Adding support for TIFF save.

Signed-off-by: Yoan Blanc <yoan@dosimple.ch>

vips.go

@@ -168,6 +168,25 @@ func VipsIsTypeSupported(t ImageType) bool {
 	return false
 }
 
+// VipsIsTypeSupportedSave returns true if the given image type
+// is supported by the current libvips compilation for the
+// save operation.
+func VipsIsTypeSupportedSave(t ImageType) bool {
+	if t == JPEG {
+		return int(C.vips_type_find_save_bridge(C.JPEG)) != 0
+	}
+	if t == WEBP {
+		return int(C.vips_type_find_save_bridge(C.WEBP)) != 0
+	}
+	if t == PNG {
+		return int(C.vips_type_find_save_bridge(C.PNG)) != 0
+	}
+	if t == TIFF {
+		return int(C.vips_type_find_save_bridge(C.TIFF)) != 0
+	}
+	return false
+}
+
 func vipsExifOrientation(image *C.VipsImage) int {
 	return int(C.vips_exif_orientation(image))
 }
@@ -367,18 +386,19 @@ func vipsSave(image *C.VipsImage, o vipsSaveOptions) ([]byte, error) {
 	interlace := C.int(boolToInt(o.Interlace))
 	quality := C.int(o.Quality)
 
+	if o.Type != 0 && !VipsIsTypeSupportedSave(o.Type) {
+		return nil, fmt.Errorf("VIPS cannot save to %#v", ImageTypes[o.Type])
+	}
 	var ptr unsafe.Pointer
 	switch o.Type {
 	case WEBP:
 		saveErr = C.vips_webpsave_bridge(tmpImage, &ptr, &length, 1, quality)
 	case PNG:
 		saveErr = C.vips_pngsave_bridge(tmpImage, &ptr, &length, 1, C.int(o.Compression), quality, interlace)
-	case 0:
-		saveErr = C.vips_jpegsave_bridge(tmpImage, &ptr, &length, 1, quality, interlace)
-	case JPEG:
-		saveErr = C.vips_jpegsave_bridge(tmpImage, &ptr, &length, 1, quality, interlace)
+	case TIFF:
+		saveErr = C.vips_tiffsave_bridge(tmpImage, &ptr, &length)
 	default:
-		return nil, fmt.Errorf("VIPS cannot save to %v.", ImageTypes[o.Type])
+		saveErr = C.vips_jpegsave_bridge(tmpImage, &ptr, &length, 1, quality, interlace)
 	}
 
 	if int(saveErr) != 0 {

vips.h

@@ -144,6 +144,23 @@ vips_type_find_bridge(int t) {
 	return 0;
 }
 
+int
+vips_type_find_save_bridge(int t) {
+	if (t == TIFF) {
+		return vips_type_find("VipsOperation", "tiffsave_buffer");
+	}
+	if (t == WEBP) {
+		return vips_type_find("VipsOperation", "webpsave_buffer");
+	}
+	if (t == PNG) {
+		return vips_type_find("VipsOperation", "pngsave_buffer");
+	}
+	if (t == JPEG) {
+		return vips_type_find("VipsOperation", "jpegsave_buffer");
+	}
+	return 0;
+}
+
 int
 vips_rotate(VipsImage *in, VipsImage **out, int angle) {
 	int rotate = VIPS_ANGLE_D0;
@@ -276,6 +293,17 @@ vips_webpsave_bridge(VipsImage *in, void **buf, size_t *len, int strip, int qual
 	);
 }
 
+int
+vips_tiffsave_bridge(VipsImage *in, void **buf, size_t *len) {
+#if (VIPS_MAJOR_VERSION >= 8 && VIPS_MINOR_VERSION >= 5)
+	return vips_tiffsave_buffer(in, buf, len,
+		NULL
+	);
+#else
+	return 0;
+#endif
+}
+
 int
 vips_is_16bit (VipsInterpretation interpretation) {
 	return interpretation == VIPS_INTERPRETATION_RGB16 || interpretation == VIPS_INTERPRETATION_GREY16;

vips_test.go

@@ -45,20 +45,16 @@ func TestVipsSave(t *testing.T) {
 	}
 }
 
-func TestVipsCannotSave(t *testing.T) {
-	types := [...]ImageType{GIF, MAGICK, PDF, SVG, TIFF}
+func TestVipsSaveTiff(t *testing.T) {
+	if !VipsIsTypeSupportedSave(TIFF) {
+		t.Skipf("Format %#v is not supported", ImageTypes[TIFF])
+	}
+	image, _, _ := vipsRead(readImage("test.jpg"))
+	options := vipsSaveOptions{Quality: 95, Type: TIFF}
+	buf, _ := vipsSave(image, options)
 
-	for _, typ := range types {
-		image, _, _ := vipsRead(readImage("test.jpg"))
-		options := vipsSaveOptions{Quality: 95, Type: typ}
-
-		buf, err := vipsSave(image, options)
-		if err == nil {
-			t.Fatalf("Format '%v' shouldn't be supported", ImageTypes[typ])
-		}
-		if len(buf) != 0 {
-			t.Fatalf("'%v' image is not empty", ImageTypes[typ])
-		}
+	if len(buf) == 0 {
+		t.Fatalf("Empty saved '%v' image", ImageTypes[TIFF])
 	}
 }