biørn 0b2051cda4 feat: better quality of image recoding (#8682)
this PR introduces a better quality of image recoding, consuming max.
900k instead of 500k (average is much less). the PR roughly doubles the
number of pixels sent in an image.

the old 1280px were set 8 years ago,
data and storage has improved since then,
so it is reasonable to double the number if pixels used for sending an
image.

this will be a quality boost for many images,
while not resulting in a doubled size for all of them; many images will
only be a little larger in bytes, see test.

we could always go higher, of course, but it comes at costs of relay
storage and data, so we stay conservative, even in that increase.

the "worse quality" setting is not adapted on purpose, there we really
stay at the end of what is bearable :)

cc @adbenitez

---------

Co-authored-by: l <link2xt@testrun.org>
2026-09-12 13:44:02 +00:00
2026-09-10 17:53:15 +00:00
2026-03-22 06:23:58 +00:00
2026-09-11 21:14:09 +00:00
2026-09-11 21:14:09 +00:00
2026-09-11 21:14:09 +00:00
2023-07-04 00:52:31 +02:00
2023-10-29 13:13:44 +00:00

Chatmail logo

Rust CI dependency status

The chatmail core library implements low-level network and encryption protocols, integrated by many chat bots and higher level applications, allowing to securely participate in the globally scaled e-mail server network. We provide reproducibly-built deltachat-rpc-server static binaries that offer a stdio-based high-level JSON-RPC API for instant messaging purposes.

The following protocols are handled without requiring API users to know much about them:

Installing Rust and Cargo

To download and install the official compiler for the Rust programming language, and the Cargo package manager, run the command in your user environment:

$ curl https://sh.rustup.rs -sSf | sh

On Windows, you may need to also install Perl to be able to compile deltachat-core.

Using the CLI client

Compile and run the command line utility, using cargo:

$ cargo run --locked -p deltachat-repl -- ~/profile-db

where ~/profile-db is the database file. The utility will create it if it does not exist.

Optionally, install deltachat-repl binary with

$ cargo install --locked --path deltachat-repl/

and run as

$ deltachat-repl ~/profile-db

Configure your account (if not already configured):

Chatmail is awaiting your commands.
> set addr your@email.org
> set mail_pw yourpassword
> configure

Connect to your mail server (if already configured):

> connect

Export your public key to a vCard file:

> make-vcard my.vcard 1

Create contacts by address or vCard file:

> addcontact yourfriends@email.org
> import-vcard key-contact.vcard

List contacts:

> listcontacts
Contact#Contact#11: key-contact@email.org <key-contact@email.org>
Contact#Contact#Self: Me √ <your@email.org>
2 key contacts.
Contact#Contact#10: yourfriends@email.org <yourfriends@email.org>
1 address contacts.

Create a chat with your friend and send a message:

> createchat 10
Single#Chat#12 created successfully.
> chat 12
Selecting chat Chat#12
Single#Chat#12: yourfriends@email.org [yourfriends@email.org] Icon: profile-db-blobs/4138c52e5bc1c576cda7dd44d088c07.png
0 messages.
81.252µs to create this list, 123.625µs to mark all messages as noticed.
> send hi

List messages when inside a chat:

> chat

For more commands type:

> help

Installing libdeltachat system wide

$ git clone https://github.com/chatmail/core.git
$ cd deltachat-core-rust
$ cmake -B build . -DCMAKE_INSTALL_PREFIX=/usr
$ cmake --build build
$ sudo cmake --install build

Development

# run tests
$ cargo test --all
# build c-ffi
$ cargo build -p deltachat_ffi --release

Debugging environment variables

  • DCC_MIME_DEBUG: if set outgoing and incoming message will be printed

  • RUST_LOG=async_imap=trace,async_smtp=trace: enable IMAP and SMTP tracing in addition to info messages.

Expensive tests

Some tests are expensive and marked with #[ignore], to run these use the --ignored argument to the test binary (not to cargo itself):

$ cargo test -- --ignored

Fuzzing

Install cargo-bolero with

$ cargo install --locked cargo-bolero

Run fuzzing tests with

$ cd fuzz
$ cargo bolero test fuzz_mailparse -s NONE

Corpus is created at fuzz/fuzz_targets/corpus, you can add initial inputs there. For fuzz_mailparse target corpus can be populated with ../test-data/message/*.eml.

Features

  • vendored: When using Openssl for TLS, this bundles a vendored version.

Update Provider Data

To add the updates from the provider-db to the core, check line REV= inside ./scripts/update-provider-database.sh and then run the script.

Language bindings and frontend projects

Language bindings are available for:

The following "frontend" projects make use of the Rust-library or its language bindings:

Description
Chatmail Rust Core library, used by Android/iOS/desktop chatmail apps, bindings and bots 📧
Readme MPL-2.0 85 MiB
Languages
Rust 75.4%
Tcl 9.8%
Python 8.8%
C 4.8%
TypeScript 0.3%
Other 0.8%