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
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
use crate::{
    render_asset::RenderAssetUsages,
    texture::{Image, TextureFormatPixelInfo},
};
use image::{DynamicImage, ImageBuffer};
use thiserror::Error;
use wgpu::{Extent3d, TextureDimension, TextureFormat};

impl Image {
    /// Converts a [`DynamicImage`] to an [`Image`].
    pub fn from_dynamic(
        dyn_img: DynamicImage,
        is_srgb: bool,
        asset_usage: RenderAssetUsages,
    ) -> Image {
        use bevy_core::cast_slice;
        let width;
        let height;

        let data: Vec<u8>;
        let format: TextureFormat;

        match dyn_img {
            DynamicImage::ImageLuma8(image) => {
                let i = DynamicImage::ImageLuma8(image).into_rgba8();
                width = i.width();
                height = i.height();
                format = if is_srgb {
                    TextureFormat::Rgba8UnormSrgb
                } else {
                    TextureFormat::Rgba8Unorm
                };

                data = i.into_raw();
            }
            DynamicImage::ImageLumaA8(image) => {
                let i = DynamicImage::ImageLumaA8(image).into_rgba8();
                width = i.width();
                height = i.height();
                format = if is_srgb {
                    TextureFormat::Rgba8UnormSrgb
                } else {
                    TextureFormat::Rgba8Unorm
                };

                data = i.into_raw();
            }
            DynamicImage::ImageRgb8(image) => {
                let i = DynamicImage::ImageRgb8(image).into_rgba8();
                width = i.width();
                height = i.height();
                format = if is_srgb {
                    TextureFormat::Rgba8UnormSrgb
                } else {
                    TextureFormat::Rgba8Unorm
                };

                data = i.into_raw();
            }
            DynamicImage::ImageRgba8(image) => {
                width = image.width();
                height = image.height();
                format = if is_srgb {
                    TextureFormat::Rgba8UnormSrgb
                } else {
                    TextureFormat::Rgba8Unorm
                };

                data = image.into_raw();
            }
            DynamicImage::ImageLuma16(image) => {
                width = image.width();
                height = image.height();
                format = TextureFormat::R16Uint;

                let raw_data = image.into_raw();

                data = cast_slice(&raw_data).to_owned();
            }
            DynamicImage::ImageLumaA16(image) => {
                width = image.width();
                height = image.height();
                format = TextureFormat::Rg16Uint;

                let raw_data = image.into_raw();

                data = cast_slice(&raw_data).to_owned();
            }
            DynamicImage::ImageRgb16(image) => {
                let i = DynamicImage::ImageRgb16(image).into_rgba16();
                width = i.width();
                height = i.height();
                format = TextureFormat::Rgba16Unorm;

                let raw_data = i.into_raw();

                data = cast_slice(&raw_data).to_owned();
            }
            DynamicImage::ImageRgba16(image) => {
                width = image.width();
                height = image.height();
                format = TextureFormat::Rgba16Unorm;

                let raw_data = image.into_raw();

                data = cast_slice(&raw_data).to_owned();
            }
            DynamicImage::ImageRgb32F(image) => {
                width = image.width();
                height = image.height();
                format = TextureFormat::Rgba32Float;

                let mut local_data =
                    Vec::with_capacity(width as usize * height as usize * format.pixel_size());

                for pixel in image.into_raw().chunks_exact(3) {
                    // TODO: use the array_chunks method once stabilised
                    // https://github.com/rust-lang/rust/issues/74985
                    let r = pixel[0];
                    let g = pixel[1];
                    let b = pixel[2];
                    let a = 1f32;

                    local_data.extend_from_slice(&r.to_ne_bytes());
                    local_data.extend_from_slice(&g.to_ne_bytes());
                    local_data.extend_from_slice(&b.to_ne_bytes());
                    local_data.extend_from_slice(&a.to_ne_bytes());
                }

                data = local_data;
            }
            DynamicImage::ImageRgba32F(image) => {
                width = image.width();
                height = image.height();
                format = TextureFormat::Rgba32Float;

                let raw_data = image.into_raw();

                data = cast_slice(&raw_data).to_owned();
            }
            // DynamicImage is now non exhaustive, catch future variants and convert them
            _ => {
                let image = dyn_img.into_rgba8();
                width = image.width();
                height = image.height();
                format = TextureFormat::Rgba8UnormSrgb;

                data = image.into_raw();
            }
        }

        Image::new(
            Extent3d {
                width,
                height,
                depth_or_array_layers: 1,
            },
            TextureDimension::D2,
            data,
            format,
            asset_usage,
        )
    }

    /// Convert a [`Image`] to a [`DynamicImage`]. Useful for editing image
    /// data. Not all [`TextureFormat`] are covered, therefore it will return an
    /// error if the format is unsupported. Supported formats are:
    /// - `TextureFormat::R8Unorm`
    /// - `TextureFormat::Rg8Unorm`
    /// - `TextureFormat::Rgba8UnormSrgb`
    /// - `TextureFormat::Bgra8UnormSrgb`
    ///
    /// To convert [`Image`] to a different format see: [`Image::convert`].
    pub fn try_into_dynamic(self) -> Result<DynamicImage, IntoDynamicImageError> {
        match self.texture_descriptor.format {
            TextureFormat::R8Unorm => ImageBuffer::from_raw(self.width(), self.height(), self.data)
                .map(DynamicImage::ImageLuma8),
            TextureFormat::Rg8Unorm => {
                ImageBuffer::from_raw(self.width(), self.height(), self.data)
                    .map(DynamicImage::ImageLumaA8)
            }
            TextureFormat::Rgba8UnormSrgb => {
                ImageBuffer::from_raw(self.width(), self.height(), self.data)
                    .map(DynamicImage::ImageRgba8)
            }
            // This format is commonly used as the format for the swapchain texture
            // This conversion is added here to support screenshots
            TextureFormat::Bgra8UnormSrgb | TextureFormat::Bgra8Unorm => {
                ImageBuffer::from_raw(self.width(), self.height(), {
                    let mut data = self.data;
                    for bgra in data.chunks_exact_mut(4) {
                        bgra.swap(0, 2);
                    }
                    data
                })
                .map(DynamicImage::ImageRgba8)
            }
            // Throw and error if conversion isn't supported
            texture_format => return Err(IntoDynamicImageError::UnsupportedFormat(texture_format)),
        }
        .ok_or(IntoDynamicImageError::UnknownConversionError(
            self.texture_descriptor.format,
        ))
    }
}

/// Errors that occur while converting an [`Image`] into a [`DynamicImage`]
#[non_exhaustive]
#[derive(Error, Debug)]
pub enum IntoDynamicImageError {
    /// Conversion into dynamic image not supported for source format.
    #[error("Conversion into dynamic image not supported for {0:?}.")]
    UnsupportedFormat(TextureFormat),

    /// Encountered an unknown error during conversion.
    #[error("Failed to convert into {0:?}.")]
    UnknownConversionError(TextureFormat),
}

#[cfg(test)]
mod test {
    use image::{GenericImage, Rgba};

    use super::*;
    use crate::render_asset::RenderAssetUsages;

    #[test]
    fn two_way_conversion() {
        // Check to see if color is preserved through an rgba8 conversion and back.
        let mut initial = DynamicImage::new_rgba8(1, 1);
        initial.put_pixel(0, 0, Rgba::from([132, 3, 7, 200]));

        let image = Image::from_dynamic(initial.clone(), true, RenderAssetUsages::RENDER_WORLD);

        // NOTE: Fails if `is_srbg = false` or the dynamic image is of the type rgb8.
        assert_eq!(initial, image.try_into_dynamic().unwrap());
    }
}