From 4c07f5b211a68824e606c7ebbdfc6fe21156b645 Mon Sep 17 00:00:00 2001
From: Krzysztof Wojciechowski <49921081+Kotochleb@users.noreply.github.com>
Date: Mon, 27 May 2024 18:03:57 +0200
Subject: [PATCH] [rolling] image_publisher: Fix image, constantly flipping
 when static image is published (#986)

Continuation of
https://github.com/ros-perception/image_pipeline/pull/984.

When publishing video stream from a camera, the image was flipped
correctly. Yet for a static image, which was loaded once, the flip
function was applied every time `ImagePublisher::doWork()` was called,
resulting in the published image being flipped back and forth all the
time.

This PR should be straightforward to port it to `Humble`, `Iron` and
`Jazzy`.

(cherry picked from commit 7f25ec90f416fceec66e7e95494d18b89cb9ed91)
---
 image_publisher/include/image_publisher/image_publisher.hpp | 1 +
 image_publisher/src/image_publisher.cpp                     | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/image_publisher/include/image_publisher/image_publisher.hpp b/image_publisher/include/image_publisher/image_publisher.hpp
index 082b5d985..dc76bf890 100644
--- a/image_publisher/include/image_publisher/image_publisher.hpp
+++ b/image_publisher/include/image_publisher/image_publisher.hpp
@@ -65,6 +65,7 @@ class ImagePublisher : public rclcpp::Node
   std::string filename_;
   bool flip_horizontal_;
   bool flip_vertical_;
+  bool image_flipped_;
   bool retry_;  // If enabled will retry loading image from the filename_
   int timeout_;  // Time after which retrying starts
 
diff --git a/image_publisher/src/image_publisher.cpp b/image_publisher/src/image_publisher.cpp
index 4859ed02b..aac9511c5 100644
--- a/image_publisher/src/image_publisher.cpp
+++ b/image_publisher/src/image_publisher.cpp
@@ -137,9 +137,11 @@ void ImagePublisher::doWork()
       if (!cap_.read(image_)) {
         cap_.set(cv::CAP_PROP_POS_FRAMES, 0);
       }
+      image_flipped_ = false;
     }
-    if (flip_image_) {
+    if (flip_image_ && !image_flipped_) {
       cv::flip(image_, image_, flip_value_);
+      image_flipped_ = true;
     }
 
     sensor_msgs::msg::Image::SharedPtr out_img =
@@ -206,6 +208,7 @@ void ImagePublisher::onInit()
   } else {
     flip_image_ = false;
   }
+  image_flipped_ = false;  // Image newly read, needs to be flipped
 
   camera_info_.width = image_.cols;
   camera_info_.height = image_.rows;