Make sharpen mask on image reduction configurable.

Gemfile.lock

@@ -10,7 +10,7 @@ GIT
 PATH
   remote: .
   specs:
-    carrierwave-vips (1.1.2)
+    carrierwave-vips (1.1.3)
       carrierwave (>= 0.11.0)
       ruby-vips (~> 1.0, >= 1.0.2)
 

README.md

@@ -45,6 +45,25 @@ You can use the following methods to change your images.
 
 To see how vips stands up to other image processing libraries, see this benchmark:  https://github.com/stanislaw/carrierwave-vips-benchmarks
 
+Configuration
+-------------
+
+When reducing the size of images, a sharpening mask is used. To change or disable this behavior:
+
+```
+CarrierWave::Vips.configure do |c|
+  c.sharpen_mask = false  # Disable sharpening mask on image reduction
+  c.sharpen_mask = [      # Default mask
+    [ -1, -1, -1 ], 
+    [ -1, 24, -1 ], 
+    [ -1, -1, -1 ] 
+  ]
+  c.sharpen_scale = 16     
+end
+```
+
+See VIPS::Image.new_from_array for more information on what these two do. 
+
 Special considerations
 ----------------------
 

carrierwave-vips.gemspec

@@ -1,7 +1,7 @@
 Gem::Specification.new do |s|
   s.name        = 'carrierwave-vips'
-  s.version     = '1.1.2'
-  s.date        = '2016-09-06'
+  s.version     = '1.1.3'
+  s.date        = '2016-10-26'
   s.summary     = "Adds VIPS support to CarrierWave"
   s.description = "Adds VIPS support to CarrierWave"
   s.authors     = ["Jeremy Nicoll"]

lib/carrierwave/vips.rb

@@ -3,13 +3,16 @@
 module CarrierWave
   module Vips
 
-    SHARPEN_MASK = begin
-      conv_mask = [
-        [ -1, -1, -1 ],
-        [ -1, 24, -1 ],
-        [ -1, -1, -1 ]
-      ]
-      ::Vips::Image.new_from_array conv_mask, 16
+    def self.configure
+      @config ||= begin
+        c = Struct.new(:sharpen_mask, :sharpen_scale).new
+        c.sharpen_mask = [ [ -1, -1, -1 ], [ -1, 24, -1 ], [ -1, -1, -1 ] ]
+        c.sharpen_scale = 16
+        c
+      end
+      @config
+      yield @config if block_given?
+      @config
     end
 
     def self.included(base)
@@ -256,7 +259,7 @@ def resize_image(image, width, height, min_or_max = :min)
         image = image.resize(ratio, kernel: :nearest)
       else
         image = image.resize(ratio, kernel: :cubic)
-        image = image.conv SHARPEN_MASK
+        image = image.conv(cwv_sharpen_mask) if cwv_config.sharpen_mask
       end
       image
     end
@@ -284,5 +287,13 @@ def ext(path)
       matches && matches[1].downcase
     end
 
+    def cwv_config
+      CarrierWave::Vips.configure
+    end
+
+    def cwv_sharpen_mask(mask = cwv_config.sharpen_mask, scale = cwv_config.sharpen_scale)
+      ::Vips::Image.new_from_array(mask, scale)
+    end
+
   end # Vips
 end # CarrierWave