Merge pull request #148 from rubycdp/feature/screenshot_with_specific_background_color

Screenshot with specific background color

Author: route

README.md

@@ -335,6 +335,7 @@ Saves screenshot on a disk or returns it as base64.
   * :full `Boolean` whether you need full page screenshot or a viewport
   * :selector `String` css selector for given element
   * :scale `Float` zoom in/out
+  * :background_color `Ferrum::RGBA.new(0, 0, 0, 0.0)` to have specific background color
 
 ```ruby
 browser.go_to("https://google.com/")
@@ -344,6 +345,8 @@ browser.screenshot(path: "google.png") # => 134660
 browser.screenshot(path: "google.jpg") # => 30902
 # Save to Base64 the whole page not only viewport and reduce quality
 browser.screenshot(full: true, quality: 60) # "iVBORw0KGgoAAAANSUhEUgAABAAAAAMACAYAAAC6uhUNAAAAAXNSR0IArs4c6Q...
+# Save with specific background color
+browser.screenshot(background_color: Ferrum::RGBA.new(0, 0, 0, 0.0)) 
 ```
 
 #### pdf(\*\*options) : `String` | `Boolean`

lib/ferrum/page/screenshot.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require "ferrum/rbga"
+
 module Ferrum
   class Page
     module Screenshot
@@ -29,7 +31,7 @@ module Screenshot
       def screenshot(**opts)
         path, encoding = common_options(**opts)
         options = screenshot_options(path, **opts)
-        data = capture_screenshot(options, opts[:full])
+        data = capture_screenshot(options, opts[:full], opts[:background_color])
         return data if encoding == :base64
 
         bin = Base64.decode64(data)
@@ -170,9 +172,11 @@ def to_camel_case(option)
         option.to_s.gsub(/(?:_|(\/))([a-z\d]*)/) { "#{$1}#{$2.capitalize}" }.to_sym
       end
 
-      def capture_screenshot(options, full)
+      def capture_screenshot(options, full, background_color)
         maybe_resize_fullscreen(full) do
-          command("Page.captureScreenshot", **options)
+          with_background_color(background_color) do
+            command("Page.captureScreenshot", **options)
+          end
         end.fetch("data")
       end
 
@@ -186,6 +190,18 @@ def maybe_resize_fullscreen(full)
       ensure
         resize(width: width, height: height) if full
       end
+
+      def with_background_color(color)
+        if color
+          raise ArgumentError, "Accept Ferrum::RGBA class only" unless color.is_a?(RGBA)
+
+          command('Emulation.setDefaultBackgroundColorOverride', color: color.to_h)
+        end
+
+        yield
+      ensure
+        command('Emulation.setDefaultBackgroundColorOverride') if color
+      end
     end
   end
 end

lib/ferrum/rbga.rb

@@ -0,0 +1,38 @@
+module Ferrum
+  class RGBA
+    def initialize(red, green, blue, alpha)
+      self.red = red
+      self.green = green
+      self.blue = blue
+      self.alpha = alpha
+
+      validate
+    end
+
+    def to_h
+      { r: red, g: green, b: blue, a: alpha }
+    end
+
+    private
+
+    attr_accessor :red, :green, :blue, :alpha
+
+    def validate
+      [red, green, blue].each(&method(:validate_color))
+      validate_alpha
+    end
+
+    def validate_color(value)
+      return if value && value.is_a?(Integer) && Range.new(0, 255).include?(value)
+
+      raise ArgumentError, "Wrong value of #{value} should be Integer from 0 to 255"
+    end
+
+    def validate_alpha
+      return if alpha && alpha.is_a?(Float) && Range.new(0.0, 1.0).include?(alpha)
+
+      raise ArgumentError,
+            "Wrong alpha value #{alpha} should be Float between 0.0 (fully transparent) and 1.0 (fully opaque)"
+    end
+  end
+end

spec/rbga_spec.rb

@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "ferrum/rbga"
+
+module Ferrum
+  describe RGBA do
+    describe '#to_h' do
+      it { expect(RGBA.new(0, 0, 0, 0.0).to_h).to eq({ r: 0, g: 0, b: 0, a: 0.0 }) }
+      it { expect(RGBA.new(255, 255, 255, 1.0).to_h).to eq({ r: 255, g: 255, b: 255, a: 1.0 }) }
+    end
+
+    it 'raises ArgumentError for not Float value of alpha' do
+      expect {
+        RGBA.new(0, 0, 0, 0)
+      }.to raise_exception(
+             ArgumentError,
+             'Wrong alpha value 0 should be Float between 0.0 (fully transparent) and 1.0 (fully opaque)')
+    end
+
+    it 'raises ArgumentError wrong value of alpha' do
+      expect {
+        RGBA.new(0, 0, 0, 2.0)
+      }.to raise_exception(
+             ArgumentError,
+             'Wrong alpha value 2.0 should be Float between 0.0 (fully transparent) and 1.0 (fully opaque)')
+    end
+
+    it 'raises ArgumentError for wrong value of red' do
+      expect {
+        RGBA.new(-1, 0, 0, 0.0)
+      }.to raise_exception(ArgumentError, 'Wrong value of -1 should be Integer from 0 to 255')
+    end
+
+    it 'raises ArgumentError for wrong value of green' do
+      expect {
+        RGBA.new(0, 256, 0, 0.0)
+      }.to raise_exception(ArgumentError, 'Wrong value of 256 should be Integer from 0 to 255')
+    end
+
+    it 'raises ArgumentError for wrong value of blue' do
+      expect {
+        RGBA.new(0, 0, 0.0, 0.0)
+      }.to raise_exception(ArgumentError, 'Wrong value of 0.0 should be Integer from 0 to 255')
+    end
+  end
+end

spec/screenshot_spec.rb

@@ -3,6 +3,7 @@
 require "image_size"
 require "pdf/reader"
 require "chunky_png"
+require "ferrum/rbga"
 
 module Ferrum
   describe Browser do
@@ -176,6 +177,29 @@ def create_screenshot(**options)
           end
         end
 
+        describe 'background_color option' do
+          it 'supports screenshotting page with the specific background color' do
+            begin
+              file = PROJECT_ROOT + "/spec/tmp/screenshot.jpeg"
+              browser.go_to
+              browser.screenshot(path: file)
+              content = File.read(file)
+              browser.screenshot(path: file, background_color: RGBA.new(0, 0, 0, 0.0))
+              content_with_specific_bc = File.read(file)
+              expect(content).not_to eq(content_with_specific_bc)
+            ensure
+              FileUtils.rm_f([file])
+            end
+          end
+
+          it 'raises ArgumentError with proper message' do
+            browser.go_to
+            expect {
+              browser.screenshot(path: file, background_color: '#FFF')
+            }.to raise_exception(ArgumentError, 'Accept Ferrum::RGBA class only')
+          end
+        end
+
         shared_examples "when scale is set" do
           it "changes image dimensions" do
             browser.go_to("/ferrum/zoom_test")