From ee21d2991c798e73e44ea43a06153cbcbf416f13 Mon Sep 17 00:00:00 2001
From: Lovell Fuller <github@lovell.info>
Date: Thu, 31 Mar 2016 20:53:15 +0100
Subject: [PATCH] Use shrink-on-load for WebP input

---
 docs/changelog.md |  6 ++++++
 src/pipeline.cc   | 23 +++++++++++++++++------
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/docs/changelog.md b/docs/changelog.md
index 13756a3b..72e4dc03 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -1,5 +1,11 @@
 # Changelog
 
+### v0.15 - "*outfit*"
+
+* Take advantage of libvips 8.3 features.
+  Use shrink-on-load for WebP input.
+  [#369](https://github.com/lovell/sharp/issues/369)
+
 ### v0.14 - "*needle*"
 
 Requires libvips v8.2.3
diff --git a/src/pipeline.cc b/src/pipeline.cc
index 2518c0f5..2fd4fa37 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -303,7 +303,8 @@ class PipelineWorker : public AsyncWorker {
       // but not when applying gamma correction or pre-resize extract
       int shrink_on_load = 1;
       if (
-        xshrink == yshrink && inputImageType == ImageType::JPEG && xshrink >= 2 &&
+        xshrink == yshrink && xshrink >= 2 &&
+        (inputImageType == ImageType::JPEG || inputImageType == ImageType::WEBP) &&
         baton->gamma == 0 && baton->topOffsetPre == -1
       ) {
         if (xshrink >= 8) {
@@ -329,15 +330,25 @@ class PipelineWorker : public AsyncWorker {
         xresidual = CalculateResidual(xshrink, xfactor);
         yresidual = CalculateResidual(yshrink, yfactor);
         // Reload input using shrink-on-load
+        VOption *option = VImage::option()->set("shrink", shrink_on_load);
         if (baton->bufferInLength > 1) {
           VipsBlob *blob = vips_blob_new(nullptr, baton->bufferIn, baton->bufferInLength);
-          image = VImage::jpegload_buffer(blob, VImage::option()->set("shrink", shrink_on_load));
+          if (inputImageType == ImageType::JPEG) {
+            // Reload JPEG buffer
+            image = VImage::jpegload_buffer(blob, option);
+          } else {
+            // Reload WebP buffer
+            image = VImage::webpload_buffer(blob, option);
+          }
           vips_area_unref(reinterpret_cast<VipsArea*>(blob));
         } else {
-          image = VImage::jpegload(
-            const_cast<char*>((baton->fileIn).data()),
-            VImage::option()->set("shrink", shrink_on_load)
-          );
+          if (inputImageType == ImageType::JPEG) {
+            // Reload JPEG file
+            image = VImage::jpegload(const_cast<char*>((baton->fileIn).data()), option);
+          } else {
+            // Reload WebP file
+            image = VImage::webpload(const_cast<char*>((baton->fileIn).data()), option);
+          }
         }
       }