From 6190ca43078cb684e3a82bc3a9361de1d25e02f6 Mon Sep 17 00:00:00 2001
From: Lovell Fuller <github@lovell.info>
Date: Tue, 7 Oct 2014 10:17:20 +0100
Subject: [PATCH] Ensure conversion to sRGB occurs before background #99

---
 src/sharp.cc  | 29 ++++++++++++++++++++---------
 tests/unit.js | 10 ++++++++++
 2 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/src/sharp.cc b/src/sharp.cc
index 60a98719..53620532 100755
--- a/src/sharp.cc
+++ b/src/sharp.cc
@@ -511,8 +511,9 @@ class ResizeWorker : public NanAsyncWorker {
       image = shrunk_on_load;
     }
 
-    // Import embedded colour profile, if present
-    if (vips_image_get_typeof(image, VIPS_META_ICC_NAME)) {
+    // Handle colour profile, if any, for non sRGB images
+    if (image->Type != VIPS_INTERPRETATION_sRGB && vips_image_get_typeof(image, VIPS_META_ICC_NAME)) {
+      // Import embedded profile
       VipsImage *profile = vips_image_new();
       vips_object_local(hook, profile);
       if (vips_icc_import(image, &profile, NULL, "embedded", TRUE, "pcs", VIPS_PCS_XYZ, NULL)) {
@@ -520,6 +521,14 @@ class ResizeWorker : public NanAsyncWorker {
       }
       g_object_unref(image);
       image = profile;
+      // Convert to sRGB colour space
+      VipsImage *colourspaced = vips_image_new();
+      vips_object_local(hook, colourspaced);
+      if (vips_colourspace(profile, &colourspaced, VIPS_INTERPRETATION_sRGB, NULL)) {
+        return resize_error(baton, hook);
+      }
+      g_object_unref(image);
+      image = colourspaced;
     }
 
     // Flatten image to remove alpha channel
@@ -710,14 +719,16 @@ class ResizeWorker : public NanAsyncWorker {
       image = gamma_decoded;
     }
 
-    // Always convert to sRGB colour space
-    VipsImage *colourspaced = vips_image_new();
-    vips_object_local(hook, colourspaced);
-    if (vips_colourspace(image, &colourspaced, VIPS_INTERPRETATION_sRGB, NULL)) {
-      return resize_error(baton, hook);
+    // Convert to sRGB colour space, if not already
+    if (image->Type != VIPS_INTERPRETATION_sRGB) {
+      VipsImage *colourspaced = vips_image_new();
+      vips_object_local(hook, colourspaced);
+      if (vips_colourspace(image, &colourspaced, VIPS_INTERPRETATION_sRGB, NULL)) {
+        return resize_error(baton, hook);
+      }
+      g_object_unref(image);
+      image = colourspaced;
     }
-    g_object_unref(image);
-    image = colourspaced;
 
     // Generate image tile cache when interlace output is required
     if (baton->progressive) {
diff --git a/tests/unit.js b/tests/unit.js
index ba1a988c..04732a00 100755
--- a/tests/unit.js
+++ b/tests/unit.js
@@ -327,6 +327,16 @@ async.series([
       done();
     });
   },
+  // Check colour space conversion from CMYK to sRGB works with background colour (yellow=fail)
+  function(done) {
+    sharp(inputJpgWithCmykProfile).resize(320, 240).background('white').embed().toFile(path.join(fixturesPath, 'output.cmyk2srgb.jpg'), function(err, info) {
+      if (err) throw err;
+      assert.strictEqual('jpeg', info.format);
+      assert.strictEqual(320, info.width);
+      assert.strictEqual(240, info.height);
+      done();
+    });
+  },
   // Interpolation: nearest neighbour
   function(done) {
     sharp(inputJpg).resize(320, 240).interpolateWith(sharp.interpolator.nearest).toBuffer(function(err, data, info) {