Add support for heightDp, widthDp, showBackground, backgroundColor

roborazzi-compose-preview-scanner-support/src/main/java/com/github/takahirom/roborazzi/RoborazziPreviewScannerSupport.kt

@@ -14,7 +14,14 @@ fun ComposablePreview<AndroidPreviewInfo>.captureRoboImage(
 ) {
   val composablePreview = this
   composablePreview.applyToRobolectricConfiguration()
-  captureRoboImage(filePath = filePath, roborazziOptions = roborazziOptions) {
+  captureSizedRoboImage(
+    filePath = filePath,
+    roborazziOptions = roborazziOptions,
+    widthDp = composablePreview.previewInfo.widthDp,
+    heightDp = composablePreview.previewInfo.heightDp,
+    showBackground = composablePreview.previewInfo.showBackground,
+    backgroundColor = composablePreview.previewInfo.backgroundColor
+  ) {
     composablePreview()
   }
 }

roborazzi-compose/build.gradle

@@ -17,6 +17,7 @@ dependencies {
 
   testImplementation libs.androidx.compose.runtime
   compileOnly libs.androidx.compose.ui
+  compileOnly libs.androidx.compose.foundation
   compileOnly libs.androidx.activity.compose
   compileOnly libs.robolectric
 }

roborazzi-compose/src/main/java/com/github/takahirom/roborazzi/RoborazziCompose.kt

@@ -1,16 +1,26 @@
 package com.github.takahirom.roborazzi
 
+import android.app.Activity
 import android.app.Application
 import android.content.ComponentName
 import android.view.ViewGroup
+import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
 import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.ComposeView
 import androidx.compose.ui.platform.ViewRootForTest
+import androidx.compose.ui.unit.dp
 import androidx.test.core.app.ActivityScenario
 import androidx.test.core.app.ApplicationProvider
 import org.robolectric.Shadows
+import org.robolectric.shadows.ShadowDisplay
 import java.io.File
+import kotlin.math.roundToInt
 
 fun captureRoboImage(
   filePath: String = DefaultFileNameGenerator.generateFilePath(),
@@ -30,7 +40,7 @@ fun captureRoboImage(
   content: @Composable () -> Unit,
 ) {
   if (!roborazziOptions.taskType.isEnabled()) return
-  registerRoborazziActivityToRobolectricIfNeeded()
+  registerRoborazziActivityToRobolectricIfNeeded(RoborazziTransparentActivity::class.java)
   val activityScenario = ActivityScenario.launch(RoborazziTransparentActivity::class.java)
   activityScenario.use {
     activityScenario.onActivity { activity ->
@@ -51,13 +61,15 @@ fun captureRoboImage(
 /**
  * Workaround for https://github.com/takahirom/roborazzi/issues/100
  */
-private fun registerRoborazziActivityToRobolectricIfNeeded() {
+internal fun registerRoborazziActivityToRobolectricIfNeeded(
+  activityClass: Class<out Activity>
+) {
   try {
     val appContext: Application = ApplicationProvider.getApplicationContext()
     Shadows.shadowOf(appContext.packageManager).addActivityIfNotPresent(
       ComponentName(
         appContext.packageName,
-        RoborazziTransparentActivity::class.java.name,
+        activityClass::class.java.name,
       )
     )
   } catch (e: ClassNotFoundException) {

roborazzi-compose/src/main/java/com/github/takahirom/roborazzi/RoborazziComposePreview.kt

@@ -0,0 +1,123 @@
+package com.github.takahirom.roborazzi
+
+import android.app.Activity
+import android.graphics.Color
+import android.view.ViewGroup
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.ComposeView
+import androidx.compose.ui.platform.ViewRootForTest
+import androidx.compose.ui.unit.dp
+import androidx.test.core.app.ActivityScenario
+import org.robolectric.Shadows
+import org.robolectric.shadows.ShadowDisplay
+import java.io.File
+import kotlin.math.roundToInt
+
+fun captureSizedRoboImage(
+  widthDp: Int,
+  heightDp: Int,
+  showBackground: Boolean,
+  backgroundColor: Long,
+  filePath: String,
+  roborazziOptions: RoborazziOptions = provideRoborazziContext().options,
+  content: @Composable () -> Unit,
+) {
+  if (!roborazziOptions.taskType.isEnabled()) return
+  registerRoborazziActivityToRobolectricIfNeeded(ComponentActivity::class.java)
+
+  val activityScenario = ActivityScenario.launch(ComponentActivity::class.java)
+
+  activityScenario.onActivity {
+    it.setShadowDisplay(
+      widthDp = widthDp,
+      heightDp = heightDp
+    )
+  }
+
+  activityScenario.use {
+    activityScenario.onActivity { activity ->
+
+      activity.setBackgroundColor(
+        showBackground = showBackground,
+        backgroundColor = backgroundColor
+      )
+
+      activity.setContent(
+        content = content.withSize(widthDp = widthDp, heightDp = heightDp)
+      )
+
+      val composeView = activity.window.decorView
+        .findViewById<ViewGroup>(android.R.id.content)
+        .getChildAt(0) as ComposeView
+
+      val viewRootForTest = composeView.getChildAt(0) as ViewRootForTest
+      viewRootForTest.view.captureRoboImage(filePath, roborazziOptions)
+    }
+
+    // Closing the activity is necessary to prevent memory leaks.
+    // If multiple captureRoboImage calls occur in a single test,
+    // they can lead to an activity leak.
+  }
+}
+
+fun Activity.setBackgroundColor(
+  showBackground: Boolean,
+  backgroundColor: Long,
+) {
+  when (showBackground) {
+    false -> window.decorView.setBackgroundColor(Color.TRANSPARENT)
+    true -> if (backgroundColor != 0L) {
+      window.decorView.setBackgroundColor(backgroundColor.toInt())
+    }
+  }
+}
+
+fun Activity.setShadowDisplay(
+  widthDp: Int,
+  heightDp: Int
+) {
+  if (widthDp > 0 || heightDp > 0) {
+    val display = ShadowDisplay.getDefaultDisplay()
+    val density = resources.displayMetrics.density
+    if (widthDp > 0) {
+      widthDp.let {
+        val widthPx = (widthDp * density).roundToInt()
+        Shadows.shadowOf(display).setWidth(widthPx)
+      }
+    }
+    if (heightDp > 0) {
+      heightDp.let {
+        val heightPx = (heightDp * density).roundToInt()
+        Shadows.shadowOf(display).setHeight(heightPx)
+      }
+    }
+    recreate()
+  }
+}
+
+/**
+ * WARNING:
+ * For this to work, it requires that the Display is within the widthDp and heightDp dimensions
+ */
+private fun (@Composable () -> Unit).withSize(
+  widthDp: Int,
+  heightDp: Int,
+): @Composable () -> Unit {
+  val resizedPreview = @Composable {
+    val modifier = when {
+      widthDp > 0 && heightDp > 0 -> Modifier.size(widthDp.dp, heightDp.dp)
+      widthDp > 0 -> Modifier.width(widthDp.dp)
+      heightDp > 0 -> Modifier.height(heightDp.dp)
+      else -> Modifier
+    }
+    Box(modifier = modifier) { this@withSize() }
+  }
+  return resizedPreview
+}