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.TH BLIND-MATRIX-SHEAR 1 blind
.SH NAME
blind-matrix-shear - Create an affine 2D-transformation matrix for shearing
.SH SYNOPSIS
.B blind-matrix-shear
[-ac]
.SH DESCRIPTION
.B blind-matrix-shear
creates an affine 2D-transformation matrix for
shearing. The parameters for the matrix is read
in stdin in format of a blind video, one matrix
per frame in stdin created and printed to stdout
in format of a blind video.
.P
Each frame in stdin shall contain exactly 2 pixel.
The first pixel holds the amount the image shall
be sheared horizontally, that is, how much all
pixels 1 pixel above the X-axis shall be moved
rightward. The second pixel holds the amount the
image shall be sheared vertically, that is, how
much all pixels 1 pixel right of the Y-axis shall
be moved downward.
.P
The luma (encoding in the Y-channel, the second
channel) multiplied by the alpha (the fourth channel)
of the input pixels are used as the values. Each
values in the resulting matrices are stored
in all channels.
.SH OPTIONS
.TP
.B -a
The pixels holds the angles of the shearing rather
than the amount of the shearing.
.TP
.B -c
Create different matrices for each channel. Use
values from each channel in stdin to create
matrices whose values are stored in the same
channels in stdout.
.SH NOTES
The description assumes the Y-axis grows downwards.
.P
Horizontal shearing and vertical shearing is not
mutually commutative, this tool performs the
shearing at the same time rather than after each
other. When shearing both horizontally and
vertically, the transformation matrix is not
necessarily invertable.
.SH SEE ALSO
.BR blind (7),
.BR blind-from-text (1),
.BR blind-matrix-orthoproject (1),
.BR blind-matrix-reflect (1),
.BR blind-matrix-rotate (1),
.BR blind-matrix-scale (1),
.BR blind-matrix-translate (1),
.BR blind-matrix-transpose (1),
.BR blind-multiply-matrices (1)
.SH AUTHORS
Mattias Andrée
.RI < maandree@kth.se >
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