screenshots

A command line utility and package for capturing screenshots for Flutter.

Screenshot with overlaid status bar and appended navigation bar placed in a device frame.

For an example of images generated with screenshots on a live app see:

Demo of screenshots in action:

For introduction to screenshots see article.

For information on automating screenshots with a CI/CD tool see
fledge.

Screenshots

screenshots is a standalone command line utility and package for capturing screenshots for
Flutter. It will start the required android emulators and iOS simulators, run your screen
capture tests on each emulator/simulator for each locale your app supports, process the images, and drop them off for Fastlane
for delivery to both stores.

It is inspired by three products from Fastlane:

1. Snapshots
   This is used to capture screenshots on iOS using iOS UI Tests.
2. Screengrab
   This captures screenshots on android using android espresso tests.
3. FrameIt
   This is used to place captured iOS screenshots in a device frame.

screenshots combines key features of all three Fastlane products.

1. Captures screenshots from any iOS simulator or android emulator and processes images.
2. Frames screenshots in an iOS or android device frame.
3. The same Flutter integration test can be used across all simulators/emulators.
   No need to use iOS UI Tests or Espresso.
4. Integrates with Fastlane's deliver
   and supply for upload to respective stores.

Usage

$ screenshots

Or, if using a config file other than the default 'screenshots.yaml':

$ screenshots -c <path to config file>

Modifying tests for screenshots

Capturing screenshots using this package is straightforward.

A special function is provided in
the screenshots package that is called by the test each time you want to capture a screenshot.
screenshots will
then process the images appropriately during a screenshots run.

To capture screenshots in your tests:

1. Include the screenshots package in your pubspec.yaml's dev_dependencies section

     screenshots: ^<current version>
   

   YAML
2. In your tests
   1. Import the dependencies

      import 'package:screenshots/config.dart';
      import 'package:screenshots/capture_screen.dart';
      

      Dart
   2. Create the config map at start of test

           final Map config = Config().config;
      

      Dart
   3. Throughout the test make calls to capture screenshots

          await screenshot(driver, config, 'myscreenshot1');
      

      Dart

Note: make sure your screenshot names are unique across all your tests.

Note: to turn off the debug banner on your screens, in your integration test's main(), call:

  WidgetsApp.debugAllowBannerOverride = false; // remove debug banner for screenshots

screenshots on Travis

To view screenshots running with the example app on travis see:
https://travis-ci.com/mmcc007/screenshots

To download the images generated by screenshots during run on travis see:
https://github.com/mmcc007/screenshots/releases/

Configuration

To run screenshots you need to setup a configuration file, screenshots.yaml:

# Screen capture tests
tests:
  - test_driver/test1.dart
  - test_driver/test2.dart

# Interim location of screenshots from tests
staging: /tmp/screenshots

# A list of locales supported by the app
locales:
  - de-DE
  - en-US

# A list of devices to emulate
devices:
  ios:
    - iPhone X
#    - iPhone 7 Plus
    - iPad Pro (12.9-inch) (2nd generation)
#   "iPhone 6",
#   "iPhone 6 Plus",
#   "iPhone 5",
#   "iPhone 4s",
#   "iPad Retina",
#   "iPad Pro"
  android:
    - Nexus 6P
#    - Nexus 5X

# Frame screenshots
frame: true

Note: emulators and simulators corresponding to the devices in your config file must be installed
on your test machine.

Changing configuration

If you want to change the list of devices to run, to get different screenshots, make sure the devices
you select have supported screens and corresponding emulators/simulators.

Within each class of ios and android device, multiple devices share the same screen size.
Devices are therefore organized by supported screens in a file called screens.yaml.

To modify the config file with the devices you select to emulate/simulate:

1. Locate each selected device in latest
   screens.yaml.
   Use the latest screens.yaml, not the sample below.
2. Modify the list of devices in screenshots.yaml to your selected devices.
   Confirm that each selected device name matches a name used in screens.yaml
3. Install an emulator/simulator for each selected device.
   Confirm that each selected device used in screenshots.yaml has an emulator/simulator
   with a matching name.

screenshots will validate the config file before running.

Sample screens.yaml:

ios:
  5.5inch:
    size: 1242x2208
    resize: 75%
    resources:
      statusbar: resources/ios/1242/statusbar_black.png
      frame: resources/ios/phones/iPhone_7_Plus_Silver.png
    offset: -0-0
    devices:
      - iPhone 7 Plus
  12.9inch:
    size: 2048x2732
    resize: 75%
    resources:
      frame: resources/ios/phones/iPad_Pro_Silver.png
    offset: -0-0
    devices:
      - iPad Pro (12.9-inch) (2nd generation)
android:
  5.2inch:
    size: 1080x1920
    resize: 80%
    resources:
      statusbar: resources/android/1080/statusbar.png
      navbar: resources/android/1080/navbar.png
      frame: resources/android/phones/Nexus_5X.png
     offset: -4-9
    devices:
      - Nexus 5X
    destName: phone

If you want to use a device that is not included in screens.yaml
, please create an issue. Include
the name of the device and preferably the size of the screen in pixels
(for example, Nexus 5X:1080x1920).

Installation

To install screenshots on the command line:

$ pub global activate screenshots

To upgrade, simply re-issue the command

$ pub global activate screenshots

Note: the screenshots version should be the same for both the command line and package:

1. If upgrading the command line version of screenshots, it is helpful to also upgrade
   the version of screenshots in your pubspec.yaml.
2. If upgrading screenshots in your pubspec.yaml, you should also upgrade the command line version.

Dependencies

screenshots depends on ImageMagick.

Since screenshots are required by both Apple and Google stores, testing should be done on a Mac
(unless you are only testing for android).

brew update && brew install imagemagick

Integration with Fastlane

Since screenshots is intended to be used with Fastlane, after screenshots completes,
the images can be found in:

android/fastlane/metadata/android
ios/fastlane/screenshots

GitHub

https://github.com/mmcc007/screenshots