[camera_web] Adopt code excerpts in README (#4584)

Updates the README to use a compiled excerpt source for its example of creating an `Image`.

Part of https://github.com/flutter/flutter/issues/102679

packages/camera/camera_web/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.3.2+1
+
+* Updates README to improve example of `Image` creation.
+
 ## 0.3.2
 
 * Changes `availableCameras` to not ask for the microphone permission.

packages/camera/camera_web/README.md

@@ -80,11 +80,13 @@ URL pointing to a location within the browser (blob) and can be displayed using
 
 See the example below:
 
+<?code-excerpt "example/lib/readme_excerpts.dart (ImageFromXFile)"?>
 ```dart
+final Image image;
 if (kIsWeb) {
-  Image.network(capturedImage.path);
+  image = Image.network(capturedImage.path);
 } else {
-  Image.file(File(capturedImage.path));
+  image = Image.file(File(capturedImage.path));
 }
 ```
 

packages/camera/camera_web/example/lib/readme_excerpts.dart

@@ -0,0 +1,22 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:io';
+
+import 'package:camera_platform_interface/camera_platform_interface.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.dart';
+
+/// Demonstrates using an XFile result as an [Image] source, for the README.
+Image getImageFromResultExample(XFile capturedImage) {
+  // #docregion ImageFromXFile
+  final Image image;
+  if (kIsWeb) {
+    image = Image.network(capturedImage.path);
+  } else {
+    image = Image.file(File(capturedImage.path));
+  }
+  // #enddocregion ImageFromXFile
+  return image;
+}

packages/camera/camera_web/example/pubspec.yaml

@@ -6,14 +6,14 @@ environment:
   flutter: ">=3.3.0"
 
 dependencies:
+  camera_platform_interface: ^2.1.0
+  camera_web:
+    path: ../
   flutter:
     sdk: flutter
 
 dev_dependencies:
   async: ^2.5.0
-  camera_platform_interface: ^2.1.0
-  camera_web:
-    path: ../
   cross_file: ^0.3.1
   flutter_test:
     sdk: flutter

packages/camera/camera_web/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera_web
 description: A Flutter plugin for getting information about and controlling the camera on Web.
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera_web
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.3.2
+version: 0.3.2+1
 
 environment:
   sdk: ">=2.18.0 <4.0.0"

script/configs/temp_exclude_excerpt.yaml

@@ -5,7 +5,6 @@
 
 # TODO(stuartmorgan): Remove everything from this list. See
 # https://github.com/flutter/flutter/issues/102679
-- camera_web
 - cross_file
 - css_colors
 - espresso