PRESCRIBE Command Reference
236
RVCD — ReceiVe Compressed raster Data
Format
RVCD[ compression-mode]; length, data, ... ;
Parameters
compression-mode:
0 = uncompressed
1 = run-length encoding
2 = TIFF (Tagged Image File Format) [rev. 4.0]
length:
bytes of raster data
data:
binary raster data, 0H to FFH
Function
The RVCD command transfers and encodes the subsequent raster data by the amount of
bytes represented by the length parameter.
The STR (SeT dot Resolution) command sets the dot resolution for raster graphics which
starts at the current cursor position. The SRO (Set Raster Options) command specifies
the orientation of the raster image in either physical (default) or logical page direction.
If the compression-mode value is zero [or omitted], the printing system simply transfers
raster data in an uncompressed binary format. A single bit means a single dot. Seventh
bit in the first byte refers to the starting dot within that raster row and bit 0 refers to the
eighth dot and continues.
In the run-length encoding mode, the printing system treats raster data in pairs of bytes.
The first byte of each pair is the repetition count for the data in second pattern byte. The
repetition count accepts any value within a range of 0H to FFH.
compression-mode 2, TIFF rev. 4.0, translates raster data to be packbits in which a
control byte precedes the raster data. A TIFF rev. 4.0 encoded data arrangement appears
below.
control byte (1 byte) + data (1–128 bytes) + control byte
(1 byte) + data (1–128 bytes) ...
A control byte with a negative value from -127 to -1 (81H to FFH) means the repetition
count for the subsequent data. A zero to 127 (0H to 7FH) indicates the number of data
bytes that follow. A control byte of -128 (80H) represents a non-operative control byte.
Related Commands
ENDR, STR
To Next Page
Loading...
Need help?
General
Weight and Dimensions
