ev3dev.hardware.display

Class OwnedDisplay

java.lang.Object

ev3dev.hardware.display.DisplayInterface

ev3dev.hardware.display.OwnedDisplay

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable

class OwnedDisplay
extends DisplayInterface

System console manager.

It manages the output mode of the display. It is possible to switch between graphics mode and text mode. Graphics mode reserves the display for drawing operation and hides text output. On the other hand, text mode suspends drawing operations and shows the text on the Linux console. This class also manages VT (= Virtual Terminal = console) switches in the case of a VT switch occuring when graphics mode is set.

Implementation of this class is based on the GRX3 linuxfb plugin.

Since:

2.4.7

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.Thread	deinitializer
private java.lang.String	fbPath
private ILibc	libc
private int	old_kbmode
private NativeTTY	ttyfd

Fields inherited from class ev3dev.hardware.display.DisplayInterface

fbInstance

Constructor Summary

Constructors

Constructor and Description
OwnedDisplay(ILibc libc) Initialize the display, register event handlers and switch to text mode.

Method Summary

Modifier and Type	Method and Description
void	close()
private void	deinitialize() Put the display to a state where it is ready for returning.
private void	initialize() Initialize the display state.
JavaFramebuffer	openFramebuffer() Get the framebuffer for the system display.
void	switchToGraphicsMode() Switch the display to a graphics mode.
void	switchToTextMode() Switch the display to a text mode.

Methods inherited from class ev3dev.hardware.display.DisplayInterface

closeFramebuffer, initializeFramebuffer, releaseFramebuffer

Methods inherited from class java.lang.Object

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

Field Detail

libc

private ILibc libc

fbPath

private java.lang.String fbPath

ttyfd

private NativeTTY ttyfd

old_kbmode

private int old_kbmode

deinitializer

private java.lang.Thread deinitializer

Constructor Detail

OwnedDisplay

public OwnedDisplay(ILibc libc)

Initialize the display, register event handlers and switch to text mode.

Throws:

java.lang.RuntimeException - when initialization or mode switch fails.

Method Detail

initialize

private void initialize()
                 throws java.io.IOException

Initialize the display state.

Opens the current VT, saves keyboard mode and identifies the appropriate framebuffer device.

Throws:

java.io.IOException - When the initialization fails.

close

public void close()

deinitialize

private void deinitialize()

Put the display to a state where it is ready for returning.

Keyboard mode is restored, text mode is set and VT autoswitch is enabled. Then, console file descriptor is closed.

switchToGraphicsMode

public void switchToGraphicsMode()

Switch the display to a graphics mode.

It switches VT to graphics mode with keyboard turned off. Then, it tells kernel to notify Java when VT switch occurs. Also, framebuffer contents are restored and write access is enabled.

Specified by:

switchToGraphicsMode in class DisplayInterface

Throws:

java.lang.RuntimeException - when the switch fails

switchToTextMode

public void switchToTextMode()

Switch the display to a text mode.

It stores framebuffer data and disables write access. Then, it switches VT to text mode and allows kernel to auto-switch it.

Specified by:

switchToTextMode in class DisplayInterface

Throws:

java.lang.RuntimeException - when the switch fails

openFramebuffer

public JavaFramebuffer openFramebuffer()

Get the framebuffer for the system display.

The framebuffer is initialized only once, later calls return references to the same instance.

Specified by:

openFramebuffer in class DisplayInterface

Returns:

Java framebuffer compatible with the system display.

Throws:

java.lang.RuntimeException - when switch to graphics mode or the framebuffer initialization fails.