public void actionPerformed(ActionEvent evt)
{
JEditTextArea textArea = getTextArea(evt);
int firstLine = textArea.getFirstLine();
int visibleLines = textArea.getVisibleLines();
int line = textArea.getCaretLine();
if(firstLine < visibleLines)
firstLine = visibleLines;
textArea.setFirstLine(firstLine - visibleLines);
int caret = textArea.getLineStartOffset(
Math.max(0,line - visibleLines));
if(select)
textArea.select(textArea.getMarkPosition(),caret);
else
textArea.setCaretPosition(caret);
}
public void actionPerformed(ActionEvent evt)
{
JEditTextArea textArea = getTextArea(evt);
int lineCount = textArea.getLineCount();
int firstLine = textArea.getFirstLine();
int visibleLines = textArea.getVisibleLines();
int line = textArea.getCaretLine();
firstLine += visibleLines;
if(firstLine + visibleLines >= lineCount - 1)
firstLine = lineCount - visibleLines;
textArea.setFirstLine(firstLine);
int caret = textArea.getLineStartOffset(
Math.min(textArea.getLineCount() - 1,
line + visibleLines));
if(select)
textArea.select(textArea.getMarkPosition(),caret);
else
textArea.setCaretPosition(caret);
}