src/com/googlecode/lanterna/terminal/swing/TextBuffer.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.terminal.swing;
  20
  21 import com.googlecode.lanterna.TerminalTextUtils;
  22 import com.googlecode.lanterna.TextCharacter;
  23 import com.googlecode.lanterna.TerminalPosition;
  24 import com.googlecode.lanterna.TerminalSize;
  25 import java.util.ArrayList;
  26 import java.util.Iterator;
  27 import java.util.LinkedList;
  28 import java.util.List;
  29 import java.util.ListIterator;
  30
  31 /**
  32  * Contains an entire text buffer used by Swing terminal
  33  * @author martin
  34  */
  35 class TextBuffer {
  36     private final int backlog;
  37     private final LinkedList<List<TextCharacter>> lineBuffer;
  38     private final TextCharacter fillCharacter;
  39
  40     TextBuffer(int backlog) {
  41         this.backlog = backlog;
  42         this.lineBuffer = new LinkedList<List<TextCharacter>>();
  43         this.fillCharacter = TextCharacter.DEFAULT_CHARACTER;
  44
  45         //Initialize the content to one line
  46         newLine();
  47     }
  48
  49     void clear() {
  50         lineBuffer.clear();
  51         newLine();
  52     }
  53
  54     void newLine() {
  55         ArrayList<TextCharacter> line = new ArrayList<TextCharacter>(200);
  56         line.add(fillCharacter);
  57         lineBuffer.addFirst(line);
  58     }
  59
  60
  61     Iterable<List<TextCharacter>> getVisibleLines(final int visibleRows, final int scrollOffset) {
  62         final int length = Math.min(visibleRows, lineBuffer.size());
  63         return new Iterable<List<TextCharacter>>() {
  64             @Override
  65             public Iterator<List<TextCharacter>> iterator() {
  66                 return new Iterator<List<TextCharacter>>() {
  67                     private final ListIterator<List<TextCharacter>> listIterator = lineBuffer.subList(scrollOffset, scrollOffset + length).listIterator(length);
  68                     @Override
  69                     public boolean hasNext() { return listIterator.hasPrevious(); }
  70                     @Override
  71                     public List<TextCharacter> next() { return listIterator.previous(); }
  72                     @Override
  73                     public void remove() { listIterator.remove(); }
  74                 };
  75             }
  76         };
  77     }
  78
  79     int getNumberOfLines() {
  80         return lineBuffer.size();
  81     }
  82
  83     void trimBacklog(int terminalHeight) {
  84         while(lineBuffer.size() - terminalHeight > backlog) {
  85             lineBuffer.removeLast();
  86         }
  87     }
  88
  89     void ensurePosition(TerminalSize terminalSize, TerminalPosition position) {
  90         getLine(terminalSize, position);
  91     }
  92
  93     public TextCharacter getCharacter(TerminalSize terminalSize, TerminalPosition position) {
  94         return getLine(terminalSize, position).get(position.getColumn());
  95     }
  96
  97     void setCharacter(TerminalSize terminalSize, TerminalPosition currentPosition, TextCharacter terminalCharacter) {
  98         List<TextCharacter> line = getLine(terminalSize, currentPosition);
  99
 100         //If we are replacing a CJK character with a non-CJK character, make the following character empty
 101         if(TerminalTextUtils.isCharCJK(line.get(currentPosition.getColumn()).getCharacter()) &&
 102                 !TerminalTextUtils.isCharCJK(terminalCharacter.getCharacter())) {
 103             line.set(currentPosition.getColumn() + 1, terminalCharacter.withCharacter(' '));
 104         }
 105
 106         //Set the character in the buffer
 107         line.set(currentPosition.getColumn(), terminalCharacter);
 108
 109         //Pad CJK character with a trailing space
 110         if(TerminalTextUtils.isCharCJK(terminalCharacter.getCharacter()) && currentPosition.getColumn() + 1 < line.size()) {
 111             ensurePosition(terminalSize, currentPosition.withRelativeColumn(1));
 112             line.set(currentPosition.getColumn() + 1, terminalCharacter.withCharacter(' '));
 113         }
 114         //If there's a CJK character immediately to our left, reset it
 115         if(currentPosition.getColumn() > 0 && TerminalTextUtils.isCharCJK(line.get(currentPosition.getColumn() - 1).getCharacter())) {
 116             line.set(currentPosition.getColumn() - 1, line.get(currentPosition.getColumn() - 1).withCharacter(' '));
 117         }
 118     }
 119
 120     private List<TextCharacter> getLine(TerminalSize terminalSize, TerminalPosition position) {
 121         while(position.getRow() >= lineBuffer.size()) {
 122             newLine();
 123         }
 124         int lineIndex = Math.min(terminalSize.getRows(), lineBuffer.size()) - 1 - position.getRow();
 125         List<TextCharacter> line = lineBuffer.get(lineIndex);
 126         while(line.size() <= position.getColumn()) {
 127             line.add(fillCharacter);
 128         }
 129         return line;
 130     }
 131 }