improvement: correct thumbnailing algorithm

This commit is contained in:
Timo Kösters 2020-10-19 15:29:36 +02:00
parent cde4178f4a
commit 6bb8284fc0
No known key found for this signature in database
GPG key ID: 24DA7517711A2BA4
3 changed files with 81 additions and 4 deletions

View file

@ -561,10 +561,10 @@ async fn join_room_by_id_helper(
.chain(iter::once(Ok((event_id, join_event)))) // Add join event we just created
.map(|r| {
let (event_id, value) = r?;
serde_json::from_value::<StateEvent>(value)
serde_json::from_value::<StateEvent>(value.clone())
.map(|ev| (event_id, Arc::new(ev)))
.map_err(|e| {
warn!("{}", e);
warn!("{}: {}", value, e);
Error::BadServerResponse("Invalid PDU bytes in send_join response.")
})
})

View file

@ -1,3 +1,5 @@
use image::{imageops::FilterType, GenericImageView};
use crate::{utils, Error, Result};
use std::mem;
@ -99,8 +101,34 @@ impl Media {
}
}
/// Returns width, height of the thumbnail and whether it should be cropped. Returns None when
/// the server should send the original file.
pub fn thumbnail_properties(&self, width: u32, height: u32) -> Option<(u32, u32, bool)> {
match (width, height) {
(0..=32, 0..=32) => Some((32, 32, true)),
(0..=96, 0..=96) => Some((96, 96, true)),
(0..=320, 0..=240) => Some((320, 240, false)),
(0..=640, 0..=480) => Some((640, 480, false)),
(0..=800, 0..=600) => Some((800, 600, false)),
_ => None,
}
}
/// Downloads a file's thumbnail.
///
/// Here's an example on how it works:
///
/// - Client requests an image with width=567, height=567
/// - Server rounds that up to (800, 600), so it doesn't have to save too many thumbnails
/// - Server rounds that up again to (958, 600) to fix the aspect ratio (only for width,height>96)
/// - Server creates the thumbnail and sends it to the user
///
/// For width,height <= 96 the server uses another thumbnailing algorithm which crops the image afterwards.
pub fn get_thumbnail(&self, mxc: String, width: u32, height: u32) -> Result<Option<FileMeta>> {
let (width, height, crop) = self
.thumbnail_properties(width, height)
.unwrap_or((0, 0, false)); // 0, 0 because that's the original file
let mut main_prefix = mxc.as_bytes().to_vec();
main_prefix.push(0xff);
@ -146,6 +174,7 @@ impl Media {
}))
} else if let Some(r) = self.mediaid_file.scan_prefix(&original_prefix).next() {
// Generate a thumbnail
let (key, file) = r?;
let mut parts = key.rsplit(|&b| b == 0xff);
@ -169,7 +198,55 @@ impl Media {
};
if let Ok(image) = image::load_from_memory(&file) {
let thumbnail = image.thumbnail(width, height);
let original_width = image.width();
let original_height = image.height();
if width > original_width || height > original_height {
return Ok(Some(FileMeta {
filename,
content_type,
file: file.to_vec(),
}));
}
let thumbnail = if crop {
image.resize_to_fill(width, height, FilterType::Triangle)
} else {
let (exact_width, exact_height) = {
// Copied from image::dynimage::resize_dimensions
let ratio = u64::from(original_width) * u64::from(height);
let nratio = u64::from(width) * u64::from(original_height);
let use_width = nratio > ratio;
let intermediate = if use_width {
u64::from(original_height) * u64::from(width) / u64::from(width)
} else {
u64::from(original_width) * u64::from(height)
/ u64::from(original_height)
};
if use_width {
if intermediate <= u64::from(::std::u32::MAX) {
(width, intermediate as u32)
} else {
(
(u64::from(width) * u64::from(::std::u32::MAX) / intermediate)
as u32,
::std::u32::MAX,
)
}
} else if intermediate <= u64::from(::std::u32::MAX) {
(intermediate as u32, height)
} else {
(
::std::u32::MAX,
(u64::from(height) * u64::from(::std::u32::MAX) / intermediate)
as u32,
)
}
};
image.thumbnail_exact(exact_width, exact_height)
};
let mut thumbnail_bytes = Vec::new();
thumbnail.write_to(&mut thumbnail_bytes, image::ImageOutputFormat::Png)?;

View file

@ -393,6 +393,7 @@ pub fn send_transaction_message_route<'a>(
let mut pdu_id = pdu.room_id.as_bytes().to_vec();
pdu_id.push(0xff);
pdu_id.extend_from_slice(&count.to_be_bytes());
db.rooms.append_to_state(&pdu_id, &pdu)?;
db.rooms.append_pdu(
&pdu,
&value,
@ -402,7 +403,6 @@ pub fn send_transaction_message_route<'a>(
&db.account_data,
&db.sending,
)?;
db.rooms.append_to_state(&pdu_id, &pdu)?;
}
}
Ok(send_transaction_message::v1::Response {