/*
* This file is part of lanterna (http://code.google.com/p/lanterna/).
*
* lanterna is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright (C) 2010-2020 Martin Berglund
*/
package com.googlecode.lanterna.screen;
What to do about the tab character when putting on a Screen
. Since tabs are a bit special, their meaning depends on which column the cursor is in when it's printed, we'll need to have some way to tell the Screen what to do when encountering a tab character. Author: martin
/**
* What to do about the tab character when putting on a {@code Screen}. Since tabs are a bit special, their meaning
* depends on which column the cursor is in when it's printed, we'll need to have some way to tell the Screen what to
* do when encountering a tab character.
*
* @author martin
*/
public enum TabBehaviour {
Tab characters are not replaced, this will probably have undefined and weird behaviour!
/**
* Tab characters are not replaced, this will probably have undefined and weird behaviour!
*/
IGNORE(null, null),
Tab characters are replaced with a single blank space, no matter where the tab was placed.
/**
* Tab characters are replaced with a single blank space, no matter where the tab was placed.
*/
CONVERT_TO_ONE_SPACE(1, null),
Tab characters are replaced with two blank spaces, no matter where the tab was placed.
/**
* Tab characters are replaced with two blank spaces, no matter where the tab was placed.
*/
CONVERT_TO_TWO_SPACES(2, null),
Tab characters are replaced with three blank spaces, no matter where the tab was placed.
/**
* Tab characters are replaced with three blank spaces, no matter where the tab was placed.
*/
CONVERT_TO_THREE_SPACES(3, null),
Tab characters are replaced with four blank spaces, no matter where the tab was placed.
/**
* Tab characters are replaced with four blank spaces, no matter where the tab was placed.
*/
CONVERT_TO_FOUR_SPACES(4, null),
Tab characters are replaced with eight blank spaces, no matter where the tab was placed.
/**
* Tab characters are replaced with eight blank spaces, no matter where the tab was placed.
*/
CONVERT_TO_EIGHT_SPACES(8, null),
Tab characters are replaced with enough space characters to reach the next column index that is evenly divisible
by 4, simulating a normal tab character when placed inside a text document.
/**
* Tab characters are replaced with enough space characters to reach the next column index that is evenly divisible
* by 4, simulating a normal tab character when placed inside a text document.
*/
ALIGN_TO_COLUMN_4(null, 4),
Tab characters are replaced with enough space characters to reach the next column index that is evenly divisible
by 8, simulating a normal tab character when placed inside a text document.
/**
* Tab characters are replaced with enough space characters to reach the next column index that is evenly divisible
* by 8, simulating a normal tab character when placed inside a text document.
*/
ALIGN_TO_COLUMN_8(null, 8),
;
private final Integer replaceFactor;
private final Integer alignFactor;
TabBehaviour(Integer replaceFactor, Integer alignFactor) {
this.replaceFactor = replaceFactor;
this.alignFactor = alignFactor;
}
Given a string, being placed on the screen at column X, returns the same string with all tab characters (\t)
replaced according to this TabBehaviour.
Params: - string – String that is going to be put to the screen, potentially containing tab characters
- columnIndex – Column on the screen where the first character of the string is going to end up
Returns: The input string with all tab characters replaced with spaces, according to this TabBehaviour
/**
* Given a string, being placed on the screen at column X, returns the same string with all tab characters (\t)
* replaced according to this TabBehaviour.
* @param string String that is going to be put to the screen, potentially containing tab characters
* @param columnIndex Column on the screen where the first character of the string is going to end up
* @return The input string with all tab characters replaced with spaces, according to this TabBehaviour
*/
public String replaceTabs(String string, int columnIndex) {
int tabPosition = string.indexOf('\t');
while(tabPosition != -1) {
String tabReplacementHere = getTabReplacement(columnIndex + tabPosition);
string = string.substring(0, tabPosition) + tabReplacementHere + string.substring(tabPosition + 1);
tabPosition += tabReplacementHere.length();
tabPosition = string.indexOf('\t', tabPosition);
}
return string;
}
Returns the String that can replace a tab at the specified position, according to this TabBehaviour.
Params: - columnIndex – Column index of where the tab character is placed
Returns: String consisting of 1 or more space character
/**
* Returns the String that can replace a tab at the specified position, according to this TabBehaviour.
* @param columnIndex Column index of where the tab character is placed
* @return String consisting of 1 or more space character
*/
public String getTabReplacement(int columnIndex) {
int replaceCount;
StringBuilder replace = new StringBuilder();
if(replaceFactor != null) {
replaceCount = replaceFactor;
}
else if (alignFactor != null) {
replaceCount = alignFactor - (columnIndex % alignFactor);
}
else {
return "\t";
}
for(int i = 0; i < replaceCount; i++) {
replace.append(" ");
}
return replace.toString();
}
}