README.md in motion-juxtapose-0.1.1 vs README.md in motion-juxtapose-0.2.0

@@ -1,11 +1,15 @@
 # Juxtapose
 
-Screenshot-driven assertions for testing RubyMotion applications.
+Screenshot-driven assertions for testing Rails and RubyMotion applications.
 
 ## Installation
 
+Motion-juxtapose uses [ImageMagick](http://www.imagemagick.org/) under the hood for image comparison. If you're using [Homebrew](http://brew.sh/), you can install it with:
+
+    brew install imagemagick
+
 Add this line to your application's Gemfile:
 
     gem 'motion-juxtapose'
 
 And then execute:
@@ -20,17 +24,19 @@
 
 Juxtapose's workflow generally goes:
 
 1. Write a test that puts your app in the state you want to capture and take a screenshot (see below for how to do this in Bacon and Frank).
 2. The first time this screenshot is captured, your test will fail with the error "No accepted screen shot".
-3. You must provide Juxtapose an accepted screenshot to match against in future test runs. Run the juxtapose server with `bundle exec juxtapose` and browse to http://localhost:4567 — you should the just-captured screenshot, like below.
+3. You must provide Juxtapose an accepted screenshot to match against in future test runs. Run the juxtapose server with `bundle exec juxtapose` and browse to http://localhost:4567 — you should see the just-captured screenshot, like below.
 4. If the screenshot looks like what you expect, click Accept to save the image. Future runs of this test will be compared against the accepted one. ![Initial view of screenshots.](images/initial-view.png)
 5. Run the tests again, and they should be green.
 6. Later, when you introduce a change (intentionally or not), the tests will fail with the message "Screenshot did not match". Open up the juxtapose server again, and you'll see a comparison of your accepted screenshot with what the test captured. ![Diff view of screenshots.](images/diff-view.png)
 7. If the change was intentional, you can accept the new screenshot - otherwise, you've got some fixin' to do!
 
 
+## Testing RubyMotion Apps
+
 ### MacBacon
 
 Juxtapose provides a single new matcher: `it_should_look_like` takes a single argument, a descriptive string predicate of what the screen should look like.
 
 Example:
@@ -68,16 +74,67 @@
   max_attempts = 20
   expect(screenshotter.attempt_verify(max_attempts)).to eq(true)
 end
 ```
 
+## Testing Rails Apps
+
+### Capybara
+
+Any Capybara driver that supports screenshot capture should work, but I've only tested this with [Poltergeist](https://github.com/teampoltergeist/poltergeist) so far.
+
+In your `spec_helper.rb`, add:
+
+```ruby
+require 'juxtapose/capybara'
+
+# if you're using Rspec, you can get the `look_like?` custom matcher with:
+require 'juxtapose/rspec'
+```
+
+Now the Capybara page object will have a `looks_like?(predicate)` method that can call to make screenshot assertions:
+
+```ruby
+feature "viewing locations", js: true do
+  scenario "should only show books at first location" do
+    visit location_path Location.find_by_name("Cambridge")
+    expect(page).to look_like("books at Cambridge")
+  end
+end
+```
+
+### Fuzzy matching
+
+Sometimes screenshots will differ slightly due to things like animation timing. Juxtapose will try to match an existing screenshot multiple times to help counteract this, but it can still be useful to be able to match screenshots using a percent similarity threshold. 
+
+In bacon specs, you can pass a fuzz factor from 0 to 100 to `it_should_look_like`, 0 meaning an exact match and 100 matching anything of the same size. The default is 0.
+
+```ruby
+# matches images that are 15% similar
+it_should_look_like 'a fancy animation', 15
+```
+
+In Frank, pass the fuzz factor in as the third argument to the Screenshotter constructor. A more exacting Frank step could be written as:
+
+```ruby
+Then /^the screen should match "([^\"]*)" within (\d+)% in (\d+) attempts$/ do |template, fuzz_factor, max_attempts|
+  wait_for_nothing_to_be_animating
+  screenshotter = Juxtapose::Screenshotter.new(self, template, fuzz_factor)
+  expect(screenshotter.attempt_verify(max_attempts)).to eq(true)
+end
+```
+
 ### Juxtapose Server
 
 Juxtapose comes with a small webapp that you can use to view your screenshot specs, see diffs between accepted and failing specs and accept any changed images that are expected changes.
 
 To start it, run `bundle exec juxtapose` in the root of your project and browse to localhost:4567.
 
 ## Release Notes
+
+#### v.0.2.0
+* Rails/rspec support
+* Fixes to work under newest version of ImageMagick
 
 #### v.0.1.1
 
 * Raise error if screenshot sizes don't match ([@mdenomy](http://github.com/mdenomy))
 * Bug fix: Differentiate image status by filename, not full path. Fixes #8.