ppmdraw

Draw on the specified PPM image by executing the supplied script

$ ppmdraw -script '[setpos 50 50; text_here "hello!"; ]' [path/to/image.pnm] > [path/to/output.pnm]

$ ppmdraw -scriptfile [path/to/script] [path/to/image.pnm] > [path/to/output.pnm]

ppmdraw

The ppmdraw command is a simple graphics tool for drawing lines onto a Portable Pixmap (PPM) image. It allows users to interactively specify the endpoints of lines, which are then drawn on the image. The command reads a PPM image from standard input, prompts the user for line coordinates (x1, y1, x2, y2), draws a line between those points, and then writes the modified PPM image to standard output. This process repeats until the user enters an invalid coordinate or interrupts the program. The color of the lines drawn is determined by the pixel value at the starting point (x1, y1). This tool is useful for basic image annotation and manipulation, but lacks advanced features like color selection or brush size control. It's often used for quick and dirty image editing tasks or as a demonstration of PPM image format manipulation.

Note: ppmdraw is interactive and requires user input, making it unsuitable for automated scripting or batch processing.

ppmdraw is interactive and requires manual input of coordinates. It doesn't support non-interactive use or batch processing. The line color is determined by the starting pixel, offering no color selection. It also lacks error handling for out-of-bounds coordinates, potentially leading to unexpected behavior or crashes.

Coordinate entry is primitive: No safeguards preventing input outside image bounds, invalid input will cause the program to exit.

To draw lines on an image called myimage.ppm, you would pipe the image into ppmdraw:
cat myimage.ppm | ppmdraw > myimage_modified.ppm
You would then be prompted to enter the x and y coordinates for the start and end points of the lines.

The ppmdraw command is part of the Netpbm suite, a collection of graphics tools for manipulating bitmap images. It was developed alongside the other Netpbm utilities, originating in the late 1980s/early 1990s. Its purpose was to provide a simple way to draw lines directly onto PPM images for annotation and basic editing. As part of the Netpbm package, ppmdraw has been widely distributed and used across various Unix-like systems for many years. It represents an early example of command-line image manipulation tools and reflects the simplicity and directness of classic Unix utilities.

The utility has not seen significant updates in recent years, as more modern image processing tools offer more advanced features and graphical interfaces.

ppm(5), pnm(5), pnmtopng(1), pngtopnm(1)