shape_editor 0.0.18

A flutter shape editor library that provides DiagramEditor widget.

example/main.dart

import 'dart:convert';
import 'dart:math' as math;
import 'dart:ui' as ui;

import 'package:flutter/foundation.dart';
import 'package:flutter/scheduler.dart';
import 'package:flutter/services.dart';
import 'package:http/http.dart' as http;
import 'package:shape_editor/shape_editor.dart';
import 'package:flutter/material.dart';

void main() => runApp(DiagramApp());

class DiagramApp extends StatefulWidget {
  const DiagramApp({Key? key}) : super(key: key);

  @override
  _DiagramAppState createState() => _DiagramAppState();
}

class _DiagramAppState extends State<DiagramApp> {
  //MyPolicySet myPolicySet = MyPolicySet();
  PolicySet policySet = PolicySet();
  late DiagramEditorContext diagramEditorContext;

  @override
  void initState() {
    diagramEditorContext = DiagramEditorContext(policySet: policySet);
    policySet.isGridVisible = false;
    policySet.buttonBackColor = Colors.deepOrange;
    policySet.loadingIndicatorColor = Colors.deepOrange;
    policySet.canvasReader.state.componentUpdateEvent
        .subscribe(onComponentEvent);

    super.initState();

    SchedulerBinding.instance.addPostFrameCallback((_) async {
      compute(initializeComponents, false);
    });
  }


  Future<void> initializeComponents(bool removeExistingRois) async {
    diagramEditorContext.canvasModel.addComponent(ComponentData(
        position: Offset(50, 50),
        size: Size(80, 150),
        minSize: Size(5, 5),
        color: Colors.orange,
        borderColor: Colors.deepOrange,
        borderWidth: 2.0,
        type: "rectangle",
        vertices: []));
    diagramEditorContext.canvasModel.addComponent(ComponentData(
        position: Offset(250, 50),
        size: Size(180, 120),
        minSize: Size(5, 5),
        color: Colors.orange,
        borderColor: Colors.deepOrange,
        borderWidth: 2.0,
        type: "ellipse",
        vertices: []));
    diagramEditorContext.canvasModel.addComponent(ComponentData(
        position: Offset(50, 250),
        size: Size(30, 35),
        minSize: Size(5, 5),
        locked: true,
        color: Color.fromARGB(30, 255, 87, 34),
        highlightColor: Color.fromARGB(30, 34, 71, 255),
        borderColor: Colors.deepOrange,
        borderWidth: 2.0,
        type: "image",
        encodedBinaryData: base64Decode("EgMaBhcIFgkUCxMMEg0RDhAPDw8PDxANEQwRCgYGBwkHFggWCRUJFggWCRYIFgkWChQOEBAOEQwTCxMKFAoUCRUIFQgWBxcFDQ=="),
        vertices: []));




    var image = await debugImage();
    policySet.canvasReader.state.canvasState.setImage(image);
    policySet.canvasReader.state.canvasState.imageRescaleFactor = 1;
    setState(() { });
  }


  void onComponentEvent(ComponentEvent? args) {
    if (args == null) return;
  }

  Future<ui.Image> debugImage() async {
    final url = 'https://63293d826eeab0f978a0119f8726d455.cdn.bubble.io/f1746189111268x549167210405818500/005.jpg?_gl=1*j3emgr*_gcl_au*MjA3MTgyMTczMS4xNzUwNjgwNTU4*_ga*MTc1NTYxMzM3My4xNzA2NzIxMzkw*_ga_BFPVR2DEE2*czE3NTA4Njk3MzkkbzMwMCRnMCR0MTc1MDg2OTczOSRqNjAkbDAkaDA.'; // 200x200 random image
    final response = await http.get(Uri.parse(url));
    final codec = await ui.instantiateImageCodec(response.bodyBytes);
    final frame = await codec.getNextFrame();
    return frame.image;
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        body: SafeArea(
          child: Stack(
            children: [
              Container(color: Colors.grey),
              Padding(
                padding: const EdgeInsets.all(36),
                child: DiagramEditor(diagramEditorContext: diagramEditorContext),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

// Custom component Data which you can assign to a component to dynamic data property.
class MyComponentData {
  MyComponentData();

  bool isHighlightVisible = false;
  Color color =
      Color((math.Random().nextDouble() * 0xFFFFFF).toInt()).withOpacity(1.0);

  showHighlight() {
    isHighlightVisible = true;
  }

  hideHighlight() {
    isHighlightVisible = false;
  }

  // Function used to deserialize the diagram. Must be passed to `canvasWriter.model.deserializeDiagram` for proper deserialization.
  MyComponentData.fromJson(Map<String, dynamic> json)
      : isHighlightVisible = json['highlight'],
        color = Color(int.parse(json['color'], radix: 16));

  // Function used to serialization of the diagram. E.g. to save to a file.
  Map<String, dynamic> toJson() => {
        'highlight': isHighlightVisible,
        'color': color.toString().split('(0x')[1].split(')')[0],
      };
}

// A set of policies compound of mixins. There are some custom policy implementations and some policies defined by diagram_editor library.
class MyPolicySet extends PolicySet
    with
        MyInitPolicy,
        MyCanvasPolicy,
        MyComponentPolicy,
        CustomPolicy,
        //
        LinkControlPolicy,
        LinkJointControlPolicy,
        LinkAttachmentRectPolicy {}

// A place where you can init the canvas or your diagram (eg. load an existing diagram).
mixin MyInitPolicy implements InitPolicy {
  @override
  initializeDiagramEditor() {
    canvasWriter.state.setCanvasColor(Colors.grey[300]!);
  }
}

// You can override the behavior of any gesture on canvas here.
// Note that it also implements CustomPolicy where own variables and functions can be defined and used here.
mixin MyCanvasPolicy implements CanvasPolicy, CustomPolicy {
  @override
  onCanvasTapUp(TapUpDetails details) {
    canvasWriter.model.hideAllLinkJoints();
    if (selectedComponentId != null) {
      hideComponentHighlight(selectedComponentId);
    } else {
      canvasWriter.model.addComponent(
        ComponentData(
          size: const Size(96, 72),
          position:
              canvasReader.state.fromCanvasCoordinates(details.localPosition),
          data: MyComponentData(),
        ),
      );
    }
  }
}

// Mixin where component behaviour is defined. In this example it is the movement, highlight and connecting two components.
mixin MyComponentPolicy implements ComponentPolicy, CustomPolicy {
  // variable used to calculate delta offset to move the component.
  late Offset lastFocalPoint;

  @override
  onComponentTap(String componentId) {
    canvasWriter.model.hideAllLinkJoints();

    bool connected = connectComponents(selectedComponentId, componentId);
    hideComponentHighlight(selectedComponentId);
    if (!connected) {
      highlightComponent(componentId);
    }
  }

  @override
  onComponentLongPress(String componentId) {
    hideComponentHighlight(selectedComponentId);
    canvasWriter.model.hideAllLinkJoints();
    canvasWriter.model.removeComponent(componentId);
  }

  @override
  onComponentScaleStart(componentId, details) {
    lastFocalPoint = details.localFocalPoint;
  }

  @override
  onComponentScaleUpdate(componentId, details) {
    Offset positionDelta = details.localFocalPoint - lastFocalPoint;
    canvasWriter.model.moveComponent(componentId, positionDelta);
    lastFocalPoint = details.localFocalPoint;
  }

  // This function tests if it's possible to connect the components and if yes, connects them
  bool connectComponents(String? sourceComponentId, String? targetComponentId) {
    if (sourceComponentId == null || targetComponentId == null) {
      return false;
    }
    // tests if the ids are not same (the same component)
    if (sourceComponentId == targetComponentId) {
      return false;
    }
    // tests if the connection between two components already exists (one way)
    if (canvasReader.model.getComponent(sourceComponentId).connections.any(
        (connection) =>
            (connection is ConnectionOut) &&
            (connection.otherComponentId == targetComponentId))) {
      return false;
    }

    // This connects two components (creates a link between), you can define the design of the link with LinkStyle.
    canvasWriter.model.connectTwoComponents(
      sourceComponentId: sourceComponentId,
      targetComponentId: targetComponentId,
      linkStyle: LinkStyle(
        arrowType: ArrowType.pointedArrow,
        lineWidth: 1.5,
        backArrowType: ArrowType.centerCircle,
      ),
    );

    return true;
  }
}

// You can create your own Policy to define own variables and functions with canvasReader and canvasWriter.
mixin CustomPolicy implements PolicySet {
  String? selectedComponentId;
  String serializedDiagram = '{"components": [], "links": []}';

  highlightComponent(String componentId) {
    canvasReader.model.getComponent(componentId).data.showHighlight();
    canvasReader.model.getComponent(componentId).updateComponent();
    selectedComponentId = componentId;
  }

  hideComponentHighlight(String? componentId) {
    if (componentId != null) {
      canvasReader.model.getComponent(componentId).data.hideHighlight();
      canvasReader.model.getComponent(componentId).updateComponent();
      selectedComponentId = null;
    }
  }

  deleteAllComponents() {
    selectedComponentId = null;
    canvasWriter.model.removeAllComponents();
  }

  // Save the diagram to String in json format.
  serialize() {
    serializedDiagram = canvasReader.model.serializeDiagram();
  }

  // Load the diagram from json format. Do it cautiously, to prevent unstable state remove the previous diagram (id collision can happen).
  deserialize() {
    canvasWriter.model.removeAllComponents();
    canvasWriter.model.deserializeDiagram(
      serializedDiagram,
      decodeCustomComponentData: (json) => MyComponentData.fromJson(json),
      decodeCustomLinkData: null,
    );
  }
}