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https://github.com/sevagh/quadtree-compression
lossy image compression with quadtrees and protobuf
https://github.com/sevagh/quadtree-compression
2d gif-animation image-compression image-processing quadtree tree-structure
Last synced: 12 days ago
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lossy image compression with quadtrees and protobuf
- Host: GitHub
- URL: https://github.com/sevagh/quadtree-compression
- Owner: sevagh
- License: mit
- Created: 2019-02-01T04:53:18.000Z (almost 6 years ago)
- Default Branch: master
- Last Pushed: 2023-08-06T03:58:21.000Z (over 1 year ago)
- Last Synced: 2024-12-21T18:05:56.564Z (14 days ago)
- Topics: 2d, gif-animation, image-compression, image-processing, quadtree, tree-structure
- Language: Go
- Homepage:
- Size: 359 KB
- Stars: 3
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# quadtree-compression
Create cool GIFs and lossily compress images with quadtrees:
### Gif creation
The above GIF was generated with the following command:
```
$ ./quadtree-compression gif \
-delayMS 50 -maxQuality 12 -ladder \
./samples/jungle.png \
./samples/jungle.gif
```
First, a point quadtree is built from the image containing colors per quadrant, and the average color of its 4 children (NE, NW, SE, SW), and their 4 children, etc.
By generating an image at level `n`, the quadtree is only descended to depth `n`.
Finally, images at levels `[1-quality]` are collated in a GIF to produce the demo; the `-ladder` flag then appends the reverse order to "ladder" back down in quality to create a loop.
This produces the effect of the image "sharpening" as the color of each quadrant is replaced with the finer granularity of its descendants.
### File compression/decompression
As a toy, there are two subcommands, `compress` and `decompress`. To compress an image and create a `.quadtree` file, the quadtree from the image is serialized to an array of uint32s, and then stored with protobuf:
```
$ ./quadtree-compression compress \
./samples/jungle.png \
./jungle.quadtree
$
$ du -h samples/jungle.png
11M samples/jungle.png
$
$ du -h ./jungle.quadtree
6.8M ./jungle.quadtree
```
`-quality` can be chosen, which, as described in the gif section, cuts the quadtree off at `depth=quality`. Low qualities create dramatically smaller quadtree files (e.g. 30K for quality=5, where the full quality is 6.8M).
Quality = 5:
