Merged in circleci-gocv (pull request #317)

Circle-CI doesn't like to build because of gocv

Approved-by: Alan Noble <anoble@gmail.com>
Approved-by: Saxon Milton <saxon.milton@gmail.com>

.circleci/config.yml

@@ -23,9 +23,9 @@ jobs:
 
       - run: go get -d -t -v ./...
 
-      - run: go build -v ./...
+      - run: go build -v -tags circleci ./...
 
-      - run: go test -v ./...
+      - run: go test -v -tags circleci ./...
 
       - save_cache:
           key: v1-pkg-cache

exp/gocv-exp/main.go

@@ -1,3 +1,5 @@
+// +build !circleci
+
 // What it does:
 //
 // This example detects motion using a delta threshold from the first frame,

filter/filters_circleci.go

@@ -0,0 +1,37 @@
+// +build circleci
+
+/*
+DESCRIPTION
+  Replaces filters that use the gocv package when Circle-CI builds revid. This
+  is needed because Circle-CI does not have a copy of Open CV installed.
+
+AUTHORS
+  Scott Barnard <scott@ausocean.org>
+
+LICENSE
+  filters_circleci.go is Copyright (C) 2019 the Australian Ocean Lab (AusOcean)
+
+  It is free software: you can redistribute it and/or modify them
+  under the terms of the GNU General Public License as published by the
+  Free Software Foundation, either version 3 of the License, or (at your
+  option) any later version.
+
+  It is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+  for more details.
+
+  You should have received a copy of the GNU General Public License
+  in gpl.txt.  If not, see http://www.gnu.org/licenses.
+*/
+
+package filter
+
+import (
+	"io"
+)
+
+// NewMOGFilter returns a pointer to a new NoOp struct for testing purposes only.
+func NewMOGFilter(dst io.WriteCloser, area, threshold float64, history, kernelSize int, debug bool) *NoOp {
+	return &NoOp{dst: dst}
+}

filter/mog.go

@@ -1,3 +1,5 @@
+// +build !circleci
+
 /*
 DESCRIPTION
   A filter that detects motion and discards frames without motion. The
@@ -45,7 +47,7 @@ type MOGFilter struct {
 	windows []*gocv.Window
 }
 
-// NewMOGFilter returns a pointer to a new MOGFilter.
+// NewMOGFilter returns a pointer to a new MOGFilter struct.
 func NewMOGFilter(dst io.WriteCloser, area, threshold float64, history, kernelSize int, debug bool) *MOGFilter {
 	bs := gocv.NewBackgroundSubtractorMOG2WithParams(history, threshold, false)
 	k := gocv.GetStructuringElement(gocv.MorphRect, image.Pt(kernelSize, kernelSize))