Configurable preview size (#2)

* Configurable preview size

* Fix configurable preview size

Sources/UIPreview/UICatalog/CatalogItem.swift

@@ -13,7 +13,10 @@ struct CatalogItem<Content: UIViewCatalogPresentable>: View {
     ForEach(values: Content.previewModels) { model in
       ForEach(values: configuration.colorSchemes) { scheme in
         ForEach(values: configuration.contentSizeCategory) { category in
-          item(model: model, scheme: scheme, category: category)
+          item(model: model,
+               scheme: scheme,
+               category: category,
+               size: configuration.size)
         }
       }
     }
@@ -21,18 +24,21 @@ struct CatalogItem<Content: UIViewCatalogPresentable>: View {
 
   func item(model: Content.PreviewModel,
             scheme: ColorScheme,
-            category: ContentSizeCategory) -> some View {
+            category: ContentSizeCategory,
+            size: CGSize?) -> some View {
 
     VStack(alignment: .center, spacing: 0) {
       HStack {
         Image(systemName: scheme.systemImageName)
         Image(systemName: category.systemImageName)
         Text(String(describing: model))
-          .frame(maxWidth: 300)
+          .lineLimit(4)
+          .frame(maxWidth: 300, alignment: .leading)
       }
       .padding()
 
       Content.preview(with: model)
+        .modifier(SizeModifier(size: size))
         .frame(maxWidth: .infinity)
         .padding()
         .background(Color(.systemBackground))
@@ -45,6 +51,19 @@ struct CatalogItem<Content: UIViewCatalogPresentable>: View {
   }
 }
 
+@available(iOS 13, *)
+private struct SizeModifier: ViewModifier {
+  let size: CGSize?
+
+  func body(content: Content) -> some View {
+    guard let size = size else {
+      return AnyView(content)
+    }
+    return AnyView(content.frame(width: size.width,
+                                 height: size.height))
+  }
+}
+
 #if DEBUG
 @available(iOS 14, *)
 struct CatalogItem_Previews: PreviewProvider {

Sources/UIPreview/UICatalog/PreviewConfiguration.swift

@@ -6,13 +6,20 @@ import UIKit
 extension UICatalog {
   public struct PreviewConfiguration {
     public init(themes: [Theme] = Theme.allCases,
-                contentSize: [UIContentSizeCategory] = [.unspecified]) {
+                contentSize: [UIContentSizeCategory] = [.unspecified],
+                size: CGSize? = nil) {
       self.themes = themes
       self.contentSize = contentSize
+      self.size = size
     }
 
     let themes: [Theme]
     let contentSize: [UIContentSizeCategory]
+    let size: CGSize?
+
+    public func with(size newSize: CGSize) -> PreviewConfiguration {
+      PreviewConfiguration(themes: themes, contentSize: contentSize, size: newSize)
+    }
   }
 
   public enum Theme: CaseIterable {