jchucomponents-qr/com.jeluchu.qr/LuminanceSource

LuminanceSource

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.

Author

dswitkin@google.com (Daniel Switkin)

Inheritors

InvertedLuminanceSource

Properties

height

val height: Int

isCropSupported

open val isCropSupported: Boolean

isRotateSupported

open val isRotateSupported: Boolean

matrix

abstract val matrix: ByteArray?

Fetches luminance data for the underlying bitmap. Values should be fetched using: int luminance = array[y * width + x] & 0xff

width

val width: Int

Functions

crop

open fun crop(left: Int, top: Int, width: Int, height: Int): LuminanceSource?

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

getRow

abstract fun getRow(y: Int, row: ByteArray?): ByteArray

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.

invert

open fun invert(): LuminanceSource?

rotateCounterClockwise

open fun rotateCounterClockwise(): LuminanceSource?

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

rotateCounterClockwise45

open fun rotateCounterClockwise45(): LuminanceSource?

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

toString

open override fun toString(): String