blind-matrix-shear.1 - blind - suckless command-line video editing utility
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       blind-matrix-shear.1 (1973B)
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            1 .TH BLIND-MATRIX-SHEAR 1 blind
            2 .SH NAME
            3 blind-matrix-shear - Create an affine 2D-transformation matrix for shearing
            4 .SH SYNOPSIS
            5 .B blind-matrix-shear
            6 [-a [-d]] [-c]
            7 .SH DESCRIPTION
            8 .B blind-matrix-shear
            9 creates an affine 2D-transformation matrix for
           10 shearing. The parameters for the matrix is read
           11 in stdin in format of a blind video, one matrix
           12 per frame in stdin created and printed to stdout
           13 in format of a blind video.
           14 .P
           15 Each frame in stdin shall contain exactly 2 pixel.
           16 The first pixel holds the amount the image shall
           17 be sheared horizontally, that is, how much all
           18 pixels 1 pixel above the X-axis shall be moved
           19 rightward. The second pixel holds the amount the
           20 image shall be sheared vertically, that is, how
           21 much all pixels 1 pixel right of the Y-axis shall
           22 be moved downward.
           23 .P
           24 The luma (encoding in the Y-channel, the second
           25 channel) multiplied by the alpha (the fourth channel)
           26 of the input pixels are used as the values. Each
           27 values in the resulting matrices are stored
           28 in all channels.
           29 .SH OPTIONS
           30 .TP
           31 .B -a
           32 The pixels holds the angles of the shearing rather
           33 than the amount of the shearing.
           34 .TP
           35 .B -c
           36 Create different matrices for each channel. Use
           37 values from each channel in stdin to create
           38 matrices whose values are stored in the same
           39 channels in stdout.
           40 .TP
           41 .B -d
           42 Input angles in degrees rather than radians.
           43 .SH NOTES
           44 The description assumes the Y-axis grows downwards.
           45 .P
           46 Horizontal shearing and vertical shearing is not
           47 mutually commutative, this tool performs the
           48 shearing at the same time rather than after each
           49 other. When shearing both horizontally and
           50 vertically, the transformation matrix is not
           51 necessarily invertable.
           52 .SH SEE ALSO
           53 .BR blind (7),
           54 .BR blind-from-text (1),
           55 .BR blind-matrix-orthoproject (1),
           56 .BR blind-matrix-reflect (1),
           57 .BR blind-matrix-rotate (1),
           58 .BR blind-matrix-scale (1),
           59 .BR blind-matrix-translate (1),
           60 .BR blind-matrix-transpose (1),
           61 .BR blind-multiply-matrices (1)
           62 .SH AUTHORS
           63 Mattias Andrée
           64 .RI < maandree@kth.se >