager {
  33
  34     /**
  35      * This type is what you use as the layout data for components added to a panel using {@code BorderLayout} for its
  36      * layout manager. This values specified where inside the panel the component should be added.
  37      */
  38     public enum Location implements LayoutData {
  39         /**
  40          * The component with this value as its layout data will occupy the center space, whatever is remaining after
  41          * the other components (if any) have allocated their space.
  42          */
  43         CENTER,
  44         /**
  45          * The component with this value as its layout data will occupy the left side of the container, attempting to
  46          * allocate the preferred width of the component and at least the preferred height, but could be more depending
  47          * on the other components added.
  48          */
  49         LEFT,
  50         /**
  51          * The component with this value as its layout data will occupy the right side of the container, attempting to
  52          * allocate the preferred width of the component and at least the preferred height, but could be more depending
  53          * on the other components added.
  54          */
  55         RIGHT,
  56         /**
  57          * The component with this value as its layout data will occupy the top side of the container, attempting to
  58          * allocate the preferred height of the component and at least the preferred width, but could be more depending
  59          * on the other components added.
  60          */
  61         TOP,
  62         /**
  63          * The component with this value as its layout data will occupy the bottom side of the container, attempting to
  64          * allocate the preferred height of the component and at least the preferred width, but could be more depending
  65          * on the other components added.
  66          */
  67         BOTTOM,
  68         ;
  69     }
  70
  71     //When components don't have a location, we'll assign an available location based on this order
  72     private static final List<Location> AUTO_ASSIGN_ORDER = Collections.unmodifiableList(Arrays.asList(
  73             Location.CENTER,
  74             Location.TOP,
  75             Location.BOTTOM,
  76             Location.LEFT,
  77             Location.RIGHT));
  78
  79     @Override
  80     public TerminalSize getPreferredSize(List<Component> components) {
  81         EnumMap<Location, Component> layout = makeLookupMap(components);
  82         int preferredHeight =
  83                 (layout.containsKey(Location.TOP) ? layout.get(Location.TOP).getPreferredSize().getRows() : 0)
  84                 +
  85                 Math.max(
  86                     layout.containsKey(Location.LEFT) ? layout.get(Location.LEFT).getPreferredSize().getRows() : 0,
  87                     Math.max(
  88                         layout.containsKey(Location.CENTER) ? layout.get(Location.CENTER).getPreferredSize().getRows() : 0,
  89                         layout.containsKey(Location.RIGHT) ? layout.get(Location.RIGHT).getPreferredSize().getRows() : 0))
  90                 +
  91                 (layout.containsKey(Location.BOTTOM) ? layout.get(Location.BOTTOM).getPreferredSize().getRows() : 0);
  92
  93         int preferredWidth =
  94                 Math.max(
  95                     (layout.containsKey(Location.LEFT) ? layout.get(Location.LEFT).getPreferredSize().getColumns() : 0) +
  96                         (layout.containsKey(Location.CENTER) ? layout.get(Location.CENTER).getPreferredSize().getColumns() : 0) +
  97                         (layout.containsKey(Location.RIGHT) ? layout.get(Location.RIGHT).getPreferredSize().getColumns() : 0),
  98                     Math.max(
  99                         layout.containsKey(Location.TOP) ? layout.get(Location.TOP).getPreferredSize().getColumns() : 0,
 100                         layout.containsKey(Location.BOTTOM) ? layout.get(Location.BOTTOM).getPreferredSize().getColumns() : 0));
 101         return new TerminalSize(preferredWidth, preferredHeight);
 102     }
 103
 104     @Override
 105     public void doLayout(TerminalSize area, List<Component> components) {
 106         EnumMap<Location, Component> layout = makeLookupMap(components);
 107         int availableHorizontalSpace = area.getColumns();
 108         int availableVerticalSpace = area.getRows();
 109
 110         //We'll need this later on
 111         int topComponentHeight = 0;
 112         int leftComponentWidth = 0;
 113
 114         //First allocate the top
 115         if(layout.containsKey(Location.TOP)) {
 116             Component topComponent = layout.get(Location.TOP);
 117             topComponentHeight = Math.min(topComponent.getPreferredSize().getRows(), availableVerticalSpace);
 118             topComponent.setPosition(TerminalPosition.TOP_LEFT_CORNER);
 119             topComponent.setSize(new TerminalSize(availableHorizontalSpace, topComponentHeight));
 120             availableVerticalSpace -= topComponentHeight;
 121         }
 122
 123         //Next allocate the bottom
 124         if(layout.containsKey(Location.BOTTOM)) {
 125             Component bottomComponent = layout.get(Location.BOTTOM);
 126             int bottomComponentHeight = Math.min(bottomComponent.getPreferredSize().getRows(), availableVerticalSpace);
 127             bottomComponent.setPosition(new TerminalPosition(0, area.getRows() - bottomComponentHeight));
 128             bottomComponent.setSize(new TerminalSize(availableHorizontalSpace, bottomComponentHeight));
 129             availableVerticalSpace -= bottomComponentHeight;
 130         }
 131
 132         //Now divide the remaining space between LEFT, CENTER and RIGHT
 133         if(layout.containsKey(Location.LEFT)) {
 134             Component leftComponent = layout.get(Location.LEFT);
 135             leftComponentWidth = Math.min(leftComponent.getPreferredSize().getColumns(), availableHorizontalSpace);
 136             leftComponent.setPosition(new TerminalPosition(0, topComponentHeight));
 137             leftComponent.setSize(new TerminalSize(leftComponentWidth, availableVerticalSpace));
 138             availableHorizontalSpace -= leftComponentWidth;
 139         }
 140         if(layout.containsKey(Location.RIGHT)) {
 141             Component rightComponent = layout.get(Location.RIGHT);
 142             int rightComponentWidth = Math.min(rightComponent.getPreferredSize().getColumns(), availableHorizontalSpace);
 143             rightComponent.setPosition(new TerminalPosition(area.getColumns() - rightComponentWidth, topComponentHeight));
 144             rightComponent.setSize(new TerminalSize(rightComponentWidth, availableVerticalSpace));
 145             availableHorizontalSpace -= rightComponentWidth;
 146         }
 147         if(layout.containsKey(Location.CENTER)) {
 148             Component centerComponent = layout.get(Location.CENTER);
 149             centerComponent.setPosition(new TerminalPosition(leftComponentWidth, topComponentHeight));
 150             centerComponent.setSize(new TerminalSize(availableHorizontalSpace, availableVerticalSpace));
 151         }
 152
 153         //Set the remaining components to 0x0
 154         for(Component component: components) {
 155             if(!layout.values().contains(component)) {
 156                 component.setPosition(TerminalPosition.TOP_LEFT_CORNER);
 157                 component.setSize(TerminalSize.ZERO);
 158             }
 159         }
 160     }
 161
 162     private EnumMap<Location, Component> makeLookupMap(List<Component> components) {
 163         EnumMap<Location, Component> map = new EnumMap<BorderLayout.Location, Component>(Location.class);
 164         List<Component> unassignedComponents = new ArrayList<Component>();
 165         for(Component component: components) {
 166             if(component.getLayoutData() instanceof Location) {
 167                 map.put((Location)component.getLayoutData(), component);
 168             }
 169             else {
 170                 unassignedComponents.add(component);
 171             }
 172         }
 173         //Try to assign components to available locations
 174         for(Component component: unassignedComponents) {
 175             for(Location location: AUTO_ASSIGN_ORDER) {
 176                 if(!map.containsKey(location)) {
 177                     map.put(location, component);
 178                     break;
 179                 }
 180             }
 181         }
 182         return map;
 183     }
 184
 185     @Override
 186     public boolean hasChanged() {
 187         //No internal state
 188         return false;
 189     }
 190 }