phomo 0.2.0

A photo mosaic generation library
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153

use std::path::Path;

extern crate image;
use image::{GenericImageView, RgbImage, SubImage};
use log::warn;

use crate::error::Error;

/// Helper function to crop am image to a width and height centered on the image.
///
/// # Arguments
/// - `img`: The image to crop.
/// - `width`: The width to crop to.
/// - `height`: The height to crop to.
pub fn crop_imm_centered<I>(img: &I, width: u32, height: u32) -> SubImage<&I>
where
    I: GenericImageView,
{
    if width > img.width() || height > img.height() {
        warn!("Attempted to crop image to a larger size than the source image");
    }
    image::imageops::crop_imm(
        img,
        (img.width() - width) / 2,
        (img.height() - height) / 2,
        width,
        height,
    )
}

/// Read all images in a directory and returns them in a vector.
///
/// # Arguments
/// - `tile_dir`: The path to the directory containing the tile images.
///
/// # Errors
/// - An error occurred while reading the directory.
/// - Failed to open the image.
pub fn read_images_from_dir<P: AsRef<Path>>(tile_dir: P) -> Result<Vec<RgbImage>, Error> {
    Ok(tile_dir
        .as_ref()
        .read_dir()?
        .filter_map(|entry| match entry {
            Ok(p) => match image::open(p.path()) {
                Ok(img) => Some(img.to_rgb8()),
                Err(e) => {
                    warn!("Failed to open image at path {:?}: {:?}", p.path(), e);
                    None
                }
            },
            Err(e) => {
                warn!("Failed to read directory entry: {:?}", e);
                None
            }
        })
        .collect::<Vec<_>>())
}

/// Read all images in a directory, cropped to the `width` and `height` and return them in a
/// vector.
///
/// # Arguments
/// - `tile_dir`: The path to the directory containing the tile images.
/// - `width`: The width to crop to.
/// - `height`: The height to crop to.
pub fn read_images_from_dir_cropped<P: AsRef<Path>>(
    tile_dir: P,
    width: u32,
    height: u32,
) -> Result<Vec<RgbImage>, Error> {
    Ok(read_images_from_dir(tile_dir)?
        .iter()
        .map(|img| crop_imm_centered(img, width, height).to_image())
        .collect::<Vec<_>>())
}

/// Read all images in a directory, resized to the `width` and `height` and returns them in a vector.
///
/// # Arguments
/// - `tile_dir`: The path to the directory containing the tile images.
/// - `width`: The width to resize to.
/// - `height`: The height to resize to.
/// - `filter`: The [`image::imageops::FilterType`] to use for resizing.
pub fn read_images_from_dir_resized<P: AsRef<Path>>(
    tile_dir: P,
    width: u32,
    height: u32,
    filter: image::imageops::FilterType,
) -> Result<Vec<RgbImage>, Error> {
    Ok(read_images_from_dir(tile_dir)?
        .iter()
        .map(|img| image::imageops::resize(img, width, height, filter))
        .collect::<Vec<_>>())
}

#[cfg(test)]
mod tests {
    use super::*;
    use std::path::PathBuf;

    fn test_dir() -> PathBuf {
        PathBuf::from("tests/data/mosaic")
    }

    fn test_tile_dir() -> PathBuf {
        // tiles are 64x64
        test_dir().join("tiles/")
    }

    #[test]
    fn test_crop_imm_centered() {
        // create white image with a black pixel centered on the image
        let mut img = image::RgbImage::from_pixel(11, 11, image::Rgb([255, 255, 255]));
        img.put_pixel(5, 5, image::Rgb([0, 0, 0]));

        let cropped = crop_imm_centered(&img, 5, 5);
        assert_eq!(cropped.dimensions(), (5, 5));
        assert_eq!(cropped.get_pixel(2, 2), image::Rgb([0, 0, 0]));

        let cropped = crop_imm_centered(&img, 1, 1);
        assert_eq!(cropped.dimensions(), (1, 1));
        assert_eq!(cropped.get_pixel(0, 0), image::Rgb([0, 0, 0]));
    }

    #[test]
    fn test_read_images_from_dir() {
        let images = read_images_from_dir(test_tile_dir()).unwrap();
        assert_eq!(images.len(), 16);
        assert!(images.iter().all(|img| img.dimensions() == (64, 64)));
    }

    #[test]
    fn test_read_images_from_dir_cropped() {
        let (width, height) = (32, 32);
        let images = read_images_from_dir_cropped(test_tile_dir(), width, height).unwrap();
        assert_eq!(images.len(), 16);
        assert!(images.iter().all(|img| img.dimensions() == (width, height)));
    }

    #[test]
    fn test_read_images_from_dir_resized() {
        let (width, height) = (32, 32);
        let images = read_images_from_dir_resized(
            test_tile_dir(),
            width,
            height,
            image::imageops::FilterType::Nearest,
        )
        .unwrap();
        assert_eq!(images.len(), 16);
        assert!(images.iter().all(|img| img.dimensions() == (width, height)));
    }
}