com.google.zxing
Class PlanarYUVLuminanceSource

java.lang.Object
  com.google.zxing.LuminanceSource
      com.google.zxing.PlanarYUVLuminanceSource

public final class PlanarYUVLuminanceSource
extends LuminanceSource

This object extends LuminanceSource around an array of YUV data returned from the camera driver, with the option to crop to a rectangle within the full data. This can be used to exclude superfluous pixels around the perimeter and speed up decoding. It works for any pixel format where the Y channel is planar and appears first, including YCbCr_420_SP and YCbCr_422_SP.

Author:

dswitkin@google.com (Daniel Switkin)

Constructor Summary

PlanarYUVLuminanceSource(byte[] yuvData, int dataWidth, int dataHeight, int left, int top, int width, int height, boolean reverseHorizontal)

Method Summary

LuminanceSource	crop(int left, int top, int width, int height) Returns a new object with cropped image data.
byte[]	getMatrix() Fetches luminance data for the underlying bitmap.
byte[]	getRow(int y, byte[] row) Fetches one row of luminance data from the underlying platform's bitmap.
boolean	isCropSupported()
int[]	renderCroppedGreyscaleBitmap()

Methods inherited from class com.google.zxing.LuminanceSource

getHeight, getWidth, isRotateSupported, rotateCounterClockwise, rotateCounterClockwise45, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

PlanarYUVLuminanceSource

public PlanarYUVLuminanceSource(byte[] yuvData,
                                int dataWidth,
                                int dataHeight,
                                int left,
                                int top,
                                int width,
                                int height,
                                boolean reverseHorizontal)

Method Detail

getRow

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

Description copied from class: LuminanceSource

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.

Specified by:

getRow in class LuminanceSource

Parameters:

y - The row to fetch, 0 <= y < getHeight().

row - 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:

An array containing the luminance data.

getMatrix

public byte[] getMatrix()

Description copied from class: LuminanceSource

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

Specified by:

getMatrix in class LuminanceSource

Returns:

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.

isCropSupported

public boolean isCropSupported()

Overrides:

isCropSupported in class LuminanceSource

Returns:

Whether this subclass supports cropping.

crop

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

Description copied from class: 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.

Overrides:

crop in class LuminanceSource

Parameters:

left - The left coordinate, 0 <= left < getWidth().

top - The top coordinate, 0 <= top <= getHeight().

width - The width of the rectangle to crop.

height - The height of the rectangle to crop.

Returns:

A cropped version of this object.

renderCroppedGreyscaleBitmap

public int[] renderCroppedGreyscaleBitmap()