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	blind-matrix-rotate.1 - blind - suckless command-line video editing utility
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	blind-matrix-rotate.1 (1656B)
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	1 .TH BLIND-MATRIX-ROTATE 1 blind
	2 .SH NAME
	3 blind-matrix-rotate - Create an affine 2D-transformation matrix for rota…
	4 .SH SYNOPSIS
	5 .B blind-matrix-rotate
	6 [-cd]
	7 .SH DESCRIPTION
	8 .B blind-matrix-rotate
	9 creates an affine 2D-transformation matrix for
	10 rotation. 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 1 pixel,
	16 this pixel holds the number of radians the image
	17 is to be rotated clockwise around origo.
	18 .P
	19 The luma (encoding in the Y-channel, the second
	20 channel) multiplied by the alpha (the fourth channel)
	21 of the input pixels are used as the values. Each
	22 values in the resulting matrices are stored
	23 in all channels.
	24 .SH OPTIONS
	25 .TP
	26 .B -c
	27 Create different matrices for each channel. Use
	28 values from each channel in stdin to create
	29 matrices whose values are stored in the same
	30 channels in stdout.
	31 .TP
	32 .B -d
	33 Input angles in degrees rather than radians.
	34 .SH NOTES
	35 The image is rotated anti-clockwise if the Y-axis
	36 grows upwards rather than downwards.
	37 .P
	38 Due to truncation error, when rotating a multiple
	39 of 90 degrees, it is preferable to use
	40 .B -d
	41 with lets
	42 .B blind-matrix-rotate
	43 eliminate the error. If this is not done,
	44 .BR blind-invert-matrix (1)
	45 may return odd results.
	46 .SH SEE ALSO
	47 .BR blind (7),
	48 .BR blind-from-text (1),
	49 .BR blind-matrix-orthoproject (1),
	50 .BR blind-matrix-reflect (1),
	51 .BR blind-matrix-scale (1),
	52 .BR blind-matrix-shear (1),
	53 .BR blind-matrix-translate (1),
	54 .BR blind-matrix-transpose (1),
	55 .BR blind-multiply-matrices (1)
	56 .SH AUTHORS
	57 Mattias Andrée
	58 .RI < [email protected] >