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Convert an image to look like an 8-bit image from an AGI-era 1980s Sierra On-Line computer game. This project consists of two parts: a command line tool (agi_image_converter) which is written in Objective-C, and a plug-in for the Acorn image editor. The script and plug-in produce similar, but not identical results. The script generates double-width pixels like in an AGI-style Sierra game (e.g. King's Quest 1-3, Space Quest 1-2) and adheres to a proper 16 color EGA palette. The Acorn plug-in produces a closer color match and the pixels are not double-width, but are pixelated and the image is reduced to 200 pixels in height.

Version 2 of the Acorn plug-in adds dithering (Floyd-Steinberg algorithm), which spreads the color quantization error across the image. This provides for a unique appearance that was not used too often in AGI games (mostly the V3 AGI games), since the double-wide pixels did not lend themselves as well for the blending of dithered color patterns as the higher resolution SCI games could provide.

"Original High Sierra Image"

Modified by agi_image_converter script
"Modified High Sierra Image - agi_image_converter script"

Modified by Agifier Acorn Plug-In Version 1.0
"Modified High Sierra Image - Agifier Plug-In"

Modified by Agifier Acorn Plug-In Version 2.0
"Modified High Sierra Image - Agifier Plug-In 2.0"

AGI Image Converter Script

The agi_image_converter is a command-line utility for the Mac written in Objective-C. It will take the given image and convert it, and then generate a new image with _agi.png appended to the file name taken from the original image.

To compile: gcc -w -framework Foundation -framework AppKit -framework QuartzCore agi_image_converter.m -o agi_image_converter

To run: ./agi_image_converter path/to/image.png

Acorn Plug-In

The Agifier project was built with Xcode 11 on macOS Mojave. The Agifier.acplugin file can be copied to ~/Library/Application Support/Acorn/Plug-Ins to work with Acorn. The Agifier plug-in is available in the Filter > Stylize > Agifier menu.


Convert an image to look like an 8-bit image from an AGI-era 1980s Sierra computer game.






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