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
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
//! Functions for performing affine transformations.

use buffer::{ImageBuffer, Pixel};
use image::GenericImageView;

/// Rotate an image 90 degrees clockwise.
// TODO: Is the 'static bound on `I` really required? Can we avoid it?
pub fn rotate90<I: GenericImageView + 'static>(
    image: &I,
) -> ImageBuffer<I::Pixel, Vec<<I::Pixel as Pixel>::Subpixel>>
where
    I::Pixel: 'static,
    <I::Pixel as Pixel>::Subpixel: 'static,
{
    let (width, height) = image.dimensions();
    let mut out = ImageBuffer::new(height, width);

    for y in 0..height {
        for x in 0..width {
            let p = image.get_pixel(x, y);
            out.put_pixel(height - 1 - y, x, p);
        }
    }

    out
}

/// Rotate an image 180 degrees clockwise.
// TODO: Is the 'static bound on `I` really required? Can we avoid it?
pub fn rotate180<I: GenericImageView + 'static>(
    image: &I,
) -> ImageBuffer<I::Pixel, Vec<<I::Pixel as Pixel>::Subpixel>>
where
    I::Pixel: 'static,
    <I::Pixel as Pixel>::Subpixel: 'static,
{
    let (width, height) = image.dimensions();
    let mut out = ImageBuffer::new(width, height);

    for y in 0..height {
        for x in 0..width {
            let p = image.get_pixel(x, y);
            out.put_pixel(width - 1 - x, height - 1 - y, p);
        }
    }

    out
}

/// Rotate an image 270 degrees clockwise.
// TODO: Is the 'static bound on `I` really required? Can we avoid it?
pub fn rotate270<I: GenericImageView + 'static>(
    image: &I,
) -> ImageBuffer<I::Pixel, Vec<<I::Pixel as Pixel>::Subpixel>>
where
    I::Pixel: 'static,
    <I::Pixel as Pixel>::Subpixel: 'static,
{
    let (width, height) = image.dimensions();
    let mut out = ImageBuffer::new(height, width);

    for y in 0..height {
        for x in 0..width {
            let p = image.get_pixel(x, y);
            out.put_pixel(y, width - 1 - x, p);
        }
    }

    out
}

/// Flip an image horizontally
// TODO: Is the 'static bound on `I` really required? Can we avoid it?
pub fn flip_horizontal<I: GenericImageView + 'static>(
    image: &I,
) -> ImageBuffer<I::Pixel, Vec<<I::Pixel as Pixel>::Subpixel>>
where
    I::Pixel: 'static,
    <I::Pixel as Pixel>::Subpixel: 'static,
{
    let (width, height) = image.dimensions();
    let mut out = ImageBuffer::new(width, height);

    for y in 0..height {
        for x in 0..width {
            let p = image.get_pixel(x, y);
            out.put_pixel(width - 1 - x, y, p);
        }
    }

    out
}

/// Flip an image vertically
// TODO: Is the 'static bound on `I` really required? Can we avoid it?
pub fn flip_vertical<I: GenericImageView + 'static>(
    image: &I,
) -> ImageBuffer<I::Pixel, Vec<<I::Pixel as Pixel>::Subpixel>>
where
    I::Pixel: 'static,
    <I::Pixel as Pixel>::Subpixel: 'static,
{
    let (width, height) = image.dimensions();
    let mut out = ImageBuffer::new(width, height);

    for y in 0..height {
        for x in 0..width {
            let p = image.get_pixel(x, y);
            out.put_pixel(x, height - 1 - y, p);
        }
    }

    out
}

#[cfg(test)]
mod test {
    use super::{flip_horizontal, flip_vertical, rotate180, rotate270, rotate90};
    use buffer::{GrayImage, ImageBuffer, Pixel};
    use image::GenericImage;

    macro_rules! assert_pixels_eq {
        ($actual:expr, $expected:expr) => {{
            let actual_dim = $actual.dimensions();
            let expected_dim = $expected.dimensions();

            if actual_dim != expected_dim {
                panic!(
                    "dimensions do not match. \
                     actual: {:?}, expected: {:?}",
                    actual_dim, expected_dim
                )
            }

            let diffs = pixel_diffs($actual, $expected);

            if !diffs.is_empty() {
                let mut err = "pixels do not match. ".to_string();

                let diff_messages = diffs
                    .iter()
                    .take(5)
                    .map(|d| format!("\nactual: {:?}, expected {:?} ", d.0, d.1))
                    .collect::<Vec<_>>()
                    .join("");

                err.push_str(&diff_messages);
                panic!(err)
            }
        }};
    }

    #[test]
    fn test_rotate90() {
        let image: GrayImage =
            ImageBuffer::from_raw(3, 2, vec![00u8, 01u8, 02u8, 10u8, 11u8, 12u8]).unwrap();

        let expected: GrayImage =
            ImageBuffer::from_raw(2, 3, vec![10u8, 00u8, 11u8, 01u8, 12u8, 02u8]).unwrap();

        assert_pixels_eq!(&rotate90(&image), &expected);
    }

    #[test]
    fn test_rotate180() {
        let image: GrayImage =
            ImageBuffer::from_raw(3, 2, vec![00u8, 01u8, 02u8, 10u8, 11u8, 12u8]).unwrap();

        let expected: GrayImage =
            ImageBuffer::from_raw(3, 2, vec![12u8, 11u8, 10u8, 02u8, 01u8, 00u8]).unwrap();

        assert_pixels_eq!(&rotate180(&image), &expected);
    }

    #[test]
    fn test_rotate270() {
        let image: GrayImage =
            ImageBuffer::from_raw(3, 2, vec![00u8, 01u8, 02u8, 10u8, 11u8, 12u8]).unwrap();

        let expected: GrayImage =
            ImageBuffer::from_raw(2, 3, vec![02u8, 12u8, 01u8, 11u8, 00u8, 10u8]).unwrap();

        assert_pixels_eq!(&rotate270(&image), &expected);
    }

    #[test]
    fn test_flip_horizontal() {
        let image: GrayImage =
            ImageBuffer::from_raw(3, 2, vec![00u8, 01u8, 02u8, 10u8, 11u8, 12u8]).unwrap();

        let expected: GrayImage =
            ImageBuffer::from_raw(3, 2, vec![02u8, 01u8, 00u8, 12u8, 11u8, 10u8]).unwrap();

        assert_pixels_eq!(&flip_horizontal(&image), &expected);
    }

    #[test]
    fn test_flip_vertical() {
        let image: GrayImage =
            ImageBuffer::from_raw(3, 2, vec![00u8, 01u8, 02u8, 10u8, 11u8, 12u8]).unwrap();

        let expected: GrayImage =
            ImageBuffer::from_raw(3, 2, vec![10u8, 11u8, 12u8, 00u8, 01u8, 02u8]).unwrap();

        assert_pixels_eq!(&flip_vertical(&image), &expected);
    }

    fn pixel_diffs<I, J, P>(left: &I, right: &J) -> Vec<((u32, u32, P), (u32, u32, P))>
    where
        I: GenericImage<Pixel = P>,
        J: GenericImage<Pixel = P>,
        P: Pixel + Eq,
    {
        left.pixels()
            .zip(right.pixels())
            .filter(|&(p, q)| p != q)
            .collect::<Vec<_>>()
    }
}