ILK(1)

✨ ILK(1) ✨

okay so bestie, welcome to the ilk manual page 💖 this is the User Commands section of the manual, and we're about to learn all about image linear transforms. grab a snack, it's giving math girlie energy and honestly? slay.

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🌸 NAME 🌸

ilk — (I)mage (L)inear Trans(X-->K)forms

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🦋 SYNOPSIS 🦋

ilk [@file ...]  [-i <image>] [-0 <origin>] -t <xform0 ...> [-k
<kernel>] [-min <xMin yMin>] [-max <xMax yMax>] [-b <boundary>] [-bg
<bg0 bg1 ...>] [-s <xSize ySize>] [-a <avg #>] [-o <filename>]

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💅 DESCRIPTION 💅

(I)mage (L)inear Trans(X-->K)forms. it literally takes a given image and applies linear (homogenous coordinate) transforms to it, and for the resampling part it uses the given kernel. that's the whole vibe. 🫶

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🎀 OPTIONS 🎀

• @file ... — response file(s) that hold command-line arguments for you. no cap, you can stash your args in a file. 📄
• -i <image> — the input image. default: "-"
• -0 <origin> — where to put (0,0) before any transforms get applied. choose your own origin adventure:
  • "u:<float>,<float>" — put the origin somewhere in a unit box [0,1]x[0,1] that covers the original image
  • "p:<float>,<float>" — put the origin at a particular pixel location, in the index space of the image

default: "p:0,0"

• -t <xform0 ...> — the transform(s) to apply to the image. heads up bestie, they get applied in the order in which they appear, so order is the moment. 👑
  • "identity" — no geometric transform at all, just resampling. it's giving minimal effort but make it valid.
  • "translate:x,y" — shift the image by the vector (x,y), measured in pixels
  • "rotate:ang" — rotate CCW by ang degrees
  • "scale:xs,ys" — scale by xs in X, and ys in Y
  • "shear:fix,amnt" — shear by amnt, keeping fixed the pixels along a direction <fix> degrees from the X axis
  • "flip:ang" — flip along an axis that's an angle <ang> degrees from the X axis
  • "a,b,tx,c,d,ty" — spell the transform out explicitly in row-major order (which is the opposite of PostScript, fyi) (1 or more 2D transforms)
• -k <kernel> — the reconstruction kernel. default: "cubic:0,0.5"
• -min <xMin yMin> — lower bounding corner of the output image. if you just don't use this option, the default is the lower corner of the input image. (2 doubles)
• -max <xMax yMax> — upper bounding corner of the output image. same deal: skip the option and the default is the upper corner of the input image. (2 doubles)
• -b <boundary> — what to do when we're sampling outside the original image. the boundary behavior vibe check:
  • "bleed" — copy the values at the image border outward
  • "wrap" — do wrap-around on image locations
  • "pad" — use a given background value (you supply it via -bg)

default: "bleed"

• -bg <bg0 bg1 ...> — the background color to use with boundary behavior "pad". defaults to all zeroes. (1 or more floats)
• -s <xSize ySize> — for each axis, the info about how many samples go in the output. two flavors:
  • "x<float>" — the number of output samples is some scaling of the number of input samples; multiplied by <float>
  • "<int>" — specify the exact number of samples (2 sampling specifications)

default: "x1 x1"

• -a <avg #> — number of averages (this one only kicks in if there there is only one rotation) (unsigned int); default: "0"
• -o <filename> — the file to write the output nrrd to (string); default: "-"

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🌈 SEE ALSO 🌈

gprobe(1), miter(1), mrender(1), nrrdSanity(1), overrgb(1), puller(1), tend(1), unu(1), vprobe(1)

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and that's the whole page, bestie 💜 this one's from the User Commands corner of the manual, dated April 2021, and yeah — it's ILK(1), iconic, no notes. go transform something pretty. 🦋✨💖