1use colorutils_rs::{
31 lch_to_rgb, lch_with_alpha_to_rgba, rgb_to_lch, rgba_to_lch_with_alpha, TransferFunction,
32 SRGB_TO_XYZ_D65, XYZ_TO_SRGB_D65,
33};
34
35use crate::pic_scale_error::PicScaleError;
36use crate::scaler::ScalingF32;
37use crate::support::check_image_size_overflow;
38use crate::{ImageStore, ImageStoreMut, ResamplingFunction, Scaler, Scaling, ThreadingPolicy};
39
40#[derive(Debug, Copy, Clone)]
41pub struct LChScaler {
43 pub(crate) scaler: Scaler,
44}
45
46impl LChScaler {
47 pub fn new(filter: ResamplingFunction) -> Self {
48 LChScaler {
49 scaler: Scaler::new(filter),
50 }
51 }
52
53 fn rgba_to_lcha<'a>(store: &ImageStore<'a, u8, 4>) -> ImageStore<'a, f32, 4> {
54 let mut source_slice = vec![f32::default(); 4 * store.width * store.height];
55 let lab_stride = store.width as u32 * 4u32 * std::mem::size_of::<f32>() as u32;
56 rgba_to_lch_with_alpha(
57 store.buffer.as_ref(),
58 store.width as u32 * 4u32,
59 &mut source_slice,
60 lab_stride,
61 store.width as u32,
62 store.height as u32,
63 &SRGB_TO_XYZ_D65,
64 TransferFunction::Srgb,
65 );
66 let new_store = ImageStore::<f32, 4> {
67 buffer: std::borrow::Cow::Owned(source_slice),
68 channels: 4,
69 width: store.width,
70 height: store.height,
71 stride: store.width * 4,
72 bit_depth: store.bit_depth,
73 };
74 new_store
75 }
76
77 fn lcha_to_srgba<'a>(store: &ImageStoreMut<'a, f32, 4>, into: &mut ImageStoreMut<'a, u8, 4>) {
78 lch_with_alpha_to_rgba(
79 store.buffer.borrow(),
80 store.width as u32 * 4u32 * std::mem::size_of::<f32>() as u32,
81 into.buffer.borrow_mut(),
82 store.width as u32 * 4u32,
83 store.width as u32,
84 store.height as u32,
85 &XYZ_TO_SRGB_D65,
86 TransferFunction::Srgb,
87 );
88 }
89}
90
91impl Scaling for LChScaler {
92 fn set_threading_policy(&mut self, threading_policy: ThreadingPolicy) {
93 self.scaler.set_threading_policy(threading_policy)
94 }
95
96 fn resize_cbcr8<'a>(
97 &'a self,
98 _: &ImageStore<'a, u8, 2>,
99 _: &mut ImageStoreMut<'a, u8, 2>,
100 ) -> Result<(), PicScaleError> {
101 unimplemented!()
102 }
103
104 fn resize_rgb<'a>(
105 &'a self,
106 store: &ImageStore<'a, u8, 3>,
107 into: &mut ImageStoreMut<'a, u8, 3>,
108 ) -> Result<(), PicScaleError> {
109 let new_size = into.get_size();
110 into.validate()?;
111 store.validate()?;
112 if store.width == 0 || store.height == 0 || new_size.width == 0 || new_size.height == 0 {
113 return Err(PicScaleError::ZeroImageDimensions);
114 }
115
116 if check_image_size_overflow(store.width, store.height, store.channels) {
117 return Err(PicScaleError::SourceImageIsTooLarge);
118 }
119
120 if check_image_size_overflow(new_size.width, new_size.height, store.channels) {
121 return Err(PicScaleError::DestinationImageIsTooLarge);
122 }
123
124 if store.width == new_size.width && store.height == new_size.height {
125 store.copied_to_mut(into);
126 return Ok(());
127 }
128
129 const COMPONENTS: usize = 3;
130
131 let mut target_vertical = vec![f32::default(); store.width * store.height * COMPONENTS];
132
133 let mut lab_store = ImageStoreMut::<f32, COMPONENTS>::from_slice(
134 &mut target_vertical,
135 store.width,
136 store.height,
137 )?;
138 lab_store.bit_depth = into.bit_depth;
139
140 let lab_stride =
141 lab_store.width as u32 * COMPONENTS as u32 * std::mem::size_of::<f32>() as u32;
142 rgb_to_lch(
143 store.buffer.as_ref(),
144 store.width as u32 * COMPONENTS as u32,
145 lab_store.buffer.borrow_mut(),
146 lab_stride,
147 lab_store.width as u32,
148 lab_store.height as u32,
149 &SRGB_TO_XYZ_D65,
150 TransferFunction::Srgb,
151 );
152
153 let new_immutable_store = ImageStore::<f32, COMPONENTS> {
154 buffer: std::borrow::Cow::Owned(target_vertical),
155 channels: COMPONENTS,
156 width: store.width,
157 height: store.height,
158 stride: store.width * COMPONENTS,
159 bit_depth: into.bit_depth,
160 };
161
162 let mut new_store = ImageStoreMut::<f32, COMPONENTS>::alloc(into.width, into.height);
163 self.scaler
164 .resize_rgb_f32(&new_immutable_store, &mut new_store)?;
165
166 let new_lab_stride =
167 new_store.width as u32 * COMPONENTS as u32 * std::mem::size_of::<f32>() as u32;
168
169 lch_to_rgb(
170 new_store.buffer.borrow(),
171 new_lab_stride,
172 into.buffer.borrow_mut(),
173 into.width as u32 * COMPONENTS as u32,
174 new_store.width as u32,
175 new_store.height as u32,
176 &XYZ_TO_SRGB_D65,
177 TransferFunction::Srgb,
178 );
179 Ok(())
180 }
181
182 fn resize_rgba<'a>(
183 &'a self,
184 store: &ImageStore<'a, u8, 4>,
185 into: &mut ImageStoreMut<'a, u8, 4>,
186 premultiply_alpha: bool,
187 ) -> Result<(), PicScaleError> {
188 let new_size = into.get_size();
189 into.validate()?;
190 store.validate()?;
191 if store.width == 0 || store.height == 0 || new_size.width == 0 || new_size.height == 0 {
192 return Err(PicScaleError::ZeroImageDimensions);
193 }
194
195 if check_image_size_overflow(store.width, store.height, store.channels) {
196 return Err(PicScaleError::SourceImageIsTooLarge);
197 }
198
199 if check_image_size_overflow(new_size.width, new_size.height, store.channels) {
200 return Err(PicScaleError::DestinationImageIsTooLarge);
201 }
202
203 if store.width == new_size.width && store.height == new_size.height {
204 store.copied_to_mut(into);
205 return Ok(());
206 }
207
208 let lab_store = Self::rgba_to_lcha(store);
209 let mut new_target_store = ImageStoreMut::alloc(new_size.width, new_size.height);
210
211 self.scaler
212 .resize_rgba_f32(&lab_store, &mut new_target_store, premultiply_alpha)?;
213 Self::lcha_to_srgba(&new_target_store, into);
214 Ok(())
215 }
216}