egui/crates/epaint/src/color.rs
2022-08-20 10:41:49 +02:00

1068 lines
29 KiB
Rust

//! Color conversions and types.
//!
//! If you want a compact color representation, use [`Color32`].
//! If you want to manipulate RGBA colors use [`Rgba`].
//! If you want to manipulate colors in a way closer to how humans think about colors, use [`HsvaGamma`].
#![allow(clippy::wrong_self_convention)]
/// This format is used for space-efficient color representation (32 bits).
///
/// Instead of manipulating this directly it is often better
/// to first convert it to either [`Rgba`] or [`Hsva`].
///
/// Internally this uses 0-255 gamma space `sRGBA` color with premultiplied alpha.
/// Alpha channel is in linear space.
#[repr(C)]
#[derive(Clone, Copy, Debug, Default, Eq, Hash, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(feature = "bytemuck", derive(bytemuck::Pod, bytemuck::Zeroable))]
pub struct Color32(pub(crate) [u8; 4]);
impl std::ops::Index<usize> for Color32 {
type Output = u8;
#[inline(always)]
fn index(&self, index: usize) -> &u8 {
&self.0[index]
}
}
impl std::ops::IndexMut<usize> for Color32 {
#[inline(always)]
fn index_mut(&mut self, index: usize) -> &mut u8 {
&mut self.0[index]
}
}
impl Color32 {
// Mostly follows CSS names:
pub const TRANSPARENT: Color32 = Color32::from_rgba_premultiplied(0, 0, 0, 0);
pub const BLACK: Color32 = Color32::from_rgb(0, 0, 0);
pub const DARK_GRAY: Color32 = Color32::from_rgb(96, 96, 96);
pub const GRAY: Color32 = Color32::from_rgb(160, 160, 160);
pub const LIGHT_GRAY: Color32 = Color32::from_rgb(220, 220, 220);
pub const WHITE: Color32 = Color32::from_rgb(255, 255, 255);
pub const BROWN: Color32 = Color32::from_rgb(165, 42, 42);
pub const DARK_RED: Color32 = Color32::from_rgb(0x8B, 0, 0);
pub const RED: Color32 = Color32::from_rgb(255, 0, 0);
pub const LIGHT_RED: Color32 = Color32::from_rgb(255, 128, 128);
pub const YELLOW: Color32 = Color32::from_rgb(255, 255, 0);
pub const LIGHT_YELLOW: Color32 = Color32::from_rgb(255, 255, 0xE0);
pub const KHAKI: Color32 = Color32::from_rgb(240, 230, 140);
pub const DARK_GREEN: Color32 = Color32::from_rgb(0, 0x64, 0);
pub const GREEN: Color32 = Color32::from_rgb(0, 255, 0);
pub const LIGHT_GREEN: Color32 = Color32::from_rgb(0x90, 0xEE, 0x90);
pub const DARK_BLUE: Color32 = Color32::from_rgb(0, 0, 0x8B);
pub const BLUE: Color32 = Color32::from_rgb(0, 0, 255);
pub const LIGHT_BLUE: Color32 = Color32::from_rgb(0xAD, 0xD8, 0xE6);
pub const GOLD: Color32 = Color32::from_rgb(255, 215, 0);
pub const DEBUG_COLOR: Color32 = Color32::from_rgba_premultiplied(0, 200, 0, 128);
/// An ugly color that is planned to be replaced before making it to the screen.
pub const TEMPORARY_COLOR: Color32 = Color32::from_rgb(64, 254, 0);
#[inline(always)]
pub const fn from_rgb(r: u8, g: u8, b: u8) -> Self {
Self([r, g, b, 255])
}
#[inline(always)]
pub const fn from_rgb_additive(r: u8, g: u8, b: u8) -> Self {
Self([r, g, b, 0])
}
/// From `sRGBA` with premultiplied alpha.
#[inline(always)]
pub const fn from_rgba_premultiplied(r: u8, g: u8, b: u8, a: u8) -> Self {
Self([r, g, b, a])
}
/// From `sRGBA` WITHOUT premultiplied alpha.
pub fn from_rgba_unmultiplied(r: u8, g: u8, b: u8, a: u8) -> Self {
if a == 255 {
Self::from_rgb(r, g, b) // common-case optimization
} else if a == 0 {
Self::TRANSPARENT // common-case optimization
} else {
let r_lin = linear_f32_from_gamma_u8(r);
let g_lin = linear_f32_from_gamma_u8(g);
let b_lin = linear_f32_from_gamma_u8(b);
let a_lin = linear_f32_from_linear_u8(a);
let r = gamma_u8_from_linear_f32(r_lin * a_lin);
let g = gamma_u8_from_linear_f32(g_lin * a_lin);
let b = gamma_u8_from_linear_f32(b_lin * a_lin);
Self::from_rgba_premultiplied(r, g, b, a)
}
}
#[inline(always)]
pub const fn from_gray(l: u8) -> Self {
Self([l, l, l, 255])
}
#[inline(always)]
pub const fn from_black_alpha(a: u8) -> Self {
Self([0, 0, 0, a])
}
pub fn from_white_alpha(a: u8) -> Self {
Rgba::from_white_alpha(linear_f32_from_linear_u8(a)).into()
}
#[inline(always)]
pub const fn from_additive_luminance(l: u8) -> Self {
Self([l, l, l, 0])
}
#[inline(always)]
pub const fn is_opaque(&self) -> bool {
self.a() == 255
}
#[inline(always)]
pub const fn r(&self) -> u8 {
self.0[0]
}
#[inline(always)]
pub const fn g(&self) -> u8 {
self.0[1]
}
#[inline(always)]
pub const fn b(&self) -> u8 {
self.0[2]
}
#[inline(always)]
pub const fn a(&self) -> u8 {
self.0[3]
}
/// Returns an opaque version of self
pub fn to_opaque(self) -> Self {
Rgba::from(self).to_opaque().into()
}
/// Returns an additive version of self
#[inline(always)]
pub const fn additive(self) -> Self {
let [r, g, b, _] = self.to_array();
Self([r, g, b, 0])
}
/// Premultiplied RGBA
#[inline(always)]
pub const fn to_array(&self) -> [u8; 4] {
[self.r(), self.g(), self.b(), self.a()]
}
/// Premultiplied RGBA
#[inline(always)]
pub const fn to_tuple(&self) -> (u8, u8, u8, u8) {
(self.r(), self.g(), self.b(), self.a())
}
pub fn to_srgba_unmultiplied(&self) -> [u8; 4] {
Rgba::from(*self).to_srgba_unmultiplied()
}
/// Multiply with 0.5 to make color half as opaque.
pub fn linear_multiply(self, factor: f32) -> Color32 {
crate::epaint_assert!(0.0 <= factor && factor <= 1.0);
// As an unfortunate side-effect of using premultiplied alpha
// we need a somewhat expensive conversion to linear space and back.
Rgba::from(self).multiply(factor).into()
}
}
// ----------------------------------------------------------------------------
/// Construct a [`Color32`] from a hex RGB or RGBA string.
///
/// ```
/// # use epaint::{hex_color, Color32};
/// assert_eq!(hex_color!("#202122"), Color32::from_rgb(0x20, 0x21, 0x22));
/// assert_eq!(hex_color!("#abcdef12"), Color32::from_rgba_unmultiplied(0xab, 0xcd, 0xef, 0x12));
/// ```
#[cfg(feature = "color-hex")]
#[macro_export]
macro_rules! hex_color {
($s:literal) => {{
let array = $crate::color_hex::color_from_hex!($s);
if array.len() == 3 {
$crate::Color32::from_rgb(array[0], array[1], array[2])
} else {
#[allow(unconditional_panic)]
$crate::Color32::from_rgba_unmultiplied(array[0], array[1], array[2], array[3])
}
}};
}
#[cfg(feature = "color-hex")]
#[test]
fn test_from_rgb_hex() {
assert_eq!(Color32::from_rgb(0x20, 0x21, 0x22), hex_color!("#202122"));
assert_eq!(
Color32::from_rgb_additive(0x20, 0x21, 0x22),
hex_color!("#202122").additive()
);
}
#[cfg(feature = "color-hex")]
#[test]
fn test_from_rgba_hex() {
assert_eq!(
Color32::from_rgba_unmultiplied(0x20, 0x21, 0x22, 0x50),
hex_color!("20212250")
);
}
// ----------------------------------------------------------------------------
/// 0-1 linear space `RGBA` color with premultiplied alpha.
#[repr(C)]
#[derive(Clone, Copy, Debug, Default, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(feature = "bytemuck", derive(bytemuck::Pod, bytemuck::Zeroable))]
pub struct Rgba(pub(crate) [f32; 4]);
impl std::ops::Index<usize> for Rgba {
type Output = f32;
#[inline(always)]
fn index(&self, index: usize) -> &f32 {
&self.0[index]
}
}
impl std::ops::IndexMut<usize> for Rgba {
#[inline(always)]
fn index_mut(&mut self, index: usize) -> &mut f32 {
&mut self.0[index]
}
}
#[allow(clippy::derive_hash_xor_eq)]
impl std::hash::Hash for Rgba {
#[inline]
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
crate::f32_hash(state, self.0[0]);
crate::f32_hash(state, self.0[1]);
crate::f32_hash(state, self.0[2]);
crate::f32_hash(state, self.0[3]);
}
}
impl Rgba {
pub const TRANSPARENT: Rgba = Rgba::from_rgba_premultiplied(0.0, 0.0, 0.0, 0.0);
pub const BLACK: Rgba = Rgba::from_rgb(0.0, 0.0, 0.0);
pub const WHITE: Rgba = Rgba::from_rgb(1.0, 1.0, 1.0);
pub const RED: Rgba = Rgba::from_rgb(1.0, 0.0, 0.0);
pub const GREEN: Rgba = Rgba::from_rgb(0.0, 1.0, 0.0);
pub const BLUE: Rgba = Rgba::from_rgb(0.0, 0.0, 1.0);
#[inline(always)]
pub const fn from_rgba_premultiplied(r: f32, g: f32, b: f32, a: f32) -> Self {
Self([r, g, b, a])
}
#[inline(always)]
pub fn from_rgba_unmultiplied(r: f32, g: f32, b: f32, a: f32) -> Self {
Self([r * a, g * a, b * a, a])
}
#[inline(always)]
pub fn from_srgba_premultiplied(r: u8, g: u8, b: u8, a: u8) -> Self {
let r = linear_f32_from_gamma_u8(r);
let g = linear_f32_from_gamma_u8(g);
let b = linear_f32_from_gamma_u8(b);
let a = linear_f32_from_linear_u8(a);
Self::from_rgba_premultiplied(r, g, b, a)
}
#[inline(always)]
pub fn from_srgba_unmultiplied(r: u8, g: u8, b: u8, a: u8) -> Self {
let r = linear_f32_from_gamma_u8(r);
let g = linear_f32_from_gamma_u8(g);
let b = linear_f32_from_gamma_u8(b);
let a = linear_f32_from_linear_u8(a);
Self::from_rgba_premultiplied(r * a, g * a, b * a, a)
}
#[inline(always)]
pub const fn from_rgb(r: f32, g: f32, b: f32) -> Self {
Self([r, g, b, 1.0])
}
#[inline(always)]
pub const fn from_gray(l: f32) -> Self {
Self([l, l, l, 1.0])
}
pub fn from_luminance_alpha(l: f32, a: f32) -> Self {
crate::epaint_assert!(0.0 <= l && l <= 1.0);
crate::epaint_assert!(0.0 <= a && a <= 1.0);
Self([l * a, l * a, l * a, a])
}
/// Transparent black
#[inline(always)]
pub fn from_black_alpha(a: f32) -> Self {
crate::epaint_assert!(0.0 <= a && a <= 1.0);
Self([0.0, 0.0, 0.0, a])
}
/// Transparent white
#[inline(always)]
pub fn from_white_alpha(a: f32) -> Self {
crate::epaint_assert!(0.0 <= a && a <= 1.0);
Self([a, a, a, a])
}
/// Return an additive version of this color (alpha = 0)
#[inline(always)]
pub fn additive(self) -> Self {
let [r, g, b, _] = self.0;
Self([r, g, b, 0.0])
}
/// Multiply with e.g. 0.5 to make us half transparent
#[inline(always)]
pub fn multiply(self, alpha: f32) -> Self {
Self([
alpha * self[0],
alpha * self[1],
alpha * self[2],
alpha * self[3],
])
}
#[inline(always)]
pub fn r(&self) -> f32 {
self.0[0]
}
#[inline(always)]
pub fn g(&self) -> f32 {
self.0[1]
}
#[inline(always)]
pub fn b(&self) -> f32 {
self.0[2]
}
#[inline(always)]
pub fn a(&self) -> f32 {
self.0[3]
}
/// How perceptually intense (bright) is the color?
#[inline]
pub fn intensity(&self) -> f32 {
0.3 * self.r() + 0.59 * self.g() + 0.11 * self.b()
}
/// Returns an opaque version of self
pub fn to_opaque(&self) -> Self {
if self.a() == 0.0 {
// Additive or fully transparent black.
Self::from_rgb(self.r(), self.g(), self.b())
} else {
// un-multiply alpha:
Self::from_rgb(
self.r() / self.a(),
self.g() / self.a(),
self.b() / self.a(),
)
}
}
/// Premultiplied RGBA
#[inline(always)]
pub fn to_array(&self) -> [f32; 4] {
[self.r(), self.g(), self.b(), self.a()]
}
/// Premultiplied RGBA
#[inline(always)]
pub fn to_tuple(&self) -> (f32, f32, f32, f32) {
(self.r(), self.g(), self.b(), self.a())
}
/// unmultiply the alpha
pub fn to_rgba_unmultiplied(&self) -> [f32; 4] {
let a = self.a();
if a == 0.0 {
// Additive, let's assume we are black
self.0
} else {
[self.r() / a, self.g() / a, self.b() / a, a]
}
}
/// unmultiply the alpha
pub fn to_srgba_unmultiplied(&self) -> [u8; 4] {
let [r, g, b, a] = self.to_rgba_unmultiplied();
[
gamma_u8_from_linear_f32(r),
gamma_u8_from_linear_f32(g),
gamma_u8_from_linear_f32(b),
linear_u8_from_linear_f32(a.abs()),
]
}
}
impl std::ops::Add for Rgba {
type Output = Rgba;
#[inline(always)]
fn add(self, rhs: Rgba) -> Rgba {
Rgba([
self[0] + rhs[0],
self[1] + rhs[1],
self[2] + rhs[2],
self[3] + rhs[3],
])
}
}
impl std::ops::Mul<Rgba> for Rgba {
type Output = Rgba;
#[inline(always)]
fn mul(self, other: Rgba) -> Rgba {
Rgba([
self[0] * other[0],
self[1] * other[1],
self[2] * other[2],
self[3] * other[3],
])
}
}
impl std::ops::Mul<f32> for Rgba {
type Output = Rgba;
#[inline(always)]
fn mul(self, factor: f32) -> Rgba {
Rgba([
self[0] * factor,
self[1] * factor,
self[2] * factor,
self[3] * factor,
])
}
}
impl std::ops::Mul<Rgba> for f32 {
type Output = Rgba;
#[inline(always)]
fn mul(self, rgba: Rgba) -> Rgba {
Rgba([
self * rgba[0],
self * rgba[1],
self * rgba[2],
self * rgba[3],
])
}
}
// ----------------------------------------------------------------------------
// Color conversion:
impl From<Color32> for Rgba {
fn from(srgba: Color32) -> Rgba {
Rgba([
linear_f32_from_gamma_u8(srgba.0[0]),
linear_f32_from_gamma_u8(srgba.0[1]),
linear_f32_from_gamma_u8(srgba.0[2]),
linear_f32_from_linear_u8(srgba.0[3]),
])
}
}
impl From<Rgba> for Color32 {
fn from(rgba: Rgba) -> Color32 {
Color32([
gamma_u8_from_linear_f32(rgba.0[0]),
gamma_u8_from_linear_f32(rgba.0[1]),
gamma_u8_from_linear_f32(rgba.0[2]),
linear_u8_from_linear_f32(rgba.0[3]),
])
}
}
/// gamma [0, 255] -> linear [0, 1].
pub fn linear_f32_from_gamma_u8(s: u8) -> f32 {
if s <= 10 {
s as f32 / 3294.6
} else {
((s as f32 + 14.025) / 269.025).powf(2.4)
}
}
/// linear [0, 255] -> linear [0, 1].
/// Useful for alpha-channel.
#[inline(always)]
pub fn linear_f32_from_linear_u8(a: u8) -> f32 {
a as f32 / 255.0
}
/// linear [0, 1] -> gamma [0, 255] (clamped).
/// Values outside this range will be clamped to the range.
pub fn gamma_u8_from_linear_f32(l: f32) -> u8 {
if l <= 0.0 {
0
} else if l <= 0.0031308 {
fast_round(3294.6 * l)
} else if l <= 1.0 {
fast_round(269.025 * l.powf(1.0 / 2.4) - 14.025)
} else {
255
}
}
/// linear [0, 1] -> linear [0, 255] (clamped).
/// Useful for alpha-channel.
#[inline(always)]
pub fn linear_u8_from_linear_f32(a: f32) -> u8 {
fast_round(a * 255.0)
}
fn fast_round(r: f32) -> u8 {
(r + 0.5).floor() as _ // rust does a saturating cast since 1.45
}
#[test]
pub fn test_srgba_conversion() {
for b in 0..=255 {
let l = linear_f32_from_gamma_u8(b);
assert!(0.0 <= l && l <= 1.0);
assert_eq!(gamma_u8_from_linear_f32(l), b);
}
}
/// gamma [0, 1] -> linear [0, 1] (not clamped).
/// Works for numbers outside this range (e.g. negative numbers).
pub fn linear_from_gamma(gamma: f32) -> f32 {
if gamma < 0.0 {
-linear_from_gamma(-gamma)
} else if gamma <= 0.04045 {
gamma / 12.92
} else {
((gamma + 0.055) / 1.055).powf(2.4)
}
}
/// linear [0, 1] -> gamma [0, 1] (not clamped).
/// Works for numbers outside this range (e.g. negative numbers).
pub fn gamma_from_linear(linear: f32) -> f32 {
if linear < 0.0 {
-gamma_from_linear(-linear)
} else if linear <= 0.0031308 {
12.92 * linear
} else {
1.055 * linear.powf(1.0 / 2.4) - 0.055
}
}
// ----------------------------------------------------------------------------
/// Hue, saturation, value, alpha. All in the range [0, 1].
/// No premultiplied alpha.
#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct Hsva {
/// hue 0-1
pub h: f32,
/// saturation 0-1
pub s: f32,
/// value 0-1
pub v: f32,
/// alpha 0-1. A negative value signifies an additive color (and alpha is ignored).
pub a: f32,
}
impl Hsva {
pub fn new(h: f32, s: f32, v: f32, a: f32) -> Self {
Self { h, s, v, a }
}
/// From `sRGBA` with premultiplied alpha
pub fn from_srgba_premultiplied(srgba: [u8; 4]) -> Self {
Self::from_rgba_premultiplied(
linear_f32_from_gamma_u8(srgba[0]),
linear_f32_from_gamma_u8(srgba[1]),
linear_f32_from_gamma_u8(srgba[2]),
linear_f32_from_linear_u8(srgba[3]),
)
}
/// From `sRGBA` without premultiplied alpha
pub fn from_srgba_unmultiplied(srgba: [u8; 4]) -> Self {
Self::from_rgba_unmultiplied(
linear_f32_from_gamma_u8(srgba[0]),
linear_f32_from_gamma_u8(srgba[1]),
linear_f32_from_gamma_u8(srgba[2]),
linear_f32_from_linear_u8(srgba[3]),
)
}
/// From linear RGBA with premultiplied alpha
pub fn from_rgba_premultiplied(r: f32, g: f32, b: f32, a: f32) -> Self {
#![allow(clippy::many_single_char_names)]
if a == 0.0 {
if r == 0.0 && b == 0.0 && a == 0.0 {
Hsva::default()
} else {
Hsva::from_additive_rgb([r, g, b])
}
} else {
let (h, s, v) = hsv_from_rgb([r / a, g / a, b / a]);
Hsva { h, s, v, a }
}
}
/// From linear RGBA without premultiplied alpha
pub fn from_rgba_unmultiplied(r: f32, g: f32, b: f32, a: f32) -> Self {
#![allow(clippy::many_single_char_names)]
let (h, s, v) = hsv_from_rgb([r, g, b]);
Hsva { h, s, v, a }
}
pub fn from_additive_rgb(rgb: [f32; 3]) -> Self {
let (h, s, v) = hsv_from_rgb(rgb);
Hsva {
h,
s,
v,
a: -0.5, // anything negative is treated as additive
}
}
pub fn from_rgb(rgb: [f32; 3]) -> Self {
let (h, s, v) = hsv_from_rgb(rgb);
Hsva { h, s, v, a: 1.0 }
}
pub fn from_srgb([r, g, b]: [u8; 3]) -> Self {
Self::from_rgb([
linear_f32_from_gamma_u8(r),
linear_f32_from_gamma_u8(g),
linear_f32_from_gamma_u8(b),
])
}
// ------------------------------------------------------------------------
pub fn to_opaque(self) -> Self {
Self { a: 1.0, ..self }
}
pub fn to_rgb(&self) -> [f32; 3] {
rgb_from_hsv((self.h, self.s, self.v))
}
pub fn to_srgb(&self) -> [u8; 3] {
let [r, g, b] = self.to_rgb();
[
gamma_u8_from_linear_f32(r),
gamma_u8_from_linear_f32(g),
gamma_u8_from_linear_f32(b),
]
}
pub fn to_rgba_premultiplied(&self) -> [f32; 4] {
let [r, g, b, a] = self.to_rgba_unmultiplied();
let additive = a < 0.0;
if additive {
[r, g, b, 0.0]
} else {
[a * r, a * g, a * b, a]
}
}
/// Represents additive colors using a negative alpha.
pub fn to_rgba_unmultiplied(&self) -> [f32; 4] {
let Hsva { h, s, v, a } = *self;
let [r, g, b] = rgb_from_hsv((h, s, v));
[r, g, b, a]
}
pub fn to_srgba_premultiplied(&self) -> [u8; 4] {
let [r, g, b, a] = self.to_rgba_premultiplied();
[
gamma_u8_from_linear_f32(r),
gamma_u8_from_linear_f32(g),
gamma_u8_from_linear_f32(b),
linear_u8_from_linear_f32(a),
]
}
pub fn to_srgba_unmultiplied(&self) -> [u8; 4] {
let [r, g, b, a] = self.to_rgba_unmultiplied();
[
gamma_u8_from_linear_f32(r),
gamma_u8_from_linear_f32(g),
gamma_u8_from_linear_f32(b),
linear_u8_from_linear_f32(a.abs()),
]
}
}
impl From<Hsva> for Rgba {
fn from(hsva: Hsva) -> Rgba {
Rgba(hsva.to_rgba_premultiplied())
}
}
impl From<Rgba> for Hsva {
fn from(rgba: Rgba) -> Hsva {
Self::from_rgba_premultiplied(rgba.0[0], rgba.0[1], rgba.0[2], rgba.0[3])
}
}
impl From<Hsva> for Color32 {
fn from(hsva: Hsva) -> Color32 {
Color32::from(Rgba::from(hsva))
}
}
impl From<Color32> for Hsva {
fn from(srgba: Color32) -> Hsva {
Hsva::from(Rgba::from(srgba))
}
}
/// All ranges in 0-1, rgb is linear.
pub fn hsv_from_rgb([r, g, b]: [f32; 3]) -> (f32, f32, f32) {
#![allow(clippy::many_single_char_names)]
let min = r.min(g.min(b));
let max = r.max(g.max(b)); // value
let range = max - min;
let h = if max == min {
0.0 // hue is undefined
} else if max == r {
(g - b) / (6.0 * range)
} else if max == g {
(b - r) / (6.0 * range) + 1.0 / 3.0
} else {
// max == b
(r - g) / (6.0 * range) + 2.0 / 3.0
};
let h = (h + 1.0).fract(); // wrap
let s = if max == 0.0 { 0.0 } else { 1.0 - min / max };
(h, s, max)
}
/// All ranges in 0-1, rgb is linear.
pub fn rgb_from_hsv((h, s, v): (f32, f32, f32)) -> [f32; 3] {
#![allow(clippy::many_single_char_names)]
let h = (h.fract() + 1.0).fract(); // wrap
let s = s.clamp(0.0, 1.0);
let f = h * 6.0 - (h * 6.0).floor();
let p = v * (1.0 - s);
let q = v * (1.0 - f * s);
let t = v * (1.0 - (1.0 - f) * s);
match (h * 6.0).floor() as i32 % 6 {
0 => [v, t, p],
1 => [q, v, p],
2 => [p, v, t],
3 => [p, q, v],
4 => [t, p, v],
5 => [v, p, q],
_ => unreachable!(),
}
}
#[test]
#[ignore] // a bit expensive
fn test_hsv_roundtrip() {
for r in 0..=255 {
for g in 0..=255 {
for b in 0..=255 {
let srgba = Color32::from_rgb(r, g, b);
let hsva = Hsva::from(srgba);
assert_eq!(srgba, Color32::from(hsva));
}
}
}
}
// ----------------------------------------------------------------------------
/// Like Hsva but with the `v` value (brightness) being gamma corrected
/// so that it is somewhat perceptually even.
#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub struct HsvaGamma {
/// hue 0-1
pub h: f32,
/// saturation 0-1
pub s: f32,
/// value 0-1, in gamma-space (~perceptually even)
pub v: f32,
/// alpha 0-1. A negative value signifies an additive color (and alpha is ignored).
pub a: f32,
}
impl From<HsvaGamma> for Rgba {
fn from(hsvag: HsvaGamma) -> Rgba {
Hsva::from(hsvag).into()
}
}
impl From<HsvaGamma> for Color32 {
fn from(hsvag: HsvaGamma) -> Color32 {
Rgba::from(hsvag).into()
}
}
impl From<HsvaGamma> for Hsva {
fn from(hsvag: HsvaGamma) -> Hsva {
let HsvaGamma { h, s, v, a } = hsvag;
Hsva {
h,
s,
v: linear_from_gamma(v),
a,
}
}
}
impl From<Rgba> for HsvaGamma {
fn from(rgba: Rgba) -> HsvaGamma {
Hsva::from(rgba).into()
}
}
impl From<Color32> for HsvaGamma {
fn from(srgba: Color32) -> HsvaGamma {
Hsva::from(srgba).into()
}
}
impl From<Hsva> for HsvaGamma {
fn from(hsva: Hsva) -> HsvaGamma {
let Hsva { h, s, v, a } = hsva;
HsvaGamma {
h,
s,
v: gamma_from_linear(v),
a,
}
}
}
// ----------------------------------------------------------------------------
/// Cheap and ugly.
/// Made for graying out disabled `Ui`s.
pub fn tint_color_towards(color: Color32, target: Color32) -> Color32 {
let [mut r, mut g, mut b, mut a] = color.to_array();
if a == 0 {
r /= 2;
g /= 2;
b /= 2;
} else if a < 170 {
// Cheapish and looks ok.
// Works for e.g. grid stripes.
let div = (2 * 255 / a as i32) as u8;
r = r / 2 + target.r() / div;
g = g / 2 + target.g() / div;
b = b / 2 + target.b() / div;
a /= 2;
} else {
r = r / 2 + target.r() / 2;
g = g / 2 + target.g() / 2;
b = b / 2 + target.b() / 2;
}
Color32::from_rgba_premultiplied(r, g, b, a)
}
#[cfg(feature = "cint")]
mod impl_cint {
use super::*;
use cint::{Alpha, ColorInterop, EncodedSrgb, Hsv, LinearSrgb, PremultipliedAlpha};
// ---- Color32 ----
impl From<Alpha<EncodedSrgb<u8>>> for Color32 {
fn from(srgba: Alpha<EncodedSrgb<u8>>) -> Self {
let Alpha {
color: EncodedSrgb { r, g, b },
alpha: a,
} = srgba;
Color32::from_rgba_unmultiplied(r, g, b, a)
}
}
// No From<Color32> for Alpha<_> because Color32 is premultiplied
impl From<PremultipliedAlpha<EncodedSrgb<u8>>> for Color32 {
fn from(srgba: PremultipliedAlpha<EncodedSrgb<u8>>) -> Self {
let PremultipliedAlpha {
color: EncodedSrgb { r, g, b },
alpha: a,
} = srgba;
Color32::from_rgba_premultiplied(r, g, b, a)
}
}
impl From<Color32> for PremultipliedAlpha<EncodedSrgb<u8>> {
fn from(col: Color32) -> Self {
let (r, g, b, a) = col.to_tuple();
PremultipliedAlpha {
color: EncodedSrgb { r, g, b },
alpha: a,
}
}
}
impl From<PremultipliedAlpha<EncodedSrgb<f32>>> for Color32 {
fn from(srgba: PremultipliedAlpha<EncodedSrgb<f32>>) -> Self {
let PremultipliedAlpha {
color: EncodedSrgb { r, g, b },
alpha: a,
} = srgba;
// This is a bit of an abuse of the function name but it does what we want.
let r = linear_u8_from_linear_f32(r);
let g = linear_u8_from_linear_f32(g);
let b = linear_u8_from_linear_f32(b);
let a = linear_u8_from_linear_f32(a);
Color32::from_rgba_premultiplied(r, g, b, a)
}
}
impl From<Color32> for PremultipliedAlpha<EncodedSrgb<f32>> {
fn from(col: Color32) -> Self {
let (r, g, b, a) = col.to_tuple();
// This is a bit of an abuse of the function name but it does what we want.
let r = linear_f32_from_linear_u8(r);
let g = linear_f32_from_linear_u8(g);
let b = linear_f32_from_linear_u8(b);
let a = linear_f32_from_linear_u8(a);
PremultipliedAlpha {
color: EncodedSrgb { r, g, b },
alpha: a,
}
}
}
impl ColorInterop for Color32 {
type CintTy = PremultipliedAlpha<EncodedSrgb<u8>>;
}
// ---- Rgba ----
impl From<PremultipliedAlpha<LinearSrgb<f32>>> for Rgba {
fn from(srgba: PremultipliedAlpha<LinearSrgb<f32>>) -> Self {
let PremultipliedAlpha {
color: LinearSrgb { r, g, b },
alpha: a,
} = srgba;
Rgba([r, g, b, a])
}
}
impl From<Rgba> for PremultipliedAlpha<LinearSrgb<f32>> {
fn from(col: Rgba) -> Self {
let (r, g, b, a) = col.to_tuple();
PremultipliedAlpha {
color: LinearSrgb { r, g, b },
alpha: a,
}
}
}
impl ColorInterop for Rgba {
type CintTy = PremultipliedAlpha<LinearSrgb<f32>>;
}
// ---- Hsva ----
impl From<Alpha<Hsv<f32>>> for Hsva {
fn from(srgba: Alpha<Hsv<f32>>) -> Self {
let Alpha {
color: Hsv { h, s, v },
alpha: a,
} = srgba;
Hsva::new(h, s, v, a)
}
}
impl From<Hsva> for Alpha<Hsv<f32>> {
fn from(col: Hsva) -> Self {
let Hsva { h, s, v, a } = col;
Alpha {
color: Hsv { h, s, v },
alpha: a,
}
}
}
impl ColorInterop for Hsva {
type CintTy = Alpha<Hsv<f32>>;
}
// ---- HsvaGamma ----
impl ColorInterop for HsvaGamma {
type CintTy = Alpha<Hsv<f32>>;
}
impl From<Alpha<Hsv<f32>>> for HsvaGamma {
fn from(srgba: Alpha<Hsv<f32>>) -> Self {
let Alpha {
color: Hsv { h, s, v },
alpha: a,
} = srgba;
Hsva::new(h, s, v, a).into()
}
}
impl From<HsvaGamma> for Alpha<Hsv<f32>> {
fn from(col: HsvaGamma) -> Self {
let Hsva { h, s, v, a } = col.into();
Alpha {
color: Hsv { h, s, v },
alpha: a,
}
}
}
}