PPMMIX(1)

💖 PPMMIX 💖

okay bestie, gather round, because today we're mixing two PPM images together and it's literally the cutest thing. this is ppmmix, a lil tool from the Netpbm(1) family, and she blends two pics into one using a fade factor you pick. no cap. 🎀

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✨ SYNOPSIS ✨

ppmmix fadefactor ppmfile1 ppmfile2

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🌸 DESCRIPTION 🌸

so like, this program is part of Netpbm(1), obviously. 💅

ppmmix takes two PPM images as input and mixes them together using the fade factor you give it. and the fade factor? it lives in the range from 0.0 (which gives you only ppmfile1's image data) to 1.0 (which gives you only ppmfile2's image data). anything in between? that's a smooth blend between the two images, a little bit of this, a little bit of that. iconic. ✨

now, the vibes have to match: the two images must have the same dimensions and the same maxval. also — and this is a glow-up moment — before Netpbm 10.54 (March 2011), they also had to have the same type (PBM/PGM/PPM). so if you're time traveling back to pre-2011, mind the type, bestie.

here's the tea though 🍵: the fade factor is applied to brightness, not light intensity. meaning? say you've got a series of images you generated using ppmmix of a black and a white image with a linearly increasing fade factor. you'll see an image getting linearly brighter, sure — but the light intensity will increase faster at the end. why? because it takes more intensity change at the bright end of the scale than at the dark end for the human eye to perceive the same brightness change. that's just how our eyeballs are built, fr fr. 👀

this also means: if the original images aren't all one color, the mixed image is distorted, since the intensity relationship between pixels is different from the original image. not a bug, just how brightness math works. 😭

wanna know about a more flexible option? pamcomp is a more general alternative. she lets you mix images of different size, and she lets the fade factor vary throughout the image (through the use of a transparency mask 👑). she does not have the same-maxval and same-type restrictions either. one difference to clock: pamcomp mixes light intensity, not brightness. main character behavior honestly.

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✨ OPTIONS ✨

• there are no command line options defined specifically for ppmmix — she's a simple girl, no notes 💅
• but she does recognize the options common to all programs based on libnetpbm (See Common Options.)

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🦋 SEE ALSO 🦋

• pamcomp(1)
• pammixmulti(1)
• ppm(1)

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👑 AUTHOR 👑

Copyright (C) 1993 by Frank Neumann

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📚 DOCUMENT SOURCE 📚

This manual page was generated by the Netpbm tool makeman from HTML source. The master documentation is at

http://netpbm.sourceforge.net/doc/ppmmix.html

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and that's the whole page, bestie 💖 this was netpbm documentation, dated 23 March 2010 — go forth and blend, you absolute icon 🫶✨🌈