add RectsPulsarCalculator and NormalizedRectsPulsarCalculator

Signed-off-by: Pierre Fenoll <pierrefenoll@gmail.com>

mediapipe/calculators/core/BUILD

@@ -278,6 +278,21 @@ cc_library(
     alwayslink = 1,
 )
 
+cc_library(
+    name = "pulsar_calculator",
+    srcs = ["pulsar_calculator.cc"],
+    hdrs = ["pulsar_calculator.h"],
+    visibility = [
+        "//visibility:public",
+    ],
+    deps = [
+        "//mediapipe/framework:calculator_framework",
+        "//mediapipe/framework/formats:rect_cc_proto",
+        "//mediapipe/framework/port:ret_check",
+    ],
+    alwayslink = 1,
+)
+
 cc_library(
     name = "packet_cloner_calculator",
     srcs = ["packet_cloner_calculator.cc"],

mediapipe/calculators/core/pulsar_calculator.cc

@@ -0,0 +1,46 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// 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.
+
+#include "mediapipe/calculators/core/pulsar_calculator.h"
+
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/formats/rect.pb.h"
+#include "mediapipe/framework/port/ret_check.h"
+
+namespace mediapipe {
+
+// Example use-case:
+// Suppose we are debugging a pipeline where a vector of NormalizedRect has to
+// be passed to a ImageCroppingCalculator somehow, which only takes non-vectors.
+//
+// Example config:
+// node {
+//   calculator: "NormalizedRectsPulsarCalculator"
+//   input_stream: "head_rects"
+//   output_stream: "head_rect"
+// }
+//
+// node {
+//   calculator: "ImageCroppingCalculator"
+//   input_stream: "IMAGE:throttled_input_video"
+//   input_stream: "NORM_RECT:head_rect"
+//   output_stream: "IMAGE:cropped_head"
+// }
+typedef PulsarCalculator<NormalizedRect> NormalizedRectsPulsarCalculator;
+REGISTER_CALCULATOR(NormalizedRectsPulsarCalculator);
+
+typedef PulsarCalculator<Rect> RectsPulsarCalculator;
+REGISTER_CALCULATOR(RectsPulsarCalculator);
+
+}  // namespace mediapipe

mediapipe/calculators/core/pulsar_calculator.h

@@ -0,0 +1,58 @@
+// Copyright 2019 The MediaPipe Authors.
+//
+// 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.
+
+#ifndef MEDIAPIPE_CALCULATORS_CORE_PULSAR_CALCULATOR_H_
+#define MEDIAPIPE_CALCULATORS_CORE_PULSAR_CALCULATOR_H_
+
+#include "mediapipe/framework/calculator_framework.h"
+#include "mediapipe/framework/port/ret_check.h"
+
+namespace mediapipe {
+
+// This turns a packet of vector<NormalizedRect> into as many NormalizedRect
+// items there are in said vector.
+template <typename T>
+class PulsarCalculator : public CalculatorBase {
+ public:
+  static ::mediapipe::Status GetContract(CalculatorContract* cc) {
+    RET_CHECK_EQ(cc->Inputs().NumEntries(), 1);
+    RET_CHECK_EQ(cc->Outputs().NumEntries(), 1);
+    cc->Inputs().Index(0).Set<std::vector<T>>();
+    cc->Outputs().Index(0).Set<T>();
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Open(CalculatorContext* cc) final {
+    cc->SetOffset(TimestampDiff(0));
+    return ::mediapipe::OkStatus();
+  }
+
+  ::mediapipe::Status Process(CalculatorContext* cc) final {
+    const auto& items = cc->Inputs().Index(0).Get<std::vector<T>>();
+    auto ts = std::max(cc->InputTimestamp(), ts_);
+    for (const auto& item : items) {
+      auto just_one = absl::make_unique<T>(item);
+      cc->Outputs().Index(0).Add(just_one.release(), ts++);
+    }
+    ts_ = ts;
+    return ::mediapipe::OkStatus();
+  }
+
+private:
+  Timestamp ts_;
+};
+
+}  // namespace mediapipe
+
+#endif  // MEDIAPIPE_CALCULATORS_CORE_PULSAR_CALCULATOR_H_