added FromImageUnsafe and tests/benchmarks

opencv/cv.go

@@ -18,8 +18,9 @@ func init() {
 }
 
 const (
-	CV_BGR2GRAY = C.CV_BGR2GRAY
-	CV_BGR2BGRA = C.CV_BGR2BGRA
+	CV_BGR2GRAY  = C.CV_BGR2GRAY
+	CV_BGR2BGRA  = C.CV_BGR2BGRA
+	CV_RGBA2BGRA = C.CV_RGBA2BGRA
 
 	CV_BLUR = C.CV_BLUR
 

opencv/cxcore.go

@@ -57,6 +57,11 @@ func CreateImage(w, h, depth, channels int) *IplImage {
 	return (*IplImage)(img)
 }
 
+/* SetData assigns user data to the image header */
+func (img *IplImage) SetData(data unsafe.Pointer, step int) {
+	C.cvSetData(unsafe.Pointer(img), data, C.int(step))
+}
+
 /* Releases (i.e. deallocates) IPL image header */
 func (img *IplImage) ReleaseHeader() {
 	img_c := (*C.IplImage)(img)

opencv/goimage.go

@@ -14,7 +14,7 @@ func DecodeImageMem(data []byte) *IplImage {
 	return DecodeImage(unsafe.Pointer(buf), CV_LOAD_IMAGE_UNCHANGED)
 }
 
-/* From Image converts a go image.Image to an opencv.IplImage. */
+/* FromImage converts a go image.Image to an opencv.IplImage. */
 func FromImage(img image.Image) *IplImage {
 	b := img.Bounds()
 	model := color.RGBAModel
@@ -36,6 +36,26 @@ func FromImage(img image.Image) *IplImage {
 	return dst
 }
 
+/* FromImageUnsafe create an opencv.IplImage that shares the buffer with the
+go image.RGBA image. All changes made from opencv might affect go! */
+func FromImageUnsafe(img *image.RGBA) *IplImage {
+	b := img.Bounds()
+	buf := CreateImageHeader(
+		b.Max.X-b.Min.X,
+		b.Max.Y-b.Min.Y,
+		IPL_DEPTH_8U, 4)
+	dst := CreateImage(
+		b.Max.X-b.Min.X,
+		b.Max.Y-b.Min.Y,
+		IPL_DEPTH_8U, 4)
+
+	buf.SetData(unsafe.Pointer(&img.Pix[0]), CV_AUTOSTEP)
+	CvtColor(buf, dst, CV_RGBA2BGRA)
+	buf.Release()
+
+	return dst
+}
+
 /* ToImage converts a opencv.IplImage to an go image.Image */
 func (img *IplImage) ToImage() image.Image {
 	out := image.NewNRGBA(image.Rect(0, 0, img.Width(), img.Height()))

opencv/goimage_test.go

@@ -0,0 +1,96 @@
+package opencv
+
+import (
+	"image"
+	_ "image/jpeg"
+	_ "image/png"
+	"os"
+	"reflect"
+	"testing"
+)
+
+func TestFromImage(t *testing.T) {
+	fh, err := os.Open("../images/pic5.png")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	img, _, err := image.Decode(fh)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ocv := FromImage(img)
+	if ocv == nil {
+		t.Fatal("failed to convert image")
+	}
+
+	width := img.Bounds().Max.X - img.Bounds().Min.X
+	height := img.Bounds().Max.Y - img.Bounds().Min.Y
+	if ocv.Width() != width || ocv.Height() != height {
+		t.Fatalf("loaded image has wrong dimensions: got %dx%d, expected %dx%d", ocv.Width(), ocv.Height(), width, height)
+	}
+
+	ex := [4]float64{98, 139, 26, 255}
+	px := ocv.Get2D(50, 90).Val()
+	if !reflect.DeepEqual(px, ex) {
+		t.Fatalf("wrong color @50,90: got %v, expected %v", px, ex)
+	}
+}
+
+func TestFromImageUnsafe(t *testing.T) {
+	fh, err := os.Open("../images/pic5.png")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	img, _, err := image.Decode(fh)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rgba, ok := img.(*image.RGBA)
+	if !ok {
+		t.Fatal("image is no RGBA image")
+	}
+
+	ocv := FromImageUnsafe(rgba)
+	if ocv == nil {
+		t.Fatal("failed to convert image")
+	}
+
+	width := img.Bounds().Max.X - img.Bounds().Min.X
+	height := img.Bounds().Max.Y - img.Bounds().Min.Y
+	if ocv.Width() != width || ocv.Height() != height {
+		t.Fatalf("loaded image has wrong dimensions: got %dx%d, expected %dx%d", ocv.Width(), ocv.Height(), width, height)
+	}
+
+	ex := [4]float64{98, 139, 26, 255}
+	px := ocv.Get2D(50, 90).Val()
+	if !reflect.DeepEqual(px, ex) {
+		t.Fatalf("wrong color @50,90: got %v, expected %v", px, ex)
+	}
+}
+
+func BenchmarkFromImage(b *testing.B) {
+	fh, _ := os.Open("../images/pic5.png")
+	img, _, _ := image.Decode(fh)
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		ocv := FromImage(img)
+		ocv.Release()
+	}
+}
+
+func BenchmarkFromImageUnsafe(b *testing.B) {
+	fh, _ := os.Open("../images/pic5.png")
+	img, _, _ := image.Decode(fh)
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		rgba := img.(*image.RGBA)
+		ocv := FromImageUnsafe(rgba)
+		ocv.Release()
+	}
+}