Rev | Author | # | Line |
---|---|---|---|
1 | perry | 1 | pnminterp |
2 | !!!pnminterp | ||
3 | NAME | ||
4 | SYNOPSIS | ||
5 | DESCRIPTION | ||
6 | OPTIONS | ||
7 | BUGS | ||
8 | SEE ALSO | ||
9 | AUTHOR | ||
10 | ---- | ||
11 | !!NAME | ||
12 | |||
13 | |||
14 | pnminterp - scale up portable anymap by interpolating between pixels. | ||
15 | !!SYNOPSIS | ||
16 | |||
17 | |||
18 | __pnminterp__ [[__-blackedge__] [[__-dropedge__] | ||
19 | ''N'' [[''pnmfile''] | ||
20 | |||
21 | |||
22 | You can use the minimum unique abbreviation of the | ||
23 | options. | ||
24 | !!DESCRIPTION | ||
25 | |||
26 | |||
27 | Pnminterp scales up pictures, producing output with one | ||
28 | ''N''x''N'' pixel for each pixel in the original | ||
29 | image. Where pnminterp improves over using | ||
30 | pnmscale/pnmenlarge for this is that it interpolates between | ||
31 | pixels, producing better-looking output. | ||
32 | |||
33 | |||
34 | To scale up to non-integer pixel sizes, e.g. 2.5, try | ||
4 | perry | 35 | pnminterp-gen(1) instead. |
1 | perry | 36 | !!OPTIONS |
37 | |||
38 | |||
39 | The options let you select alternative methods of dealing | ||
40 | with the right/bottom edges of the picture. Since the | ||
41 | interpolation is done between the top-left corners of the | ||
42 | scaled-up pixels, it's not obvious what to do with the | ||
43 | right/bottom edges. The default behaviour is to scale those | ||
44 | up without interpolation (more precisely, the right edge is | ||
45 | only interpolated vertically, and the bottom edge is only | ||
46 | interpolated horizontally), but there are two other | ||
47 | possibilities, listed below. | ||
48 | |||
49 | |||
50 | __-blackedge__ | ||
51 | |||
52 | |||
53 | interpolate to black at right/bottom edges. | ||
54 | |||
55 | |||
56 | __-dropedge__ | ||
57 | |||
58 | |||
59 | drop one (source) pixel at right/bottom edges. This is | ||
60 | arguably more logical than the default behaviour, but it | ||
61 | means producing output which is a slightly odd | ||
62 | size. | ||
63 | !!BUGS | ||
64 | |||
65 | |||
66 | Usually produces fairly ugly output for PBMs. For most PBM | ||
67 | input you'll probably want to reduce the `noise' first using | ||
68 | something like pnmnlfilt(1). | ||
69 | |||
70 | |||
71 | Always produces images with a maxval of 255, which may lose | ||
72 | sample resolution if the input is (say) a 16-bit | ||
73 | PGM. | ||
74 | !!SEE ALSO | ||
75 | |||
76 | |||
77 | pnmenlarge(1), pnmscale(1), | ||
78 | pnmnlfilt(1) | ||
79 | !!AUTHOR | ||
80 | |||
81 | |||
82 | Russell Marks (russell.marks@ntlworld.com). | ||
83 | ---- |