This crate provides raster printing capability for Brother P-Touch QL series label printers connected as USB device.
It allows to print programmatically generated label images.
Bunch of labels are represented as a struct implemnting Iterator trait which allows lazy generation.
The label data is represented as a two dimensional array, Vec<Vec<u8>>, conversion from other image formats can be easily done.
This driver supports printing with multiple printers at a same time.
- Support USB connection
- Print multiple labels at once.
- High resolution printing support.
- [] Two colors printing support.
- Support multiple printers on one computer.
Choose a media tape you want to use and install it in the printer, then specify the matching media.
let media = ptouch::Media::Continuous(ContinuousType::Continuous62);Theare are two types of media tape, Continuous and DieCut, each one has several size variations. In this example we choose Continuous tape with 62mm width.
You can inspect USB ports by lsusb -v which will show something like follows where iProduct and iSerial are what we need.
Bus 001 Device 003: ID 04f9:209b Brother Industries, Ltd
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x04f9 Brother Industries, Ltd
idProduct 0x209b
bcdDevice 1.00
iManufacturer 1 Brother
iProduct 2 QL-800
iSerial 3 000G0Z000000
With these information we can initialize our configurations as follows.
let config: Config = Config::new(Model::QL800, "000G0Z000000".to_string(), media)
.high_resolution(false)
.cut_at_end(true)
.two_colors(false)
.enable_auto_cut(1);These are default settings, high_resolution and two_colors options work but you need to provide appropriate data.
This part is tricky, since this crate provides only printing capabilities, label data must be prepared with compatible format. As shown in the printer manual, QL series expects image data with a 1bit index bitmap split by lines in an appropriate orders. Please see the manual for more detail.
In this example we create an image data with 720 x 400 px size by using an application. Then using image crate to read and convert it to a grayscale data. Then using step_filter_normal function, which is supplied with this crate, we binalize and pack bits 90 bytes width vector data.
let file = "examples/rust-logo.png";
let image: image::DynamicImage = image::open(file).unwrap();
let (_, length) = image.dimensions();
let gray = image.grayscale();
let mut buffer = image::DynamicImage::new_luma8(ptouch::WIDE_PRINTER_WIDTH, length);
buffer.invert();
buffer.copy_from(&gray, 0, 0).unwrap();
buffer.invert();
let bytes = buffer.to_bytes();
let bw = ptouch::utils::step_filter_normal(80, length, bytes);In this crate, the width of image data must be 720px, which is the number of pins the printer have. The length varies depending on the label media. For the DieCut labels, there is a specif value. In case of the Continous labels, you can choose any length between 150px to 11811px for normal resolution (for 300 dpi). If you are specifying high_resolution or two_clolors options, it must be halved. After determing the size, place your contets in the area where actual labels go through. If you are using 62mm media, full width will be printed. But for 29mm media, you need to give an offset of 408 pixel on the left side then place content in 306 pixel width. You can check the details of media specification in the manual.
Once you get the bitmap data, you can supply them as a Vec.
match Printer::new(config) {
Ok(printer) => {
printer.print(vec![bw.clone()]).unwrap();
}
Err(err) => panic!("Printer Error {}", err),
}If the configuration value is invalid the new function will return an error.
Note: When sending a long label, rusb will timeout and return error. The maximum length is around 1000mm for continuous labels.
The following models are tested by myself.
- QL-720NW
- QL-800
- QL-820NWB
Anothre printers listed in the ptouch::Model should also work but we might need to some tweaking.
In the example, there is a small tool to read the printer status.
RUST_LOG=debug cargo run --example read_status
This will show something like follows.
[2020-10-27T06:05:45Z DEBUG ptouch::printer] Raw status code: [80, 20, 42, 34, 38, 30, 0, 0, 0, 0, 1D, A, 0, 0, 14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0]
[2020-10-27T06:05:45Z DEBUG ptouch::printer] Parsed Status struct: Status { model: QL800, error: UnknownError(0), media: Some(Continuous(Continuous29)), mode: 0, status_type: ReplyToRequest, phase: Receiving, notification: NotAvailable }
Some gathered data are saved in printer_status.txt.
- [] Better error handling and reporting, what to do when label ends ?
- [] Binalization with dithering support
- [] Binalization with two colors support
For my system with ubuntu 18.04 on Raspberry Pi 4, I got an error about permission to /dev/usb/lp0. To fix that I needed to add something like follows.
Add the current user to plugdev group.
$ sudo gpasswd -a $USER plugdevAdd a new rule as /etc/udev/udev/rules.d/65-ptouch.rules. Here the number in filename must be higher than 60 to be effective.
SUBSYSTEMS=="usb", ATTRS{idVendor}=="04f9", ATTRS{idProduct}=="209b|209c|209d", MODE="664", GROUP="plugdev"
Reload the rules.
sudo udevadm trigger
sudo udevadm control --reload-rules
Also if you are using Ubuntu 21.10, we need to install extra packages as follows.
sudo apt install linux-modules-extra-raspi
sudo reboot
https://gill.net.in/posts/reverse-engineering-a-usb-device-with-rust/
MIT