magnifying_glass 2.1.1

Flutter real-time magnifying glass lens widget with Barrel/Pincushion distortion.

example/lib/main.dart

import 'package:flutter/material.dart';
import 'package:magnifying_glass/magnifying_glass.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(),
    );
  }
}

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

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  ValueNotifier<int> diameter = ValueNotifier(150);
  ValueNotifier<double> distortion = ValueNotifier(1.0);
  ValueNotifier<double> magnification = ValueNotifier(1.2);
  ValueNotifier<GlassPosition> glassPosition =
      ValueNotifier(GlassPosition.touchPosition);

  @override
  Widget build(BuildContext context) {
    MagnifyingGlassController magnifyingGlassController =
        MagnifyingGlassController();
    return MagnifyingGlass(
      controller: magnifyingGlassController,
      glassPosition: glassPosition.value,
      borderThickness: 8.0,
      borderColor: Colors.black,
      elevation: 12,
      shadowOffset: const Offset(8, 8),
      glassParams: GlassParams(
        // startingPosition: Offset(150, 150),
        diameter: diameter.value,
        distortion: distortion.value,
        magnification: magnification.value,
        padding: const EdgeInsets.all(10),
      ),
      child: Scaffold(
        body: SingleChildScrollView(
          child: Padding(
            padding: const EdgeInsets.all(16.0),
            child: Column(children: [
              Image.asset('assets/dash.png'),

              /// Diameter
              Row(
                children: [
                  const Text('Diameter'),
                  ValueListenableBuilder<int>(
                      valueListenable: diameter,
                      builder: (_, diam, __) {
                        return Expanded(
                          child: Slider(
                              value: diam.toDouble(),
                              min: 10,
                              max: 300,
                              divisions: 29,
                              label: diameter.value.toString(),
                              onChanged: (value) {
                                diameter.value = value.toInt();
                                magnifyingGlassController
                                    .setDiameter(diameter.value);
                              }),
                        );
                      }),
                ],
              ),

              /// Distortion
              Row(
                children: [
                  const Text('Distortion'),
                  ValueListenableBuilder<double>(
                      valueListenable: distortion,
                      builder: (_, d, __) {
                        return Expanded(
                          child: Slider(
                              value: d,
                              min: -3.0,
                              max: 3.0,
                              divisions: 60,
                              label: distortion.value.toStringAsFixed(2),
                              onChanged: (value) {
                                distortion.value = value;
                                magnifyingGlassController.setDistortion(
                                    distortion.value, magnification.value);
                              }),
                        );
                      }),
                ],
              ),

              /// Magnification
              Row(
                children: [
                  const Text('Magnification'),
                  ValueListenableBuilder<double>(
                      valueListenable: magnification,
                      builder: (_, mag, __) {
                        return Expanded(
                          child: Slider(
                              value: mag,
                              min: -2.0,
                              max: 2.0,
                              divisions: 100,
                              label: magnification.value.toStringAsFixed(2),
                              onChanged: (value) {
                                magnification.value = value;
                                magnifyingGlassController.setDistortion(
                                    distortion.value, magnification.value);
                              }),
                        );
                      }),
                ],
              ),

              /// Glass Position top
              ValueListenableBuilder<GlassPosition>(
                  valueListenable: glassPosition,
                  builder: (_, pos, __) {
                    return Row(
                      mainAxisSize: MainAxisSize.max,
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        Checkbox(
                          value: pos == GlassPosition.topLeft,
                          onChanged: (bool? value) {
                            glassPosition.value = GlassPosition.topLeft;
                            setState(() {});
                          },
                        ),
                        Checkbox(
                          value: pos == GlassPosition.topRight,
                          onChanged: (bool? value) {
                            glassPosition.value = GlassPosition.topRight;
                            setState(() {});
                          },
                        ),
                      ],
                    );
                  }),

              /// Glass Position touch
              ValueListenableBuilder<GlassPosition>(
                  valueListenable: glassPosition,
                  builder: (_, pos, __) {
                    return Checkbox(
                      value: pos == GlassPosition.touchPosition,
                      onChanged: (bool? value) {
                        glassPosition.value = GlassPosition.touchPosition;
                        setState(() {});
                      },
                    );
                  }),

              /// Glass Position top
              ValueListenableBuilder<GlassPosition>(
                  valueListenable: glassPosition,
                  builder: (_, pos, __) {
                    return Row(
                      mainAxisSize: MainAxisSize.max,
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: [
                        Checkbox(
                          value: pos == GlassPosition.bottomLeft,
                          onChanged: (bool? value) {
                            glassPosition.value = GlassPosition.bottomLeft;
                            setState(() {});
                          },
                        ),
                        Checkbox(
                          value: pos == GlassPosition.bottomRight,
                          onChanged: (bool? value) {
                            glassPosition.value = GlassPosition.bottomRight;
                            setState(() {});
                          },
                        ),
                      ],
                    );
                  }),

              const Text(
                'Lorem ipsum dolor sit amet, consectetur adipiscing elit. '
                'Phasellus dictum maximus tortor ac porta. Aenean aliquet '
                'erat eu mi commodo, ut feugiat enim consectetur. ',
                style: TextStyle(fontSize: 20),
                textAlign: TextAlign.justify,
              ),
            ]),
          ),
        ),
        floatingActionButton: FloatingActionButton(
          onPressed: () => magnifyingGlassController.openGlass(),
          child: const Icon(Icons.search),
        ),
      ),
    );
  }
}