Gridarta Editor
PrevPage.java
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1 /*
2  * InputHandler.java - Manages key bindings and executes actions
3  * Copyright (C) 1999 Slava Pestov
4  * Copyright (C) 2000-2015 The Gridarta Developers.
5  *
6  * You may use and modify this package for any purpose. Redistribution is
7  * permitted, in both source and binary form, provided that this notice
8  * remains intact in all source distributions of this package.
9  */
10 
11 package net.sf.gridarta.textedit.textarea.actions;
12 
13 import java.awt.event.ActionEvent;
14 import java.awt.event.ActionListener;
17 
18 public class PrevPage implements ActionListener {
19 
20  private final boolean select;
21 
22  public PrevPage(final boolean select) {
23  this.select = select;
24  }
25 
26  @Override
27  public void actionPerformed(final ActionEvent e) {
28  final JEditTextArea textArea = InputHandler.getTextArea(e);
29  int firstLine = textArea.getFirstLine();
30  final int visibleLines = textArea.getVisibleLines();
31  final int line = textArea.getCaretLine();
32 
33  if (firstLine < visibleLines) {
34  firstLine = visibleLines;
35  }
36 
37  textArea.setFirstLine(firstLine - visibleLines);
38 
39  final int caret = textArea.getLineStartOffset(Math.max(0, line - visibleLines));
40  if (select) {
41  textArea.select(textArea.getMarkPosition(), caret);
42  } else {
43  textArea.setCaretPosition(caret);
44  }
45  }
46 
47 }
int getMarkPosition()
Returns the mark position.
An input handler converts the user&#39;s key strokes into concrete actions.
Base package of all Gridarta classes.
int getLineStartOffset(final int line)
Returns the start offset of the specified line.
void select(final int start, final int end)
Selects from the start offset to the end offset.
This package contains the other part of the script editor.
int getFirstLine()
Returns the line displayed at the text area&#39;s origin.
static JEditTextArea getTextArea(final EventObject evt)
Returns the text area that fired the specified event.
void setFirstLine(final int firstLine)
Sets the line displayed at the text area&#39;s origin without updating the scroll bars.
void setCaretPosition(final int caret)
Sets the caret position.
int getVisibleLines()
Returns the number of lines visible in this text area.