Add pixel-transform

crates/lib/pixel-transform/src/chain.rs

@@ -0,0 +1,145 @@
+use image::{DynamicImage, ImageFormat};
+use serde::{Deserialize, Deserializer, de};
+use std::{fmt::Display, hash::Hash, io::Cursor, str::FromStr};
+use thiserror::Error;
+use toolbox::mime::MimeType;
+
+use crate::transformers::{ImageTransformer, TransformerEnum};
+
+#[derive(Debug, Error)]
+pub enum TransformBytesError {
+	#[error("{0} is not a valid image type")]
+	NotAnImage(String),
+
+	#[error("error while processing image")]
+	ImageError(#[from] image::ImageError),
+}
+
+#[derive(Debug, Clone)]
+pub struct TransformerChain {
+	pub steps: Vec<TransformerEnum>,
+}
+
+impl TransformerChain {
+	#[inline]
+	pub fn mime_is_image(mime: &MimeType) -> bool {
+		ImageFormat::from_mime_type(mime.to_string()).is_some()
+	}
+
+	pub fn transform_image(&self, mut image: DynamicImage) -> DynamicImage {
+		for step in &self.steps {
+			match step {
+				TransformerEnum::Format { .. } => {}
+				TransformerEnum::MaxDim(t) => t.transform(&mut image),
+				TransformerEnum::Crop(t) => t.transform(&mut image),
+			}
+		}
+
+		return image;
+	}
+
+	pub fn transform_bytes(
+		&self,
+		image_bytes: &[u8],
+		image_format: Option<&MimeType>,
+	) -> Result<(MimeType, Vec<u8>), TransformBytesError> {
+		let format: ImageFormat = match image_format {
+			Some(x) => ImageFormat::from_mime_type(x.to_string())
+				.ok_or(TransformBytesError::NotAnImage(x.to_string()))?,
+			None => image::guess_format(image_bytes)?,
+		};
+
+		let out_format = self
+			.steps
+			.last()
+			.and_then(|x| match x {
+				TransformerEnum::Format { format } => Some(format),
+				_ => None,
+			})
+			.unwrap_or(&format);
+
+		let img = image::load_from_memory_with_format(image_bytes, format)?;
+		let img = self.transform_image(img);
+
+		let out_mime = MimeType::from(out_format.to_mime_type());
+		let mut out_bytes = Cursor::new(Vec::new());
+		img.write_to(&mut out_bytes, *out_format)?;
+
+		return Ok((out_mime, out_bytes.into_inner()));
+	}
+}
+
+impl FromStr for TransformerChain {
+	type Err = String;
+	fn from_str(s: &str) -> Result<Self, Self::Err> {
+		let steps_str = s.split(";");
+
+		let mut steps = Vec::new();
+		for s in steps_str {
+			let s = s.trim();
+			if s.is_empty() {
+				continue;
+			}
+
+			let step = s.parse();
+			match step {
+				Ok(x) => steps.push(x),
+				Err(msg) => return Err(format!("invalid step `{s}`: {msg}")),
+			}
+		}
+
+		let n_format = steps
+			.iter()
+			.filter(|x| matches!(x, TransformerEnum::Format { .. }))
+			.count();
+		if n_format > 2 {
+			return Err("provide at most one format()".to_owned());
+		}
+
+		if n_format == 1 && !matches!(steps.last(), Some(TransformerEnum::Format { .. })) {
+			return Err("format() must be last".to_owned());
+		}
+
+		return Ok(Self { steps });
+	}
+}
+
+impl<'de> Deserialize<'de> for TransformerChain {
+	fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+	where
+		D: Deserializer<'de>,
+	{
+		let s = String::deserialize(deserializer)?;
+		Self::from_str(&s).map_err(de::Error::custom)
+	}
+}
+
+impl Display for TransformerChain {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		let mut first = true;
+		for step in &self.steps {
+			if first {
+				write!(f, "{step}")?;
+				first = false
+			} else {
+				write!(f, ";{step}")?;
+			}
+		}
+
+		return Ok(());
+	}
+}
+
+impl PartialEq for TransformerChain {
+	fn eq(&self, other: &Self) -> bool {
+		self.to_string() == other.to_string()
+	}
+}
+
+impl Eq for TransformerChain {}
+
+impl Hash for TransformerChain {
+	fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+		self.to_string().hash(state);
+	}
+}

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

@@ -0,0 +1,6 @@
+mod pixeldim;
+
+pub mod transformers;
+
+mod chain;
+pub use chain::*;

crates/lib/pixel-transform/src/pixeldim.rs

@@ -0,0 +1,68 @@
+use serde::{Deserialize, Deserializer};
+use std::fmt;
+use std::str::FromStr;
+
+// TODO: parse -, + (100vw - 10px)
+// TODO: parse 100vw [min] 10
+// TODO: parse 100vw [max] 10
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum PixelDim {
+	Pixels(u32),
+	WidthPercent(f32),
+	HeightPercent(f32),
+}
+
+impl FromStr for PixelDim {
+	type Err = String;
+
+	fn from_str(s: &str) -> Result<Self, Self::Err> {
+		let numeric_end = s.find(|c: char| !c.is_ascii_digit() && c != '.');
+
+		let (quantity, unit) = numeric_end.map(|x| s.split_at(x)).unwrap_or((s, "px"));
+		let quantity = quantity.trim();
+		let unit = unit.trim();
+
+		match unit {
+			"vw" => Ok(PixelDim::WidthPercent(
+				quantity
+					.parse()
+					.map_err(|_err| format!("invalid quantity {quantity}"))?,
+			)),
+
+			"vh" => Ok(PixelDim::HeightPercent(
+				quantity
+					.parse()
+					.map_err(|_err| format!("invalid quantity {quantity}"))?,
+			)),
+
+			"px" => Ok(PixelDim::Pixels(
+				quantity
+					.parse()
+					.map_err(|_err| format!("invalid quantity {quantity}"))?,
+			)),
+
+			_ => Err(format!("invalid unit {unit}")),
+		}
+	}
+}
+
+impl<'de> Deserialize<'de> for PixelDim {
+	fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+	where
+		D: Deserializer<'de>,
+	{
+		let s = String::deserialize(deserializer)?;
+		FromStr::from_str(&s).map_err(serde::de::Error::custom)
+	}
+}
+
+impl fmt::Display for PixelDim {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		match self {
+			PixelDim::Pixels(px) => write!(f, "{px}"),
+			PixelDim::WidthPercent(p) => write!(f, "{p:.2}vw"),
+			PixelDim::HeightPercent(p) => write!(f, "{p:.2}vh"),
+		}
+	}
+}

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);
+		}
+	}
+}

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

@@ -0,0 +1,82 @@
+use std::fmt::Display;
+
+use image::{DynamicImage, imageops::FilterType};
+
+use crate::{pixeldim::PixelDim, transformers::ImageTransformer};
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct MaxDimTransformer {
+	w: PixelDim,
+	h: PixelDim,
+}
+
+impl MaxDimTransformer {
+	pub fn new(w: PixelDim, h: PixelDim) -> Self {
+		Self { w, h }
+	}
+
+	fn target_dim(&self, img_width: u32, img_height: u32) -> (u32, u32) {
+		let max_width = match self.w {
+			PixelDim::Pixels(w) => Some(w),
+			PixelDim::WidthPercent(pct) => Some(((img_width as f32) * pct / 100.0) as u32),
+			PixelDim::HeightPercent(_) => None,
+		};
+
+		let max_height = match self.h {
+			PixelDim::Pixels(h) => Some(h),
+			PixelDim::HeightPercent(pct) => Some(((img_height as f32) * pct / 100.0) as u32),
+			PixelDim::WidthPercent(_) => None,
+		};
+
+		if max_width.map(|x| img_width <= x).unwrap_or(true)
+			&& max_height.map(|x| img_height <= x).unwrap_or(true)
+		{
+			return (img_width, img_height);
+		}
+
+		let width_ratio = max_width
+			.map(|x| x as f32 / img_width as f32)
+			.unwrap_or(1.0);
+
+		let height_ratio = max_height
+			.map(|x| x as f32 / img_height as f32)
+			.unwrap_or(1.0);
+
+		let ratio = width_ratio.min(height_ratio);
+
+		(
+			(img_width as f32 * ratio) as u32,
+			(img_height as f32 * ratio) as u32,
+		)
+	}
+}
+
+impl Display for MaxDimTransformer {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "maxdim({},{})", self.w, self.h)
+	}
+}
+
+impl ImageTransformer for MaxDimTransformer {
+	fn parse_args(args: &str) -> Result<Self, String> {
+		let args: Vec<&str> = args.split(",").collect();
+		if args.len() != 2 {
+			return Err(format!("expected 2 args, got {}", args.len()));
+		}
+
+		let w = args[0].parse::<PixelDim>()?;
+		let h = args[1].parse::<PixelDim>()?;
+
+		Ok(Self { w, h })
+	}
+
+	fn transform(&self, input: &mut DynamicImage) {
+		let (img_width, img_height) = (input.width(), input.height());
+		let (target_width, target_height) = self.target_dim(img_width, img_height);
+
+		// Only resize if needed
+		if target_width != img_width || target_height != img_height {
+			*input = input.resize(target_width, target_height, FilterType::Lanczos3);
+		}
+	}
+}

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

@@ -0,0 +1,165 @@
+use image::{DynamicImage, ImageFormat};
+use std::fmt;
+use std::fmt::{Debug, Display};
+use std::str::FromStr;
+
+mod crop;
+pub use crop::*;
+
+mod maxdim;
+pub use maxdim::*;
+
+pub trait ImageTransformer
+where
+	Self: PartialEq,
+	Self: Sized + Clone,
+	Self: Display + Debug,
+{
+	/// Transform the given image in place
+	fn transform(&self, input: &mut DynamicImage);
+
+	/// Parse an arg string.
+	///
+	/// `name({arg_string})`
+	fn parse_args(args: &str) -> Result<Self, String>;
+}
+
+use serde::{Deserialize, Deserializer};
+
+/// An enum of all [`ImageTransformer`]s
+#[derive(Debug, Clone, PartialEq)]
+pub enum TransformerEnum {
+	/// Usage: `maxdim(w, h)`
+	///
+	/// Scale the image so its width is smaller than `w`
+	/// and its height is smaller than `h`. Aspect ratio is preserved.
+	///
+	/// To only limit the size of one dimension, use `vw` or `vh`.
+	/// For example, `maxdim(50,100vh)` will not limit width.
+	MaxDim(MaxDimTransformer),
+
+	/// Usage: `crop(w, h, float)`
+	///
+	/// Crop the image to at most `w` by `h` pixels,
+	/// floating the crop area in the specified direction.
+	///
+	/// Directions are one of:
+	/// - Cardinal: n,e,s,w
+	/// - Diagonal: ne,nw,se,sw,
+	/// - Centered: c
+	///
+	/// Examples:
+	/// - `crop(100vw, 50)` gets the top 50 pixels of the image \
+	///   (or fewer, if the image's height is smaller than 50)
+	///
+	/// To only limit the size of one dimension, use `vw` or `vh`.
+	/// For example, `maxdim(50,100vh)` will not limit width.
+	Crop(CropTransformer),
+
+	/// Usage: `format(format)`
+	///
+	/// Transcode the image to the given format.
+	/// This step must be last, and cannot be provided
+	/// more than once.
+	///
+	/// Valid formats:
+	/// - bmp
+	/// - gif
+	/// - ico
+	/// - jpeg or jpg
+	/// - png
+	/// - qoi
+	/// - webp
+	///
+	/// Example:
+	/// - `format(png)`
+	///
+	/// When transcoding an animated gif, the first frame is taken
+	/// and all others are thrown away. This happens even if we
+	/// transcode from a gif to a gif.
+	Format { format: ImageFormat },
+}
+
+impl FromStr for TransformerEnum {
+	type Err = String;
+
+	fn from_str(s: &str) -> Result<Self, Self::Err> {
+		let s = s.trim();
+
+		let (name, args) = {
+			let name_len = match s.find('(') {
+				Some(x) => x + 1,
+				None => {
+					return Err(format!(
+						"invalid transformation {s}. Must look like name(args)."
+					));
+				}
+			};
+
+			let mut balance = 1;
+			let mut end = name_len;
+			for i in s[name_len..].bytes() {
+				match i {
+					b')' => balance -= 1,
+					b'(' => balance += 1,
+					_ => {}
+				}
+
+				if balance == 0 {
+					break;
+				}
+
+				end += 1;
+			}
+
+			if balance != 0 {
+				return Err(format!("mismatched parenthesis in {s}"));
+			}
+
+			let name = s[0..name_len - 1].trim();
+			let args = s[name_len..end].trim();
+			let trail = s[end + 1..].trim();
+			if !trail.is_empty() {
+				return Err(format!(
+					"invalid transformation {s}. Must look like name(args)."
+				));
+			}
+
+			(name, args)
+		};
+
+		match name {
+			"maxdim" => Ok(Self::MaxDim(MaxDimTransformer::parse_args(args)?)),
+			"crop" => Ok(Self::Crop(CropTransformer::parse_args(args)?)),
+
+			"format" => Ok(TransformerEnum::Format {
+				format: ImageFormat::from_extension(args)
+					.ok_or(format!("invalid image format {args}"))?,
+			}),
+
+			_ => Err(format!("unknown transformation {name}")),
+		}
+	}
+}
+
+impl<'de> Deserialize<'de> for TransformerEnum {
+	fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+	where
+		D: Deserializer<'de>,
+	{
+		let s = String::deserialize(deserializer)?;
+		s.parse().map_err(serde::de::Error::custom)
+	}
+}
+
+impl Display for TransformerEnum {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		match self {
+			TransformerEnum::MaxDim(x) => Display::fmt(x, f),
+			TransformerEnum::Crop(x) => Display::fmt(x, f),
+			TransformerEnum::Format { format } => {
+				write!(f, "format({})", format.extensions_str()[0])
+			}
+		}
+	}
+}