fis_lib_measure/lib/view/gesture/annotation/label_drag_target_pannel.dart

import 'package:fis_measure/interfaces/enums/annotation.dart';
import 'package:fis_measure/interfaces/process/workspace/application.dart';
import 'package:fis_measure/interfaces/process/workspace/point_info.dart';
import 'package:fis_measure/view/gesture/mouse_gesture.dart';
import 'package:flutter/material.dart';
import 'package:get/get.dart';

import '../positioned_cursor.dart';

/// 文本注释拖拽目标面板
class AnnotationLabelDragTargetPanel extends StatefulWidget {
  const AnnotationLabelDragTargetPanel({Key? key}) : super(key: key);

  @override
  State<StatefulWidget> createState() => _PanelState();
}

class _PanelState extends State<AnnotationLabelDragTargetPanel> {
  late final application = Get.find<IApplication>();
  final mouseState = Get.find<IMouseState>();
  CursorDisplayType displayType = CursorDisplayType.none;

  @override
  void initState() {
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return DragTarget<String>(
      builder: (context, candidateData, rejectedData) {
        return GestureDetector(
          onPanDown: (details) {
            application.createPointInfo(
              details.localPosition,
              PointInfoType.mouseDown,
            );
            application.switchAnnotation(AnnotationType.input);
          },
          child: MouseRegion(
            cursor: SystemMouseCursors.none,
            onHover: (event) {
              mouseState.mousePosition = event.localPosition;
            },
            onEnter: (e) {
              setState(() {
                displayType = CursorDisplayType.normal;
              });
            },
            onExit: (e) {
              setState(() {
                displayType = CursorDisplayType.none;
              });
            },
            child: Stack(
              children: [
                _buildCursor(),
              ],
            ),
          ),
        );
      },
      onMove: (details) {
        _notifyPosition(context, details.offset, PointInfoType.mouseMove);
      },
      onAcceptWithDetails: (details) {
        _notifyPosition(context, details.offset, PointInfoType.mouseUp);
      },
    );
  }

  void _notifyPosition(
    BuildContext context,
    Offset offset,
    PointInfoType type,
  ) {
    final localOffset = _findLocalPosition(context, offset);
    mouseState.mousePosition = localOffset;
    application.createPointInfo(localOffset, type);
  }

  Offset _findLocalPosition(BuildContext context, Offset globalPosition) {
    final renderBox = context.findRenderObject() as RenderBox?;
    if (renderBox == null) return globalPosition;
    return renderBox.globalToLocal(globalPosition);
  }

  Widget _buildCursor() {
    switch (displayType) {
      case CursorDisplayType.none:
        return Container();
      case CursorDisplayType.normal:
        return const PositionedCursor();
      default:
        return const PositionedCursor();
    }
  }

  @override
  void dispose() {
    super.dispose();
  }
}