Keeping your Pixels Perfect: Paparazzi 1.0

Unit tests allow you refactor your code with confidence and -- if architected correctly -- run blazingly fast!

But how do you ensure that your UI looks as expected? Espresso tests are hard to set up, prone to flakiness and require APKs, emulators, dexing, ADB...ugh. Snapshot tests get you closer but also rely on instrumentation tests.

Come find out how we're improving the UI testing loop on Cash App with Paparazzi -- an Android testing library to render your application screens without a physical device or emulator!

Video: https://player.vimeo.com/video/646415398

Transcript

1. Keeping your Pixels Perfect
   Paparazzi 1.0
   

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34. class LaunchViewTest
    {
    
    @get:Rul
    e
    
    val paparazzi = Paparazzi(
    )
    
    @Tes
    t
    
    fun launch()
    {
    
    val view = paparazzi.inflate(R.layout.launch
    )
    
    paparazzi.snapshot(view
    )
    
    }
    
    }
    

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35. class LaunchViewTest
    {
    
    @get:Rul
    e
    
    val paparazzi = Paparazzi(
    )
    
    @Tes
    t
    
    fun launch()
    {
    
    val view = paparazzi.inflate(R.layout.launch
    )
    
    paparazzi.snapshot(view
    )
    
    }
    
    }
    

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36. class LaunchViewTest
    {
    
    @get:Rul
    e
    
    val paparazzi = Paparazzi(
    )
    
    @Tes
    t
    
    fun launch()
    {
    
    val view = paparazzi.inflate(R.layout.launch
    )
    
    paparazzi.snapshot(view
    )
    
    }
    
    }
    

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37. class LaunchViewTest
    {
    
    @get:Rul
    e
    
    val paparazzi = Paparazzi(
    )
    
    @Tes
    t
    
    fun launch()
    {
    
    val view = LaunchView(paparazzi.context
    )
    
    paparazzi.snapshot(view
    )
    
    }
    
    }
    

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38. class LaunchViewTest
    {
    
    @get:Rul
    e
    
    val paparazzi = Paparazzi(
    )
    
    @Tes
    t
    
    fun launch()
    {
    
    val view = LaunchView(paparazzi.context
    )
    
    paparazzi.snapshot(view
    )
    
    }
    
    }
    

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39. $ ./gradlew sample:testDebug
    

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40. $ ./gradlew sample:recordPaparazziDebug
    

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41. $ ./gradlew sample:verifyPaparazziDebug
    

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42. @RunWith(TestParameterInjector::class
    )
    
    class TestParameterInjectorTest
    

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43. @RunWith(TestParameterInjector::class
    )
    
    class TestParameterInjectorTest
    (
    
    @TestParameter config: Confi
    g
    
    )
    {
    
    enum class Config(val deviceConfig: DeviceConfig) {…}a
    enum class Theme(val themeName: String) {…}a
    @get:Rul
    e
    
    val paparazzi = Paparazzi(deviceConfig = config.deviceConfig
    )
    
    @Tes
    t
    
    fun simpleWithTheme(@TestParameter theme: Theme)
    {
    
    val launch = paparazzi.inflate(R.layout.launch
    )
    
    paparazzi.snapshot(launch, theme = theme.themeName
    )
    
    }
    
    }
    

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44. @RunWith(TestParameterInjector::class
    )
    
    class TestParameterInjectorTest
    (
    
    @TestParameter config: Confi
    g
    
    )
    {
    
    enum class Config(val deviceConfig: DeviceConfig)
    {
    
    PIXEL_4(deviceConfig =aDeviceConfig.PIXEL_4)
    ,
    
    PIXEL_5(deviceConfig =aDeviceConfig.PIXEL_5)
    ,
    
    }a
    enum class Theme(val themeName: String)
    {
    
    LIGHT("android:Theme.Material.Light")
    ,
    
    LIGHT_NO_ACTION_BAR("android:Theme.Material.Light.NoActionBar"
    )
    
    }a
    @get:Rul
    e
    
    val paparazzi = Paparazzi(deviceConfig = config.deviceConfig
    )
    
    @Tes
    t
    
    fun simpleWithTheme(@TestParameter theme: Theme)
    {
    
    val launch = paparazzi.inflate(R.layout.launch
    )
    
    )
    
    

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45. @RunWith(TestParameterInjector::class
    )
    
    class TestParameterInjectorTest
    (
    
    @TestParameter config: Confi
    g
    
    )
    {
    
    enum class Config(val deviceConfig: DeviceConfig) {…}a
    enum class Theme(val themeName: String) {…}a
    @get:Rul
    e
    
    val paparazzi = Paparazzi(deviceConfig = config.deviceConfig
    )
    
    @Tes
    t
    
    fun simpleWithTheme(@TestParameter theme: Theme)
    {
    
    val launch = paparazzi.inflate(R.layout.launch
    )
    
    paparazzi.snapshot(launch, theme = theme.themeName
    )
    
    }
    
    }
    

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46. @RunWith(TestParameterInjector::class
    )
    
    class TestParameterInjectorTest
    (
    
    @TestParameter config: Confi
    g
    
    )
    {
    
    enum class Config(val deviceConfig: DeviceConfig) {…}a
    enum class Theme(val themeName: String) {…}a
    @get:Rul
    e
    
    val paparazzi = Paparazzi(deviceConfig = config.deviceConfig
    )
    
    @Tes
    t
    
    fun simpleWithTheme(@TestParameter theme: Theme)
    {
    
    val launch = paparazzi.inflate(R.layout.launch
    )
    
    paparazzi.snapshot(launch, theme = theme.themeName
    )
    
    }
    
    }
    

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48. Presenter View
    Ui
    Presenter
    

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49. class CardPreviewView
    (
    
    context: Context
    ,
    
    attrs: AttributeSet? = null
    ,
    
    ) : FrameLayout(context, attrs)
    ,
    
    Ui
    {
    
    
    
    override fun setModel(model: CardPreviewViewModel)
    {
    
    title.text = model.titl
    e
    
    description.text = model.descriptio
    n
    
    orderButton.text = model.orde
    r
    
    …
    
    cardView.render(model.cardViewModel)
    }
    
    }
    

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50. class CardPreviewView
    (
    
    context: Context
    ,
    
    attrs: AttributeSet? = null
    ,
    
    ) : FrameLayout(context, attrs)
    ,
    
    Ui
    {
    
    
    
    override fun setModel(model: CardPreviewViewModel)
    {
    
    title.text = model.titl
    e
    
    description.text = model.descriptio
    n
    
    orderButton.text = model.orde
    r
    
    …
    
    cardView.render(model.cardViewModel)
    }
    
    }
    

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51. class CardPreviewViewTest
    {
    
    @get:Rul
    e
    
    val paparazzi = Paparazzi
    (
    
    theme = "Theme.Cash.Default.Accent"
    ,
    
    deviceConfig = DeviceConfig.PIXEL_
    5
    
    )
    
    @Tes
    t
    
    fun cardPreview() {
    val view = paparazzi.inflate(R.layout.card_preview_view
    )
    
    view.setModel(CardPreviewViewModel(…)
    )
    
    paparazzi.snapshot(view
    )
    
    }
    

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54. JUnit
    

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55. JUnit
    Paparazzi
    

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56. JUnit
    Paparazzi
    layoutlib
    

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57. JUnit
    Paparazzi
    layoutlib
    Android Framework
    

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58. JUnit
    Paparazzi
    layoutlib
    Android Framework
    *_Delegates
    

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59. JUnit
    Paparazzi
    layoutlib
    Android Framework
    *_Delegates
    

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62. /*
    *
    
    * Entry point of the Layout Library
    .
    
    *
    /
    
    public abstract class Bridge
    {
    
    public boolean init
    (
    
    Map platformProperties
    ,
    
    File fontLocation
    ,
    
    String nativeLibDirPath
    ,
    
    String icuDataPath
    ,
    
    Map> enumValueMap
    ,
    
    ILayoutLog log) { …
    }
    
    public RenderSession createSession(SessionParams params) { …
    }
    
    }
    

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63. public class RenderSessionImpl
    {
    
    publicaResultainit(longatimeout)a{…}a
    

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64. publicaResultainit(longatimeout)a
    {
    
    Result result = super.init(timeout)
    ;
    
    if (!result.isSuccess())
    {
    
    return result
    ;
    
    } else
    {
    
    SessionParams params = (SessionParams)this.getParams()
    ;
    
    BridgeContext context = this.getContext()
    ;
    
    this.mIsAlphaChannelImage = …
    this.mLayoutBuilder = new Builder(params, context)
    ;
    
    this.mInflater =
    
    
    new BridgeInflater(context, params.getLayoutlibCallback())
    ;
    
    context.setBridgeInflater(this.mInflater)
    ;
    
    ILayoutPullParser layoutParser = params.getLayoutDescription()
    ;
    
    this.mBlockParser = new BridgeXmlBlockParser
    (
    
    layoutParser, context, layoutParser.getLayoutNamespace(
    )
    
    )
    ;
    
    return Status.SUCCESS.createResult()
    ;
    
    }
    
    }a
    

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65. public Result init(long timeout)
    {
    
    Result result = super.init(timeout)
    ;
    
    if (!result.isSuccess())
    {
    
    return result
    ;
    
    } else
    {
    
    SessionParams params = (SessionParams)this.getParams()
    ;
    
    BridgeContext context = this.getContext()
    ;
    
    this.mIsAlphaChannelImage = …
    this.mLayoutBuilder = new Builder(params, context)
    ;
    
    this.mInflater =
    
    
    new BridgeInflater(context, params.getLayoutlibCallback())
    ;
    
    context.setBridgeInflater(this.mInflater)
    ;
    
    ILayoutPullParser layoutParser = params.getLayoutDescription()
    ;
    
    this.mBlockParser = new BridgeXmlBlockParser
    (
    
    layoutParser, context, layoutParser.getLayoutNamespace(
    )
    
    )
    ;
    
    return Status.SUCCESS.createResult()
    ;
    
    }
    
    }
    

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66. public Result init(long timeout)
    {
    
    Result result = super.init(timeout)
    ;
    
    if (!result.isSuccess())
    {
    
    return result
    ;
    
    } else
    {
    
    SessionParams params = (SessionParams)this.getParams()
    ;
    
    BridgeContext context = this.getContext()
    ;
    
    this.mIsAlphaChannelImage = …
    this.mLayoutBuilder = new Builder(params, context)
    ;
    
    this.mInflater =
    
    
    new BridgeInflater(context, params.getLayoutlibCallback())
    ;
    
    context.setBridgeInflater(this.mInflater)
    ;
    
    ILayoutPullParser layoutParser = params.getLayoutDescription()
    ;
    
    this.mBlockParser = new BridgeXmlBlockParser
    (
    
    layoutParser, context, layoutParser.getLayoutNamespace(
    )
    
    )
    ;
    
    return Status.SUCCESS.createResult()
    ;
    
    }
    
    }
    

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67. public Result init(long timeout)
    {
    
    Result result = super.init(timeout)
    ;
    
    if (!result.isSuccess())
    {
    
    return result
    ;
    
    } else
    {
    
    SessionParams params = (SessionParams)this.getParams()
    ;
    
    BridgeContext context = this.getContext()
    ;
    
    this.mIsAlphaChannelImage = …
    this.mLayoutBuilder = new Builder(params, context)
    ;
    
    this.mInflater =
    
    
    new BridgeInflater(context, params.getLayoutlibCallback())
    ;
    
    context.setBridgeInflater(this.mInflater)
    ;
    
    ILayoutPullParser layoutParser = params.getLayoutDescription()
    ;
    
    this.mBlockParser = new BridgeXmlBlockParser
    (
    
    layoutParser, context, layoutParser.getLayoutNamespace(
    )
    
    )
    ;
    
    return Status.SUCCESS.createResult()
    ;
    
    }
    
    }
    

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68. $ unzip cash-master-internal-debug-11892.apk
    Archive: cash-master-internal-debug-11892.apk
    
    
    inflating: AndroidManifest.xml
    
    
    inflating: DebugProbesKt.bin
    
    
    inflating: LICENSE_OFL
    
    
    inflating: LICENSE_UNICODE
    
    
    inflating: META-INF/services/kotlin.reflect.jvm.internal.impl.builtins.BuiltInsLoader
    
    
    inflating: META-INF/services/kotlin.reflect.jvm.internal.impl.resolve.ExternalOverridabilityCondition
    
    
    inflating: META-INF/services/kotlinx.coroutines.CoroutineExceptionHandler
    
    
    inflating: META-INF/services/kotlinx.coroutines.internal.MainDispatcherFactory
    
    
    extracting: assets/appmessage/activity-card-promo-fallback.png
    
    
    extracting: assets/appmessage/activity-card-promo-placeholder.png
    
    
    extracting: assets/appmessage/activity-card-promo.mp4
    
    
    extracting: assets/appmessage/activity-fullscreen-ad.png
    
    
    extracting: assets/appmessage/bitcoin-activity-fallback.png
    
    
    extracting: assets/appmessage/bitcoin-activity-placeholder.png
    
    
    extracting: assets/appmessage/bitcoin-activity.mp4
    
    
    extracting: assets/appmessage/bitcoin-full-screen.mp4
    
    
    extracting: assets/appmessage/cage-banner.jpeg
    
    
    extracting: assets/appmessage/cage-ceo.jpg
    
    
    extracting: assets/appmessage/cage-face-off.jpg
    
    
    extracting: assets/appmessage/cage-feature1.jpg
    
    
    extracting: assets/appmessage/cage-feature2.jpg
    
    
    extracting: assets/appmessage/cage-feature3.jpg
    
    
    extracting: assets/appmessage/cage-handsome.jpg
    
    
    
    

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69. $ cd res/layout && ls -1
    abc_action_bar_title_item.xml
    
    
    abc_action_bar_up_container.xml
    
    
    abc_action_menu_item_layout.xml
    
    
    abc_action_menu_layout.xml
    
    
    abc_action_mode_bar.xml
    
    
    abc_action_mode_close_item_material.xml
    
    
    abc_activity_chooser_view.xml
    
    
    abc_activity_chooser_view_list_item.xml
    
    
    abc_alert_dialog_button_bar_material.xml
    
    
    abc_alert_dialog_material.xml
    
    
    abc_alert_dialog_title_material.xml
    
    
    abc_cascading_menu_item_layout.xml
    
    
    abc_dialog_title_material.xml
    
    
    abc_expanded_menu_layout.xml
    
    
    abc_list_menu_item_checkbox.xml
    
    
    abc_list_menu_item_icon.xml
    
    
    abc_list_menu_item_layout.xml
    
    
    abc_list_menu_item_radio.xml
    
    
    abc_popup_menu_header_item_layout.xml
    
    
    abc_popup_menu_item_layout.xml
    
    
    abc_screen_content_include.xml
    
    
    abc_screen_simple.xml
    
    
    abc_screen_simple_overlay_action_mode.xml
    
    
    abc_screen_toolbar.xml
    
    
    
    

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70. $ less blockers_selection_detail_row.xml
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    ^?^N^@^@^@^G^@^@^@^H^@^@^E^A^@^@^@^N^@^@^@^H^@^@^@^H^@^@^P^N^@^@^@
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71. $ less blockers_selection_detail_row.xml
    ^C^@^H^@
    ^D^@^@^A^@^\^@t^A^@^@^P^@^@^@^@^@^@^@^@^A^@^@\^@^@^@^@^@^@^@^@^@^@^@^Q^@^@^@^]^@^@^@'^@^@^@5^@^@^@:^@^@^@G^@^@^@W^@^
    @^@f^@^@^@v^@^@^@<86>^@^@^@<91>^@^@^@<9B>^@^@^@^@^@^@
    
    
    ^@^@^@^O^A^@^@^N^NtextAppearance^@ textColor^@^G^Ggravity^@^K^Korientation^@^B^Bid^@
    
    
    paddingTop^@^MpaddingBottom^@^L^Llayout_width^@^Mlayout_height^@^Mlayout_weight^@^H^HTextView^@^G^Gandroid^@^E^Eclas
    s^@<android^@^D^Dview^@^@^@<80>^A^H^@0^@^@^@4^@^A^A<98>^@^A^A^@^A^A^@^A^A^@^A^A^@^A^A^@^A^A^@^A^
    A^@^A^A<81>^A^A^A^@^A^P^@^X
    
    
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    ^?^N^@^@^@^G^@^@^@^H^@^@^E^A^@^@^@^N^@^@^@^H^@^@^@^H^@^@^P^N^@^@^@
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73. JUnit
    Paparazzi
    layoutlib
    Android Framework
    *_Delegates
    

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74. JUnit
    Paparazzi
    layoutlib
    Android Framework
    *_Delegates
    

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77. Drawable getDrawable(@DrawableRes int id, Theme theme)
    {
    
    return getDrawableForDensity(id, 0, theme);
    }
    
    android.content.res.Resources (android-29)
    

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78. Drawable getDrawable_Original(@DrawableRes int id, Theme theme)
    {
    
    return this.getDrawableForDensity(id, 0, theme)
    ;
    
    }
    
    @LayoutlibDelegat
    e
    
    Drawable getDrawable(@DrawableRes int id, Theme theme)
    {
    
    return Resources_Delegate.getDrawable(this, id, theme)
    ;
    
    }
    android.content.res.Resources (layoutlib)
    

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79. @LayoutlibDelegat
    e
    
    static Drawable getDrawable(Resources resources, int id, Theme theme)
    {
    
    Pair value = getResourceValue(resources, id)
    ;
    
    …
    
    return ResourceHelper.getDrawable
    (
    
    value.getSecond(), getContext(resources), them
    e
    
    );
    }
    android.content.res.Resources_Delegate (layoutlib)
    

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80. $ find ~/.gradle/caches -name layoutlib.jar | xargs jar tf | grep
    _Delegate
    android/animation/PropertyValuesHolder_Delegate.class
    
    
    android/app/Fragment_Delegate.class
    
    
    android/content/res/AssetManager_Delegate.class
    
    
    android/content/res/Resources_Delegate.class
    
    
    android/content/res/Resources_Theme_Delegate.class
    
    
    android/content/res/TypedArray_Delegate.class
    
    
    android/graphics/BaseCanvas_Delegate$1.class
    
    
    android/graphics/BaseCanvas_Delegate.class
    
    
    android/graphics/BitmapFactory_Delegate.class
    
    
    android/graphics/BitmapShader_Delegate$1.class
    
    
    android/graphics/BitmapShader_Delegate$BitmapShaderPaint$BitmapShaderContext.class
    
    
    android/graphics/BitmapShader_Delegate$BitmapShaderPaint.class
    
    
    android/graphics/BitmapShader_Delegate.class
    
    
    android/graphics/Bitmap_Delegate$BitmapCreateFlags.class
    
    
    android/graphics/Bitmap_Delegate.class
    
    
    android/graphics/BlendModeColorFilter_Delegate.class
    
    
    android/graphics/BlurMaskFilter_Delegate.class
    
    
    android/graphics/Canvas_Delegate.class
    
    
    android/graphics/ColorFilter_Delegate.class
    
    
    android/graphics/ColorMatrixColorFilter_Delegate.class
    
    
    android/graphics/ColorSpace_Rgb_Delegate.class
    
    
    android/graphics/Color_Delegate.class
    
    
    

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81. JUnit
    Paparazzi
    layoutlib
    Android Framework
    *_Delegates
    

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82. JUnit
    Paparazzi
    layoutlib
    Android Framework
    Android runtime
    *_Delegates
    

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83. View Slide

84. View Slide

85. JUnit
    Paparazzi
    layoutlib
    Android Framework
    Android runtime
    *_Delegates
    

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86. JUnit
    Paparazzi
    layoutlib
    Android Framework
    Android runtime
    *_Delegates
    

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87. class Paparazzi
    (
    
    private val environment: Environment
    ,
    
    private val deviceConfig: DeviceConfig
    ,
    
    private val theme: String
    ,
    
    private val appCompatEnabled: Boolean
    ,
    
    private val maxPercentDifference: Double
    ,
    
    private val snapshotHandler: SnapshotHandler
    ,
    
    private val renderExtensions: Set>
    
    ) : TestRule {
    

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88. class Paparazzi
    (
    
    private val environment: Environment(= detectEnvironment()
    ,
    
    private val deviceConfig: DeviceConfig = DeviceConfig.NEXUS_5
    ,
    
    private val theme: String =
    
    
    "android:Theme.Material.NoActionBar.Fullscreen"
    ,
    
    private val appCompatEnabled: Boolean = true
    ,
    
    private val maxPercentDifference: Double = 0.1
    ,
    
    private val snapshotHandler: SnapshotHandler =
    
    
    determineHandler(maxPercentDifference)
    ,
    
    private val renderExtensions: Set = setOf(
    )
    
    ) : TestRule {…}
    

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89. class Paparazzi
    (
    
    private val environment: Environment(= detectEnvironment()
    ,
    
    private val deviceConfig: DeviceConfig = DeviceConfig.NEXUS_5
    ,
    
    private val theme: String =
    
    
    "android:Theme.Material.NoActionBar.Fullscreen"
    ,
    
    private val appCompatEnabled: Boolean = true
    ,
    
    private val maxPercentDifference: Double = 0.1
    ,
    
    private val snapshotHandler: SnapshotHandler =
    
    
    determineHandler(maxPercentDifference)
    ,
    
    private val renderExtensions: Set = setOf(
    )
    
    ) : TestRule {…}
    

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90. private fun determineHandler
    (
    
    maxPercentDifference: Doubl
    e
    
    ): SnapshotHandler
    =
    
    if (isVerifying)
    {
    
    SnapshotVerifier(maxPercentDifference
    )
    
    } else
    {
    
    HtmlReportWriter(
    )
    
    }
    
    

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91. class Paparazzi
    (
    
    private val environment: Environment(= detectEnvironment()
    ,
    
    private val deviceConfig: DeviceConfig = DeviceConfig.NEXUS_5
    ,
    
    private val theme: String =
    
    
    "android:Theme.Material.NoActionBar.Fullscreen"
    ,
    
    private val appCompatEnabled: Boolean = true
    ,
    
    private val maxPercentDifference: Double = 0.1
    ,
    
    private val snapshotHandler: SnapshotHandler =
    
    
    determineHandler(maxPercentDifference)
    ,
    
    private val renderExtensions: Set = setOf(
    )
    
    ) : TestRule {…}
    

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92. class Paparazzi
    (
    
    private val environment: Environment(= detectEnvironment()
    ,
    
    private val deviceConfig: DeviceConfig = DeviceConfig.NEXUS_5
    ,
    
    private val theme: String =
    
    
    "android:Theme.Material.NoActionBar.Fullscreen"
    ,
    
    private val appCompatEnabled: Boolean = true
    ,
    
    private val maxPercentDifference: Double = 0.1
    ,
    
    private val snapshotHandler: SnapshotHandler =
    
    
    determineHandler(maxPercentDifference)
    ,
    
    private val renderExtensions: Set = setOf(
    )
    
    ) : TestRule {…}
    

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93. data class Environment
    (
    
    val platformDir: String
    ,
    
    val appTestDir: String
    ,
    
    val resDir: String
    ,
    
    val assetsDir: String
    ,
    
    val packageName: String
    ,
    
    val compileSdkVersion: Int
    ,
    
    val platformDataDir: String
    ,
    
    )
    

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94. fun detectEnvironment(): Environment
    {
    
    val resourcesFile = File(getProperty("paparazzi.test.resources")
    )
    
    val configLines = resourcesFile.readLines(
    )
    
    val appTestDir = Paths.get(System.getProperty("user.dir")
    )
    
    val androidHome = Paths.get(androidHome()
    )
    
    return Environment
    (
    
    platformDir = androidHome.resolve(configLines[3]).toString()
    ,
    
    appTestDir = appTestDir.toString()
    ,
    
    resDir = appTestDir.resolve(configLines[1]).toString()
    ,
    
    …
    )
    
    }
    

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95. fun detectEnvironment(): Environment
    {
    
    val resourcesFile = File(getProperty("paparazzi.test.resources")
    )
    
    val configLines = resourcesFile.readLines(
    )
    
    val appTestDir = Paths.get(System.getProperty("user.dir")
    )
    
    val androidHome = Paths.get(androidHome()
    )
    
    return Environment
    (
    
    platformDir = androidHome.resolve(configLines[3]).toString()
    ,
    
    appTestDir = appTestDir.toString()
    ,
    
    resDir = appTestDir.resolve(configLines[1]).toString()
    ,
    
    …
    )
    
    }
    

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96. View Slide

97. preparePaparazzi{VARIANT}Resources
    

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98. Android Gradle Plugin
    Paparazzi Gradle Plugin
    merge{VARIANT}Resources
    preparePaparazzi{VARIANT}Resources
    compile{VARIANT}Kotlin
    

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99. Android Gradle Plugin
    Paparazzi Gradle Plugin
    merge{VARIANT}Resources
    preparePaparazzi{VARIANT}Resources
    compile{VARIANT}Kotlin
    merge{VARIANT}
    Assets
    compile{VARIANT}JavaWithJavac
    

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100. Android Gradle Plugin
     Paparazzi Gradle Plugin
     merge{VARIANT}Resources
     preparePaparazzi{VARIANT}Resources
     

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101. Android Gradle Plugin
     Paparazzi Gradle Plugin
     merge{VARIANT}Resources
     preparePaparazzi{VARIANT}Resources
     "build/intermediates/res/merged/debug"
     

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102. Android Gradle Plugin
     Paparazzi Gradle Plugin
     merge{VARIANT}Resources
     preparePaparazzi{VARIANT}Resources
     "build/intermediates/res/merged/debug"
     build/intermediates/paparazzi/resources.txt
     

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103. Android Gradle Plugin
     Paparazzi Gradle Plugin
     merge{VARIANT}Resources
     preparePaparazzi{VARIANT}Resources
     test{VARIANT}UnitTest
     …
     

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104. Android Gradle Plugin
     Paparazzi Gradle Plugin
     merge{VARIANT}Resources
     preparePaparazzi{VARIANT}Resources
     test{VARIANT}UnitTest
     systemProperties["paparazzi.test.resources"] =
     
     
     "build/intermediates/paparazzi/resources.txt"
     …
     

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105. Android Gradle Plugin
     Paparazzi Gradle Plugin
     preparePaparazzi{VARIANT}Resources
     test{VARIANT}UnitTest
     …
     systemProperties["paparazzi.test.record"] = "true"
     systemProperties["paparazzi.test.verify"] = "true"
     

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106. /PROJECT/build.gradle
     dependencies {
     testImplementation "app.cash.paparazzi:paparazzi:${VERSION}
     "
     
     }
     

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107. /build.gradle
     buildscript
     {
     
     dependencies {
     classpath "app.cash.paparazzi:paparazzi-gradle-plugin:${VERSION}
     "
     
     }
     
     }
     /PROJECT/build.gradle
     apply plugin: 'app.cash.paparazzi'
     

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108. $ tree prebuilts/studio/layoutlib/data/
     prebuilts/studio/layoutlib/data/
     
     
     ├── layoutlib_native.jar
     
     
     ├── linux
     
     
     │ └── lib64
     
     
     │ ├── libandroid_runtime.so
     
     
     │ ├── libbinder.so
     
     
     │ └── libhidlbase.so
     
     
     ├── mac
     
     
     │ └── lib64
     
     
     │ └── libandroid_runtime.dylib
     
     
     ├── win
     
     
     │ └── lib64
     
     
     │ ├── libandroid_runtime.dll
     
     
     │ ├── libicuuc-host.dll
     
     
     │ └── libicuuc_stubdata.dll
     
     
     …
     

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109. JUnit
     Paparazzi
     layoutlib
     Android Framework
     Android runtime
     *_Delegates
     

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110. $ tree prebuilts/studio/layoutlib/data/
     prebuilts/studio/layoutlib/data/
     
     
     ├── layoutlib_native.jar
     
     
     ├── linux
     
     
     │ └── lib64
     
     
     │ ├── libandroid_runtime.so
     
     
     │ ├── libbinder.so
     
     
     │ └── libhidlbase.so
     
     
     ├── mac
     
     
     │ └── lib64
     
     
     │ └── libandroid_runtime.dylib
     
     
     ├── win
     
     
     │ └── lib64
     
     
     │ ├── libandroid_runtime.dll
     
     
     │ ├── libicuuc-host.dll
     
     
     │ └── libicuuc_stubdata.dll
     
     
     …
     

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111. $ tree prebuilts/studio/layoutlib/data/
     prebuilts/studio/layoutlib/data/
     
     
     ├── layoutlib_native.jar
     
     
     ├── linux
     
     
     │ └── lib64
     
     
     │ ├── libandroid_runtime.so
     
     
     │ ├── libbinder.so
     
     
     │ └── libhidlbase.so
     
     
     ├── mac
     
     
     │ └── lib64
     
     
     │ └── libandroid_runtime.dylib
     
     
     ├── win
     
     
     │ └── lib64
     
     
     │ ├── libandroid_runtime.dll
     
     
     │ ├── libicuuc-host.dll
     
     
     │ └── libicuuc_stubdata.dll
     
     
     …
     layoutlib-native-jdk11.jar
     layoutlib-native-linux.jar
     layoutlib-native-mac.jar
     layoutlib-native-win.jar
     

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112. $ tree ~/.gradle/caches/modules-2/files-2.1/app.cash.paparazzi/
     ~/.gradle/caches/modules-2/files-2.1/app.cash.paparazzi/
     
     
     ├── layoutlib-native-jdk11
     
     
     │ └── 4.1.0-ae77d65
     
     
     │ └── 7f954f19f39672bd8802ef030d47bb269ab2ffd2
     
     
     │ └── layoutlib-native-jdk11-4.1.0-ae77d65.jar
     
     
     ├── layoutlib-native-macosx
     
     
     │ ├── 4.1.0-ae77d65
     
     
     │ │ └── c893f66979493e8f4249de4e825fca5975e906e8
     
     
     │ │ └── layoutlib-native-macosx-4.1.0-ae77d65.jar
     
     
     ├── paparazzi
     
     
     │ ├── 0.8.0
     
     
     │ │ ├── d6b8ec9f82ad120e34d7e07d3be3c909f5dd0a4
     
     
     │ │ │ └── paparazzi-0.8.0.jar
     
     
     ├── paparazzi-agent
     
     
     │ ├── 0.8.0
     
     
     │ │ ├── ee13c27af0028005e42e221d576e76fdac6a6ba5
     
     
     │ │ │ └── paparazzi-agent-0.8.0.jar
     
     
     └── paparazzi-gradle-plugin
     
     
     ├── 0.8.0
     
     
     │ ├── 6f4e990290c5f1c1e190f3c38ab9059785e1432d
     
     
     │ │ └── paparazzi-gradle-plugin-0.8.0.jar
     
     
     

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113. /*
     *
     
     * Entry point of the Layout Library
     .
     
     *
     /
     
     public abstract class Bridge
     {
     
     public boolean init
     (
     
     Map platformProperties
     ,
     
     File fontLocation
     ,
     
     String nativeLibDirPath
     ,
     
     String icuDataPath
     ,
     
     Map> enumValueMap
     ,
     
     ILayoutLog log) { …
     }
     
     public RenderSession createSession(SessionParams params) { …
     }
     
     }
     

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114. /*
     *
     
     * Entry point of the Layout Library
     .
     
     *
     /
     
     public abstract class Bridge
     {
     
     public boolean init
     (
     
     Map platformProperties
     ,
     
     File fontLocation
     ,
     
     String nativeLibDirPath
     ,
     
     String icuDataPath
     ,
     
     Map> enumValueMap
     ,
     
     ILayoutLog log) { …
     }
     
     public RenderSession createSession(SessionParams params) { …
     }
     
     }
     

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115. $ find ~/.gradle/caches/transforms-3/ -name layoutlib*
     ~/.gradle/caches/transforms-3/4a38ac62d09a6fd091f06e54d5f69fe1/transformed/
     layoutlib-native-macosx-4.1.0-ae77d65
     

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116. $ tree ~/.gradle/caches/transforms-3/4a38ac62d09a6fd091f06e54d5f69fe1/
     transformed/layoutlib-native-macosx-4.1.0-ae77d65
     ~/.gradle/caches/transforms-3/4a38ac62d09a6fd091f06e54d5f69fe1/transformed/
     layoutlib-native-macosx-4.1.0-ae77d65
     
     
     └── data
     
     
     ├── fonts
     
     
     │ ├── AndroidClock.ttf
     
     
     │ ├── CarroisGothicSC-Regular.ttf
     
     
     │ ├── …
     
     
     ├── icu
     
     
     │ └── icudt63l.dat
     
     
     └── mac
     
     
     └── lib64
     
     
     ├── libandroid_runtime.dylib
     
     
     ├── libc++.dylib
     
     
     └── liblog.dylib
     

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117. View Slide

118. ?
     

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119. ?
     Contributions welcome!
     

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120. View Slide

121. @RunWith(TestParameterInjector::class
     )
     
     class DirectDepositSetupViewTest
     (
     
     @TestParameter private val theme: DesignTheme
     ,
     
     @TestParameter private val a11yTextSize: AccessibilityTextSize
     ,
     
     )
     {
     
     @get:Rule val paparazzi = Paparazzi(…
     )
     
     @Tes
     t
     
     fun default()
     {
     
     val context = paparazzi.contex
     t
     
     .wrapWithTheme(theme.provide
     )
     
     .scaledFontSizeBy(accessibilityTextSize.scale
     )
     
     val view = DirectDepositSetupView(context
     )
     
     view.setModel(…
     )
     
     paparazzi.scrollingSnapshot(view
     )
     
     }
     
     }
     

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122. @RunWith(TestParameterInjector::class
     )
     
     class DirectDepositSetupViewTest
     (
     
     @TestParameter private val theme: DesignTheme
     ,
     
     @TestParameter private val a11yTextSize: AccessibilityTextSize
     ,
     
     )
     {
     
     @get:Rule val paparazzi = Paparazzi(…
     )
     
     @Tes
     t
     
     fun default()
     {
     
     val context = paparazzi.contex
     t
     
     .wrapWithTheme(theme.provide
     )
     
     .scaledFontSizeBy(accessibilityTextSize.scale
     )
     
     val view = DirectDepositSetupView(context
     )
     
     view.setModel(…
     )
     
     paparazzi.scrollingSnapshot(view
     )
     
     }
     
     }
     enum class DesignTheme(val provide: Context.() -> ThemeInfo)
     {
     
     Light({ moonCakeLight() })
     ,
     
     Dark({ moonCakeDark() }
     )
     
     }
     
     enum class AccessibilityTextSize(val scale: Float)
     {
     
     NORMAL(scale = 1f)
     ,
     
     LARGE(scale = 2f)
     ,
     
     }
     
     

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123. @RunWith(TestParameterInjector::class
     )
     
     class DirectDepositSetupViewTest
     (
     
     @TestParameter private val theme: DesignTheme
     ,
     
     @TestParameter private val a11yTextSize: AccessibilityTextSize
     ,
     
     )
     {
     
     @get:Rule val paparazzi = Paparazzi(…
     )
     
     @Tes
     t
     
     fun default()
     {
     
     val context = paparazzi.contex
     t
     
     .wrapWithTheme(theme.provide
     )
     
     .scaledFontSizeBy(accessibilityTextSize.scale
     )
     
     val view = DirectDepositSetupView(context
     )
     
     view.setModel(…
     )
     
     paparazzi.scrollingSnapshot(view
     )
     
     }
     
     }
     

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124. @RunWith(TestParameterInjector::class
     )
     
     class DirectDepositSetupViewTest
     (
     
     @TestParameter private val theme: DesignTheme
     ,
     
     @TestParameter private val a11yTextSize: AccessibilityTextSize
     ,
     
     )
     {
     
     @get:Rule val paparazzi = Paparazzi(…
     )
     
     @Tes
     t
     
     fun default()
     {
     
     val context = paparazzi.contex
     t
     
     .wrapWithTheme(theme.provide
     )
     
     .scaledFontSizeBy(accessibilityTextSize.scale
     )
     
     val view = DirectDepositSetupView(context
     )
     
     view.setModel(…
     )
     
     paparazzi.scrollingSnapshot(view
     )
     
     }
     
     }
     

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125. fun Paparazzi.scrollingSnapshot
     (
     
     view: View
     ,
     
     scrollableView: View = vie
     w
     
     )
     {
     
     var scrollCount =
     0
     
     snapshot(view, scrollCount.toString()
     )
     
     while (scrollableView.canScrollVertically(1))
     {
     
     scrollableView.scrollBy(0, scrollableView.height
     )
     
     scrollCount+
     +
     
     check(scrollCount < 10)
     {
     
     "This view has been scrolled 10 times! Bad input?
     "
     
     }
     
     snapshot(view, name = scrollCount.toString()
     )
     
     }
     
     }
     

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126. $ ./gradlew banking:views:testDebug
     
     
     --tests=com.squareup.cash.banking.views.DirectDepositSetupViewTest
     

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127. class Paparazzi
     (
     
     private val environment: Environment(= detectEnvironment()
     ,
     
     private val deviceConfig: DeviceConfig
     ,
     
     private val theme: String
     ,
     
     private val appCompatEnabled: Boolean
     ,
     
     private val maxPercentDifference: Double
     ,
     
     private val snapshotHandler: SnapshotHandler
     ,
     
     private val renderExtensions: Set>
     
     ) : TestRule {…}
     

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128. class Paparazzi
     (
     
     private val environment: Environment(= detectEnvironment()
     ,
     
     private val deviceConfig: DeviceConfig
     ,
     
     private val theme: String
     ,
     
     private val appCompatEnabled: Boolean
     ,
     
     private val maxPercentDifference: Double
     ,
     
     private val snapshotHandler: SnapshotHandler
     ,
     
     private val renderExtensions: Set
     <​
     RenderExtensio
     n​ >
     
     ) : TestRulea{…}a
     

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129. /*
     *
     
     * An extension for overlaying additional information on top of
     
     
     * each rendered frame
     .
     
     *
     /
     
     interface RenderExtensio
     n​ {
     
     fun render
     (
     
     snapshot: Snapshot,
     
     
     view: View,
     
     
     image: BufferedImag
     e
     
     ): BufferedImag
     e
     
     }
     

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130. /*
     *
     
     * An extension for overlaying additional information on top of
     
     
     * each rendered frame
     .
     
     *
     /
     
     interface RenderExtension
     {
     
     fun render
     (
     
     snapshot: Snapshot,
     
     
     view: View,
     
     
     image: BufferedImag
     e
     
     ): BufferedImag
     e
     
     }
     frameHandler.handle(scaleImage(bridgeRenderSession.image))
     

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131. /*
     *
     
     * An extension for overlaying additional information on top of
     
     
     * each rendered frame
     .
     
     *
     /
     
     interface RenderExtension
     {
     
     fun render
     (
     
     snapshot: Snapshot,
     
     
     view: View,
     
     
     image: BufferedImag
     e
     
     ): BufferedImag
     e
     
     }
     var image = bridgeRenderSession.imag
     e
     
     renderExtensions.forEach
     {
     
     image = it.render(snapshot, view, image
     )
     
     }
     
     frameHandler.handle(scaleImage(image))
     

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132. View Slide

133. View Slide

134. View Slide

135. class AccessibilityTest
     {
     
     @get:Rul
     e
     
     val paparazzi = Paparazzi()a
     @Tes
     t
     
     fun test()
     {
     
     val view = buildView(paparazzi.context
     )
     
     paparazzi.snapshot(view
     )
     
     }
     
     }
     

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136. class AccessibilityTest
     {
     
     @get:Rul
     e
     
     val paparazzi = Paparazzi
     (
     
     renderExtensions = setOf(AccessibilityRenderExtension()
     )
     
     )a
     @Tes
     t
     
     fun test()
     {
     
     val view = buildView(paparazzi.context
     )
     
     paparazzi.snapshot(view
     )
     
     }
     
     }
     

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137. View Slide

138. View Slide

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140. fun registerMatrixMultiplyInterception()
     {
     
     val matrixClass = Class.forName("android.opengl.Matrix"
     )
     
     InterceptorRegistrar.addMethodInterceptors
     (
     
     matrixClass
     ,
     
     setOf
     (
     
     "multiplyMM" to MatrixMatrixMultiplicationInterceptor::class.java
     ,
     
     "multiplyMV" to MatrixVectorMultiplicationInterceptor::class.jav
     a
     
     )
     
     )
     
     }
     

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141. fun registerMatrixMultiplyInterception()
     {
     
     val matrixClass = Class.forName("android.opengl.Matrix"
     )
     
     InterceptorRegistrar.addMethodInterceptors
     (
     
     matrixClass
     ,
     
     setOf
     (
     
     "multiplyMM" to MatrixMatrixMultiplicationInterceptor::class.java
     ,
     
     "multiplyMV" to MatrixVectorMultiplicationInterceptor::class.jav
     a
     
     )
     
     )
     
     }
     

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142. fun registerMatrixMultiplyInterception()
     {
     
     val matrixClass = Class.forName("android.opengl.Matrix"
     )
     
     InterceptorRegistrar.addMethodInterceptors
     (
     
     matrixClass
     ,
     
     setOf
     (
     
     "multiplyMM" to MatrixMatrixMultiplicationIntercepto
     r​
     ::class.java
     ,
     
     "multiplyMV" to MatrixVectorMultiplicationInterceptor::class.jav
     a
     
     )
     
     )
     
     }
     

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143. object MatrixMatrixMultiplicationIntercepto
     r​ {
     
     fun intercept
     (
     
     result: FloatArray, resultOffset: Int
     ,
     
     lhs: FloatArray, lhsOffset: Int
     ,
     
     rhs: FloatArray, rhsOffset: In
     t
     
     ) {
     for (i in 0..3)
     {
     
     val rhs_i0 = rhs[I(i, 0, rhsOffset)
     ]
     
     var ri0 = lhs[I(0, 0, lhsOffset)] * rhs_i
     0
     
     …
     
     for (j in 1..3)
     {
     
     val rhs_ij = rhs[I(i, j, rhsOffset)
     ]
     
     ri0 += lhs[I(j, 0, lhsOffset)] * rhs_i
     j
     
     …
     
     }
     
     result[I(i, 0, resultOffset)] = ri
     0
     
     …
     
     }
     
     }
     
     }
     

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144. /*
     *
     
     * See
     :
     
     * https://github.com/cashapp/paparazzi/issues/11
     9
     
     * https://issuetracker.google.com/issues/15606547
     2
     
     *
     /
     
     private fun registerFontLookupInterceptionIfResourceCompatDetected()
     {
     
     val clz = Class.forName("androidx.core.content.res.ResourcesCompat"
     )
     
     InterceptorRegistrar.addMethodInterceptor
     (
     
     clz, "getFont", ResourcesInterceptor::class.jav
     a
     
     )
     }
     

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145. /*
     *
     
     * See
     :
     
     * https://github.com/cashapp/paparazzi/issues/11
     9
     
     * https://issuetracker.google.com/issues/15606547
     2
     
     *
     /
     
     private fun registerFontLookupInterceptionIfResourceCompatDetected()
     {
     
     val clz = Class.forName("androidx.core.content.res.ResourcesCompat"
     )
     
     InterceptorRegistrar.addMethodInterceptor
     (
     
     clz, "getFont", ResourcesInterceptor::class.jav
     a
     
     )
     }
     
     private fun registerViewEditModeInterception()
     {
     
     val clz = Class.forName("android.view.View"
     )
     
     InterceptorRegistrar.addMethodInterceptor
     (
     
     clz, "isInEditMode", EditModeInterceptor::class.jav
     a
     
     )
     
     }
     

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146. Coming soon!
     

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147. View Slide

148. View Slide

149. Keeping your Pixels Perfect
     Paparazzi 1.0
     @jrodbx
     

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