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|
//! Load and operate on images.
use crate::core::image::{Data, Handle};
use bitflags::bitflags;
pub use ::image as image_rs;
/// Tries to load an image by its [`Handle`].
pub fn load(handle: &Handle) -> image_rs::ImageResult<image_rs::DynamicImage> {
match handle.data() {
Data::Path(path) => {
let image = ::image::open(path)?;
let operation = std::fs::File::open(path)
.ok()
.map(std::io::BufReader::new)
.and_then(|mut reader| Operation::from_exif(&mut reader).ok())
.unwrap_or_else(Operation::empty);
Ok(operation.perform(image))
}
Data::Bytes(bytes) => {
let image = ::image::load_from_memory(bytes)?;
let operation =
Operation::from_exif(&mut std::io::Cursor::new(bytes))
.ok()
.unwrap_or_else(Operation::empty);
Ok(operation.perform(image))
}
Data::Rgba {
width,
height,
pixels,
} => {
if let Some(image) = image_rs::ImageBuffer::from_vec(
*width,
*height,
pixels.to_vec(),
) {
Ok(image_rs::DynamicImage::ImageRgba8(image))
} else {
Err(image_rs::error::ImageError::Limits(
image_rs::error::LimitError::from_kind(
image_rs::error::LimitErrorKind::DimensionError,
),
))
}
}
}
}
bitflags! {
struct Operation: u8 {
const FLIP_HORIZONTALLY = 0b001;
const ROTATE_180 = 0b010;
const FLIP_DIAGONALLY = 0b100;
}
}
impl Operation {
// Meaning of the returned value is described e.g. at:
// https://magnushoff.com/articles/jpeg-orientation/
fn from_exif<R>(reader: &mut R) -> Result<Self, exif::Error>
where
R: std::io::BufRead + std::io::Seek,
{
let exif = exif::Reader::new().read_from_container(reader)?;
Ok(exif
.get_field(exif::Tag::Orientation, exif::In::PRIMARY)
.and_then(|field| field.value.get_uint(0))
.and_then(|value| u8::try_from(value).ok())
.and_then(|value| Self::from_bits(value.saturating_sub(1)))
.unwrap_or_else(Self::empty))
}
fn perform(self, mut image: image::DynamicImage) -> image::DynamicImage {
use image::imageops;
if self.contains(Self::FLIP_DIAGONALLY) {
imageops::flip_vertical_in_place(&mut image)
}
if self.contains(Self::ROTATE_180) {
imageops::rotate180_in_place(&mut image);
}
if self.contains(Self::FLIP_HORIZONTALLY) {
imageops::flip_horizontal_in_place(&mut image);
}
image
}
}
|
