From 82ec2715f1bc33844806c77c1f3e8881f098569c Mon Sep 17 00:00:00 2001
From: Matt Hirsch <mhirsch@media.mit.edu>
Date: Sat, 13 Aug 2016 09:55:15 -0400
Subject: [PATCH] Prevent bandbool creating a single channel sRGB image (#519)

---
 src/operations.cc     |  3 ++-
 test/unit/bandbool.js | 13 ++++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/operations.cc b/src/operations.cc
index b1a3f1d9..1c05d2db 100644
--- a/src/operations.cc
+++ b/src/operations.cc
@@ -396,7 +396,8 @@ namespace sharp {
     Perform boolean/bitwise operation on image color channels - results in one channel image
   */
   VImage Bandbool(VImage image, VipsOperationBoolean const boolean) {
-    return image.bandbool(boolean);
+    image = image.bandbool(boolean);
+    return image.copy(VImage::option()->set("interpretation", VIPS_INTERPRETATION_B_W));
   }
 
   /*
diff --git a/test/unit/bandbool.js b/test/unit/bandbool.js
index d1d9de0b..2194dcc4 100644
--- a/test/unit/bandbool.js
+++ b/test/unit/bandbool.js
@@ -16,15 +16,26 @@ describe('Bandbool per-channel boolean operations', function() {
       sharp(fixtures.inputPngBooleanNoAlpha)
         .bandbool(op)
         .toBuffer(function(err, data, info) {
+          // should use .toColourspace('b-w') here to get 1 channel output, when it is merged
           if (err) throw err;
           assert.strictEqual(200, info.width);
           assert.strictEqual(200, info.height);
-          assert.strictEqual(1, info.channels);
+          //assert.strictEqual(1, info.channels);
+          assert.strictEqual(3, info.channels);
           fixtures.assertSimilar(fixtures.expected('bandbool_' + op + '_result.png'), data, done);
         });
     });
   });
 
+  it('sRGB image retains 3 channels', function(done) {
+    sharp(fixtures.inputJpg)
+      .bandbool('and')
+      .toBuffer(function(err, data, info) {
+        assert.strictEqual(3, info.channels);
+        done();
+      });
+  });          
+
   it('Invalid operation', function() {
     assert.throws(function() {
       sharp().bandbool('fail');