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Fix PDF export of grayscale image (#3219)

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Laurenz Stampfl 2024-01-25 16:12:31 +01:00 committed by GitHub
parent b4b17871d6
commit 11abc1f1e3
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1 changed files with 16 additions and 34 deletions
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50
crates/typst-pdf/src/image.rs
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@ -113,42 +113,24 @@ pub(crate) fn write_images(ctx: &mut PdfContext) {
/// Skips the alpha channel as that's encoded separately.
fn encode_raster_image(image: &RasterImage) -> (Vec<u8>, Filter, bool) {
let dynamic = image.dynamic();
match (image.format(), dynamic) {
// 8-bit gray JPEG.
(RasterFormat::Jpg, DynamicImage::ImageLuma8(_)) => {
let mut data = Cursor::new(vec![]);
dynamic.write_to(&mut data, image::ImageFormat::Jpeg).unwrap();
(data.into_inner(), Filter::DctDecode, false)
}
// 8-bit RGB JPEG (CMYK JPEGs get converted to RGB earlier).
(RasterFormat::Jpg, DynamicImage::ImageRgb8(_)) => {
let mut data = Cursor::new(vec![]);
dynamic.write_to(&mut data, image::ImageFormat::Jpeg).unwrap();
(data.into_inner(), Filter::DctDecode, true)
}
let channel_count = dynamic.color().channel_count();
let has_color = channel_count > 2;
if image.format() == RasterFormat::Jpg {
let mut data = Cursor::new(vec![]);
dynamic.write_to(&mut data, image::ImageFormat::Jpeg).unwrap();
(data.into_inner(), Filter::DctDecode, has_color)
} else {
// TODO: Encode flate streams with PNG-predictor?
// 8-bit gray PNG.
(RasterFormat::Png, DynamicImage::ImageLuma8(luma)) => {
let data = deflate(luma.as_raw());
(data, Filter::FlateDecode, false)
}
// Anything else (including Rgb(a) PNGs).
(_, buf) => {
let (width, height) = buf.dimensions();
let mut pixels = Vec::with_capacity(3 * width as usize * height as usize);
for (_, _, Rgba([r, g, b, _])) in buf.pixels() {
pixels.push(r);
pixels.push(g);
pixels.push(b);
}
let data = deflate(&pixels);
(data, Filter::FlateDecode, true)
}
let data = match (dynamic, channel_count) {
(DynamicImage::ImageLuma8(luma), _) => deflate(luma.as_raw()),
(DynamicImage::ImageRgb8(rgb), _) => deflate(rgb.as_raw()),
// Grayscale image
(_, 1 | 2) => deflate(dynamic.to_luma8().as_raw()),
// Anything else
_ => deflate(dynamic.to_rgb8().as_raw()),
};
(data, Filter::FlateDecode, has_color)
}
}