Class LuminanceSource

Namespace

ZXing

Assembly

zxing.dll

The purpose of this class hierarchy is to abstract different bitmap implementations across platforms into a standard interface for requesting greyscale luminance values. The interface only provides immutable methods; therefore crop and rotation create copies. This is to ensure that one Reader does not modify the original luminance source and leave it in an unknown state for other Readers in the chain.

public abstract class LuminanceSource

Inheritance

object

LuminanceSource

Derived

BaseLuminanceSource

InvertedLuminanceSource

Inherited Members

object.GetType()

object.MemberwiseClone()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Constructors

LuminanceSource(int, int)

initializing constructor

protected LuminanceSource(int width, int height)

Parameters

width int

height int

Properties

CropSupported

public virtual bool CropSupported { get; }

Property Value

bool

Whether this subclass supports cropping.

Height

public virtual int Height { get; protected set; }

Property Value

int

The height of the bitmap.

InversionSupported

public virtual bool InversionSupported { get; }

Property Value

bool

Whether this subclass supports invertion.

Matrix

Fetches luminance data for the underlying bitmap. Values should be fetched using:

int luminance = array[y * width + x] & 0xff

public abstract byte[] Matrix { get; }

Property Value

byte[]

A row-major 2D array of luminance values. Do not use result.length as it may be larger than width * height bytes on some platforms. Do not modify the contents of the result.

RotateSupported

public virtual bool RotateSupported { get; }

Property Value

bool

Whether this subclass supports counter-clockwise rotation.

Width

public virtual int Width { get; protected set; }

Property Value

int

The width of the bitmap.

Methods

ToString()

public override string ToString()

Returns

string

crop(int, int, int, int)

Returns a new object with cropped image data. Implementations may keep a reference to the original data rather than a copy. Only callable if CropSupported is true.

public virtual LuminanceSource crop(int left, int top, int width, int height)

Parameters

left int

The left coordinate, which must be in [0, Width)

top int

The top coordinate, which must be in [0, Height)

width int

The width of the rectangle to crop.

height int

The height of the rectangle to crop.

Returns

LuminanceSource

A cropped version of this object.

getRow(int, byte[])

Fetches one row of luminance data from the underlying platform's bitmap. Values range from 0 (black) to 255 (white). Because Java does not have an unsigned byte type, callers will have to bitwise and with 0xff for each value. It is preferable for implementations of this method to only fetch this row rather than the whole image, since no 2D Readers may be installed and getMatrix() may never be called.

public abstract byte[] getRow(int y, byte[] row)

Parameters

y int

The row to fetch, which must be in [0, bitmap height)

row byte[]

An optional preallocated array. If null or too small, it will be ignored. Always use the returned object, and ignore the .length of the array.

Returns

byte[]

An array containing the luminance data.

invert()

inverts the luminance values, not supported here. has to implemented in sub classes

public virtual LuminanceSource invert()

Returns

LuminanceSource

rotateCounterClockwise()

Returns a new object with rotated image data by 90 degrees counterclockwise. Only callable if RotateSupported is true.

public virtual LuminanceSource rotateCounterClockwise()

Returns

LuminanceSource

A rotated version of this object.

rotateCounterClockwise45()

Returns a new object with rotated image data by 45 degrees counterclockwise. Only callable if RotateSupported is true.

public virtual LuminanceSource rotateCounterClockwise45()

Returns

LuminanceSource

A rotated version of this object.