From 03de94d3a4a868fa5d377cc5aa12606804beb9e6 Mon Sep 17 00:00:00 2001
From: mapleyuan <yuanweinan00@gmail.com>
Date: Thu, 5 Nov 2020 20:20:51 +0800
Subject: [PATCH] add rgbaToGray at ColorConvertCalculator

---
 mediapipe/calculators/image/color_convert_calculator.cc | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/mediapipe/calculators/image/color_convert_calculator.cc b/mediapipe/calculators/image/color_convert_calculator.cc
index f31586d9d..7891463c0 100644
--- a/mediapipe/calculators/image/color_convert_calculator.cc
+++ b/mediapipe/calculators/image/color_convert_calculator.cc
@@ -57,6 +57,8 @@ constexpr char kGrayOutTag[] = "GRAY_OUT";
 //   RGB  -> RGBA
 //   RGBA -> BGRA
 //   BGRA -> RGBA
+//   RGBA -> GRAY
+
 //
 // This calculator only supports a single input stream and output stream at a
 // time. If more than one input stream or output stream is present, the
@@ -196,6 +198,12 @@ REGISTER_CALCULATOR(ColorConvertCalculator);
                             cv::COLOR_RGBA2BGRA, cc);
   }
 
+  // RGBA -> GRAY
+  if (cc->Inputs().HasTag(kRgbaInTag) && cc->Outputs().HasTag(kGrayOutTag)) {
+      return ConvertAndOutput(kRgbaInTag, kGrayOutTag, ImageFormat::GRAY8,
+                              cv::COLOR_RGBA2GRAY, cc);
+  }
+
   return ::mediapipe::InvalidArgumentErrorBuilder(MEDIAPIPE_LOC)
          << "Unsupported image format conversion.";
 }