* Build OpenCV without UI when environment variable HEADLESS=yes (…

…pull #667)

opencv/cppbuild.sh

@@ -52,6 +52,11 @@ BUILD_X="-DBUILD_ANDROID_EXAMPLES=OFF -DBUILD_ANDROID_PROJECTS=OFF -DBUILD_TESTS
 # support for OpenMP is NOT thread-safe so make sure to never enable it and use pthreads instead
 WITH_X="-DWITH_1394=OFF -DWITH_FFMPEG=OFF -DWITH_GSTREAMER=OFF -DWITH_IPP=OFF -DWITH_LAPACK=OFF -DWITH_OPENCL=ON -DWITH_OPENMP=OFF -DOPENCV_ENABLE_NONFREE=ON"
 
+# support headless
+if [[ "${HEADLESS:-no}" == "yes" ]]; then
+    WITH_X="$WITH_X -DWITH_WIN32UI=OFF -DWITH_QT=OFF -DWITH_GTK=OFF"
+fi
+
 BUILD_CONTRIB_X="-DBUILD_opencv_stereo=OFF -DBUILD_opencv_plot=ON -DBUILD_opencv_fuzzy=OFF -DBUILD_opencv_aruco=ON -DBUILD_opencv_adas=OFF -DBUILD_opencv_bgsegm=ON -DBUILD_opencv_bioinspired=ON -DBUILD_opencv_ccalib=OFF -DBUILD_opencv_datasets=OFF -DBUILD_opencv_dnn_modern=OFF -DBUILD_opencv_dnn_objdetect=OFF -DBUILD_opencv_freetype=OFF -DBUILD_opencv_dpm=OFF -DBUILD_opencv_face=ON -DBUILD_opencv_hfs=OFF -DBUILD_opencv_latentsvm=OFF -DBUILD_opencv_line_descriptor=OFF -DBUILD_opencv_matlab=OFF -DBUILD_opencv_optflow=ON -DBUILD_opencv_phase_unwrapping=ON -DBUILD_opencv_plot=ON -DBUILD_opencv_reg=OFF -DBUILD_opencv_rgbd=OFF -DBUILD_opencv_saliency=ON -DBUILD_opencv_structured_light=ON -DBUILD_opencv_surface_matching=OFF -DBUILD_opencv_text=ON -DBUILD_opencv_tracking=ON -DBUILD_opencv_xfeatures2d=ON -DBUILD_opencv_ximgproc=ON -DBUILD_opencv_xobjdetect=OFF -DBUILD_opencv_xphoto=ON -DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib-$OPENCV_VERSION/modules"
 
 GPU_FLAGS="-DWITH_CUDA=OFF"