From aba1d58246c7bd015d691b2c696730291d723ead Mon Sep 17 00:00:00 2001
From: Joseph Wynn <joseph@wildlyinaccurate.com>
Date: Sun, 16 Jul 2017 21:19:43 +0100
Subject: [PATCH] Enable "cache" option in _config.yml

Fixes #66
---
 README.md                               | 30 +++++++++++++++++++++++++
 lib/jekyll-responsive-image/config.rb   |  3 ++-
 lib/jekyll-responsive-image/renderer.rb |  6 ++---
 lib/jekyll-responsive-image/version.rb  |  2 +-
 4 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 60d600b..07cc999 100644
--- a/README.md
+++ b/README.md
@@ -75,6 +75,11 @@ responsive_image:
   # Whether or not to save the generated assets into the source folder.
   save_to_source: false
 
+  # [Optional, Default: false]
+  # Cache the result of {% responsive_image %} and {% responsive_image_block %}
+  # tags. See the "Caching" section of the README for more information.
+  cache: false
+
   # [Optional, Default: []]
   # By default, only images referenced by the responsive_image and responsive_image_block
   # tags are resized. Here you can set a list of paths or path globs to resize other
@@ -213,3 +218,28 @@ Image objects (like `original` and each object in `resized`) contain the followi
 | `dirname`   | String  | Directory of the file relative to `base_path` (`assets/sub/dir/some-file.jpg` => `sub/dir`). |
 | `filename`  | String  | Basename without the extension (`assets/some-file.jpg` => `some-file`).                      |
 | `extension` | String  | Extension of the file (`assets/some-file.jpg` => `jpg`).                                     |
+
+### Caching
+
+You may be able to speed up the build of large sites by enabling render caching. This is usually only effective when the same image is used many times, for example a header image that is rendered in every post.
+
+The recommended way to enable caching is on an image-by-image basis, by adding `cache: true` to the tag:
+
+```twig
+{% responsive_image path: 'assets/my-file.jpg' cache: true %}
+
+{% responsive_image_block %}
+    path: assets/my-file.jpg
+    cache: true
+{% endresponsive_image_block %}
+```
+
+You can also enable it for all images by adding `cache: true` to your `_config.yml`:
+
+```yaml
+responsive_image:
+  cache: true
+  template: _includes/responsive-image.html
+  sizes:
+    - ...
+```
diff --git a/lib/jekyll-responsive-image/config.rb b/lib/jekyll-responsive-image/config.rb
index 261035e..7d4f368 100644
--- a/lib/jekyll-responsive-image/config.rb
+++ b/lib/jekyll-responsive-image/config.rb
@@ -8,7 +8,8 @@ module Jekyll
         'sizes'              => [],
         'extra_images'       => [],
         'auto_rotate'        => false,
-        'save_to_source'     => true
+        'save_to_source'     => true,
+        'cache'              => false
       }
 
       def initialize(site)
diff --git a/lib/jekyll-responsive-image/renderer.rb b/lib/jekyll-responsive-image/renderer.rb
index 06a3263..2175af3 100644
--- a/lib/jekyll-responsive-image/renderer.rb
+++ b/lib/jekyll-responsive-image/renderer.rb
@@ -9,12 +9,12 @@ module Jekyll
       end
 
       def render_responsive_image
+        config = Config.new(@site).to_h
+        use_cache = config['cache'] || @attributes['cache']
         cache_key = @attributes.to_s
-        result = @attributes['cache'] ? RenderCache.get(cache_key) : nil
+        result = use_cache ? RenderCache.get(cache_key) : nil
 
         if result.nil?
-          config = Config.new(@site).to_h
-
           image = ImageProcessor.process(@attributes['path'], config)
           @attributes['original'] = image[:original]
           @attributes['resized'] = image[:resized]
diff --git a/lib/jekyll-responsive-image/version.rb b/lib/jekyll-responsive-image/version.rb
index 29ebf7d..c93c025 100644
--- a/lib/jekyll-responsive-image/version.rb
+++ b/lib/jekyll-responsive-image/version.rb
@@ -1,5 +1,5 @@
 module Jekyll
   module ResponsiveImage
-    VERSION = '1.3.1'.freeze
+    VERSION = '1.4.0'.freeze
   end
 end