com.google.zxing.common

Class BitMatrix

  • All Implemented Interfaces:
    Cloneable 

    public final class BitMatrix
extends Object
implements Cloneable

    Represents a 2D matrix of bits. In function arguments below, and throughout the common module, x is the column position, and y is the row position. The ordering is always x, y. The origin is at the top-left.

    Internally the bits are represented in a 1-D array of 32-bit ints. However, each row begins with a new int. This is done intentionally so that we can copy out a row into a BitArray very efficiently.

    The ordering of bits is row-major. Within each int, the least significant bits are used first, meaning they represent lower x values. This is compatible with BitArray's implementation.

    • Constructor Summary

      Constructors

      Constructor and Description
      BitMatrix(int dimension)
       
      BitMatrix(int width, int height)
       

    • Method Summary

      Modifier and Type Method and Description
      void clear()
      Clears all bits (sets to false).
      BitMatrix clone()
       
      boolean equals(Object o)
       
      void flip(int x, int y)
      Flips the given bit.
      boolean get(int x, int y)
      Gets the requested bit, where true means black.
      int[] getBottomRightOnBit()
       
      int[] getEnclosingRectangle()
      This is useful in detecting the enclosing rectangle of a 'pure' barcode.
      int getHeight()
       
      BitArray getRow(int y, BitArray row)
      A fast method to retrieve one row of data from the matrix as a BitArray.
      int[] getTopLeftOnBit()
      This is useful in detecting a corner of a 'pure' barcode.
      int getWidth()
       
      int hashCode()
       
      void rotate180()
      Modifies this BitMatrix to represent the same but rotated 180 degrees
      void set(int x, int y)
      Sets the given bit to true.
      void setRegion(int left, int top, int width, int height)
      Sets a square region of the bit matrix to true.
      void setRow(int y, BitArray row)
       
      String toString()
       

    • Constructor Detail

      • BitMatrix

        public BitMatrix(int dimension)

      • BitMatrix

        public BitMatrix(int width,
                 int height)

    • Method Detail

      • get

        public boolean get(int x,
                   int y)

        Gets the requested bit, where true means black.

        Parameters:
        x - The horizontal component (i.e. which column)
        y - The vertical component (i.e. which row)
        Returns:
        value of given bit in matrix

      • set

        public void set(int x,
                int y)

        Sets the given bit to true.

        Parameters:
        x - The horizontal component (i.e. which column)
        y - The vertical component (i.e. which row)

      • flip

        public void flip(int x,
                 int y)

        Flips the given bit.

        Parameters:
        x - The horizontal component (i.e. which column)
        y - The vertical component (i.e. which row)

      • clear

        public void clear()
        Clears all bits (sets to false).

      • setRegion

        public void setRegion(int left,
                      int top,
                      int width,
                      int height)

        Sets a square region of the bit matrix to true.

        Parameters:
        left - The horizontal position to begin at (inclusive)
        top - The vertical position to begin at (inclusive)
        width - The width of the region
        height - The height of the region

      • getRow

        public BitArray getRow(int y,
                       BitArray row)
        A fast method to retrieve one row of data from the matrix as a BitArray.
        Parameters:
        y - The row to retrieve
        row - An optional caller-allocated BitArray, will be allocated if null or too small
        Returns:
        The resulting BitArray - this reference should always be used even when passing your own row

      • setRow

        public void setRow(int y,
                   BitArray row)
        Parameters:
        y - row to set
        row - BitArray to copy from

      • rotate180

        public void rotate180()
        Modifies this BitMatrix to represent the same but rotated 180 degrees

      • getEnclosingRectangle

        public int[] getEnclosingRectangle()
        This is useful in detecting the enclosing rectangle of a 'pure' barcode.
        Returns:
        left,top,width,height enclosing rectangle of all 1 bits, or null if it is all white

      • getTopLeftOnBit

        public int[] getTopLeftOnBit()
        This is useful in detecting a corner of a 'pure' barcode.
        Returns:
        x,y coordinate of top-left-most 1 bit, or null if it is all white

      • getBottomRightOnBit

        public int[] getBottomRightOnBit()

      • getWidth

        public int getWidth()
        Returns:
        The width of the matrix

      • getHeight

        public int getHeight()
        Returns:
        The height of the matrix

      • equals

        public boolean equals(Object o)

      • hashCode

        public int hashCode()

      • toString

        public String toString()