blind-matrix-rotate.1 (1656B)
1 .TH BLIND-MATRIX-ROTATE 1 blind 2 .SH NAME 3 blind-matrix-rotate - Create an affine 2D-transformation matrix for rotation 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 < maandree@kth.se >