Rendering error (#90)

Author: noahsmartin

Sources/SnapshotPreviewsCore/View+Snapshot.swift

@@ -10,16 +10,16 @@ import Foundation
 import SwiftUI
 import UIKit
 
-enum RenderingError: Error {
-  case failedRendering
+public enum RenderingError: Error {
+  case failedRendering(CGSize)
 }
 
 extension View {
   public func snapshot(
     layout: PreviewLayout,
     window: UIWindow,
     async: Bool,
-    completion: @escaping (Result<UIImage, Error>, Float?) -> Void)
+    completion: @escaping (Result<UIImage, RenderingError>, Float?) -> Void)
   {
     UIView.setAnimationsEnabled(false)
     let animationDisabledView = self.transaction { transaction in
@@ -82,7 +82,7 @@ extension View {
     layout: PreviewLayout,
     renderingMode: EmergeRenderingMode?,
     rootVC: UIViewController,
-    controller: UIViewController) -> Result<UIImage, Error>
+    controller: UIViewController) -> Result<UIImage, RenderingError>
   {
     let view = controller.view!
     let drawCode: (CGContext) -> Void
@@ -117,7 +117,7 @@ extension View {
       drawCode(context.cgContext)
     }
     if !success {
-      return .failure(RenderingError.failedRendering)
+      return .failure(RenderingError.failedRendering(targetSize))
     }
     return .success(image)
   }

Sources/SnapshottingSwift/Snapshots.swift

@@ -102,15 +102,15 @@ class Snapshots {
     try await server.start()
   }
 
-  @MainActor func display(typeName: String, id: String) async -> (Result<UIImage, Error>, SnapshotPreviewsCore.Preview) {
+  @MainActor func display(typeName: String, id: String) async -> (Result<UIImage, RenderingError>, SnapshotPreviewsCore.Preview) {
     await withCheckedContinuation { continuation in
       display(typeName: typeName, id: id) { result, preview in
         continuation.resume(returning: (result, preview))
       }
     }
   }
 
-  @MainActor func display(typeName: String, id: String, completion: @escaping (Result<UIImage, Error>, SnapshotPreviewsCore.Preview) -> Void) {
+  @MainActor func display(typeName: String, id: String, completion: @escaping (Result<UIImage, RenderingError>, SnapshotPreviewsCore.Preview) -> Void) {
     let previewTypes = findPreviews { name in
       return name == typeName
     }
@@ -122,7 +122,7 @@ class Snapshots {
     }
   }
 
-  @MainActor func display(preview: SnapshotPreviewsCore.Preview, completion: @escaping (Result<UIImage, Error>, Float?) -> Void) throws {
+  @MainActor func display(preview: SnapshotPreviewsCore.Preview, completion: @escaping (Result<UIImage, RenderingError>, Float?) -> Void) throws {
     var view = preview.view()
     view = AnyView(PreferredColorSchemeWrapper { view })
     view.snapshot(