Scale images before displaying in NetImage

Author: QuantumBadger

src/main/java/org/quantumbadger/redreader/compose/net/NetWrapper.kt

@@ -18,6 +18,7 @@
 package org.quantumbadger.redreader.compose.net
 
 import android.graphics.BitmapFactory
+import android.util.Log
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.Immutable
@@ -32,6 +33,7 @@ import androidx.compose.ui.graphics.ImageBitmap
 import androidx.compose.ui.graphics.asImageBitmap
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
+import androidx.core.graphics.scale
 import org.quantumbadger.redreader.R
 import org.quantumbadger.redreader.account.RedditAccount
 import org.quantumbadger.redreader.account.RedditAccountId
@@ -55,8 +57,11 @@ import org.quantumbadger.redreader.compose.ctx.GlobalNetworkRetry
 import org.quantumbadger.redreader.compose.ctx.LocalRedditUser
 import org.quantumbadger.redreader.image.AlbumInfo
 import org.quantumbadger.redreader.image.GetAlbumInfoListener
+import org.quantumbadger.redreader.image.ImageSize
 import java.io.IOException
 import java.util.UUID
+import kotlin.math.max
+import kotlin.math.roundToInt
 
 @Immutable
 sealed interface NetRequestStatus<out R> {
@@ -165,36 +170,60 @@ fun fetchAlbum(
 fun fetchImage(
 	uri: UriString,
 	user: RedditAccountId = LocalRedditUser.current,
+	scaleToMaxAxis: Int = 2048
 ): State<NetRequestStatus<FileRequestResult<ImageBitmap>>> {
 
+	val TAG = "NetWrapper:fetchImage"
+
 	val context = LocalContext.current.applicationContext
 
-	val filter: (FileRequestMetadata) -> NetRequestStatus<FileRequestResult<ImageBitmap>> = remember(uri, user) {
-		{
-			try {
-				val result = BitmapFactory.decodeStream(it.streamFactory.create())?.asImageBitmap()
+	val filter: (FileRequestMetadata) -> NetRequestStatus<FileRequestResult<ImageBitmap>> =
+		remember(uri, user) {
+			{
+				try {
+					val result = BitmapFactory.decodeStream(it.streamFactory.create())
+						?: throw RuntimeException("Decoded bitmap was null")
+
+					val maxAxis = max(result.width, result.height)
+
+					val scaledResult = result.invokeIf(maxAxis > scaleToMaxAxis) {
+
+						val newSize = if (result.width > result.height) {
+							val scale = scaleToMaxAxis / result.width.toFloat()
+							ImageSize(
+								scaleToMaxAxis,
+								(result.height.toFloat() * scale).roundToInt()
+							)
+						} else {
+							val scale = scaleToMaxAxis / result.height.toFloat()
+							ImageSize((result.width.toFloat() * scale).roundToInt(), scaleToMaxAxis)
+						}
+
+						Log.i(
+							TAG,
+							"Scaling image from ${result.width}x${result.height} to $newSize"
+						)
+
+						scale(newSize.width, newSize.height)
+					}
 
-				if (result == null) {
-					throw RuntimeException("Decoded bitmap was null")
-				} else {
 					NetRequestStatus.Success(
 						FileRequestResult(
 							metadata = it,
-							data = result
+							data = scaledResult.asImageBitmap()
 						)
 					)
-				}
-			} catch (e: Exception) {
-				NetRequestStatus.Failed(
-					RRError(
-						title = context.getString(R.string.error_image_decode_failed),
-						url = uri,
-						t = e
+				} catch (e: Exception) {
+					NetRequestStatus.Failed(
+						RRError(
+							title = context.getString(R.string.error_image_decode_failed),
+							url = uri,
+							t = e
+						)
 					)
-				)
+				}
 			}
 		}
-	}
 
 	return fetchFile(
 		uri = uri,

src/main/java/org/quantumbadger/redreader/compose/ui/NetImage.kt

@@ -50,7 +50,8 @@ fun NetImage(
 	modifier: Modifier,
 	image: ImageUrlInfo,
 	cropToAspect: Float? = null,
-	showVideoPlayOverlay: Boolean = false
+	showVideoPlayOverlay: Boolean = false,
+	maxCanvasDimension: Int = 2048
 ) {
 	val theme = LocalComposeTheme.current
 
@@ -60,7 +61,7 @@ fun NetImage(
 
 	val url = image.url
 
-	val data by fetchImage(url)
+	val data by fetchImage(url, scaleToMaxAxis = maxCanvasDimension)
 
 	Box(
 		modifier = modifier

src/main/java/org/quantumbadger/redreader/image/ImageInfo.kt

@@ -53,6 +53,8 @@ data class ImageSize(
 			obj?.getLong(fieldHeight)
 		)
 	}
+
+	override fun toString() = "${width}x$height"
 }
 
 @Immutable
@@ -184,11 +186,13 @@ data class ImageInfo(
 
 			val original = fileObj.getString("url")?.let { originalUrl ->
 				ImageUrlInfo(
-					url = UriString(if (originalUrl.startsWith("//")) {
-						"https:$originalUrl"
-					} else {
-						originalUrl
-					}),
+					url = UriString(
+						if (originalUrl.startsWith("//")) {
+							"https:$originalUrl"
+						} else {
+							originalUrl
+						}
+					),
 					size = ImageSize.fromJson(fileObj)
 				)
 			}
@@ -216,11 +220,13 @@ data class ImageInfo(
 
 			val original = links?.getString("original")?.let { originalUrl ->
 				ImageUrlInfo(
-					url = UriString(if (isAnimated) {
-						originalUrl.replace(".gif", ".mp4")
-					} else {
-						originalUrl
-					}),
+					url = UriString(
+						if (isAnimated) {
+							originalUrl.replace(".gif", ".mp4")
+						} else {
+							originalUrl
+						}
+					),
 					size = ImageSize.fromJson(image),
 					sizeBytes = image?.getLong("size")
 				)