Add support for different image formats in ImageCallback

The april tag code is faster in halide than opencv.

Change-Id: I6531c5a45158e8bd5e50ee0b0ff69cc1978bf588
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/frc971/vision/charuco_lib.h b/frc971/vision/charuco_lib.h
index fdf25e1..f4f1233 100644
--- a/frc971/vision/charuco_lib.h
+++ b/frc971/vision/charuco_lib.h
@@ -51,10 +51,19 @@
 // full-service callback functionality
 class ImageCallback {
  public:
+  enum class Format {
+    YUYV2 = 0,
+    BGR = 1,
+    GRAYSCALE = 2,
+  };
   ImageCallback(aos::EventLoop *event_loop, std::string_view channel,
                 std::function<void(cv::Mat, aos::monotonic_clock::time_point)>
                     &&handle_image_fn);
 
+  void set_format(Format format) {
+    format_ = format;
+  }
+
  private:
   void DisableTracing();
 
@@ -67,6 +76,8 @@
   bool disabling_ = false;
 
   aos::Ftrace ftrace_;
+
+  Format format_ = Format::BGR;
 };
 
 // Class which calls a callback each time an image arrives with the information