Improved ICC profiles handling

CHANGELOG.md

@@ -1,6 +1,9 @@
 # Changelog
 
 ## [Unreleased]
+### Change
+- Improved ICC profiles handling.
+
 ### Fix
 - (pro) Fix parsing metadata of extended sequential JPEGs.
 

processing/export_color_profile.go

@@ -31,10 +31,6 @@ func exportColorProfile(pctx *pipelineContext, img *vips.Image, po *options.Proc
 		}
 	}
 
-	if err := img.RgbColourspace(); err != nil {
-		return err
-	}
-
 	if !keepProfile {
 		return img.RemoveColourProfile()
 	}

processing/finalize.go

@@ -7,14 +7,6 @@ import (
 )
 
 func finalize(pctx *pipelineContext, img *vips.Image, po *options.ProcessingOptions, imgdata *imagedata.ImageData) error {
-	if err := img.RgbColourspace(); err != nil {
-		return err
-	}
-
-	if err := img.CastUchar(); err != nil {
-		return err
-	}
-
 	if po.StripMetadata {
 		if err := img.Strip(); err != nil {
 			return err

processing/import_color_profile.go

@@ -14,7 +14,7 @@ func importColorProfile(pctx *pipelineContext, img *vips.Image, po *options.Proc
 
 	convertToLinear := config.UseLinearColorspace && (pctx.wscale != 1 || pctx.hscale != 1)
 
-	if convertToLinear {
+	if convertToLinear || img.IsCMYK() {
 		if err := img.ImportColourProfile(); err != nil {
 			return err
 		}

processing/processing.go

@@ -27,12 +27,12 @@ var mainPipeline = pipeline{
 	rotateAndFlip,
 	crop,
 	fixWebpSize,
-	exportColorProfile,
 	applyFilters,
 	extend,
 	padding,
 	flatten,
 	watermark,
+	exportColorProfile,
 	finalize,
 }
 

processing/watermark.go

@@ -16,7 +16,6 @@ var watermarkPipeline = pipeline{
 	importColorProfile,
 	scale,
 	rotateAndFlip,
-	exportColorProfile,
 	finalize,
 }
 

vips/vips.c

@@ -293,22 +293,22 @@ vips_has_embedded_icc(VipsImage *in) {
 
 int
 vips_icc_import_go(VipsImage *in, VipsImage **out) {
-  return vips_icc_import(in, out, "embedded", TRUE, "pcs", VIPS_PCS_XYZ, NULL);
+  return vips_icc_import(in, out, "embedded", TRUE, "pcs", VIPS_PCS_LAB, NULL);
 }
 
 int
 vips_icc_export_go(VipsImage *in, VipsImage **out) {
-  return vips_icc_export(in, out, NULL);
+  return vips_icc_export(in, out, "pcs", VIPS_PCS_LAB, NULL);
 }
 
 int
 vips_icc_export_srgb(VipsImage *in, VipsImage **out) {
-  return vips_icc_export(in, out, "output_profile", "sRGB", NULL);
+  return vips_icc_export(in, out, "output_profile", "sRGB", "pcs", VIPS_PCS_LAB, NULL);
 }
 
 int
 vips_icc_transform_go(VipsImage *in, VipsImage **out) {
-  return vips_icc_transform(in, out, "sRGB", "embedded", TRUE, "pcs", VIPS_PCS_XYZ, NULL);
+  return vips_icc_transform(in, out, "sRGB", "embedded", TRUE, "pcs", VIPS_PCS_LAB, NULL);
 }
 
 int
@@ -456,15 +456,13 @@ vips_replicate_go(VipsImage *in, VipsImage **out, int width, int height) {
 
 int
 vips_embed_go(VipsImage *in, VipsImage **out, int x, int y, int width, int height) {
-  VipsImage *base = vips_image_new();
-	VipsImage **t = (VipsImage **) vips_object_local_array(VIPS_OBJECT(base), 2);
+  VipsImage *tmp;
 
   int ret =
-    vips_colourspace(in, &t[0], VIPS_INTERPRETATION_sRGB, NULL) ||
-    vips_ensure_alpha(t[0], &t[1]) ||
-    vips_embed(t[1], out, x, y, width, height, "extend", VIPS_EXTEND_BLACK, NULL);
+    vips_ensure_alpha(in, &tmp) ||
+    vips_embed(tmp, out, x, y, width, height, "extend", VIPS_EXTEND_BLACK, NULL);
 
-  clear_image(&base);
+  clear_image(&tmp);
 
   return ret;
 }

vips/vips.go

@@ -573,6 +573,10 @@ func (img *Image) Sharpen(sigma float32) error {
 	return nil
 }
 
+func (img *Image) IsCMYK() bool {
+	return C.vips_image_guess_interpretation(img.VipsImage) == C.VIPS_INTERPRETATION_CMYK
+}
+
 func (img *Image) ImportColourProfile() error {
 	var tmp *C.VipsImage