Package org.jline.utils

Class Display

java.lang.Object

org.jline.utils.Display

public class Display
extends java.lang.Object

Manages terminal display and efficient screen updates with cursor positioning.

The Display class provides functionality for managing the display of content on the terminal screen. It handles the complexities of cursor positioning, line wrapping, and efficient screen updates to minimize the amount of data sent to the terminal.

This class supports two main modes of operation:

• Full-screen mode - Takes over the entire terminal screen
• Partial-screen mode - Updates only a portion of the screen, preserving content above

Key features include:

• Efficient screen updates using cursor positioning
• Support for multi-line content with proper wrapping
• Handling of ANSI-styled text (colors, attributes)
• Size-aware rendering that adapts to terminal dimensions
• Cursor positioning relative to the display area

This class is used by various JLine components, such as LineReader, to provide efficient terminal display management for features like command-line editing, completion menus, and status messages.

Field Summary

Fields

Modifier and Type	Field	Description
protected boolean	canScroll
protected int	columns
protected int	columns1
protected java.util.Map<InfoCmp.Capability,java.lang.Integer>	cost
protected boolean	cursorDownIsNewLine
protected int	cursorPos
protected boolean	delayedWrapAtEol
protected boolean	delayLineWrap
protected boolean	fullScreen
protected java.util.List<AttributedString>	oldLines
protected boolean	reset
protected int	rows
protected Terminal	terminal
protected boolean	terminalDelayedWrapAtEol
protected boolean	terminalWrapAtEol
protected boolean	wrapAtEol

Constructor Summary

Constructors

Constructor	Description
Display(Terminal terminal, boolean fullscreen)

Method Summary

Modifier and Type	Method	Description
protected boolean	can(InfoCmp.Capability single, InfoCmp.Capability multi)
void	clear()	Clears the whole screen.
boolean	delayLineWrap()	If cursor is at right margin, don't wrap immediately.
protected boolean	deleteChars(int nb)
protected boolean	deleteLines(int nb)
protected boolean	insertChars(int nb)
protected boolean	insertLines(int nb)
protected int	moveVisualCursorTo(int i1)
protected void	moveVisualCursorTo(int targetPos, java.util.List<AttributedString> newLines)
protected boolean	perform(InfoCmp.Capability single, InfoCmp.Capability multi, int nb)
void	reset()
void	resize(int rows, int columns)
void	setDelayLineWrap(boolean v)
void	update(java.util.List<AttributedString> newLines, int targetCursorPos)	Update the display according to the new lines and flushes the output.
void	update(java.util.List<AttributedString> newLines, int targetCursorPos, boolean flush)	Update the display according to the new lines.
void	updateAnsi(java.util.List<java.lang.String> newLines, int targetCursorPos)
int	wcwidth(java.lang.String str)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

terminal

protected final Terminal terminal

fullScreen

protected final boolean fullScreen

oldLines

protected java.util.List<AttributedString> oldLines

cursorPos

protected int cursorPos

columns

protected int columns

columns1

protected int columns1

rows

protected int rows

reset

protected boolean reset

delayLineWrap

protected boolean delayLineWrap

cost

protected final java.util.Map<InfoCmp.Capability,java.lang.Integer> cost

canScroll

protected final boolean canScroll

terminalWrapAtEol

protected final boolean terminalWrapAtEol

terminalDelayedWrapAtEol

protected final boolean terminalDelayedWrapAtEol

wrapAtEol

protected boolean wrapAtEol

delayedWrapAtEol

protected boolean delayedWrapAtEol

cursorDownIsNewLine

protected final boolean cursorDownIsNewLine

Constructor Detail

Display

public Display(Terminal terminal,
               boolean fullscreen)

Method Detail

delayLineWrap

public boolean delayLineWrap()

If cursor is at right margin, don't wrap immediately. See org.jline.reader.LineReader.Option#DELAY_LINE_WRAP.

Returns:

true if line wrap is delayed, false otherwise

setDelayLineWrap

public void setDelayLineWrap(boolean v)

resize

public void resize(int rows,
                   int columns)

reset

public void reset()

clear

public void clear()

Clears the whole screen. Use this method only when using full-screen / application mode.

updateAnsi

public void updateAnsi(java.util.List<java.lang.String> newLines,
                       int targetCursorPos)

update

public void update(java.util.List<AttributedString> newLines,
                   int targetCursorPos)

Update the display according to the new lines and flushes the output.

Parameters:

newLines - the lines to display

targetCursorPos - desired cursor position - see Size.cursorPos.

update

public void update(java.util.List<AttributedString> newLines,
                   int targetCursorPos,
                   boolean flush)

Update the display according to the new lines.

Parameters:

newLines - the lines to display

targetCursorPos - desired cursor position - see Size.cursorPos.

flush - whether the output should be flushed or not

deleteLines

protected boolean deleteLines(int nb)

insertLines

protected boolean insertLines(int nb)

insertChars

protected boolean insertChars(int nb)

deleteChars

protected boolean deleteChars(int nb)

can

protected boolean can(InfoCmp.Capability single,
                      InfoCmp.Capability multi)

perform

protected boolean perform(InfoCmp.Capability single,
                          InfoCmp.Capability multi,
                          int nb)

moveVisualCursorTo

protected void moveVisualCursorTo(int targetPos,
                                  java.util.List<AttributedString> newLines)

moveVisualCursorTo

protected int moveVisualCursorTo(int i1)

wcwidth

public int wcwidth(java.lang.String str)