refactor canvas painter

lib/core/background.dart

@@ -34,12 +34,12 @@ class SingleColorBackround extends CanvasBackground {
   }
 }
 
-class DotGridBackround extends CanvasBackground {
+class DotGridBackground extends CanvasBackground {
   final double size;
   final double spacing;
   final Color color;
 
-  const DotGridBackround({this.size = 2.0, this.spacing = 50.0, this.color = Colors.black12}) : super();
+  const DotGridBackground({this.size = 2.0, this.spacing = 50.0, this.color = Colors.black12}) : super();
 
   @override
   void paint(Canvas canvas, Offset screenOffset, Offset canvasOffset, double scale, Size canvasSize) {

lib/core/controller/controller.dart

@@ -1,6 +1,7 @@
 import 'dart:collection';
 
 import 'package:flutter/material.dart';
+import 'package:infinite_lazy_grid/core/background.dart';
 import '../../utils/measure_size.dart';
 import '../spatial_hashing.dart';
 import '../../utils/offset_extensions.dart';
@@ -28,6 +29,7 @@ class LazyCanvasController with ChangeNotifier {
   late BuildContext _context;
   bool _firstBuild = true;
   int? _focusChildOnInit; // if set, will focus on this child on first build
+  CanvasBackground background;
 
   bool debug;
   final Duration defaultAnimationDuration;
@@ -37,6 +39,7 @@ class LazyCanvasController with ChangeNotifier {
     Offset? buildCacheExtent,
     Size hashCellSize = const Size(100, 100),
     this.defaultAnimationDuration = const Duration(milliseconds: 300),
+    this.background = const DotGridBackground(),
   }) : _hashCellSize = hashCellSize,
        _buildCacheExtent = buildCacheExtent != null ? buildCacheExtent + Offset(50, 50) : null
   // only top left is considered so if a widget has long width, it'll not be rendered

lib/core/render.dart

@@ -9,10 +9,9 @@ import 'controller/controller.dart';
 /// An infinite canvas that places all the children at the specified positions.
 /// Needs a [LazyCanvasController] to control the canvas and a [CanvasBackground] to draw the background.
 class LazyCanvas extends StatefulWidget {
-  final CanvasBackground canvasBackground;
   final LazyCanvasController controller;
 
-  const LazyCanvas({required this.controller, required this.canvasBackground, super.key});
+  const LazyCanvas({required this.controller, super.key});
 
   @override
   State<LazyCanvas> createState() => _LazyCanvasState();
@@ -47,7 +46,7 @@ class _LazyCanvasState extends State<LazyCanvas> with TickerProviderStateMixin<L
           final children = childrenWithPositions.map((e) => e.child).toList();
           final canvas = _CanvasRenderObject(
             childrenIds: childrenIds,
-            canvasBackground: widget.canvasBackground,
+            canvasBackground: widget.controller.background,
             ssPositions: ssPositions,
             scale: widget.controller.scale,
             gridSpaceOffset: widget.controller.offset,