src/com/googlecode/lanterna/screen/ScreenBuffer.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.screen;
  20
  21 import com.googlecode.lanterna.TerminalPosition;
  22 import com.googlecode.lanterna.TextCharacter;
  23 import com.googlecode.lanterna.TerminalSize;
  24 import com.googlecode.lanterna.graphics.BasicTextImage;
  25 import com.googlecode.lanterna.graphics.TextGraphics;
  26 import com.googlecode.lanterna.graphics.TextImage;
  27
  28 /**
  29  * Defines a buffer used by AbstractScreen and its subclasses to keep its state of what's currently displayed and what
  30  * the edit buffer looks like. A ScreenBuffer is essentially a two-dimensional array of TextCharacter with some utility
  31  * methods to inspect and manipulate it in a safe way.
  32  * @author martin
  33  */
  34 public class ScreenBuffer implements TextImage {
  35     private final BasicTextImage backend;
  36
  37     /**
  38      * Creates a new ScreenBuffer with a given size and a TextCharacter to initially fill it with
  39      * @param size Size of the buffer
  40      * @param filler What character to set as the initial content of the buffer
  41      */
  42     public ScreenBuffer(TerminalSize size, TextCharacter filler) {
  43         this(new BasicTextImage(size, filler));
  44     }
  45
  46     private ScreenBuffer(BasicTextImage backend) {
  47         this.backend = backend;
  48     }
  49
  50     @Override
  51     public ScreenBuffer resize(TerminalSize newSize, TextCharacter filler) {
  52         BasicTextImage resizedBackend = backend.resize(newSize, filler);
  53         return new ScreenBuffer(resizedBackend);
  54     }
  55
  56     boolean isVeryDifferent(ScreenBuffer other, int threshold) {
  57         if(!getSize().equals(other.getSize())) {
  58             throw new IllegalArgumentException("Can only call isVeryDifferent comparing two ScreenBuffers of the same size!"
  59                     + " This is probably a bug in Lanterna.");
  60         }
  61         int differences = 0;
  62         for(int y = 0; y < getSize().getRows(); y++) {
  63             for(int x = 0; x < getSize().getColumns(); x++) {
  64                 if(!getCharacterAt(x, y).equals(other.getCharacterAt(x, y))) {
  65                     if(++differences >= threshold) {
  66                         return true;
  67                     }
  68                 }
  69             }
  70         }
  71         return false;
  72     }
  73
  74     ///////////////////////////////////////////////////////////////////////////////
  75     //  Delegate all TextImage calls (except resize) to the backend BasicTextImage
  76     @Override
  77     public TerminalSize getSize() {
  78         return backend.getSize();
  79     }
  80
  81     @Override
  82     public TextCharacter getCharacterAt(TerminalPosition position) {
  83         return backend.getCharacterAt(position);
  84     }
  85
  86     @Override
  87     public TextCharacter getCharacterAt(int column, int row) {
  88         return backend.getCharacterAt(column, row);
  89     }
  90
  91     @Override
  92     public void setCharacterAt(TerminalPosition position, TextCharacter character) {
  93         backend.setCharacterAt(position, character);
  94     }
  95
  96     @Override
  97     public void setCharacterAt(int column, int row, TextCharacter character) {
  98         backend.setCharacterAt(column, row, character);
  99     }
 100
 101     @Override
 102     public void setAll(TextCharacter character) {
 103         backend.setAll(character);
 104     }
 105
 106     @Override
 107     public TextGraphics newTextGraphics() {
 108         return backend.newTextGraphics();
 109     }
 110
 111     @Override
 112     public void copyTo(TextImage destination) {
 113         if(destination instanceof ScreenBuffer) {
 114             //This will allow the BasicTextImage's copy method to use System.arraycopy (micro-optimization?)
 115             destination = ((ScreenBuffer)destination).backend;
 116         }
 117         backend.copyTo(destination);
 118     }
 119
 120     @Override
 121     public void copyTo(TextImage destination, int startRowIndex, int rows, int startColumnIndex, int columns, int destinationRowOffset, int destinationColumnOffset) {
 122         if(destination instanceof ScreenBuffer) {
 123             //This will allow the BasicTextImage's copy method to use System.arraycopy (micro-optimization?)
 124             destination = ((ScreenBuffer)destination).backend;
 125         }
 126         backend.copyTo(destination, startRowIndex, rows, startColumnIndex, columns, destinationRowOffset, destinationColumnOffset);
 127     }
 128
 129     /**
 130      * Copies the content from a TextImage into this buffer.
 131      * @param source Source to copy content from
 132      * @param startRowIndex Which row in the source image to start copying from
 133      * @param rows How many rows to copy
 134      * @param startColumnIndex Which column in the source image to start copying from
 135      * @param columns How many columns to copy
 136      * @param destinationRowOffset The row offset in this buffer of where to place the copied content
 137      * @param destinationColumnOffset The column offset in this buffer of where to place the copied content
 138      */
 139     public void copyFrom(TextImage source, int startRowIndex, int rows, int startColumnIndex, int columns, int destinationRowOffset, int destinationColumnOffset) {
 140         source.copyTo(backend, startRowIndex, rows, startColumnIndex, columns, destinationRowOffset, destinationColumnOffset);
 141     }
 142
 143     @Override
 144     public void scrollLines(int firstLine, int lastLine, int distance) {
 145         backend.scrollLines(firstLine, lastLine, distance);
 146     }
 147
 148     @Override
 149     public String toString() {
 150         return backend.toString();
 151     }
 152 }