[C# api] add c sharp api for fastdeploy (#1246)

* add c sharp api for fastdeploy

* update accroding to c apis

* add cmakelist for c sharp api

* add cmakelists for c sharp

* fix cmakelists

* fix cmakelists

* add c sharp api for fastdeploy

* add ppyoloe demo

* add ppyoloe demo

* modify demo namespace code

* add readme

* fix format

* format code

* fix doc

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Co-authored-by: heliqi <1101791222@qq.com>

csharp/fastdeploy/vision/visualize.cs

@@ -0,0 +1,45 @@
+// Copyright (c) 2023 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Collections.Generic;
+using OpenCvSharp;
+using fastdeploy.types_internal_c;
+
+namespace fastdeploy {
+namespace vision {
+
+public class Visualize {
+
+  public static Mat VisDetection(Mat im, DetectionResult detection_result,
+                                 float score_threshold = 0.0f,
+                                 int line_size = 1, float font_size = 0.5f) {
+    FD_DetectionResult fd_detection_result =
+        ConvertResult.ConvertDetectionResultToCResult(detection_result);
+    IntPtr result_ptr =
+        FD_C_VisDetection(im.CvPtr, ref fd_detection_result, score_threshold,
+                          line_size, font_size);
+    return new Mat(result_ptr);
+  }
+
+  [DllImport("fastdeploy.dll", EntryPoint = "FD_C_VisDetection")]
+  private static extern IntPtr
+  FD_C_VisDetection(IntPtr im, ref FD_DetectionResult fd_detection_result,
+                    float score_threshold, int line_size, float font_size);
+}
+
+}
+}