Test to verify that images for offscreen tiles aren't loaded

saket · Nov 12, 2024 · 4dbb9c6 · 4dbb9c6
1 parent 37b9e2a
commit 4dbb9c6
Showing 1 changed file with 46 additions and 0 deletions.
diff --git a/...pling-image/src/androidTest/kotlin/me/saket/telephoto/subsampling/SubSamplingImageTest.kt b/...pling-image/src/androidTest/kotlin/me/saket/telephoto/subsampling/SubSamplingImageTest.kt
@@ -42,6 +42,7 @@ import androidx.compose.ui.unit.IntRect
 import androidx.compose.ui.unit.dp
 import assertk.assertThat
 import assertk.assertions.containsExactly
+import assertk.assertions.isEqualTo
 import com.dropbox.dropshots.Dropshots
 import com.google.testing.junit.testparameterinjector.TestParameter
 import com.google.testing.junit.testparameterinjector.TestParameterInjector
@@ -81,6 +82,7 @@ import org.junit.rules.TestName
 import org.junit.rules.Timeout
 import org.junit.runner.RunWith
 import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicInteger
 import kotlin.time.Duration.Companion.seconds
 
 @RunWith(TestParameterInjector::class)
@@ -719,6 +721,50 @@ class SubSamplingImageTest {
     }
   }
 
+  @Test fun do_not_load_images_for_tiles_that_are_not_visible() {
+    val decodedRegionCount = AtomicInteger(0)
+    val recordingDecoderFactory = ImageRegionDecoder.Factory { params ->
+      val real = AndroidImageRegionDecoder.Factory.create(params)
+      object : ImageRegionDecoder by real {
+        override suspend fun decodeRegion(region: ImageRegionTile) =
+          real.decodeRegion(region).also {
+            if (region.sampleSize == ImageSampleSize(1)) {
+              decodedRegionCount.incrementAndGet()
+            }
+          }
+      }
+    }
+
+    lateinit var imageState: SubSamplingImageState
+    rule.setContent {
+      val zoomableState = rememberZoomableState(
+        zoomSpec = ZoomSpec(maxZoomFactor = 1f)
+      )
+      CompositionLocalProvider(LocalImageRegionDecoderFactory provides recordingDecoderFactory) {
+        imageState = rememberSubSamplingImageState(
+          zoomableState = zoomableState,
+          imageSource = SubSamplingImageSource.asset("pahade.jpg"),
+        )
+        SubSamplingImage(
+          modifier = Modifier
+            .fillMaxSize()
+            .zoomable(zoomableState)
+            .testTag("image"),
+          state = imageState,
+          contentDescription = null,
+        )
+      }
+    }
+
+    rule.waitUntil { imageState.isImageDisplayed }
+    rule.onNodeWithTag("image").performTouchInput { doubleClick() }
+
+    rule.waitUntil(3.seconds) { imageState.isImageDisplayedInFullQuality }
+    rule.runOnIdle {
+      assertThat(decodedRegionCount.get()).isEqualTo(4)
+    }
+  }
+
   // Regression test for https://github.com/saket/telephoto/issues/110
   @Test fun unknown_color_space() {
     val bitmap = rule.activity.assets.open("grayscale.jpg").use {