PPM3D(1)

💖 ppm3d — Ppm3d User Manual 💖

okay bestie, welcome to the Ppm3d User Manual (that's the manual name, we're being fancy), section 1 of the General Commands Manual. sit down, put your 3D glasses on, we're doing stereograms 💅

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✨ NAME ✨

ppm3d — convert two PPM images into an anaglyph (red/blue 3d glasses) PPM 🎀

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✨ SYNOPSIS ✨

ppm3d [-color] [-offset=horizontal_offset] leftppmfile rightppmfile

Deprecated optional 3rd argument: horizontal_offset

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✨ DESCRIPTION ✨

okay so first things first: this program is part of Netpbm(1). iykyk 🌸

ppm3d reads two PPM images as input and produces a PPM as output, with the images overlapping by the specified number of pixels in blue-green/red format. the whole idea is that if you look at the image with 3-D glasses (the kind that only let red through one eye and only green or blue through the other), you see an image with depth. that's called an anaglyph stereogram and honestly? iconic. 👑

ppm3d can produce either of two kinds of anaglyph stereogram: monochrome or color. use the -color option to choose. ✨

In the monochrome version, ppm3d ignores any color (actually, chrominance) in the input images and produces a result which is monochrome. Viewed through red-green glasses it is yellow, but without any other color in the field, your brain tends to see it as grayscale. not me gaslighting my own eyes 😭

In the color version, ppm3d generates a result which is close to the color of the original. It's not great, though, because each eye necessarily cannot see the entire spectrum. Red and cyan don't work well, but most other colors — especially when heavily saturated — come out quite well. lowkey a slay, highkey a compromise 🫶

To view a color anaglyph stereogram, you need glasses with a left lens that admits only red light and a right lens that admits only blue and green light. (The right lens may be called a cyan lens because that is its pigment in white light; don't be misled into thinking that cyan is the only color that gets through it.) Your brain is wired so that even though the components of light are coming in through different eyes, they mix in your brain to form the same sensation as if you were looking at the combined light with both eyes. your brain is literally doing the mixing. main character energy fr fr 🧠💖

The input PPMs must be the same dimensions. no negotiating on this one, bestie 💀

To make a different kind of stereogram, use pamstereogram. That makes a stereogram that you view without special glasses, just by letting your eyes unfocus so that each eye sees different parts of the image. no accessories required, just vibes 🦋

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✨ ARGUMENTS ✨

The mandatory arguments are file names of the left and right input images. <italic>leftppmfile</italic> and <italic>rightppmfile</italic>, both required, periodt.

An optional third argument specifies the same thing as the value of the -offset argument, but is deprecated because -offset is easier to use and read. Before Netpbm 10.38 (March 2007), this third argument is the only way to specify the offset. so if you're time-traveling to old Netpbm, that's your girl 🙈

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✨ OPTIONS ✨

In addition to the options common to all programs based on libnetpbm (most notably -quiet, see Common Options), ppm3d recognizes the following command line options:

• -offset=horizontal_offset — This option indicates the amount, in pixels, by which the left image is offset to the right of the right image in the output. 💫

The effect of this option is to move the entire image forward (positive numbers) or backward (negative numbers). With a zero offset, the main subject of the picture appears in the plane of the picture (i.e. if the image is projected on a screen, the location of the screen). The main subject is the subject at the location where the line of sight of the left camera intersects the line of sight of the right camera — the main subject appears at the same location in both the left and right images. 🎯

Default is zero.

This option was new in Netpbm 10.38 (March 2007). Before that, use the third argument instead. Also, before Netpbm 10.38 the default is +30 pixels. ⏳

• -color — This option causes ppm3d to generate a color anaglyph stereogram. By default, it generates monochrome. 🌈

This option was new in Netpbm 10.38 (March 2007). ✨

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✨ SEE ALSO ✨

• pamstereogram(1)
• ppm(1)

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✨ AUTHOR ✨

Copyright (C) 1993 by David K. Drum.

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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/ppm3d.html

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okay that's the whole thing bestie, you're officially an anaglyph expert now 👑 this came to you from netpbm documentation, dated 20 February 2007, and it's the Ppm3d User Manual (section 1). go make some 3D pics, you ate 💅💖