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a3b510ab NR |
1 | package com.googlecode.lanterna.graphics; |
2 | ||
3 | import java.io.IOException; | |
4 | ||
5 | /** | |
6 | * Describes an area that can be 'scrolled', by moving a range of lines up or down. Certain terminals will implement | |
7 | * this through extensions and are much faster than if lanterna tries to manually erase and re-print the text. | |
8 | * | |
9 | * @author Andreas | |
10 | */ | |
11 | public interface Scrollable { | |
12 | /** | |
13 | * Scroll a range of lines of this Scrollable according to given distance. | |
14 | * | |
15 | * If scroll-range is empty (firstLine > lastLine || distance == 0) then | |
16 | * this method does nothing. | |
17 | * | |
18 | * Lines that are scrolled away from are cleared. | |
19 | * | |
20 | * If absolute value of distance is equal or greater than number of lines | |
21 | * in range, then all lines within the range will be cleared. | |
22 | * | |
23 | * @param firstLine first line of the range to be scrolled (top line is 0) | |
24 | * @param lastLine last (inclusive) line of the range to be scrolled | |
25 | * @param distance if > 0: move lines up, else if < 0: move lines down. | |
26 | */ | |
27 | void scrollLines(int firstLine, int lastLine, int distance) throws IOException; | |
28 | } |