From 3e41f8b65e99176fc64d4669f753f42fefc84add Mon Sep 17 00:00:00 2001
From: Lovell Fuller <github@lovell.info>
Date: Fri, 21 Mar 2025 09:36:25 +0000
Subject: [PATCH] Non-animated GIF output defaults to no-loop #3394

---
 docs/src/content/docs/changelog.md |  3 +++
 lib/constructor.js                 |  2 ++
 src/pipeline.cc                    |  9 ++-------
 src/pipeline.h                     |  2 +-
 test/unit/gif.js                   | 14 ++++++++++++++
 5 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/docs/src/content/docs/changelog.md b/docs/src/content/docs/changelog.md
index e66f042f..9e30b970 100644
--- a/docs/src/content/docs/changelog.md
+++ b/docs/src/content/docs/changelog.md
@@ -14,6 +14,9 @@ Requires libvips v8.16.1
 * Breaking: Ensure `removeAlpha` removes all alpha channels.
   [#2266](https://github.com/lovell/sharp/issues/2266)
 
+* Breaking: Non-animated GIF output defaults to no-loop instead of loop-forever.
+  [#3394](https://github.com/lovell/sharp/issues/3394)
+
 * Breaking: Support `info.size` on wide-character systems via upgrade to C++17.
   [#3943](https://github.com/lovell/sharp/issues/3943)
 
diff --git a/lib/constructor.js b/lib/constructor.js
index 7290d368..32a80ede 100644
--- a/lib/constructor.js
+++ b/lib/constructor.js
@@ -296,6 +296,8 @@ const Sharp = function (input, options) {
     withExif: {},
     withExifMerge: true,
     resolveWithObject: false,
+    loop: 1,
+    delay: [],
     // output format
     jpegQuality: 80,
     jpegProgressive: false,
diff --git a/src/pipeline.cc b/src/pipeline.cc
index 69715aa7..770c2bbd 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -1705,6 +1705,8 @@ Napi::Value pipeline(const Napi::CallbackInfo& info) {
   }
   baton->withExifMerge = sharp::AttrAsBool(options, "withExifMerge");
   baton->timeoutSeconds = sharp::AttrAsUint32(options, "timeoutSeconds");
+  baton->loop = sharp::AttrAsUint32(options, "loop");
+  baton->delay = sharp::AttrAsInt32Vector(options, "delay");
   // Format-specific
   baton->jpegQuality = sharp::AttrAsUint32(options, "jpegQuality");
   baton->jpegProgressive = sharp::AttrAsBool(options, "jpegProgressive");
@@ -1774,13 +1776,6 @@ Napi::Value pipeline(const Napi::CallbackInfo& info) {
   baton->jxlEffort = sharp::AttrAsUint32(options, "jxlEffort");
   baton->jxlLossless = sharp::AttrAsBool(options, "jxlLossless");
   baton->rawDepth = sharp::AttrAsEnum<VipsBandFormat>(options, "rawDepth", VIPS_TYPE_BAND_FORMAT);
-  // Animated output properties
-  if (sharp::HasAttr(options, "loop")) {
-    baton->loop = sharp::AttrAsUint32(options, "loop");
-  }
-  if (sharp::HasAttr(options, "delay")) {
-    baton->delay = sharp::AttrAsInt32Vector(options, "delay");
-  }
   baton->tileSize = sharp::AttrAsUint32(options, "tileSize");
   baton->tileOverlap = sharp::AttrAsUint32(options, "tileOverlap");
   baton->tileAngle = sharp::AttrAsInt32(options, "tileAngle");
diff --git a/src/pipeline.h b/src/pipeline.h
index be53d6ad..90d6f85c 100644
--- a/src/pipeline.h
+++ b/src/pipeline.h
@@ -380,7 +380,7 @@ struct PipelineBaton {
     ensureAlpha(-1.0),
     colourspacePipeline(VIPS_INTERPRETATION_LAST),
     colourspace(VIPS_INTERPRETATION_LAST),
-    loop(-1),
+    loop(1),
     tileSize(256),
     tileOverlap(0),
     tileContainer(VIPS_FOREIGN_DZ_CONTAINER_FS),
diff --git a/test/unit/gif.js b/test/unit/gif.js
index f067dcc1..3b041b69 100644
--- a/test/unit/gif.js
+++ b/test/unit/gif.js
@@ -224,4 +224,18 @@ describe('GIF input', () => {
     const after = await input.gif({ interPaletteMaxError: 100 }).toBuffer();
     assert.strict(before.length > after.length);
   });
+
+  it('non-animated input defaults to no-loop', async () => {
+    for (const input of [fixtures.inputGif, fixtures.inputPng]) {
+      const data = await sharp(input)
+        .resize(8)
+        .gif({ effort: 1 })
+        .toBuffer();
+
+      const { format, pages, loop } = await sharp(data).metadata();
+      assert.strictEqual('gif', format);
+      assert.strictEqual(1, pages);
+      assert.strictEqual(1, loop);
+    }
+  });
 });