version 4 showing authors affecting page license.
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pnminterp |
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!!!pnminterp |
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NAME |
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SYNOPSIS |
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DESCRIPTION |
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OPTIONS |
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BUGS |
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SEE ALSO |
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AUTHOR |
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---- |
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!!NAME |
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pnminterp - scale up portable anymap by interpolating between pixels. |
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!!SYNOPSIS |
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__pnminterp__ [[__-blackedge__] [[__-dropedge__] |
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''N'' [[''pnmfile''] |
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You can use the minimum unique abbreviation of the |
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options. |
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!!DESCRIPTION |
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Pnminterp scales up pictures, producing output with one |
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''N''x''N'' pixel for each pixel in the original |
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image. Where pnminterp improves over using |
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pnmscale/pnmenlarge for this is that it interpolates between |
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pixels, producing better-looking output. |
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To scale up to non-integer pixel sizes, e.g. 2.5, try |
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pnminterp-gen(1) instead. |
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!!OPTIONS |
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The options let you select alternative methods of dealing |
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with the right/bottom edges of the picture. Since the |
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interpolation is done between the top-left corners of the |
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scaled-up pixels, it's not obvious what to do with the |
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right/bottom edges. The default behaviour is to scale those |
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up without interpolation (more precisely, the right edge is |
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only interpolated vertically, and the bottom edge is only |
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interpolated horizontally), but there are two other |
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possibilities, listed below. |
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__-blackedge__ |
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interpolate to black at right/bottom edges. |
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__-dropedge__ |
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drop one (source) pixel at right/bottom edges. This is |
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arguably more logical than the default behaviour, but it |
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means producing output which is a slightly odd |
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size. |
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!!BUGS |
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Usually produces fairly ugly output for PBMs. For most PBM |
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input you'll probably want to reduce the `noise' first using |
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something like pnmnlfilt(1). |
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Always produces images with a maxval of 255, which may lose |
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sample resolution if the input is (say) a 16-bit |
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PGM. |
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!!SEE ALSO |
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pnmenlarge(1), pnmscale(1), |
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pnmnlfilt(1) |
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!!AUTHOR |
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Russell Marks (russell.marks@ntlworld.com). |
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---- |