blind-matrix-shear.1 (1973B)

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 AndrĂ©e 64 .RI < maandree@kth.se >