# distance-field
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### [Documentation](https://docs.rs/distance-field/)
Generate distance field bitmaps for rendering as pseudo-vector images in shaders.
An example usecase for the library would be to automatically convert asset images. You can achieve this by having a `build.rs` similar to this:
```rust
use std::fs::File;
use distance_field::DistanceFieldExt;
fn convert_image_to_dfield(input: &str, output: &str) {
// Load the 'input' image
let img = image::open(input).unwrap();
// Generate a distance field from the image
let outbuf = img.grayscale().distance_field(distance_field::Options {
size: (128, 128),
max_distance: 256,
..Default::default()
});
// Save it to 'output' as a PNG
image::DynamicImage::ImageLuma8(outbuf).save(output).unwrap();
}
fn main() {
convert_image_to_dfield("img/input.png", "output.png");
}
```
# Generator binary
Checkout the repository and `cd` into it; then run:
cargo run --example generator -- img/input.png output.png 64 64
This will take the following image as input:
![Rust logo](img/input.png?raw=true)
And generate a 64x64 distance field:
![Distance field](img/output.png?raw=true)
Now we can use the generated distance field to create a vector image.
### Using the distance field
First we need to scale it up with a linear interpolation:
![Upscaled linear](img/linear.png?raw=true)
Then we apply a treshold function:
![Treshold](img/treshold.png?raw=true)
You can see that we have something which looks very similar to the original input image and that just from a 64x64 image! But it's still very pixelated and doesn't look like a vector image. This can be fixed by not doing a hard treshold but allowing some shades of gray.