Add Transform ICC Profile API (#208)

* Add TransformICCProfile method

* Add tests for transform ICC profile method

* Fix transform ICC case for images without ICC profile

vips/image.go

@@ -1133,6 +1133,24 @@ func (r *ImageRef) RemoveICCProfile() error {
 	return nil
 }
 
+// TransformICCProfile transforms from the embedded ICC profile of the image to the icc profile at the given path.
+func (r *ImageRef) TransformICCProfile(outputProfilePath string) error {
+
+	// If the image has an embedded profile, that will be used and the input profile ignored.
+	// Otherwise, images without an input profile are assumed to use a standard RGB profile.
+	embedded := r.HasICCProfile()
+	inputProfile := SRGBIEC6196621ICCProfilePath
+
+	out, err := vipsICCTransform(r.image, outputProfilePath, inputProfile, IntentPerceptual, 0, embedded)
+	if err != nil {
+		govipsLog("govips", LogLevelError, fmt.Sprintf("failed to do icc transform: %v", err.Error()))
+		return err
+	}
+
+	r.setImage(out)
+	return nil
+}
+
 // OptimizeICCProfile optimizes the ICC color profile of the image.
 // For two color channel images, it sets a grayscale profile.
 // For color images, it sets a CMYK or non-CMYK profile based on the image metadata.

vips/image_golden_test.go

@@ -92,6 +92,28 @@ func TestImage_EmbedBackground_NoAlpha(t *testing.T) {
 		}, nil)
 }
 
+func TestImage_TransformICCProfile_RGB_No_Profile(t *testing.T) {
+	goldenTest(t, resources+"jpg-24bit.jpg",
+		func(img *ImageRef) error {
+			return img.TransformICCProfile(SRGBIEC6196621ICCProfilePath)
+		},
+		func(result *ImageRef) {
+			assert.True(t, result.HasICCProfile())
+			assert.Equal(t, InterpretationSRGB, result.Interpretation())
+		}, nil)
+}
+
+func TestImage_TransformICCProfile_RGB_Embedded(t *testing.T) {
+	goldenTest(t, resources+"jpg-24bit-icc-adobe-rgb.jpg",
+		func(img *ImageRef) error {
+			return img.TransformICCProfile(SRGBIEC6196621ICCProfilePath)
+		},
+		func(result *ImageRef) {
+			assert.True(t, result.HasICCProfile())
+			assert.Equal(t, InterpretationSRGB, result.Interpretation())
+		}, nil)
+}
+
 func TestImage_OptimizeICCProfile_CMYK(t *testing.T) {
 	goldenTest(t, resources+"jpg-32bit-cmyk-icc-swop.jpg",
 		func(img *ImageRef) error {

vips/image_test.go

@@ -428,6 +428,22 @@ func TestImageRef_RemoveICCProfile(t *testing.T) {
 	assert.True(t, image.HasIPTC())
 }
 
+func TestImageRef_TransformICCProfile(t *testing.T) {
+	Startup(nil)
+
+	image, err := NewImageFromFile(resources + "jpg-24bit-icc-adobe-rgb.jpg")
+	require.NoError(t, err)
+
+	require.True(t, image.HasIPTC())
+	require.True(t, image.HasICCProfile())
+
+	err = image.TransformICCProfile(SRGBIEC6196621ICCProfilePath)
+	require.NoError(t, err)
+
+	assert.True(t, image.HasIPTC())
+	assert.True(t, image.HasICCProfile())
+}
+
 func TestImageRef_Close(t *testing.T) {
 	Startup(nil)