refa image preview

Signed-off-by: dom <githubaccount56556@proton.me>

lib/common/widgets/image_viewer/loading_indicator.dart

@@ -0,0 +1,148 @@
+/*
+ * This file is part of PiliPlus
+ *
+ * PiliPlus is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * PiliPlus is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with PiliPlus.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import 'dart:io' show Platform;
+import 'dart:math' show pi;
+
+import 'package:flutter/material.dart';
+
+///
+/// created by dom on 2026/02/14
+///
+
+class LoadingIndicator extends LeafRenderObjectWidget {
+  const LoadingIndicator({
+    super.key,
+    required this.size,
+    required this.progress,
+  });
+
+  final double size;
+  final double progress;
+
+  @override
+  RenderObject createRenderObject(BuildContext context) {
+    return RenderLoadingIndicator(
+      preferredSize: size,
+      progress: progress,
+    );
+  }
+
+  @override
+  void updateRenderObject(
+    BuildContext context,
+    RenderLoadingIndicator renderObject,
+  ) {
+    renderObject
+      ..preferredSize = size
+      ..progress = progress;
+  }
+}
+
+class RenderLoadingIndicator extends RenderBox {
+  RenderLoadingIndicator({
+    required double preferredSize,
+    required double progress,
+  }) : _preferredSize = preferredSize,
+       _progress = progress;
+
+  double _preferredSize;
+  double get preferredSize => _preferredSize;
+  set preferredSize(double value) {
+    if (_preferredSize == value) return;
+    _preferredSize = value;
+    markNeedsLayout();
+  }
+
+  double _progress;
+  double get progress => _progress;
+  set progress(double value) {
+    if (_progress == value) return;
+    _progress = value;
+    markNeedsPaint();
+  }
+
+  @override
+  void performLayout() {
+    size = constraints.constrainDimensions(_preferredSize, _preferredSize);
+  }
+
+  @override
+  void paint(PaintingContext context, Offset offset) {
+    if (_progress == 0) {
+      return;
+    }
+    const padding = 8.0;
+    const strokeWidth = 1.4;
+    const startAngle = -pi / 2;
+
+    final paint = Paint()..isAntiAlias = true;
+    final size = this.size;
+    final radius = size.width / 2 - strokeWidth;
+    final center = size.center(.zero);
+
+    if (Platform.isIOS) {
+      context.canvas
+        ..drawCircle(
+          center,
+          radius,
+          paint
+            ..strokeWidth = strokeWidth
+            ..color = Colors.white,
+        )
+        ..drawCircle(
+          center,
+          radius - strokeWidth,
+          paint..color = const Color(0x80000000),
+        )
+        ..drawArc(
+          Rect.fromCircle(center: center, radius: radius - padding),
+          startAngle,
+          progress * 2 * pi,
+          true,
+          paint..color = Colors.white,
+        );
+    } else {
+      context.canvas
+        ..drawCircle(
+          center,
+          radius,
+          paint
+            ..style = .fill
+            ..color = const Color(0x80000000),
+        )
+        ..drawCircle(
+          center,
+          radius,
+          paint
+            ..style = .stroke
+            ..strokeWidth = strokeWidth
+            ..color = Colors.white,
+        )
+        ..drawArc(
+          Rect.fromCircle(center: center, radius: radius - padding),
+          startAngle,
+          progress * 2 * pi,
+          true,
+          paint..style = .fill,
+        );
+    }
+  }
+
+  @override
+  bool get isRepaintBoundary => true;
+}