canvas/src/utils.rs

#[allow(unused_imports)]
use log::{debug, error, info, trace, warn};

use winit;

use cgmath::{Vector3, Vector2};

//--Position struct---------------------------------------------------------------------------------
#[derive(Copy, Clone, Debug)]
pub struct Position {
    pub x: i32,
    pub y: i32,
}

impl Position {

    pub fn origin() -> Self {
        Position {
            x: 0,
            y: 0,
        }
    }
}

impl From<Position> for Vector3<f32> {

    fn from(pos: Position) -> Self {
        Self::new(pos.x as f32, pos.y as f32, 0.0)
    }
}

impl From<Position> for Vector2<f32> {

    fn from(pos: Position) -> Self {
        Self::new(pos.x as f32, pos.y as f32)
    }
}

impl std::ops::Add for Position {
    type Output = Self;

    fn add(self, rhs: Self) -> Self::Output {
        Position {
            x: self.x + rhs.x,
            y: self.y + rhs.y,
        }
    }
}

impl std::ops::Mul<f32> for Position {
    type Output = Self;

    fn mul(self, rhs: f32) -> Self::Output {
        Position {
            x: ((self.x as f32) * rhs) as i32,
            y: ((self.y as f32) * rhs) as i32,
        }
    }
}

//--Size struct-------------------------------------------------------------------------------------
#[derive(Copy, Clone)]
pub struct Size {
    pub w: u32,
    pub h: u32,
}

impl From<Size> for winit::dpi::Size {

    fn from(size: Size) -> Self {
        winit::dpi::Size::Physical (
            winit::dpi::PhysicalSize {
                width: size.w,
                height: size.h,
        })
    }
}

impl From<Size> for wgpu::Extent3d {

    fn from(size: Size) -> Self {
        wgpu::Extent3d {
            width: size.w,
            height: size.h,
            depth_or_array_layers: 1,
        }
    }
}

impl From<winit::dpi::PhysicalSize<u32>> for Size {

    fn from(size: winit::dpi::PhysicalSize<u32>) -> Self {
        Self {
            w: size.width,
            h: size.height,
        }
    }
}

impl From<Size> for Vector2<f32> {

    fn from(size: Size) -> Self {
        Self::new(size.w as f32, size.h as f32)
    }
}

//--Pixel struct------------------------------------------------------------------------------------
#[repr(packed, C)]
#[derive(Copy, Clone, PartialEq, bytemuck::Pod, bytemuck::Zeroable)]
pub struct Pixel {
	pub r: u8,
	pub g: u8,
	pub b: u8,
	pub a: u8,
}

impl From<Color> for Pixel {

	fn from(value: Color) -> Self {
		value.into_pixel()
	}
}

impl Pixel {

    pub const fn from_hex(hex: u32) -> Self {
		let bytes = hex.to_be_bytes();
		Self { r: bytes[0], g: bytes[1], b: bytes[2], a: bytes[3] }
	}

}

//--Color values------------------------------------------------------------------------------------
#[non_exhaustive]
#[derive(Copy, Clone, PartialEq)]
pub struct Color {
	r: f32,
	g: f32,
	b: f32,
	a: f32,
}

impl From<Pixel> for Color {

	fn from(value: Pixel) -> Self {
		Self {
			r: f32::from(value.r) / 255.0,
			g: f32::from(value.g) / 255.0,
			b: f32::from(value.b) / 255.0,
			a: f32::from(value.a) / 255.0,
		}
	}
}

impl Color {

	pub fn set_alpha(&mut self, a: u8) {
		self.a = f32::from(a) / 255.0;
	}

	pub fn from_rgb(r: u8, g: u8, b: u8) -> Self {
        Pixel { r, g, b, a: 255 }.into()
    }

    pub fn from_rgba(r: u8, g: u8, b: u8, a: u8) -> Self {
        Pixel { r, g, b, a }.into()
    }

	pub fn from_hex(hex: u32) -> Self {
        Pixel::from_hex(hex).into()
	}

	pub fn into_pixel(self) -> Pixel {
		//unsafe block is used here for "to_int_unchecked" since the struct's invariant garentees
		//that the values are within [0.0, 1.0], meaning we won't ever overflow an u8
		unsafe {
			Pixel {
				r: self.r.to_int_unchecked::<u8>() * 255,
				g: self.g.to_int_unchecked::<u8>() * 255,
				b: self.b.to_int_unchecked::<u8>() * 255,
				a: self.a.to_int_unchecked::<u8>() * 255,
			}
		}
	}

	pub fn into_wgpu_color(self) -> wgpu::Color {
		wgpu::Color {
			r: f64::from(self.r),
			g: f64::from(self.g),
			b: f64::from(self.b),
			a: f64::from(self.a),
		}
	}

    pub fn alpha_blend(&self, other: &Self) -> Self {
		//apply alpha compisting's "over" operator, see
		//[https://en.wikipedia.org/wiki/Alpha_compositing] for more detail
		let a = self.a + other.a * (1.0 - self.a);
		Self {
			r: (self.r * self.a + other.r * other.a * (1.0 - self.a)) / a,
			g: (self.g * self.a + other.g * other.a * (1.0 - self.a)) / a,
			b: (self.b * self.a + other.b * other.a * (1.0 - self.a)) / a,
			a,
		}
    }

    pub const NONE:  Self = Self {r: 0.0, g: 0.0, b: 0.0, a: 0.0};
    pub const WHITE: Self = Self {r: 1.0, g: 1.0, b: 1.0, a: 1.0};
    pub const BLACK: Self = Self {r: 0.0, g: 0.0, b: 0.0, a: 1.0};
    pub const RED:   Self = Self {r: 1.0, g: 0.0, b: 0.0, a: 1.0};
    pub const GREEN: Self = Self {r: 0.0, g: 1.0, b: 0.0, a: 1.0};
    pub const BLUE:  Self = Self {r: 0.0, g: 0.0, b: 1.0, a: 1.0};
}