ci: Consider env variables in Travis CI settings

.travis.yml

@@ -19,15 +19,15 @@ env:
   # versions of VTK for each OS
   # - On Ubuntu, use default version installed by apt-get
   # - On macOS, build recent VTK version from sources and cache installation
-  - LINUX_VTK_VERSION=6.0.0
-  - MACOS_VTK_VERSION=9.0  # Homebrew versions: 8.2, 9.0; otherwise build from sources
-  - WITH_CCACHE=ON    # speed up MIRTK build itself using ccache
-  - WITH_ARPACK=OFF   # requires time consuming build of gcc on macOS
-  - WITH_UMFPACK=OFF  # ARPACK & UMFPACK dependencies come in pairs
-  - WITH_TBB=ON       # build with TBB is always recommended
-  - WITH_FLANN=ON     # build with FLANN is optional, but requires only little extra build time
-  - WITH_FLTK=ON      # build with FLTK-based Viewer when WITH_VTK is turned ON
-  - WITH_ITK=OFF      # required by ANTs N4 which is included in DrawEM package
+  - VTK_VERSION_LINUX=${VTK_VERSION_LINUX:-6.0.0}  # trusty: 6.0.0, xenial: 6.2.0, bionic: 6.3.0, 7.1.1
+  - VTK_VERSION_MACOS=${VTK_VERSION_MACOS:-9.0}    # Homebrew versions: 8.2, 9.0; otherwise build from sources
+  - WITH_CCACHE=${WITH_CCACHE:-ON}     # speed up MIRTK build itself using ccache
+  - WITH_ARPACK=${WITH_ARPACK:-OFF}    # requires time consuming build of gcc on macOS
+  - WITH_UMFPACK=${WITH_UMFPACK:-OFF}  # ARPACK & UMFPACK dependencies come in pairs
+  - WITH_TBB=${WITH_TBB:-ON}           # build with TBB is always recommended
+  - WITH_FLANN=$(WITH_FLANN:-ON}       # build with FLANN is optional, but requires only little extra build time
+  - WITH_FLTK=${WITH_FLTK:-ON}         # build with FLTK-based Viewer when WITH_VTK is turned ON
+  - WITH_ITK=${WITH_ITK:-OFF}          # required by ANTs N4 which is included in DrawEM package
                       # exclude DrawEM from Travis CI build for now, see https://github.com/MIRTK/DrawEM/pull/27
   # build and deployment of AppImage for Linux
   - AppImage_BUILD=${AppImage_BUILD:-ON}
@@ -65,8 +65,8 @@ cache:
   ccache: true
   timeout: 1000
   directories:
-  - "$HOME/VTK-$LINUX_VTK_VERSION"
-  - "$HOME/VTK-$MACOS_VTK_VERSION"
+  - "$HOME/VTK-$VTK_VERSION_LINUX"
+  - "$HOME/VTK-$VTK_VERSION_MACOS"
 
 before_install:
   - . Scripts/install_depends.sh  # sourcing will enable export of env variables

Scripts/install_depends.sh

@@ -105,8 +105,8 @@ if [ $os = linux ] || [ $os = Linux ]; then
   fi
 
   if [ $WITH_VTK = ON ]; then
-    if [ -n "$LINUX_VTK_VERSION" ]; then
-      VTK_VERSION="$LINUX_VTK_VERSION"
+    if [ -n "$VTK_VERSION_LINUX" ]; then
+      VTK_VERSION="$VTK_VERSION_LINUX"
     fi
     if [ "$DISTRIB_CODENAME" = "trusty" ]; then
       if [ -z "$VTK_VERSION" ] || [ $VTK_VERSION = '6.0.0' ]; then
@@ -182,7 +182,7 @@ if [ $os = osx ] || [ $os = Darwin ]; then
     brew_install suite-sparse
   fi
   if [ $WITH_VTK = ON ]; then
-    VTK_VERSION="$MACOS_VTK_VERSION"
+    VTK_VERSION="$VTK_VERSION_MACOS"
     if [ -z "$VTK_VERSION" ]; then
       echo "Installing VTK using Homebrew"
       brew_install vtk

Scripts/travis.sh

@@ -60,8 +60,8 @@ if [ $WITH_VTK = ON ]; then
     modules=(${modules[@]} Viewer)
   fi
   if [ $os = osx ] || [ $os = Darwin ]; then
-    if [ -d "/usr/local/opt/vtk@$MACOS_VTK_VERSION" ]; then
-      cmake_args+=(-D DEPENDS_VTK_DIR="/usr/local/opt/vtk@$MACOS_VTK_VERSION")
+    if [ -d "/usr/local/opt/vtk@$VTK_VERSION_MACOS" ]; then
+      cmake_args+=(-D DEPENDS_VTK_DIR="/usr/local/opt/vtk@$VTK_VERSION_MACOS")
     fi
   fi
 fi