TRANSPOSE(9.1) TRANSPOSE(9.1)
NAME
rotate, transpose - re-orient an image
SYNOPSIS
fb/rotate angle [ input ]
fb/transpose [ -vhadrlui ] [ -ox y ] [ input ]
DESCRIPTION
Rotate rotates the image in its input picture file (default
standard input) clockwise by angle degrees, writing the
resulting picture file on standard output.
Transpose turns its input picture file on its side by
reflection through its major (descending from left to right)
diagonal, writing the resulting picture file on standard
output. If no file name is given, the picture is read from
standard input. Options yield all possible symmetries of
the square grid:
-d reflects the image through its descending diagonal (the
default).
-a reflects the image through its ascending diagonal.
-v reflects the image left-to-right through its vertical
center line.
-h inverts the image top-to-bottom through its horizontal
center line.
-r rotates the image to the right (clockwise) 90 degrees.
-l rotates the image to the left (counterclockwise) 90
degrees.
-u rotates the image upside down (180 degrees).
-i identity transformation (for completeness only.)
-o x y
translates by (x,y). Without -o, the input and output
files have the same upper-left corner.
Transpose is particularly useful to convince programs that
work on the rows of a picture file to operate on columns.
For example
fb/transpose big |
fb/resample 48 |
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TRANSPOSE(9.1) TRANSPOSE(9.1)
fb/transpose |
fb/resample 48 >tiny
makes a tiny 48×48 version of a big picture.
SOURCE
/sys/src/fb/rotate.c
/sys/src/fb/transpose.c
SEE ALSO
picfile(9.6), resample(9.1)
BUGS
Very large images may not fit in memory. The result of
rotate is not anti-aliased.
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