Top Description Fields Constructors Methods
com.sun.glass.ui.monocle

pack-priv Class FramebufferY8

extends Framebuffer
Class Inheritance
Imports
com.sun.javafx.logging.PlatformLogger, com.sun.javafx.util.Logging, java.io.IOException, java.nio.Buffer, .ByteBuffer, .ByteOrder, .IntBuffer, .ShortBuffer, java.nio.channels.WritableByteChannel, java.text.MessageFormat
Provides a buffer for composing JavaFX scenes. This class is given a 32-bit composition buffer that is either the Linux frame buffer itself or an off-screen byte buffer. It can write the contents of this buffer to a target channel, or copy them to a buffer, in one of three pixel formats: 32-bit ARGB32 color, 16-bit RGB565 color, or 8-bit Y8 grayscale.

Field Summary

Modifier and TypeField and Description
private final ByteBuffer
bb

Hides com.sun.glass.ui.monocle.Framebuffer.bb.

private final int
bitDepth

private static final int
BITS_TO_BYTES

The arithmetic right shift value to convert a bit depth to a byte depth.

private final int
byteDepth

Hides com.sun.glass.ui.monocle.Framebuffer.byteDepth.

private final int
height

Hides com.sun.glass.ui.monocle.Framebuffer.height.

private ByteBuffer
lineByteBuffer

Hides com.sun.glass.ui.monocle.Framebuffer.lineByteBuffer.

private Buffer
linePixelBuffer

Hides com.sun.glass.ui.monocle.Framebuffer.linePixelBuffer.

private final PlatformLogger
logger

private final int
width

Hides com.sun.glass.ui.monocle.Framebuffer.width.

Constructor Summary

AccessConstructor and Description
pack-priv
FramebufferY8(ByteBuffer
the 32-bit composition buffer
bb, int
the width of the composition buffer in pixels
width, int
the height of the composition buffer in pixels
height, int
the color depth of the target channel or buffer in bits per pixel
depth, boolean
true to clear the composition buffer on the first upload of each frame unless that upload already overwrites the entire buffer; otherwise false
clear)

Creates a new FramebufferY8 with the given 32-bit composition buffer and target color depth.

Method Summary

Modifier and TypeMethod and Description
private void
copyNextPixel(IntBuffer
the source integer buffer in ARGB32 format
source, ByteBuffer
the target byte buffer in Y8 format
target)

Copies the next 32-bit ARGB32 pixel to a byte buffer with 8-bit Y8 pixels.

private void
copyNextPixel(IntBuffer
the source integer buffer in ARGB32 format
source, ShortBuffer
the target short buffer in RGB565 format
target)

Copies the next 32-bit ARGB32 pixel to a short buffer with 16-bit RGB565 pixels.

pack-priv void
copyToBuffer(ByteBuffer
the output buffer
out)

Overrides com.sun.glass.ui.monocle.Framebuffer.copyToBuffer.

Copies the contents of the composition buffer to the output buffer, converting the pixel format as necessary.

public String
toString()

Overrides java.lang.Object.toString.

Returns a string representation of the object.

pack-priv void
write(WritableByteChannel
the output channel
out)

Overrides com.sun.glass.ui.monocle.Framebuffer.write.

Writes the contents of the composition buffer to the output channel, converting the pixel format as necessary.

Inherited from com.sun.glass.ui.monocle.Framebuffer:
clearBufferContentscomposePixelsgetBufferhasReceivedDataresetsetStartAddress

Field Detail

bbback to summary
private final ByteBuffer bb

Hides com.sun.glass.ui.monocle.Framebuffer.bb.

bitDepthback to summary
private final int bitDepth
BITS_TO_BYTESback to summary
private static final int BITS_TO_BYTES

The arithmetic right shift value to convert a bit depth to a byte depth.

byteDepthback to summary
private final int byteDepth

Hides com.sun.glass.ui.monocle.Framebuffer.byteDepth.

heightback to summary
private final int height

Hides com.sun.glass.ui.monocle.Framebuffer.height.

lineByteBufferback to summary
private ByteBuffer lineByteBuffer

Hides com.sun.glass.ui.monocle.Framebuffer.lineByteBuffer.

linePixelBufferback to summary
private Buffer linePixelBuffer

Hides com.sun.glass.ui.monocle.Framebuffer.linePixelBuffer.

loggerback to summary
private final PlatformLogger logger
widthback to summary
private final int width

Hides com.sun.glass.ui.monocle.Framebuffer.width.

Constructor Detail

FramebufferY8back to summary
pack-priv FramebufferY8(ByteBuffer bb, int width, int height, int depth, boolean clear)

Creates a new FramebufferY8 with the given 32-bit composition buffer and target color depth.

Parameters
bb:ByteBuffer

the 32-bit composition buffer

width:int

the width of the composition buffer in pixels

height:int

the height of the composition buffer in pixels

depth:int

the color depth of the target channel or buffer in bits per pixel

clear:boolean

true to clear the composition buffer on the first upload of each frame unless that upload already overwrites the entire buffer; otherwise false

Method Detail

copyNextPixelback to summary
private void copyNextPixel(IntBuffer source, ByteBuffer target)

Copies the next 32-bit ARGB32 pixel to a byte buffer with 8-bit Y8 pixels. Luma Y' can be calculated from gamma-corrected R'G'B' using the following coefficients. This method uses the coefficients from Rec. 709, which defines the same primaries and white point as the sRGB color space. 

Simple average:  Y' = (R' + G' + B') / 3
Rec. 601 (SDTV): Y' = 0.299  * R' + 0.587  * G' + 0.114  * B'
Rec. 709 (HDTV): Y' = 0.2126 * R' + 0.7152 * G' + 0.0722 * B'
Rec. 2100 (HDR): Y' = 0.2627 * R' + 0.6780 * G' + 0.0593 * B'

Implementation Note

Java rounds toward zero when converting a float to an int. The calculation of luma could be rounded to the nearest integer by adding 0.5 before the type conversion, but the extra operation seems unnecessary for a display with only 16 levels of gray.

Parameters
source:IntBuffer

the source integer buffer in ARGB32 format

target:ByteBuffer

the target byte buffer in Y8 format

copyNextPixelback to summary
private void copyNextPixel(IntBuffer source, ShortBuffer target)

Copies the next 32-bit ARGB32 pixel to a short buffer with 16-bit RGB565 pixels. This method truncates the low-order bits of each color component.

Parameters
source:IntBuffer

the source integer buffer in ARGB32 format

target:ShortBuffer

the target short buffer in RGB565 format

copyToBufferback to summary
pack-priv void copyToBuffer(ByteBuffer out)

Overrides com.sun.glass.ui.monocle.Framebuffer.copyToBuffer.

Copies the contents of the composition buffer to the output buffer, converting the pixel format as necessary.

Parameters
out:ByteBuffer

the output buffer

Annotations
@Override
Exceptions
IllegalArgumentException:
if the buffer has an unsupported color depth
toStringback to summary
public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object. Satisfying this method's contract implies a non-null result must be returned.

Returns:String

a string representation of the object

Annotations
@Override
writeback to summary
pack-priv void write(WritableByteChannel out) throws IOException

Overrides com.sun.glass.ui.monocle.Framebuffer.write.

Writes the contents of the composition buffer to the output channel, converting the pixel format as necessary.

Parameters
out:WritableByteChannel

the output channel

Annotations
@Override
Exceptions
IOException:
if an error occurs writing to the channel
IllegalArgumentException:
if the channel has an unsupported color depth