feat: API to render a single section of the board (#56)

* feat: section render

* adding missing tests

* missing test

* missing test

* missing tests

* add missing tests

---------

Co-authored-by: Jaime <52668514+jsgalarraga@users.noreply.github.com>

api/packages/board_renderer/lib/src/board_renderer.dart

@@ -1,6 +1,7 @@
 import 'dart:math' as math;
 import 'dart:typed_data';
 import 'package:game_domain/game_domain.dart';
+import 'package:http/http.dart' as http;
 import 'package:image/image.dart' as img;
 
 /// A function that creates a command to execute.
@@ -26,6 +27,31 @@ typedef DrawRect = img.Image Function(
   img.Channel maskChannel,
 });
 
+/// A function that composites an image.
+typedef CompositeImage = img.Image Function(
+  img.Image dst,
+  img.Image src, {
+  int? dstX,
+  int? dstY,
+  int? dstW,
+  int? dstH,
+  int? srcX,
+  int? srcY,
+  int? srcW,
+  int? srcH,
+  img.BlendMode blend,
+  bool linearBlend,
+  bool center,
+  img.Image? mask,
+  img.Channel maskChannel,
+});
+
+/// A function that makes a GET request.
+typedef GetCall = Future<http.Response> Function(Uri uri);
+
+/// A function that decodes a PNG image.
+typedef DecodePng = img.Image? Function(Uint8List data);
+
 /// {@template board_renderer_failure}
 /// Exception thrown when a board rendering fails.
 /// {@endtemplate}
@@ -49,19 +75,28 @@ class BoardRenderer {
     CreateCommand createCommand = img.Command.new,
     CreateImage createImage = img.Image.new,
     DrawRect drawRect = img.drawRect,
+    CompositeImage compositeImage = img.compositeImage,
+    DecodePng decodePng = img.decodePng,
+    GetCall get = http.get,
   })  : _createCommand = createCommand,
         _createImage = createImage,
-        _drawRect = drawRect;
+        _drawRect = drawRect,
+        _compositeImage = compositeImage,
+        _decodePng = decodePng,
+        _get = get;
 
   final CreateCommand _createCommand;
   final CreateImage _createImage;
   final DrawRect _drawRect;
+  final CompositeImage _compositeImage;
+  final DecodePng _decodePng;
 
-  /// The size of each cell in the board.
-  static const cellSize = 4;
+  final GetCall _get;
 
   /// Renders the full board in a single image.
   Future<Uint8List> renderBoard(List<Word> words) async {
+    /// The size of each cell in the board when rendering in full size.
+    const cellSize = 4;
     var minPositionX = 0;
     var minPositionY = 0;
 
@@ -143,4 +178,95 @@ class BoardRenderer {
 
     return outputBytes;
   }
+
+  Future<Uint8List> _getFile(Uri uri) async {
+    final response = await _get(uri);
+
+    if (response.statusCode != 200) {
+      throw BoardRendererFailure('Failed to get image from $uri');
+    }
+
+    return response.bodyBytes;
+  }
+
+  /// Renders a section of the board in an image.
+  Future<Uint8List> renderSection(BoardSection section) async {
+    final words = section.words;
+
+    const cellSize = 40;
+
+    var maxPositionX = 0;
+    var maxPositionY = 0;
+
+    for (final word in words) {
+      final x = word.position.x - section.position.x * section.size;
+      final y = word.position.y - section.position.y * section.size;
+
+      final sizeX = word.axis == Axis.horizontal ? word.answer.length : 1;
+      final sizeY = word.axis == Axis.vertical ? word.answer.length : 1;
+
+      maxPositionX = math.max(maxPositionX, x + sizeX);
+      maxPositionY = math.max(maxPositionY, y + sizeY);
+    }
+
+    final totalWidth = maxPositionX * cellSize;
+    final totalHeight = maxPositionY * cellSize;
+
+    final image = _createImage(
+      width: totalWidth,
+      height: totalHeight,
+    );
+
+    const url = 'http://127.0.0.1:8080/assets/letters.png';
+    final textureImage = await _getFile(Uri.parse(url));
+
+    final texture = _decodePng(textureImage);
+    if (texture == null) {
+      throw BoardRendererFailure('Failed to load the texture');
+    }
+
+    for (final word in words) {
+      final x = word.position.x - section.position.x * section.size;
+      final y = word.position.y - section.position.y * section.size;
+
+      final position = (x, y);
+
+      final wordCharacters = word.answer.split('');
+
+      for (var c = 0; c < wordCharacters.length; c++) {
+        final char = wordCharacters.elementAt(c).toUpperCase();
+        final charIndex = char.codeUnitAt(0) - 65;
+
+        _compositeImage(
+          image,
+          texture,
+          dstX: word.axis == Axis.horizontal
+              ? (position.$1 + c) * cellSize
+              : position.$1 * cellSize,
+          dstY: word.axis == Axis.vertical
+              ? (position.$2 + c) * cellSize
+              : position.$2 * cellSize,
+          dstW: cellSize,
+          dstH: cellSize,
+          srcX: charIndex * cellSize,
+          srcY: 0,
+          srcW: cellSize,
+          srcH: cellSize,
+        );
+      }
+    }
+
+    final createdCommand = _createCommand()
+      ..image(image)
+      ..encodePng();
+
+    await createdCommand.execute();
+
+    final outputBytes = createdCommand.outputBytes;
+    if (outputBytes == null) {
+      throw BoardRendererFailure('Failed to render the section');
+    }
+
+    return outputBytes;
+  }
 }

api/packages/board_renderer/pubspec.yaml

@@ -9,6 +9,7 @@ environment:
 dependencies:
   game_domain:
     path: ../game_domain
+  http: ^1.2.1
   image: ^4.1.7
 
 dev_dependencies: