OpenCV: Fix Python support

OpenCV relies on the CMake FindPythonLibs module which get pwned pretty hard if
more than one Python installation is available. Copied some code from the VTK
formula that straightens things out manually.

Also added a numpy dependency.

Fixes #7740.

1 files changed, 31 insertions, 3 deletions

diff --git a/Library/Formula/opencv.rb b/Library/Formula/opencv.rb
index 6ee9a569a..274e520ce 100644
--- a/Library/Formula/opencv.rb
+++ b/Library/Formula/opencv.rb
@@ -21,6 +21,8 @@ class Opencv < Formula
   depends_on 'jasper'  => :optional
   depends_on 'tbb'     => :optional
 
+  depends_on 'numpy' => :python
+
   # Can also depend on ffmpeg, but this pulls in a lot of extra stuff that
   # you don't need unless you're doing video analysis, and some of it isn't
   # in Homebrew anyway.
@@ -36,9 +38,35 @@ class Opencv < Formula
   end
 
   def install
-    makefiles = "cmake -G 'Unix Makefiles' -DCMAKE_INSTALL_PREFIX:PATH=#{prefix} ."
-    makefiles += " -DOPENCV_EXTRA_C_FLAGS='-arch i386 -m32'" if ARGV.include? '--build32'
-    system makefiles
+    args = std_cmake_parameters.split
+    args << " -DOPENCV_EXTRA_C_FLAGS='-arch i386 -m32'" if ARGV.include? '--build32'
+
+    # The CMake `FindPythonLibs` Module is dumber than a bag of hammers when
+    # more than one python installation is available---for example, it clings
+    # to the Header folder of the system Python Framework like a drowning
+    # sailor.
+    #
+    # This code was cribbed from the VTK formula and uses the output to
+    # `python-config` to do the job FindPythonLibs should be doing in the first
+    # place.
+    python_prefix = `python-config --prefix`.strip
+    # Python is actually a library. The libpythonX.Y.dylib points to this lib, too.
+    if File.exist? "#{python_prefix}/Python"
+      # Python was compiled with --framework:
+      args << "-DPYTHON_LIBRARY='#{python_prefix}/Python'"
+      args << "-DPYTHON_INCLUDE_DIR='#{python_prefix}/Headers'"
+    else
+      python_lib = "#{python_prefix}/lib/lib#{which_python}"
+      if File.exists? "#{python_lib}.a"
+        args << "-DPYTHON_LIBRARY='#{python_lib}.a'"
+      else
+        args << "-DPYTHON_LIBRARY='#{python_lib}.dylib'"
+      end
+      args << "-DPYTHON_INCLUDE_DIR='#{python_prefix}/include/#{which_python}'"
+    end
+
+    system 'cmake', '.', *args
+    interactive_shell
     system "make"
     system "make install"
   end