winprint
A crate for printing to a Windows printer device using Windows API.
About Safety
This crate interfaces with several Windows API functions, necessitating the use of unsafe code blocks. Nevertheless, this crate is designed to be safe and sound to use. If you find any case that will break safety or soundness, please report it as a bug.
Development
Testing on Windows
Just run cargo test on a Windows machine, null printer will be automatically created and used for testing. The tests cover basic printer operations like getting printer information, writing to the printer, etc.
Three visual regression tests also run under the test-utils feature (plus
pdfium for the PDF test):
tests/visual_regression_pdfium.rs—PdfiumPrintertests/visual_regression_xps.rs—XpsPrintertests/visual_regression_image.rs—ImagePrinter
Each prints the matching origin file from
test_data/visual_regression/<kind>/origin.* through a virtual Microsoft PWG
Raster printer, decodes the PWG bitstream, and SSIM-compares each page
against the corresponding expected.tiff rendered by a deliberately
different renderer (Poppler for PDF, libgxps for XPS, ImageMagick for
Image). That second-source property means a shared regression between
renderer and baseline would have to coincidentally produce matching pixels
for the test to silently pass. Set WINPRINT_DUMP_DIR=<path> to have failing
tests dump the actual/expected page PNGs for inspection.
Day-to-day development never needs to regenerate these fixtures — the repo
ships them and cargo test consumes them as-is. If you do need to rebuild
them (e.g. after tweaking the source drawing or bumping a baseline renderer),
run python utils/gen_visual_regression_data/run.py; see the README in that
directory for tool prerequisites and determinism guarantees.
For testing with multiple features in one command, cargo hack may be used for convenience.
Testing on Linux Host
Since this crate is designed for Windows, it cannot be directly tested on a Linux host. However, a script is provided to run the test suite inside a Windows 11 VM on a Linux host.
Prerequisites: Docker with BuildKit, KVM support (/dev/kvm), and sufficient disk space & memory for the VM.
The script will spins up a Windows VM and then run the test suite inside it. On first run it initializes the VM (very slowly). Subsequent runs reuse the cached VM state (relatively fast).
To clear the cached VM state, run with --destroy flag:
License
Licensed under BSD 3 Clause
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, shall be licensed as BSD 3 Clause, without any additional terms or conditions.