keyfork-qrcode: restructure to prefer libzbar and compile with both enabled

Cargo.lock

@@ -1942,6 +1942,7 @@ dependencies = [
 name = "keyfork-qrcode"
 version = "0.1.2"
 dependencies = [
+ "cfg-if",
  "image",
  "keyfork-bug",
  "keyfork-zbar",
@@ -2907,9 +2908,9 @@ dependencies = [
 
 [[package]]
 name = "rqrr"
-version = "0.7.1"
+version = "0.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ad0cd0432e6beb2f86aa4c8af1bb5edcf3c9bcb9d4836facc048664205458575"
+checksum = "f126a9b02152815d84315316e7a759ee18a216d057095d56d19cec68a428b385"
 dependencies = [
  "g2p",
  "image",

crates/qrcode/keyfork-qrcode/Cargo.toml

@@ -15,8 +15,9 @@ decode-backend-zbar = ["dep:keyfork-zbar"]
 
 [dependencies]
 keyfork-bug = { workspace = true }
-keyfork-zbar = { workspace = true, optional = true }
+keyfork-zbar = { workspace = true, optional = true, features = ["image"] }
 image = { workspace = true, default-features = false, features = ["jpeg"] }
-rqrr = { version = "0.7.0", optional = true }
+rqrr = { version = "0.9.0", optional = true }
 thiserror = { workspace = true }
 v4l = { workspace = true }
+cfg-if = "1.0.0"

crates/qrcode/keyfork-qrcode/src/bin/keyfork-qrcode-scan.rs

@@ -5,7 +5,7 @@ use std::time::Duration;
 use keyfork_qrcode::scan_camera;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let output = scan_camera(Duration::from_secs(60 * 10), 0)?;
+    let output = scan_camera(Duration::from_secs(15), 0)?;
     if let Some(scanned_text) = output {
         println!("{scanned_text}");
     }

crates/qrcode/keyfork-qrcode/src/lib.rs

@@ -2,18 +2,17 @@
 
 use keyfork_bug as bug;
 
-use image::ImageReader;
+use image::{ImageBuffer, ImageReader, Luma};
 use std::{
     io::{Cursor, Write},
-    time::{Duration, Instant},
     process::{Command, Stdio},
+    time::{Duration, Instant},
 };
 use v4l::{
     buffer::Type,
-    io::{userptr::Stream, traits::CaptureStream},
+    io::{traits::CaptureStream, userptr::Stream},
     video::Capture,
-    FourCC,
-    Device,
+    Device, FourCC,
 };
 
 /// A QR code could not be generated.
@@ -102,70 +101,117 @@ pub fn qrencode(
 
 const VIDEO_FORMAT_READ_ERROR: &str = "Failed to read video device format";
 
+trait Scanner {
+    fn scan_image(&mut self, image: ImageBuffer<Luma<u8>, Vec<u8>>) -> Option<String>;
+}
+
+#[cfg(feature = "decode-backend-zbar")]
+mod zbar {
+    use super::{ImageBuffer, Luma, Scanner};
+
+    pub struct Zbar {
+        scanner: keyfork_zbar::image_scanner::ImageScanner,
+    }
+
+    impl Zbar {
+        #[allow(dead_code)]
+        pub fn new() -> Self {
+            Self::default()
+        }
+    }
+
+    impl Default for Zbar {
+        fn default() -> Self {
+            Self {
+                scanner: keyfork_zbar::image_scanner::ImageScanner::new(),
+            }
+        }
+    }
+
+    impl Scanner for Zbar {
+        fn scan_image(
+            &mut self,
+            image: ImageBuffer<Luma<u8>, Vec<u8>>,
+        ) -> Option<String> {
+            let image = keyfork_zbar::image::Image::from(image);
+            self.scanner.scan_image(&image).into_iter().next().map(|symbol| {
+                String::from_utf8_lossy(symbol.data()).into()
+            })
+        }
+    }
+}
+
+#[cfg(feature = "decode-backend-rqrr")]
+mod rqrr {
+    use super::{ImageBuffer, Luma, Scanner};
+
+    pub struct Rqrr;
+
+    impl Scanner for Rqrr {
+        fn scan_image(
+            &mut self,
+            image: ImageBuffer<Luma<u8>, Vec<u8>>,
+        ) -> Option<String> {
+            let mut image = rqrr::PreparedImage::prepare(image);
+            for grid in image.detect_grids() {
+                if let Ok((_, content)) = grid.decode() {
+                    return Some(content);
+                }
+            }
+            None
+        }
+    }
+}
+
+#[allow(dead_code)]
+fn dbg_elapsed(count: u64, instant: Instant) {
+    let elapsed = instant.elapsed().as_secs();
+    let framerate = count as f64 / elapsed as f64;
+    eprintln!("framerate: {count}/{elapsed} = {framerate}");
+}
+
 /// Continuously scan the `index`-th camera for a QR code.
 ///
 /// # Errors
 ///
 /// The function may return an error if the hardware is unable to scan video or if an image could
 /// not be decoded.
-#[cfg(feature = "decode-backend-rqrr")]
 pub fn scan_camera(timeout: Duration, index: usize) -> Result<Option<String>, QRCodeScanError> {
     let device = Device::new(index)?;
-    let mut fmt = device.format().unwrap_or_else(bug::panic!(VIDEO_FORMAT_READ_ERROR));
+    let mut fmt = device
+        .format()
+        .unwrap_or_else(bug::panic!(VIDEO_FORMAT_READ_ERROR));
     fmt.fourcc = FourCC::new(b"MPG1");
     device.set_format(&fmt)?;
     let mut stream = Stream::with_buffers(&device, Type::VideoCapture, 4)?;
     let start = Instant::now();
+    cfg_if::cfg_if! {
+        if #[cfg(feature = "decode-backend-zbar")] {
+            let mut scanner = zbar::Zbar::default();
+        } else if #[cfg(feature = "decode-backend-rqrr")] {
+            let mut scanner = rqrr::Rqrr;
+        } else {
+            unimplemented!("neither decode-backend-zbar nor decode-backend-rqrr were selected")
+        }
+    };
 
-    while Instant::now()
-        .duration_since(start)
-        < timeout
-    {
+    #[allow(unused)]
+    let mut count = 0;
+
+    while Instant::now().duration_since(start) < timeout {
+        count += 1;
         let (buffer, _) = stream.next()?;
         let image = ImageReader::new(Cursor::new(buffer))
             .with_guessed_format()?
             .decode()?
             .to_luma8();
-        let mut image = rqrr::PreparedImage::prepare(image);
-        for grid in image.detect_grids() {
-            if let Ok((_, content)) = grid.decode() {
-                return Ok(Some(content))
-            }
-        }
-    }
-
-    Ok(None)
-}
-
-/// Continuously scan the `index`-th camera for a QR code.
-///
-/// # Errors
-///
-/// The function may return an error if the hardware is unable to scan video or if an image could
-/// not be decoded.
-#[cfg(feature = "decode-backend-zbar")]
-pub fn scan_camera(timeout: Duration, index: usize) -> Result<Option<String>, QRCodeScanError> {
-    let device = Device::new(index)?;
-    let mut fmt = device.format().unwrap_or_else(bug::panic!(VIDEO_FORMAT_READ_ERROR));
-    fmt.fourcc = FourCC::new(b"MPG1");
-    device.set_format(&fmt)?;
-    let mut stream = Stream::with_buffers(&device, Type::VideoCapture, 4)?;
-    let start = Instant::now();
-    let mut scanner = keyfork_zbar::image_scanner::ImageScanner::new();
-
-    while Instant::now()
-        .duration_since(start)
-        < timeout
-    {
-        let (buffer, _) = stream.next()?;
-        let image = ImageReader::new(Cursor::new(buffer))
-            .with_guessed_format()?
-            .decode()?;
-        let image = keyfork_zbar::image::Image::from(image);
-        for symbol in scanner.scan_image(&image) {
-            return Ok(Some(String::from_utf8_lossy(symbol.data()).to_string()));
+        if let Some(content) = scanner.scan_image(image) {
+            // dbg_elapsed(count, start);
+            return Ok(Some(content));
         }
     }
 
+    // dbg_elapsed(count, start);
+
     Ok(None)
 }

crates/qrcode/keyfork-zbar/src/image.rs

@@ -58,7 +58,7 @@ impl Image {
 #[cfg(feature = "image")]
 mod impls {
     use super::*;
-    use image::{DynamicImage, GenericImageView};
+    use image::{DynamicImage, GenericImageView, ImageBuffer, Luma};
 
     impl From<DynamicImage> for Image {
         fn from(value: DynamicImage) -> Self {
@@ -70,6 +70,17 @@ mod impls {
             image
         }
     }
+
+    impl From<ImageBuffer<Luma<u8>, Vec<u8>>> for Image {
+        fn from(value: ImageBuffer<Luma<u8>, Vec<u8>>) -> Self {
+            let mut image = Self::alloc();
+            let (width, height) = value.dimensions();
+            image.set_size(width, height);
+            image.set_format(b"Y800");
+            image.set_data(value.into_raw());
+            image
+        }
+    }
 }
 
 impl Drop for Image {