1//! This module provides useful traits that were deprecated in rust
2
3// Note copied from the stdlib under MIT license
4
5use num_traits::{Bounded, Num, NumCast};
6use std::ops::AddAssign;
7
8use crate::color::{ColorType, Luma, LumaA, Rgb, Rgba};
9
10/// Types which are safe to treat as an immutable byte slice in a pixel layout
11/// for image encoding.
12pub trait EncodableLayout: seals::EncodableLayout {
13 /// Get the bytes of this value.
14 fn as_bytes(&self) -> &[u8];
15}
16
17impl EncodableLayout for [u8] {
18 fn as_bytes(&self) -> &[u8] {
19 bytemuck::cast_slice(self)
20 }
21}
22
23impl EncodableLayout for [u16] {
24 fn as_bytes(&self) -> &[u8] {
25 bytemuck::cast_slice(self)
26 }
27}
28
29impl EncodableLayout for [f32] {
30 fn as_bytes(&self) -> &[u8] {
31 bytemuck::cast_slice(self)
32 }
33}
34
35/// The type of each channel in a pixel. For example, this can be `u8`, `u16`, `f32`.
36// TODO rename to `PixelComponent`? Split up into separate traits? Seal?
37pub trait Primitive: Copy + NumCast + Num + PartialOrd<Self> + Clone + Bounded {
38 /// The maximum value for this type of primitive within the context of color.
39 /// For floats, the maximum is `1.0`, whereas the integer types inherit their usual maximum values.
40 const DEFAULT_MAX_VALUE: Self;
41
42 /// The minimum value for this type of primitive within the context of color.
43 /// For floats, the minimum is `0.0`, whereas the integer types inherit their usual minimum values.
44 const DEFAULT_MIN_VALUE: Self;
45}
46
47macro_rules! declare_primitive {
48 ($base:ty: ($from:expr)..$to:expr) => {
49 impl Primitive for $base {
50 const DEFAULT_MAX_VALUE: Self = $to;
51 const DEFAULT_MIN_VALUE: Self = $from;
52 }
53 };
54}
55
56declare_primitive!(usize: (0)..Self::MAX);
57declare_primitive!(u8: (0)..Self::MAX);
58declare_primitive!(u16: (0)..Self::MAX);
59declare_primitive!(u32: (0)..Self::MAX);
60declare_primitive!(u64: (0)..Self::MAX);
61
62declare_primitive!(isize: (Self::MIN)..Self::MAX);
63declare_primitive!(i8: (Self::MIN)..Self::MAX);
64declare_primitive!(i16: (Self::MIN)..Self::MAX);
65declare_primitive!(i32: (Self::MIN)..Self::MAX);
66declare_primitive!(i64: (Self::MIN)..Self::MAX);
67declare_primitive!(f32: (0.0)..1.0);
68declare_primitive!(f64: (0.0)..1.0);
69
70/// An Enlargable::Larger value should be enough to calculate
71/// the sum (average) of a few hundred or thousand Enlargeable values.
72pub trait Enlargeable: Sized + Bounded + NumCast {
73 type Larger: Copy + NumCast + Num + PartialOrd<Self::Larger> + Clone + Bounded + AddAssign;
74
75 fn clamp_from(n: Self::Larger) -> Self {
76 if n > Self::max_value().to_larger() {
77 Self::max_value()
78 } else if n < Self::min_value().to_larger() {
79 Self::min_value()
80 } else {
81 NumCast::from(n).unwrap()
82 }
83 }
84
85 fn to_larger(self) -> Self::Larger {
86 NumCast::from(self).unwrap()
87 }
88}
89
90impl Enlargeable for u8 {
91 type Larger = u32;
92}
93impl Enlargeable for u16 {
94 type Larger = u32;
95}
96impl Enlargeable for u32 {
97 type Larger = u64;
98}
99impl Enlargeable for u64 {
100 type Larger = u128;
101}
102impl Enlargeable for usize {
103 // Note: On 32-bit architectures, u64 should be enough here.
104 type Larger = u128;
105}
106impl Enlargeable for i8 {
107 type Larger = i32;
108}
109impl Enlargeable for i16 {
110 type Larger = i32;
111}
112impl Enlargeable for i32 {
113 type Larger = i64;
114}
115impl Enlargeable for i64 {
116 type Larger = i128;
117}
118impl Enlargeable for isize {
119 // Note: On 32-bit architectures, i64 should be enough here.
120 type Larger = i128;
121}
122impl Enlargeable for f32 {
123 type Larger = f64;
124}
125impl Enlargeable for f64 {
126 type Larger = f64;
127}
128
129/// Linear interpolation without involving floating numbers.
130pub trait Lerp: Bounded + NumCast {
131 type Ratio: Primitive;
132
133 fn lerp(a: Self, b: Self, ratio: Self::Ratio) -> Self {
134 let a: ::Ratio = <Self::Ratio as NumCast>::from(a).unwrap();
135 let b: ::Ratio = <Self::Ratio as NumCast>::from(b).unwrap();
136
137 let res: ::Ratio = a + (b - a) * ratio;
138
139 if res > NumCast::from(Self::max_value()).unwrap() {
140 Self::max_value()
141 } else if res < NumCast::from(0).unwrap() {
142 NumCast::from(0).unwrap()
143 } else {
144 NumCast::from(res).unwrap()
145 }
146 }
147}
148
149impl Lerp for u8 {
150 type Ratio = f32;
151}
152
153impl Lerp for u16 {
154 type Ratio = f32;
155}
156
157impl Lerp for u32 {
158 type Ratio = f64;
159}
160
161impl Lerp for f32 {
162 type Ratio = f32;
163
164 fn lerp(a: Self, b: Self, ratio: Self::Ratio) -> Self {
165 a + (b - a) * ratio
166 }
167}
168
169/// The pixel with an associated `ColorType`.
170/// Not all possible pixels represent one of the predefined `ColorType`s.
171pub trait PixelWithColorType: Pixel + self::private::SealedPixelWithColorType {
172 /// This pixel has the format of one of the predefined `ColorType`s,
173 /// such as `Rgb8`, `La16` or `Rgba32F`.
174 /// This is needed for automatically detecting
175 /// a color format when saving an image as a file.
176 const COLOR_TYPE: ColorType;
177}
178
179impl PixelWithColorType for Rgb<u8> {
180 const COLOR_TYPE: ColorType = ColorType::Rgb8;
181}
182impl PixelWithColorType for Rgb<u16> {
183 const COLOR_TYPE: ColorType = ColorType::Rgb16;
184}
185impl PixelWithColorType for Rgb<f32> {
186 const COLOR_TYPE: ColorType = ColorType::Rgb32F;
187}
188
189impl PixelWithColorType for Rgba<u8> {
190 const COLOR_TYPE: ColorType = ColorType::Rgba8;
191}
192impl PixelWithColorType for Rgba<u16> {
193 const COLOR_TYPE: ColorType = ColorType::Rgba16;
194}
195impl PixelWithColorType for Rgba<f32> {
196 const COLOR_TYPE: ColorType = ColorType::Rgba32F;
197}
198
199impl PixelWithColorType for Luma<u8> {
200 const COLOR_TYPE: ColorType = ColorType::L8;
201}
202impl PixelWithColorType for Luma<u16> {
203 const COLOR_TYPE: ColorType = ColorType::L16;
204}
205impl PixelWithColorType for LumaA<u8> {
206 const COLOR_TYPE: ColorType = ColorType::La8;
207}
208impl PixelWithColorType for LumaA<u16> {
209 const COLOR_TYPE: ColorType = ColorType::La16;
210}
211
212/// Prevents down-stream users from implementing the `Primitive` trait
213mod private {
214 use crate::color::*;
215
216 pub trait SealedPixelWithColorType {}
217 impl SealedPixelWithColorType for Rgb<u8> {}
218 impl SealedPixelWithColorType for Rgb<u16> {}
219 impl SealedPixelWithColorType for Rgb<f32> {}
220
221 impl SealedPixelWithColorType for Rgba<u8> {}
222 impl SealedPixelWithColorType for Rgba<u16> {}
223 impl SealedPixelWithColorType for Rgba<f32> {}
224
225 impl SealedPixelWithColorType for Luma<u8> {}
226 impl SealedPixelWithColorType for LumaA<u8> {}
227
228 impl SealedPixelWithColorType for Luma<u16> {}
229 impl SealedPixelWithColorType for LumaA<u16> {}
230}
231
232/// A generalized pixel.
233///
234/// A pixel object is usually not used standalone but as a view into an image buffer.
235pub trait Pixel: Copy + Clone {
236 /// The scalar type that is used to store each channel in this pixel.
237 type Subpixel: Primitive;
238
239 /// The number of channels of this pixel type.
240 const CHANNEL_COUNT: u8;
241
242 /// Returns the components as a slice.
243 fn channels(&self) -> &[Self::Subpixel];
244
245 /// Returns the components as a mutable slice
246 fn channels_mut(&mut self) -> &mut [Self::Subpixel];
247
248 /// A string that can help to interpret the meaning each channel
249 /// See [gimp babl](http://gegl.org/babl/).
250 const COLOR_MODEL: &'static str;
251
252 /// Returns the channels of this pixel as a 4 tuple. If the pixel
253 /// has less than 4 channels the remainder is filled with the maximum value
254 #[deprecated(since = "0.24.0", note = "Use `channels()` or `channels_mut()`")]
255 fn channels4(
256 &self,
257 ) -> (
258 Self::Subpixel,
259 Self::Subpixel,
260 Self::Subpixel,
261 Self::Subpixel,
262 );
263
264 /// Construct a pixel from the 4 channels a, b, c and d.
265 /// If the pixel does not contain 4 channels the extra are ignored.
266 #[deprecated(
267 since = "0.24.0",
268 note = "Use the constructor of the pixel, for example `Rgba([r,g,b,a])` or `Pixel::from_slice`"
269 )]
270 fn from_channels(
271 a: Self::Subpixel,
272 b: Self::Subpixel,
273 c: Self::Subpixel,
274 d: Self::Subpixel,
275 ) -> Self;
276
277 /// Returns a view into a slice.
278 ///
279 /// Note: The slice length is not checked on creation. Thus the caller has to ensure
280 /// that the slice is long enough to prevent panics if the pixel is used later on.
281 fn from_slice(slice: &[Self::Subpixel]) -> &Self;
282
283 /// Returns mutable view into a mutable slice.
284 ///
285 /// Note: The slice length is not checked on creation. Thus the caller has to ensure
286 /// that the slice is long enough to prevent panics if the pixel is used later on.
287 fn from_slice_mut(slice: &mut [Self::Subpixel]) -> &mut Self;
288
289 /// Convert this pixel to RGB
290 fn to_rgb(&self) -> Rgb<Self::Subpixel>;
291
292 /// Convert this pixel to RGB with an alpha channel
293 fn to_rgba(&self) -> Rgba<Self::Subpixel>;
294
295 /// Convert this pixel to luma
296 fn to_luma(&self) -> Luma<Self::Subpixel>;
297
298 /// Convert this pixel to luma with an alpha channel
299 fn to_luma_alpha(&self) -> LumaA<Self::Subpixel>;
300
301 /// Apply the function ```f``` to each channel of this pixel.
302 fn map<F>(&self, f: F) -> Self
303 where
304 F: FnMut(Self::Subpixel) -> Self::Subpixel;
305
306 /// Apply the function ```f``` to each channel of this pixel.
307 fn apply<F>(&mut self, f: F)
308 where
309 F: FnMut(Self::Subpixel) -> Self::Subpixel;
310
311 /// Apply the function ```f``` to each channel except the alpha channel.
312 /// Apply the function ```g``` to the alpha channel.
313 fn map_with_alpha<F, G>(&self, f: F, g: G) -> Self
314 where
315 F: FnMut(Self::Subpixel) -> Self::Subpixel,
316 G: FnMut(Self::Subpixel) -> Self::Subpixel;
317
318 /// Apply the function ```f``` to each channel except the alpha channel.
319 /// Apply the function ```g``` to the alpha channel. Works in-place.
320 fn apply_with_alpha<F, G>(&mut self, f: F, g: G)
321 where
322 F: FnMut(Self::Subpixel) -> Self::Subpixel,
323 G: FnMut(Self::Subpixel) -> Self::Subpixel;
324
325 /// Apply the function ```f``` to each channel except the alpha channel.
326 fn map_without_alpha<F>(&self, f: F) -> Self
327 where
328 F: FnMut(Self::Subpixel) -> Self::Subpixel,
329 {
330 let mut this = *self;
331 this.apply_with_alpha(f, |x| x);
332 this
333 }
334
335 /// Apply the function ```f``` to each channel except the alpha channel.
336 /// Works in place.
337 fn apply_without_alpha<F>(&mut self, f: F)
338 where
339 F: FnMut(Self::Subpixel) -> Self::Subpixel,
340 {
341 self.apply_with_alpha(f, |x| x);
342 }
343
344 /// Apply the function ```f``` to each channel of this pixel and
345 /// ```other``` pairwise.
346 fn map2<F>(&self, other: &Self, f: F) -> Self
347 where
348 F: FnMut(Self::Subpixel, Self::Subpixel) -> Self::Subpixel;
349
350 /// Apply the function ```f``` to each channel of this pixel and
351 /// ```other``` pairwise. Works in-place.
352 fn apply2<F>(&mut self, other: &Self, f: F)
353 where
354 F: FnMut(Self::Subpixel, Self::Subpixel) -> Self::Subpixel;
355
356 /// Invert this pixel
357 fn invert(&mut self);
358
359 /// Blend the color of a given pixel into ourself, taking into account alpha channels
360 fn blend(&mut self, other: &Self);
361}
362
363/// Private module for supertraits of sealed traits.
364mod seals {
365 pub trait EncodableLayout {}
366
367 impl EncodableLayout for [u8] {}
368 impl EncodableLayout for [u16] {}
369 impl EncodableLayout for [f32] {}
370}
371