Add option to resolve all asset scales for sources (facebook#45989)

Summary:
Pull Request resolved: facebook#45989

Some React Native platforms have multiple display resolutions to contend with. In such cases, the PixelRatio API, which assumes a single display resolution value for the whole app, does not correctly resolve the scale for a particular Image.

Adding an API to resolve each scale variant to a packaged asset allows other platforms to override the Image component to pass all scale options to the Image native component, rather than only the one matching the value from PixelRatio.

## Changelog

[General][Added] Capability to resolve specific asset scale

Differential Revision: D61172622

packages/react-native/Libraries/Image/AssetSourceResolver.js

@@ -36,9 +36,9 @@ const invariant = require('invariant');
 /**
  * Returns a path like 'assets/AwesomeModule/icon@2x.png'
  */
-function getScaledAssetPath(asset: PackagerAsset): string {
-  const scale = pickScale(asset.scales, PixelRatio.get());
-  const scaleSuffix = scale === 1 ? '' : '@' + scale + 'x';
+function getScaledAssetPath(asset: PackagerAsset, scale?: number): string {
+  const resolvedScale = scale ?? pickScale(asset.scales, PixelRatio.get());
+  const scaleSuffix = resolvedScale === 1 ? '' : '@' + resolvedScale + 'x';
   const assetDir = getBasePath(asset);
   return assetDir + '/' + asset.name + scaleSuffix + '.' + asset.type;
 }
@@ -116,15 +116,16 @@ class AssetSourceResolver {
    * Returns an absolute URL which can be used to fetch the asset
    * from the devserver
    */
-  assetServerURL(): ResolvedAssetSource {
+  assetServerURL(scale?: number): ResolvedAssetSource {
     invariant(this.serverUrl != null, 'need server to load from');
     return this.fromSource(
       this.serverUrl +
-        getScaledAssetPath(this.asset) +
+        getScaledAssetPath(this.asset, scale) +
         '?platform=' +
         Platform.OS +
         '&hash=' +
         this.asset.hash,
+      scale,
     );
   }
 
@@ -140,13 +141,14 @@ class AssetSourceResolver {
    * Resolves to where the bundle is running from, with a scaled asset filename
    * E.g. 'file:///sdcard/bundle/assets/AwesomeModule/icon@2x.png'
    */
-  scaledAssetURLNearBundle(): ResolvedAssetSource {
+  scaledAssetURLNearBundle(scale?: number): ResolvedAssetSource {
     const path = this.jsbundleUrl ?? 'file://';
     return this.fromSource(
       // Assets can have relative paths outside of the project root.
       // When bundling them we replace `../` with `_` to make sure they
       // don't end up outside of the expected assets directory.
-      path + getScaledAssetPath(this.asset).replace(/\.\.\//g, '_'),
+      path + getScaledAssetPath(this.asset, scale).replace(/\.\.\//g, '_'),
+      scale,
     );
   }
 
@@ -174,13 +176,13 @@ class AssetSourceResolver {
     return this.fromSource(path + getAssetPathInDrawableFolder(this.asset));
   }
 
-  fromSource(source: string): ResolvedAssetSource {
+  fromSource(source: string, scale?: number): ResolvedAssetSource {
     return {
       __packager_asset: true,
       width: this.asset.width,
       height: this.asset.height,
       uri: source,
-      scale: pickScale(this.asset.scales, PixelRatio.get()),
+      scale: scale ?? pickScale(this.asset.scales, PixelRatio.get()),
     };
   }
 

packages/react-native/Libraries/__tests__/__snapshots__/public-api-test.js.snap

@@ -4751,12 +4751,12 @@ declare class AssetSourceResolver {
   isLoadedFromFileSystem(): boolean;
   defaultAsset(): ResolvedAssetSource;
   getAssetUsingResolver(resolver: AssetDestPathResolver): ResolvedAssetSource;
-  assetServerURL(): ResolvedAssetSource;
+  assetServerURL(scale?: number): ResolvedAssetSource;
   scaledAssetPath(): ResolvedAssetSource;
-  scaledAssetURLNearBundle(): ResolvedAssetSource;
+  scaledAssetURLNearBundle(scale?: number): ResolvedAssetSource;
   resourceIdentifierWithoutScale(): ResolvedAssetSource;
   drawableFolderInBundle(): ResolvedAssetSource;
-  fromSource(source: string): ResolvedAssetSource;
+  fromSource(source: string, scale?: number): ResolvedAssetSource;
   static pickScale: (scales: Array<number>, deviceScale?: number) => number;
 }
 declare module.exports: AssetSourceResolver;