# blind

suckless command-line video editing utility
git clone git://git.suckless.org/blind

```      1 .TH BLIND-RADIAL-GRADIENT 1 blind
2 .SH NAME
4 .SH SYNOPSIS
6 -w
7 .I width
8 -h
9 .I height
10 .SH DESCRIPTION
13 parameters for each from is read from each frame
14 in stdin. The gradient is stored in all channels
15 of the video.
16 .P
17 The video in stdin must contain exactly 2 or 3
18 pixels per frame. The first pixel shall point to
19 the beginning of the gradient (where the value is
20 0) and the second pixel shall point to the end of
21 the gradient (where the value is 1). In these
22 pixels, the value of the first channel specifies
23 the X-position and the value of the second
24 channel specifies Y-position, the other channels
25 are ignored.
26 .P
27 If there is a third pixel, in frames in stdin, it
28 specified parameters to make the gradient elliptic
29 or superelliptic. For a completely circular
30 gradient its values should be 2, 2, and 1 for the
31 first, second, and third channels, respectively;
32 the fourth channel (the alpha channel) is ignored.
33 If we name these values,
34 .IR a ,
35 .IR b ,
36 and
37 .IR m ,
38 their is an imaginary superelliptic, on which the
39 values of the gradient is 1, determined by the
40 equation
41 .RI || p ||^ a +|| r / m ||^ b =1,
42 where
43 .I p
44 and
45 .I r
46 is the projection and rejection, respectively,
47 of the normalised vector from beginning of the
48 gradient to a pixel onto the vector from the
49 beginning of the gradient to the end of the
51 .SH NOTES
52 Pixels after the end of the gradient have values
53 larger than 1.
54 .BR blind-*-wave (1)
55 commands can be used to put all values between
56 0 and 1.
57 .SH OPTIONS
58 .TP
59 .BR -w " "\fIwidth\fP
60 The width of the video, in pixels.
61 .TP
62 .BR -h " "\fIheight\fP
63 The height of the video, in pixels.
65 .BR blind (7),
66 .BR blind-from-text (7),