Previous Next

                                               79
            SECTION 3.3                                                                  Filters



KEY                       TYPE      VALUE

EndOfLine                 boolean   A flag indicating whether end-of-line bit patterns are required to be
                                    present in the encoding. The CCITTFaxDecode filter always accepts
                                    end-of-line bit patterns, but requires them only if EndOfLine is true.
                                    Default value: false.

EncodedByteAlign          boolean   A flag indicating whether the filter expects extra 0 bits before each
                                    encoded line so that the line begins on a byte boundary. If true, the
                                    filter skips over encoded bits to begin decoding each line at a byte
                                    boundary. If false, the filter does not expect extra bits in the encod-
                                    ed representation. Default value: false.

Columns                   integer   The width of the image in pixels. If the value is not a multiple of 8,
                                    the filter adjusts the width of the unencoded image to the next mul-
                                    tiple of 8 so that each line starts on a byte boundary. Default value:
                                    1728.

Rows                      integer   The height of the image in scan lines. If the value is 0 or absent, the
                                    image’s height is not predetermined, and the encoded data must be
                                    terminated by an end-of-block bit pattern or by the end of the fil-
                                    ter’s data. Default value: 0.

EndOfBlock                boolean   A flag indicating whether the filter expects the encoded data to be
                                    terminated by an end-of-block pattern, overriding the Rows param-
                                    eter. If false, the filter stops when it has decoded the number of lines
                                    indicated by Rows or when its data has been exhausted, whichever
                                    occurs first. The end-of-block pattern is the CCITT end-of-facsim-
                                    ile-block (EOFB) or return-to-control (RTC) appropriate for the K
                                    parameter. Default value: true.

BlackIs1                  boolean   A flag indicating whether 1 bits are to be interpreted as black pixels
                                    and 0 bits as white pixels, the reverse of the normal PDF convention
                                    for image data. Default value: false.

DamagedRowsBeforeError    integer   The number of damaged rows of data to be tolerated before an error
                                    occurs. This entry applies only if EndOfLine is true and K is non-
                                    negative. Tolerating a damaged row means locating its end in the
                                    encoded data by searching for an EndOfLine pattern and then sub-
                                    stituting decoded data from the previous row if the previous row
                                    was not damaged, or a white scan line if the previous row was also
                                    damaged. Default value: 0.

Previous Next