From 0153ede05a6507f09e588698550237c90493cdf7 Mon Sep 17 00:00:00 2001
From: Chris Lalancette <clalancette@gmail.com>
Date: Wed, 15 Jul 2020 17:34:36 -0400
Subject: [PATCH] Opencv 3 compatibility (#564)

* Remove GTK from image_view.

It is no longer used at all in image_view.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>

* Reinstate OpenCV 3 compatibility.

While Foxy only supports Ubuntu 20.04 (and hence OpenCV 4),
we still strive to maintain Ubuntu 18.04 (which has OpenCV 3).
In this case, it is trivial to keep keep image_pipeline working
with OpenCV 3, so reintroduce compatibility with it.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>

* Fixes from review.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>

* One more fix.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>
---
 image_proc/CMakeLists.txt        | 5 ++++-
 image_proc/src/crop_decimate.cpp | 7 ++++---
 image_publisher/CMakeLists.txt   | 9 +--------
 image_view/CMakeLists.txt        | 6 ------
 image_view/package.xml           | 1 -
 5 files changed, 9 insertions(+), 19 deletions(-)

diff --git a/image_proc/CMakeLists.txt b/image_proc/CMakeLists.txt
index e4dffcf33..756b737e1 100644
--- a/image_proc/CMakeLists.txt
+++ b/image_proc/CMakeLists.txt
@@ -18,7 +18,10 @@ find_package(rcutils REQUIRED)
 find_package(cv_bridge REQUIRED)
 find_package(image_transport REQUIRED)
 find_package(sensor_msgs REQUIRED)
-find_package(OpenCV 3 REQUIRED)
+find_package(OpenCV REQUIRED)
+if(OpenCV_VERSION VERSION_LESS "3.2.0")
+  message(FATAL "Minimum OpenCV version is 3.2.0 (found version ${OpenCV_VERSION})")
+endif()
 find_package(image_geometry REQUIRED)
 
 include_directories(
diff --git a/image_proc/src/crop_decimate.cpp b/image_proc/src/crop_decimate.cpp
index 68a6eb871..3e8261dac 100644
--- a/image_proc/src/crop_decimate.cpp
+++ b/image_proc/src/crop_decimate.cpp
@@ -46,11 +46,12 @@ void debayer2x2toBGR(
   int R, int G1, int G2, int B)
 {
   typedef cv::Vec<T, 3> DstPixel;  // 8- or 16-bit BGR
-  #if CV_MAJOR_VERSION >= 3 && CV_MINOR_VERSION > 2
+#if CV_VERSION_MAJOR >= 4
   dst.create(src.rows / 2, src.cols / 2, cv::traits::Type<DstPixel>::value);
-  #else
+#else
+  // Assume OpenCV 3 API
   dst.create(src.rows / 2, src.cols / 2, cv::DataType<DstPixel>::type);
-  #endif
+#endif
 
   int src_row_step = src.step1();
   int dst_row_step = dst.step1();
diff --git a/image_publisher/CMakeLists.txt b/image_publisher/CMakeLists.txt
index 439e7aa5c..045454414 100644
--- a/image_publisher/CMakeLists.txt
+++ b/image_publisher/CMakeLists.txt
@@ -29,15 +29,8 @@ set( DEPENDENCIES
   cv_bridge
 )
 
-set(opencv_2_components core highgui)
-set(opencv_3_components core imgcodecs videoio)
-find_package(OpenCV REQUIRED COMPONENTS core)
+find_package(OpenCV REQUIRED COMPONENTS core imgcodecs videoio)
 message(STATUS "opencv version ${OpenCV_VERSION}")
-if(OpenCV_VERSION VERSION_LESS "3.0.0")
-  find_package(OpenCV 2 REQUIRED COMPONENTS ${opencv_2_components})
-else()
-  find_package(OpenCV 3 REQUIRED COMPONENTS ${opencv_3_components})
-endif()
 
 include_directories(include)
 
diff --git a/image_view/CMakeLists.txt b/image_view/CMakeLists.txt
index a357a1ff1..315b288ca 100644
--- a/image_view/CMakeLists.txt
+++ b/image_view/CMakeLists.txt
@@ -33,10 +33,6 @@ if(ANDROID)
   return()
 endif()
 
-find_package(GTK2)
-add_definitions(-DHAVE_GTK)
-include_directories(${GTK2_INCLUDE_DIRS})
-
 add_library(image_view_nodes SHARED
   src/disparity_view_node.cpp
   src/extract_images_node.cpp
@@ -56,8 +52,6 @@ ament_target_dependencies(image_view_nodes
   stereo_msgs
 )
 target_link_libraries(image_view_nodes
-  ${GTK_LIBRARIES}
-  ${GTK2_LIBRARIES}
   ${OpenCV_LIBRARIES}
   ${Boost_LIBRARIES}
 )
diff --git a/image_view/package.xml b/image_view/package.xml
index 418513d4f..ead92c393 100644
--- a/image_view/package.xml
+++ b/image_view/package.xml
@@ -18,7 +18,6 @@
 
   <depend>camera_calibration_parsers</depend>
   <depend>cv_bridge</depend>
-  <depend>gtk2</depend>
   <depend>image_transport</depend>
   <depend>message_filters</depend>
   <depend>rclcpp</depend>