Forcing option GTK3 induces an error as findGTK3.cmake is not in path (OpenSUSE)

[dominig]

@Rasbats
@jongough

When force the selection of GTK3 (as auto selection still complains of missing gtk2) by the option in make cmake command and fails to complete the configuration.

BUILD_GTK3="true";\
cmake -DCMAKE_SKIP_RPATH=ON \
      -DOCPN_FORCE_GTK3=ON  \
      -DCMAKE_INSTALL_PREFIX=%{_prefix} \
      -DCFLAGS="-O2 -march=native" \
      ../
make

I still get an configuration error (see details bellow).
The following patch corrects the GTK3 issue.

diff --git a/cmake/PluginConfigure.cmake b/cmake/PluginConfigure.cmake
index 069bfd7..03e1fe6 100644
--- a/cmake/PluginConfigure.cmake
+++ b/cmake/PluginConfigure.cmake
@@ -393,7 +393,8 @@ if(NOT WIN32
         set(GTK_LIBRARIES ${GTK2_LIBRARIES})
         message(STATUS "${CMLOC}Building against GTK2...")
     else(GTK2_FOUND)
-        find_package(GTK3)
+       find_package(PkgConfig)
+        pkg_check_modules(GTK3 gtk+-3.0)
         include_directories(${GTK3_INCLUDE_DIRS})
         set(GTK_LIBRARIES ${GTK3_LIBRARIES})
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D__WXGTK3__")

---------- configuration error log extract without the patch----------------

[    5s] CMake Warning at cmake/PluginConfigure.cmake:396 (find_package):
[    5s]   By not providing "FindGTK3.cmake" in CMAKE_MODULE_PATH this project has
[    5s]   asked CMake to find a package configuration file provided by "GTK3", but
[    5s]   CMake did not find one.
[    5s] 
[    5s]   Could not find a package configuration file provided by "GTK3" with any of
[    5s]   the following names:
[    5s] 
[    5s]     GTK3Config.cmake
[    5s]     gtk3-config.cmake
[    5s] 
[    5s]   Add the installation prefix of "GTK3" to CMAKE_PREFIX_PATH or set
[    5s]   "GTK3_DIR" to a directory containing one of the above files.  If "GTK3"
[    5s]   provides a separate development package or SDK, be sure it has been
[    5s]   installed.
[    5s] Call Stack (most recent call first):
[    5s]   CMakeLists.txt:123 (include)

[Rasbats]

Thanks Dominiq. This stuff is beyond my skills but Alec Leamas has been looking at this in relation to another plugin. I will copy him in on this.

[leamas]

Welll, it's says what it is. It wants a cmake/FindGTK3.cmake file, and it cannot find it. There is one available on main openCPN with the following contents:

# - Try to find GTK+ 3
# Once done, this will define
#
#  GTK3_FOUND - system has GTK+ 3.
#  GTK3_INCLUDE_DIRS - the GTK+ 3. include directories
#  GTK3_LIBRARIES - link these to use GTK+ 3.
#
# Copyright (C) 2012 Raphael Kubo da Costa <rakuco@webkit.org>
# Copyright (C) 2013 Igalia S.L.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1.  Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer.
# 2.  Redistributions in binary form must reproduce the above copyright
#     notice, this list of conditions and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND ITS CONTRIBUTORS ``AS
# IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR ITS
# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
find_package(PkgConfig)
pkg_check_modules(GTK3 gtk+-3.0)
set(VERSION_OK TRUE)
if (GTK3_VERSION)
    if (GTK3_FIND_VERSION_EXACT)
        if (NOT("${GTK3_FIND_VERSION}" VERSION_EQUAL "${GTK3_VERSION}"))
            set(VERSION_OK FALSE)
        endif ()
    else ()
        if ("${GTK3_VERSION}" VERSION_LESS "${GTK3_FIND_VERSION}")
            set(VERSION_OK FALSE)
        endif ()
    endif ()
endif ()
include(FindPackageHandleStandardArgs)
FIND_PACKAGE_HANDLE_STANDARD_ARGS(GTK3 DEFAULT_MSG GTK3_INCLUDE_DIRS GTK3_LIBRARIES VERSION_OK)

I guess dropping this file in the cmake/ dir should fix it.