src/com/googlecode/lanterna/gui2/LayoutManager.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.TerminalSize;
  22 import java.util.List;
  23
  24 /**
  25  * A layout manager is a class that takes an area of usable space and a list of components to fit on that space. This
  26  * is very similar to how AWT/Swing/SWT works. Lanterna contains a number of layout managers built-in that will arrange
  27  * components in various ways, but you can also write your own. The typical way of providing customization and tuning,
  28  * so the layout manager can distinguish between components and treat them in different ways, is to create a class
  29  * and/or objects based on the {@code LayoutData} object, which can be assigned to each {@code Component}.
  30  * @see AbsoluteLayout
  31  * @see BorderLayout
  32  * @see GridLayout
  33  * @see LinearLayout
  34  * @author Martin
  35  */
  36 public interface LayoutManager {
  37
  38     /**
  39      * This method returns the dimensions it would prefer to have to be able to layout all components while giving all
  40      * of them as much space as they are asking for.
  41      * @param components List of components
  42      * @return Size the layout manager would like to have
  43      */
  44     TerminalSize getPreferredSize(List<Component> components);
  45
  46     /**
  47      * Given a size constraint, update the location and size of each component in the component list by laying them out
  48      * in the available area. This method will call {@code setPosition(..)} and {@code setSize(..)} on the Components.
  49      * @param area Size available to this layout manager to lay out the components on
  50      * @param components List of components to lay out
  51      */
  52     void doLayout(TerminalSize area, List<Component> components);
  53
  54     /**
  55      * Returns true if the internal state of this LayoutManager has changed since the last call to doLayout. This will
  56      * tell the container that it needs to call doLayout again.
  57      * @return {@code true} if this layout manager's internal state has changed since the last call to {@code doLayout}
  58      */
  59     boolean hasChanged();
  60 }