Add pixel-transform

crates/lib/pixel-transform/src/transformers/crop.rs

@@ -0,0 +1,184 @@
+use std::{fmt::Display, str::FromStr};
+
+use image::DynamicImage;
+use serde::{Deserialize, Serialize};
+use strum::{Display, EnumString};
+
+use crate::{pixeldim::PixelDim, transformers::ImageTransformer};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, EnumString, Serialize, Deserialize, Display)]
+pub enum Direction {
+	#[serde(rename = "n")]
+	#[strum(to_string = "n")]
+	#[strum(serialize = "north")]
+	North,
+
+	#[serde(rename = "e")]
+	#[strum(serialize = "e")]
+	#[strum(serialize = "east")]
+	East,
+
+	#[serde(rename = "s")]
+	#[strum(serialize = "s")]
+	#[strum(serialize = "south")]
+	South,
+
+	#[serde(rename = "w")]
+	#[strum(to_string = "w")]
+	#[strum(serialize = "west")]
+	West,
+
+	#[serde(rename = "c")]
+	#[strum(serialize = "c")]
+	#[strum(serialize = "center")]
+	Center,
+
+	#[serde(rename = "ne")]
+	#[strum(serialize = "ne")]
+	#[strum(serialize = "northeast")]
+	NorthEast,
+
+	#[serde(rename = "se")]
+	#[strum(serialize = "se")]
+	#[strum(serialize = "southeast")]
+	SouthEast,
+
+	#[serde(rename = "nw")]
+	#[strum(serialize = "nw")]
+	#[strum(serialize = "northwest")]
+	NorthWest,
+
+	#[serde(rename = "sw")]
+	#[strum(serialize = "sw")]
+	#[strum(serialize = "southwest")]
+	SouthWest,
+}
+
+/// Crop an image to the given size.
+/// - does not crop width if `w` is greater than image width
+/// - does not crop height if `h` is greater than image height
+/// - does nothing if `w` or `h` are less than or equal to zero.
+#[derive(Debug, Clone, PartialEq)]
+pub struct CropTransformer {
+	w: PixelDim,
+	h: PixelDim,
+	float: Direction,
+}
+
+impl CropTransformer {
+	pub fn new(w: PixelDim, h: PixelDim, float: Direction) -> Self {
+		Self { w, h, float }
+	}
+
+	fn crop_dim(&self, img_width: u32, img_height: u32) -> (u32, u32) {
+		let crop_width = match self.w {
+			PixelDim::Pixels(w) => w,
+			PixelDim::WidthPercent(pct) => ((img_width as f32) * pct / 100.0) as u32,
+			PixelDim::HeightPercent(pct) => ((img_height as f32) * pct / 100.0) as u32,
+		};
+
+		let crop_height = match self.h {
+			PixelDim::Pixels(h) => h,
+			PixelDim::WidthPercent(pct) => ((img_width as f32) * pct / 100.0) as u32,
+			PixelDim::HeightPercent(pct) => ((img_height as f32) * pct / 100.0) as u32,
+		};
+
+		(crop_width, crop_height)
+	}
+
+	#[expect(clippy::integer_division)]
+	fn crop_pos(
+		&self,
+		img_width: u32,
+		img_height: u32,
+		crop_width: u32,
+		crop_height: u32,
+	) -> (u32, u32) {
+		match self.float {
+			Direction::North => {
+				let x = (img_width - crop_width) / 2;
+				let y = 0;
+				(x, y)
+			}
+			Direction::East => {
+				let x = img_width - crop_width;
+				let y = (img_height - crop_height) / 2;
+				(x, y)
+			}
+			Direction::South => {
+				let x = (img_width - crop_width) / 2;
+				let y = img_height - crop_height;
+				(x, y)
+			}
+			Direction::West => {
+				let x = 0;
+				let y = (img_height - crop_height) / 2;
+				(x, y)
+			}
+			Direction::Center => {
+				let x = (img_width - crop_width) / 2;
+				let y = (img_height - crop_height) / 2;
+				(x, y)
+			}
+			Direction::NorthEast => {
+				let x = img_width - crop_width;
+				let y = 0;
+				(x, y)
+			}
+			Direction::SouthEast => {
+				let x = img_width - crop_width;
+				let y = img_height - crop_height;
+				(x, y)
+			}
+			Direction::NorthWest => {
+				let x = 0;
+				let y = 0;
+				(x, y)
+			}
+			Direction::SouthWest => {
+				let x = 0;
+				let y = img_height - crop_height;
+				(x, y)
+			}
+		}
+	}
+}
+
+impl Display for CropTransformer {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "crop({},{},{})", self.w, self.h, self.float)
+	}
+}
+
+impl ImageTransformer for CropTransformer {
+	fn parse_args(args: &str) -> Result<Self, String> {
+		let args: Vec<&str> = args.split(",").collect();
+		if args.len() != 3 {
+			return Err(format!("expected 3 args, got {}", args.len()));
+		}
+
+		let w = args[0].trim().parse::<PixelDim>()?;
+		let h = args[1].trim().parse::<PixelDim>()?;
+
+		let direction = args[2].trim();
+		let direction = Direction::from_str(direction)
+			.map_err(|_err| format!("invalid direction {direction}"))?;
+
+		Ok(Self {
+			w,
+			h,
+			float: direction,
+		})
+	}
+
+	fn transform(&self, input: &mut DynamicImage) {
+		let (img_width, img_height) = (input.width(), input.height());
+		let (crop_width, crop_height) = self.crop_dim(img_width, img_height);
+
+		if (crop_width < img_width || crop_height < img_height) && crop_width > 0 && crop_height > 0
+		{
+			let (x, y) = self.crop_pos(img_width, img_height, crop_width, crop_height);
+			*input = input.crop(x, y, crop_width, crop_height);
+		}
+	}
+}