change: detect multiple datamatrix symbols

This changes how datamatrix symbols are detected in an image. Previously only the first possible symbol was returned. After this change all possible symbols are returned. This addresses the issue presented in #51

src/datamatrix/data_matrix_reader.rs

@@ -87,9 +87,16 @@ impl Reader for DataMatrixReader {
             decoderRXingResult = if let Ok(fnd) = || -> Result<DecoderRXingResult> {
                 let detectorRXingResult =
                     zxing_cpp_detector::detect(image.get_black_matrix(), try_harder, true)?;
-                let decoded = DECODER.decode(detectorRXingResult.getBits())?;
-                points = detectorRXingResult.getPoints().to_vec();
-                Ok(decoded)
+                for symbol in detectorRXingResult {
+                    let decoded = DECODER.decode(symbol.getBits());
+                    if decoded.is_ok() {
+                        points = symbol.getPoints().to_vec();
+                        return Ok(decoded?);
+                    } else {
+                        continue;
+                    }
+                }
+                Err(Exceptions::NOT_FOUND)
             }() {
                 fnd
             } else if try_harder {

src/datamatrix/detector/zxing_cpp_detector/cpp_new_detector.rs

@@ -15,8 +15,8 @@ use std::{cell::RefCell, rc::Rc};
 
 use crate::{
     common::{
-        cpp_essentials::RegressionLineTrait, BitMatrix, DefaultGridSampler, GridSampler,
-        Quadrilateral, Result,
+        cpp_essentials::RegressionLineTrait, BitMatrix, DefaultGridSampler, DetectorRXingResult,
+        GridSampler, Quadrilateral, Result,
     },
     datamatrix::detector::{
         zxing_cpp_detector::{util::intersect, BitMatrixCursorTrait},
@@ -246,7 +246,7 @@ pub fn detect(
     image: &BitMatrix,
     tryHarder: bool,
     tryRotate: bool,
-) -> Result<DatamatrixDetectorResult> {
+) -> Result<Vec<DatamatrixDetectorResult>> {
     // #ifdef PRINT_DEBUG
     // 	LogMatrixWriter lmw(log, image, 1, "dm-log.pnm");
     // //	tryRotate = tryHarder = false;
@@ -257,6 +257,8 @@ pub fn detect(
     // 	tryHarder = false;
     // #endif
 
+    let mut found_symbols = Vec::new();
+
     // a history log to remember where the tracing already passed by to prevent a later trace from doing the same work twice
     let mut history = None;
     if tryHarder {
@@ -323,7 +325,10 @@ pub fn detect(
             // #else
             if let Ok(res) = Scan(&mut tracer, &mut lines) {
                 // if res.isValid(){
-                return Ok(res);
+                //return Ok(res);
+                // i += res.getPoints()[2].distance( res.getPoints()[0] ) as i32;
+                i += MIN_SYMBOL_SIZE as i32;
+                found_symbols.push(res);
                 // }
             }
 
@@ -343,6 +348,10 @@ pub fn detect(
     }
 
     // #ifndef __cpp_impl_coroutine
-    Err(Exceptions::NOT_FOUND)
+    if found_symbols.is_empty() {
+        Err(Exceptions::NOT_FOUND)
+    } else {
+        Ok(found_symbols)
+    }
     // #endif
 }

tests/github_issues.rs

@@ -396,3 +396,77 @@ fn test_issue_49() {
 
     assert_eq!(EXPECTED_ITF_TEXT, itf_result.getText());
 }
+
+#[cfg(feature = "image")]
+#[test]
+fn issue_51_multiple_detection() {
+    use image::DynamicImage;
+    use rxing::{
+        common::HybridBinarizer,
+        multi::{GenericMultipleBarcodeReader, MultipleBarcodeReader},
+        BarcodeFormat, BinaryBitmap, BufferedImageLuminanceSource, DecodeHintType, DecodeHintValue,
+        DecodingHintDictionary, Exceptions, MultiUseMultiFormatReader,
+    };
+
+    const FILE_NAME : &str = "test_resources/blackbox/github_issue_cases/349949736-8e3b9d66-d114-41ca-a8e0-f1332d111827.jpeg";
+
+    let mut hints = DecodingHintDictionary::default();
+
+    let img = DynamicImage::from(
+        image::open(FILE_NAME)
+            .map_err(|e| Exceptions::runtime_with(format!("couldn't read {FILE_NAME}: {e}")))
+            .unwrap()
+            .to_luma8(),
+    );
+    let multi_format_reader = MultiUseMultiFormatReader::default();
+    let mut scanner = GenericMultipleBarcodeReader::new(multi_format_reader);
+
+    hints
+        .entry(DecodeHintType::TRY_HARDER)
+        .or_insert(DecodeHintValue::TryHarder(true));
+
+    let results = scanner
+        .decode_multiple_with_hints(
+            &mut BinaryBitmap::new(HybridBinarizer::new(BufferedImageLuminanceSource::new(img))),
+            &hints,
+        )
+        .expect("must not fault during read image 1");
+
+    assert_eq!(
+        results.len(),
+        1,
+        "must detect 1 barcodes, found: {}",
+        results.len()
+    );
+
+    const FILE_NAME2 : &str = "test_resources/blackbox/github_issue_cases/349949791-1e8b67a7-0994-46fb-bd86-a5f3cd79f0e5.jpeg";
+
+    let mut hints = DecodingHintDictionary::default();
+
+    let img = DynamicImage::from(
+        image::open(FILE_NAME2)
+            .map_err(|e| Exceptions::runtime_with(format!("couldn't read {FILE_NAME2}: {e}")))
+            .unwrap()
+            .to_luma8(),
+    );
+    let multi_format_reader = MultiUseMultiFormatReader::default();
+    let mut scanner = GenericMultipleBarcodeReader::new(multi_format_reader);
+
+    hints
+        .entry(DecodeHintType::TRY_HARDER)
+        .or_insert(DecodeHintValue::TryHarder(true));
+
+    let results = scanner
+        .decode_multiple_with_hints(
+            &mut BinaryBitmap::new(HybridBinarizer::new(BufferedImageLuminanceSource::new(img))),
+            &hints,
+        )
+        .expect("must not fault during read of image 2");
+
+    assert_eq!(
+        results.len(),
+        1,
+        "must detect 1 barcodes, found: {}",
+        results.len()
+    );
+}