use runmat_builtins::{NumericDType, Value};
use runmat_macros::runtime_builtin;
use crate::builtins::common::spec::{
BroadcastSemantics, BuiltinFusionSpec, BuiltinGpuSpec, ConstantStrategy, GpuOpKind,
ReductionNaN, ResidencyPolicy, ShapeRequirements,
};
use crate::builtins::image::color::common;
use crate::builtins::image::color::type_resolvers::same_shape_type;
use crate::BuiltinResult;
const NAME: &str = "rgb2hsv";
#[runmat_macros::register_gpu_spec(builtin_path = "crate::builtins::image::color::rgb2hsv")]
pub const GPU_SPEC: BuiltinGpuSpec = BuiltinGpuSpec {
name: NAME,
op_kind: GpuOpKind::Custom("rgb2hsv"),
supported_precisions: &[],
broadcast: BroadcastSemantics::None,
provider_hooks: &[],
constant_strategy: ConstantStrategy::InlineLiteral,
residency: ResidencyPolicy::GatherImmediately,
nan_mode: ReductionNaN::Include,
two_pass_threshold: None,
workgroup_size: None,
accepts_nan_mode: false,
notes: "Host implementation; float RGB/HSV GPU providers are tracked separately.",
};
#[runmat_macros::register_fusion_spec(builtin_path = "crate::builtins::image::color::rgb2hsv")]
pub const FUSION_SPEC: BuiltinFusionSpec = BuiltinFusionSpec {
name: NAME,
shape: ShapeRequirements::Any,
constant_strategy: ConstantStrategy::InlineLiteral,
elementwise: None,
reduction: None,
emits_nan: false,
notes: "Not fused yet; conversion operates across RGB channels.",
};
#[runtime_builtin(
name = "rgb2hsv",
category = "image/color",
summary = "Convert RGB values to HSV color space.",
keywords = "rgb2hsv,rgb,hsv,color,image,colormap",
accel = "sink",
type_resolver(same_shape_type),
builtin_path = "crate::builtins::image::color::rgb2hsv"
)]
async fn rgb2hsv_builtin(rgb: Value, rest: Vec<Value>) -> BuiltinResult<Value> {
if !rest.is_empty() {
return Err(common::builtin_error(
NAME,
"rgb2hsv: too many input arguments",
));
}
let tensor = common::gather_tensor(NAME, rgb).await?;
let layout = common::color_layout(&tensor, NAME)?;
let dtype = common::image_output_dtype(tensor.dtype);
let mut data = vec![0.0; tensor.data.len()];
for pixel in 0..layout.pixels() {
let r = common::clamp01(common::unit_value(
tensor.data[layout.index(pixel, 0)],
tensor.dtype,
));
let g = common::clamp01(common::unit_value(
tensor.data[layout.index(pixel, 1)],
tensor.dtype,
));
let b = common::clamp01(common::unit_value(
tensor.data[layout.index(pixel, 2)],
tensor.dtype,
));
let (h, s, v) = rgb_to_hsv_unit(r, g, b);
data[layout.index(pixel, 0)] = cast_float(h, dtype);
data[layout.index(pixel, 1)] = cast_float(s, dtype);
data[layout.index(pixel, 2)] = cast_float(v, dtype);
}
Ok(common::image_value_from_tensor(common::tensor_with_dtype(
data,
layout.output_shape(),
dtype,
NAME,
)?))
}
pub(crate) fn rgb_to_hsv_unit(r: f64, g: f64, b: f64) -> (f64, f64, f64) {
let max = r.max(g).max(b);
let min = r.min(g).min(b);
let delta = max - min;
let h = if delta == 0.0 {
0.0
} else if max == r {
((g - b) / delta).rem_euclid(6.0) / 6.0
} else if max == g {
((b - r) / delta + 2.0) / 6.0
} else {
((r - g) / delta + 4.0) / 6.0
};
let s = if max == 0.0 { 0.0 } else { delta / max };
(h, s, max)
}
fn cast_float(value: f64, dtype: NumericDType) -> f64 {
if matches!(dtype, NumericDType::F32) {
(value as f32) as f64
} else {
value
}
}
#[cfg(test)]
mod tests {
use super::*;
use futures::executor::block_on;
use runmat_builtins::Tensor;
fn call(tensor: Tensor) -> BuiltinResult<Tensor> {
let Value::Tensor(out) =
block_on(rgb2hsv_builtin(Value::Tensor(tensor), Vec::new())).expect("rgb2hsv")
else {
panic!("expected tensor");
};
Ok(out)
}
fn assert_close(actual: f64, expected: f64) {
assert!(
(actual - expected).abs() < 1e-12,
"expected {expected}, got {actual}"
);
}
#[test]
fn converts_red_to_hsv() {
let rgb = Tensor::new(vec![1.0, 0.0, 0.0], vec![1, 1, 3]).unwrap();
let out = call(rgb).unwrap();
assert_eq!(out.shape, vec![1, 1, 3]);
assert_close(out.data[0], 0.0);
assert_close(out.data[1], 1.0);
assert_close(out.data[2], 1.0);
}
#[test]
fn converts_colormap_secondary_and_gray_values() {
let rgb = Tensor::new(
vec![0.0, 1.0, 1.0, 0.5, 1.0, 0.0, 1.0, 0.5, 1.0, 1.0, 0.0, 0.5],
vec![4, 3],
)
.unwrap();
let out = call(rgb).unwrap();
assert_eq!(out.shape, vec![4, 3]);
let expected = vec![
0.5,
5.0 / 6.0,
1.0 / 6.0,
0.0,
1.0,
1.0,
1.0,
0.0,
1.0,
1.0,
1.0,
0.5,
];
for (actual, expected) in out.data.iter().zip(expected) {
assert_close(*actual, expected);
}
}
#[test]
fn scales_uint8_rgb_before_conversion() {
let rgb = Tensor::new_with_dtype(vec![128.0, 64.0, 32.0], vec![1, 1, 3], NumericDType::U8)
.unwrap();
let out = call(rgb).unwrap();
assert_eq!(out.dtype, NumericDType::F64);
assert_close(out.data[0], 1.0 / 18.0);
assert_close(out.data[1], 0.75);
assert_close(out.data[2], 128.0 / 255.0);
}
#[test]
fn rejects_grayscale_shape() {
let gray = Tensor::new(vec![1.0, 2.0, 3.0, 4.0], vec![2, 2]).unwrap();
let err = block_on(rgb2hsv_builtin(Value::Tensor(gray), Vec::new())).unwrap_err();
assert!(err
.message()
.contains("expected an MxNx3 RGB image or an Nx3 colormap"));
}
}