Fix WeChatQRCode wrapper: replace static factory with constructor, add Point2f[][] overload, expand tests

src/OpenCvSharp/Internal/PInvoke/NativeMethods/NativeMethods_wechat_qrcode.cs

@@ -15,9 +15,13 @@ public static extern ExceptionStatus wechat_qrcode_create1([MarshalAs(UnmanagedT
         [MarshalAs(UnmanagedType.LPStr)] string detector_caffe_model_path,
         [MarshalAs(UnmanagedType.LPStr)] string super_resolution_prototxt_path ,
         [MarshalAs(UnmanagedType.LPStr)] string super_resolution_caffe_model_path,out IntPtr ptr);
+
     [DllImport(DllExtern, CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
     public static extern ExceptionStatus wechat_qrcode_WeChatQRCode_detectAndDecode(IntPtr obj, IntPtr inputImage, IntPtr points, IntPtr texts);
 
+    [DllImport(DllExtern, CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+    public static extern ExceptionStatus wechat_qrcode_WeChatQRCode_detectAndDecode_points(IntPtr obj, IntPtr inputImage, IntPtr points, IntPtr texts);
+
 
     [DllImport(DllExtern, CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
     public static extern ExceptionStatus wechat_qrcode_delete(IntPtr ptr);

src/OpenCvSharp/Modules/wechat_qrcode/WeChatQRCode.cs

@@ -11,54 +11,81 @@ namespace OpenCvSharp;
 /// </summary>
 public class WeChatQRCode : CvObject
 {
-    internal WeChatQRCode(IntPtr ptr)
-    {
-        SetSafeHandle(new OpenCvPtrSafeHandle(ptr, ownsHandle: true,
-            releaseAction: h => NativeMethods.HandleException(NativeMethods.wechat_qrcode_delete(h))));
-    }
-
     /// <summary>
     /// Initialize the WeChatQRCode.
     /// It includes two models, which are packaged with caffe format.
     /// Therefore, there are prototxt and caffe models (In total, four paramenters).
+    /// Pass empty strings to create a detector without neural network models.
     /// </summary>
     /// <param name="detectorPrototxtPath">prototxt file path for the detector</param>
     /// <param name="detectorCaffeModelPath">caffe model file path for the detector</param>
     /// <param name="superResolutionPrototxtPath">prototxt file path for the super resolution model</param>
     /// <param name="superResolutionCaffeModelPath">caffe file path for the super resolution model</param>
-    /// <returns></returns>
-    /// <exception cref="ArgumentException"></exception>
-    public static WeChatQRCode Create(
-        string detectorPrototxtPath,
-        string detectorCaffeModelPath,
-        string superResolutionPrototxtPath,
-        string superResolutionCaffeModelPath)
+    public WeChatQRCode(
+        string detectorPrototxtPath = "",
+        string detectorCaffeModelPath = "",
+        string superResolutionPrototxtPath = "",
+        string superResolutionCaffeModelPath = "")
     {
-        if (string.IsNullOrWhiteSpace(detectorPrototxtPath))
-            throw new ArgumentException("empty string", nameof(detectorPrototxtPath));
-        if (string.IsNullOrWhiteSpace(detectorCaffeModelPath))
-            throw new ArgumentException("empty string", nameof(detectorCaffeModelPath));
-        if (string.IsNullOrWhiteSpace(superResolutionPrototxtPath))
-            throw new ArgumentException("empty string", nameof(superResolutionPrototxtPath));
-        if (string.IsNullOrWhiteSpace(superResolutionCaffeModelPath))
-            throw new ArgumentException("empty string", nameof(superResolutionCaffeModelPath));
+        if (detectorPrototxtPath is null)
+            throw new ArgumentNullException(nameof(detectorPrototxtPath));
+        if (detectorCaffeModelPath is null)
+            throw new ArgumentNullException(nameof(detectorCaffeModelPath));
+        if (superResolutionPrototxtPath is null)
+            throw new ArgumentNullException(nameof(superResolutionPrototxtPath));
+        if (superResolutionCaffeModelPath is null)
+            throw new ArgumentNullException(nameof(superResolutionCaffeModelPath));
 
         NativeMethods.HandleException(
             NativeMethods.wechat_qrcode_create1(
                 detectorPrototxtPath, detectorCaffeModelPath, superResolutionPrototxtPath, superResolutionCaffeModelPath,
                 out var ptr));
 
-        return new WeChatQRCode(ptr);
+        SetSafeHandle(new OpenCvPtrSafeHandle(ptr, ownsHandle: true,
+            releaseAction: h => NativeMethods.HandleException(NativeMethods.wechat_qrcode_delete(h))));
     }
 
     /// <summary>
     /// Both detects and decodes QR code.
     /// To simplify the usage, there is a only API: detectAndDecode
     /// </summary>
     /// <param name="inputImage">supports grayscale or color(BGR) image.</param>
-    /// <param name="bbox">optional output array of vertices of the found QR code quadrangle.Will be empty if not found.</param>
-    /// <param name="results">list of decoded string.</param>
-    public void DetectAndDecode(InputArray inputImage, out Mat[] bbox, out string[] results)
+    /// <param name="points">
+    /// output array of vertices of the found QR code quadrangles.
+    /// Each element is an array of 4 <see cref="Point2f"/> representing the corners of one detected QR code.
+    /// Will be empty if not found.
+    /// </param>
+    /// <returns>list of decoded string.</returns>
+    public string[] DetectAndDecode(InputArray inputImage, out Point2f[][] points)
+    {
+        if (inputImage is null)
+            throw new ArgumentNullException(nameof(inputImage));
+        inputImage.ThrowIfDisposed();
+
+        using var pointsVec = new VectorOfVectorPoint2f();
+        using var texts = new VectorOfString();
+        NativeMethods.HandleException(
+            NativeMethods.wechat_qrcode_WeChatQRCode_detectAndDecode_points(
+                CvPtr, inputImage.CvPtr, pointsVec.CvPtr, texts.CvPtr));
+
+        points = pointsVec.ToArray();
+        GC.KeepAlive(this);
+        GC.KeepAlive(inputImage);
+        return texts.ToArray();
+    }
+
+    /// <summary>
+    /// Both detects and decodes QR code.
+    /// Returns each QR code's corner points as a raw <see cref="Mat"/> (4x2, CV_32FC1),
+    /// which can be passed directly to other OpenCV functions.
+    /// </summary>
+    /// <param name="inputImage">supports grayscale or color(BGR) image.</param>
+    /// <param name="bbox">
+    /// output array of vertices of the found QR code quadrangles as raw <see cref="Mat"/> (4x2, CV_32FC1).
+    /// Will be empty if not found.
+    /// </param>
+    /// <returns>list of decoded string.</returns>
+    public string[] DetectAndDecodeRaw(InputArray inputImage, out Mat[] bbox)
     {
         if (inputImage is null)
             throw new ArgumentNullException(nameof(inputImage));
@@ -71,9 +98,8 @@ public void DetectAndDecode(InputArray inputImage, out Mat[] bbox, out string[]
                 CvPtr, inputImage.CvPtr, bboxVec.CvPtr, texts.CvPtr));
 
         bbox = bboxVec.ToArray();
-        results = texts.ToArray();
         GC.KeepAlive(this);
         GC.KeepAlive(inputImage);
+        return texts.ToArray();
     }
-
-    }
+}

src/OpenCvSharpExtern/wechat_qrcode.h

@@ -3,6 +3,7 @@
 #ifndef NO_CONTRIB
 
 #include "include_opencv.h"
+
 CVAPI(ExceptionStatus) wechat_qrcode_create1(const char *detector_prototxt_path,
     const char *detector_caffe_model_path ,
     const char *super_resolution_prototxt_path ,
@@ -14,6 +15,7 @@ CVAPI(ExceptionStatus) wechat_qrcode_create1(const char *detector_prototxt_path,
         super_resolution_prototxt_path, super_resolution_caffe_model_path);
     END_WRAP
 }
+
 CVAPI(ExceptionStatus) wechat_qrcode_delete(cv::wechat_qrcode::WeChatQRCode* obj)
 {
     BEGIN_WRAP
@@ -29,4 +31,20 @@ CVAPI(ExceptionStatus) wechat_qrcode_WeChatQRCode_detectAndDecode(cv::wechat_qrc
     END_WRAP
 }
 
+CVAPI(ExceptionStatus) wechat_qrcode_WeChatQRCode_detectAndDecode_points(cv::wechat_qrcode::WeChatQRCode* obj, cv::_InputArray* inputImage, std::vector<std::vector<cv::Point2f> >* points, std::vector<std::string>* texts)
+{
+    BEGIN_WRAP
+    std::vector<cv::Mat> matPoints;
+    *texts = obj->detectAndDecode(*inputImage, matPoints);
+    points->clear();
+    for (const auto& mat : matPoints)
+    {
+        std::vector<cv::Point2f> pts;
+        for (int i = 0; i < mat.rows; i++)
+            pts.emplace_back(mat.at<float>(i, 0), mat.at<float>(i, 1));
+        points->push_back(std::move(pts));
+    }
+    END_WRAP
+}
+
 #endif // NO_CONTRIB

test/OpenCvSharp.Tests/wechat_qrcode/WeChatQRCodeTest.cs

@@ -2,33 +2,208 @@
 
 namespace OpenCvSharp.Tests.WeChatQRCode;
 
+#pragma warning disable CA1707 // Identifiers should not contain underscores
+
 public class WeChatQRCodeTest(ITestOutputHelper testOutputHelper) : TestBase
 {
-    private const string WechatQcodeDetectorPrototxtPath = "_data/wechat_qrcode/detect.prototxt";
-    private const string WechatQcodeDetectorCaffeModelPath = "_data/wechat_qrcode/detect.caffemodel";
-    private const string WechatQcodeSuperResolutionPrototxtPath = "_data/wechat_qrcode/sr.prototxt";
-    private const string WechatQcodeSuperResolutionCaffeModelPath = "_data/wechat_qrcode/sr.caffemodel";
+    private const string DetectorPrototxtPath = "_data/wechat_qrcode/detect.prototxt";
+    private const string DetectorCaffeModelPath = "_data/wechat_qrcode/detect.caffemodel";
+    private const string SuperResolutionPrototxtPath = "_data/wechat_qrcode/sr.prototxt";
+    private const string SuperResolutionCaffeModelPath = "_data/wechat_qrcode/sr.caffemodel";
+
+    private static readonly string[] ExpectedMultiQRTexts =
+    [
+        "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!\"#$%&'()*+,-./:;<=>?@[]^_`{|}",
+        "Helloこんにちは你好안녕하세요"
+    ];
+
+    /// <summary>
+    /// Requires no model files. Verifies the no-arg constructor succeeds.
+    /// </summary>
+    [Fact]
+    public void Constructor_Default_DoesNotThrow()
+    {
+        using var qr = new OpenCvSharp.WeChatQRCode();
+    }
+
+    /// <summary>
+    /// Passing null for any string argument must throw ArgumentNullException.
+    /// </summary>
+    [Theory]
+    [InlineData(null, "", "", "")]
+    [InlineData("", null, "", "")]
+    [InlineData("", "", null, "")]
+    [InlineData("", "", "", null)]
+    public void Constructor_NullArguments_ThrowsArgumentNullException(
+        string? a, string? b, string? c, string? d)
+    {
+        Assert.Throws<ArgumentNullException>(() => new OpenCvSharp.WeChatQRCode(a!, b!, c!, d!));
+    }
+
+    /// <summary>
+    /// DetectAndDecode must throw ArgumentNullException when inputImage is null.
+    /// Does not require model files.
+    /// </summary>
+    [Fact]
+    public void DetectAndDecode_NullInput_ThrowsArgumentNullException()
+    {
+        using var qr = new OpenCvSharp.WeChatQRCode();
+        Assert.Throws<ArgumentNullException>(() => qr.DetectAndDecode(null!, out _));
+    }
+
+    /// <summary>
+    /// Grayscale image containing 2 QR codes. Both must be decoded correctly.
+    /// </summary>
+    [Fact]
+    public void DetectAndDecode_WithModels_MultiQR_ReturnsTexts()
+    {
+        SkipIfModelFilesNotFound();
+
+        using var qr = CreateWithModels();
+        using var src = Cv2.ImRead("_data/image/qr_multi.png", ImreadModes.Grayscale);
 
+        var texts = qr.DetectAndDecode(src, out _);
+
+        Assert.Equal(2, texts.Length);
+        foreach (var text in texts)
+        {
+            testOutputHelper.WriteLine(text);
+            Assert.NotEmpty(text);
+        }
+        Assert.Equal(
+            ExpectedMultiQRTexts.OrderBy(x => x),
+            texts.OrderBy(x => x));
+    }
+
+    /// <summary>
+    /// Point2f[][] overload must return one array of 4 corners per detected QR code.
+    /// </summary>
     [Fact]
-    public void WechatQrcodeDecodeRun()
+    public void DetectAndDecode_WithModels_Point2fOverload_Returns4CornersPerQR()
     {
-        Assert.True(File.Exists(WechatQcodeDetectorPrototxtPath), $"DetectorPrototxt '{WechatQcodeDetectorPrototxtPath}' not found");
-        Assert.True(File.Exists(WechatQcodeDetectorCaffeModelPath), $"DetectorcaffeModel '{WechatQcodeDetectorCaffeModelPath}' not found");
-        Assert.True(File.Exists(WechatQcodeSuperResolutionPrototxtPath), $"SuperResolutionprototxt '{WechatQcodeSuperResolutionPrototxtPath}' not found");
-        Assert.True(File.Exists(WechatQcodeSuperResolutionCaffeModelPath), $"SuperResolutionCaffe_model '{WechatQcodeSuperResolutionCaffeModelPath}' not found");
+        SkipIfModelFilesNotFound();
+
+        using var qr = CreateWithModels();
+        using var src = Cv2.ImRead("_data/image/qr_multi.png", ImreadModes.Grayscale);
+
+        var texts = qr.DetectAndDecode(src, out var points);
+
+        Assert.Equal(2, texts.Length);
+        Assert.Equal(2, points.Length);
+        foreach (var corners in points)
+        {
+            Assert.Equal(4, corners.Length);
+        }
+    }
+
+    /// <summary>
+    /// Mat[] overload (DetectAndDecodeRaw) must return one non-empty Mat per detected QR code,
+    /// with 4 rows (corners) and 2 columns (x, y).
+    /// </summary>
+    [Fact]
+    public void DetectAndDecodeRaw_WithModels_MatOverload_ReturnsCorrectShape()
+    {
+        SkipIfModelFilesNotFound();
+
+        using var qr = CreateWithModels();
+        using var src = Cv2.ImRead("_data/image/qr_multi.png", ImreadModes.Grayscale);
 
-        using var wechatQrcode = OpenCvSharp.WeChatQRCode.Create(
-            WechatQcodeDetectorPrototxtPath, WechatQcodeDetectorCaffeModelPath,
-            WechatQcodeSuperResolutionPrototxtPath, WechatQcodeSuperResolutionCaffeModelPath);
-        using var src = Cv2.ImRead(@"_data/image/qr_multi.png", ImreadModes.Grayscale);
+        var texts = qr.DetectAndDecodeRaw(src, out var bbox);
 
-        wechatQrcode.DetectAndDecode(src, out var rects, out var texts);
-        Assert.NotEmpty(texts);
         Assert.Equal(2, texts.Length);
-        foreach (var item in texts)
+        Assert.Equal(2, bbox.Length);
+        foreach (var mat in bbox)
         {
-            testOutputHelper.WriteLine(item);
-            Assert.NotEmpty(item);
+            Assert.False(mat.Empty());
+            // each corner mat stores 4 (x,y) values → Total() * Channels() == 8
+            Assert.Equal(8, (int)(mat.Total() * mat.Channels()));
         }
     }
+
+    /// <summary>
+    /// QR code containing single-byte (ASCII) characters must decode to the expected string.
+    /// </summary>
+    [Fact]
+    public void DetectAndDecode_WithModels_SinglebyteLetters()
+    {
+        SkipIfModelFilesNotFound();
+
+        using var qr = CreateWithModels();
+        using var src = Cv2.ImRead("_data/image/qr_singlebyte_letters.png", ImreadModes.Grayscale);
+
+        var texts = qr.DetectAndDecode(src, out _);
+
+        Assert.Single(texts);
+        Assert.Equal(
+            "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ!\"#$%&'()*+,-./:;<=>?@[]^_`{|}",
+            texts[0]);
+    }
+
+    /// <summary>
+    /// QR code containing multibyte (Unicode) characters must decode to the expected string.
+    /// </summary>
+    [Fact]
+    public void DetectAndDecode_WithModels_MultibyteLetters()
+    {
+        SkipIfModelFilesNotFound();
+
+        using var qr = CreateWithModels();
+        using var src = Cv2.ImRead("_data/image/qr_multibyte_letters.png", ImreadModes.Grayscale);
+
+        var texts = qr.DetectAndDecode(src, out _);
+
+        Assert.Single(texts);
+        Assert.Equal("Helloこんにちは你好안녕하세요", texts[0]);
+    }
+
+    /// <summary>
+    /// detectAndDecode accepts a color (BGR) image in addition to grayscale.
+    /// The result must be identical to processing the grayscale version.
+    /// </summary>
+    [Fact]
+    public void DetectAndDecode_WithModels_ColorBGRImage_DetectsQR()
+    {
+        SkipIfModelFilesNotFound();
+
+        using var qr = CreateWithModels();
+        using var colorSrc = Cv2.ImRead("_data/image/qr_multi.png", ImreadModes.Color);
+
+        var texts = qr.DetectAndDecode(colorSrc, out _);
+
+        Assert.Equal(2, texts.Length);
+        Assert.Equal(
+            ExpectedMultiQRTexts.OrderBy(x => x),
+            texts.OrderBy(x => x));
+    }
+
+    /// <summary>
+    /// An image that contains no QR codes must yield empty result arrays.
+    /// </summary>
+    [Fact]
+    public void DetectAndDecode_WithModels_NoQRCode_ReturnsEmpty()
+    {
+        SkipIfModelFilesNotFound();
+
+        using var qr = CreateWithModels();
+        using var src = LoadImage("lenna.png", ImreadModes.Grayscale);
+
+        var texts = qr.DetectAndDecode(src, out var points);
+
+        Assert.Empty(texts);
+        Assert.Empty(points);
+    }
+
+    // -------------------------------------------------------------------------
+
+    private static OpenCvSharp.WeChatQRCode CreateWithModels() =>
+        new(DetectorPrototxtPath, DetectorCaffeModelPath,
+            SuperResolutionPrototxtPath, SuperResolutionCaffeModelPath);
+
+    private static void SkipIfModelFilesNotFound()
+    {
+        Assert.True(File.Exists(DetectorPrototxtPath),       $"Model file not found: '{DetectorPrototxtPath}'");
+        Assert.True(File.Exists(DetectorCaffeModelPath),     $"Model file not found: '{DetectorCaffeModelPath}'");
+        Assert.True(File.Exists(SuperResolutionPrototxtPath),    $"Model file not found: '{SuperResolutionPrototxtPath}'");
+        Assert.True(File.Exists(SuperResolutionCaffeModelPath),  $"Model file not found: '{SuperResolutionCaffeModelPath}'");
+    }
 }