3 releases (breaking)
|0.3.0||May 14, 2022|
|0.2.0||Mar 8, 2022|
|0.1.0||Apr 25, 2021|
#312 in Images
Convert images to appear to be reproduced on retro IBM hardware.
|original (640x480, 24-bit RGB)||VGA (320x200, 256 colors, 4:5 pixels)||EGA (320x200, 16 colors, 4:5 pixels)||CGA (320x200, 4 colors + bkg)|
The full image processing pipeline is composed of the following steps:
- Image cropping and resizing to a low resolution;
- Master palette color quantization and mapping to a restricted color palette, plus color limit with dithering;
- Nearest-neighbor resizing to a high resolution, to make pixels look good, also enabling non-square pixels.
Note: This application does not claim to achieve a perfect emulation of old hardware, but it should hopefully attain sufficiently good results for the intended nostalgia kick.
Using the tool
The main options are:
--standard: the video graphics standard to emulate. This only affects the colors used, not the image resolution. Possible options:
bw: 1 bit, black and white
cgamode4: CGA in mode 4, attempts to choose the best sub-palette and background color
fullcga: all 16 colors of the CGA master palette
cgamode4high1: CGA in mode 4, always subpalette 1 of high intensity (black, magenta, white, black)
ega: all 64 colors from the EGA master palette
16bit: 16-bit color depth (4-5-4 RGB)
18bit: 18-bit master palette
24bit: 24-bit RGB color depth
-R WxH: the resolution to resize the image into.
-S WxH: the full image output size, resized from the previous option.
To convert an image to look like it was presented in VGA mode 13h, with non-square pixels:
retroimg «IMAGEFILE» -s vga -R 320x200 -S 1440x1080 -o «out.png»
This chooses the 256-color palette with the least loss. To use less colors (e.g. 100):
retroimg «IMAGEFILE» -s vga -R 320x200 -S 1440x1080 -c 100 -o «out.png»
To choose an output width or height and let the program pick the other dimensions based on pixel ratio:
retroimg «IMAGEFILE» -s vga -R 320x200 --height 1080 -r 4:5 -o «out.png»
This will stretch the image proportionally to the pixel size 4:5, meaning that it works best for images designed for this.
The full list of options is presented via
retroimg -h or
Using the library
The operations required for doing this are available as independent functions.
To remove dependencies related with the command line application,
exclude the default feature
[dependencies.retroimg] version = "0.2" default-features = false
Licensed under either of
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.