[minimagick] Add #define as a wrapper around -define

There is no reason this method shouldn't be public, and it's nice in
cases where settings we're defining don't apply to neither saving nor
loading images.

CHANGELOG.md

@@ -1,3 +1,7 @@
+## HEAD
+
+* [minimagick] Add `#define` as a wrapper around `-define` (@janko-m)
+
 ## 1.1.0 (2018-04-05)
 
 * [minimagick] Disallow splitting multi-layer images into multiple single-layer

doc/minimagick.md

@@ -153,6 +153,16 @@ File.extname(result.path)
 By default the original format is retained when writing the image to a file. If
 the source file doesn't have a file extension, the format will default to JPEG.
 
+#### `#define`
+
+Adds coder/decoder options with [`-define`] from the specified Hash.
+
+```rb
+ImageProcessing::MiniMagick
+  .define(png: { compression_level: 8, format: "png8" }) # -define png:compression-level=8 -define png:format=png8
+  # ...
+```
+
 #### `#method_missing`
 
 Any unknown methods will be delegated to [`MiniMagick::Tool::Convert`].

lib/image_processing/mini_magick.rb

@@ -43,6 +43,22 @@ module ImageProcessing
         magick.extent "#{width}x#{height}"
       end
 
+      def define(magick, options)
+        return magick.define(options) if options.is_a?(String)
+
+        options.each do |namespace, options|
+          namespace = namespace.to_s.gsub("_", "-")
+
+          options.each do |key, value|
+            key = key.to_s.gsub("_", "-")
+
+            magick.define "#{namespace}:#{key}=#{value}"
+          end
+        end
+
+        magick
+      end
+
       def limits(magick, options)
         limit_args = options.flat_map { |type, value| %W[-limit #{type} #{value}] }
         prepend_args(magick, limit_args)
@@ -98,19 +114,7 @@ module ImageProcessing
 
       def apply_options(magick, define: {}, **options)
         apply(magick, options)
-        apply_define(magick, define)
-      end
-
-      def apply_define(magick, define)
-        define.each do |namespace, options|
-          namespace = namespace.to_s.gsub("_", "-")
-
-          options.each do |key, value|
-            key = key.to_s.gsub("_", "-")
-
-            magick.define "#{namespace}:#{key}=#{value}"
-          end
-        end
+        define(magick, define)
       end
 
       def prepend_args(magick, args)

test/mini_magick_test.rb

@@ -39,19 +39,6 @@ describe "ImageProcessing::MiniMagick" do
     assert_similar expected, actual
   end
 
-  it "applies appended options" do
-    actual = ImageProcessing::MiniMagick.append("-resize", "400x400").call(@portrait)
-    expected = Tempfile.new(["result", ".jpg"], binmode: true).tap do |tempfile|
-      MiniMagick::Tool::Convert.new do |cmd|
-        cmd << @portrait.path
-        cmd.resize("400x400")
-        cmd << tempfile.path
-      end
-    end
-
-    assert_similar expected, actual
-  end
-
   it "applies format" do
     result = ImageProcessing::MiniMagick.convert("png").call(@portrait)
     assert_equal ".png", File.extname(result.path)
@@ -301,6 +288,26 @@ describe "ImageProcessing::MiniMagick" do
     end
   end
 
+  describe "#define" do
+    it "adds -define options from a Hash" do
+      magick = ImageProcessing::MiniMagick
+        .source(@portrait)
+        .define(png: { compression_level: 8, format: "png8" })
+        .call(save: false)
+
+      assert_equal %W[-define png:compression-level=8 -define png:format=png8], magick.args[2..-1]
+    end
+
+    it "adds -define options from a String" do
+      magick = ImageProcessing::MiniMagick
+        .source(@portrait)
+        .define("png:compression-level=8")
+        .call(save: false)
+
+      assert_equal %W[-define png:compression-level=8], magick.args[2..-1]
+    end
+  end
+
   describe "#limits" do
     it "adds resource limits" do
       pipeline = ImageProcessing::MiniMagick.limits(time: 0.001).source(@portrait)
@@ -308,4 +315,19 @@ describe "ImageProcessing::MiniMagick" do
       assert_includes exception.message, "time limit exceeded"
     end
   end
+
+  describe "#append" do
+    it "appends CLI arguments" do
+      actual = ImageProcessing::MiniMagick.append("-resize", "400x400").call(@portrait)
+      expected = Tempfile.new(["result", ".jpg"], binmode: true).tap do |tempfile|
+        MiniMagick::Tool::Convert.new do |cmd|
+          cmd << @portrait.path
+          cmd.resize("400x400")
+          cmd << tempfile.path
+        end
+      end
+
+      assert_similar expected, actual
+    end
+  end
 end