# Purr
It's a rust implementation of fogleman's [primitive](https://github.com/fogleman/primitive).
Created at Rusty Days Hackathon, 2020.
For more details about the algorithm, check this out: [Hill Climbing](https://en.wikipedia.org/wiki/Hill_climbing)
## Feature
Simple rule, powerful result
### Usage
Use this as lib
> purrmitive = "\*"
or as cli
> cargo run --release --features=cli --bin=purr -- -i ./assets/input.png -o output.gif -n 100
most `primitive` flags are supported.
| `i` | n/a | input file |
| `o` | n/a | output file |
| `n` | n/a | number of shapes |
| `m` | 1 | mode: 0=combo 1=triangle 2=rect 3=ellipse 4=circle 5=rotatedrect 6=beziers 7=rotatedellipse 8=polygon(default 1) |
| `j` | 0 | number of parallel workers (default uses all cores) |
| `r` | 256 | resize large input images to this size before processing |
| `s` | 1024 | output image size |
## Example
using
> -i ./assets/input.png -o output.gif -n 150
| triangle | <img src="assets/input.png" width="1024"/> | <img src="https://i.imgur.com/QTCWJQt.png" /> | <img src="https://i.imgur.com/oGO2rnR.gif" /> |
| ellipse | <img src="assets/input.png" width="1024"/> | <img src="https://i.imgur.com/xuWuvs0.png" /> | <img src="https://i.imgur.com/5e4Q8J0.gif" /> |
try it yourself for more.
## Differences
### Output Difference
All the graphs supported by primitive are implemented, and the output of all graphs (except the bezier curves) is basically the same.
The original primitive version of bezier curves supports line thickness adjustment, which is not possible in purr. But the result is still not bad.
### Usage Difference
The key options and parameters of purr are the same as primitive, and in most cases you can just replace primitive with purr.
The rest of the parameters not listed above have not been implemented yet(these parameters will be supported in the future)
### Performance Difference
All types of graphical fits are faster than primitive on my computer. See the next section for more specific data.
One possible factor is that in my implementation, the "next-step" buffer is skiped, by modified the diff function. It costs less comapring to copy the current buffer, update it then read it.
## About Performance
This program is CPU intensive, it does all rendering in memory.
Purr is faster than the original implementation.
Benchmark using `-n 100 -m {0-8}`, see the results below.
> hyperfine --parameter-scan m 0 8 -D 1 './target/release/purr -i ./assets/input.png -o assets/purr.{m}.png -n 100 -m {m}' '~/go/bin/primitive -i ./assets/input.png -o assets/primitive.{m}.png -n 100 -m {m}' --export-json benchmark.json
|purr|combo| 10.256 ± 0.385|9.202|10.467| |
|primitive|combo| 15.068 ± 0.213|14.785|15.405| |
|purr|triangle| 6.927 ± 0.201|6.510|7.136| |
|primitive|triangle| 10.577 ± 0.266|10.109|10.879| |
|purr|rect| 6.224 ± 0.087|6.132|6.380| |
|primitive|rect| 7.505 ± 0.105|7.388|7.765| |
|purr|ellipse| 12.516 ± 0.098|12.354|12.674| |
|primitive|ellipse| 14.643 ± 0.279|14.189|15.193| |
|purr|circle| 15.054 ± 0.236|14.739|15.452| |
|primitive|circle| 17.375 ± 0.187|17.156|17.760| |
|purr|rotatedrect| 8.045 ± 0.081|7.938|8.220| |
|primitive|rotatedrect| 9.181 ± 0.154|8.922|9.496| |
|purr|beziers| 3.050 ± 0.127|2.815|3.223| |
|primitive|beziers| 11.951 ± 0.173|11.563|12.114| |
|purr|rotatedellipse| 12.282 ± 0.166|11.942|12.496| |
|primitive|rotatedellipse| 27.795 ± 0.401|27.273|28.694| |
|purr|polygon| 8.355 ± 0.219|7.988|8.748| |
|primitive|polygon| 15.995 ± 0.275|15.426|16.431| |