gistfile1.txt

import 'package:flutter/material.dart';

class ColorFiltersDemo extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => ColorFilterDemoState();
}

class ColorFilterDemoState extends State<ColorFiltersDemo> {
  int selectedBlendModeIndex = 0;

  Map<String, BlendMode> blendModeMap = Map();

  @override
  void initState() {
    super.initState();
    blendModeMap.putIfAbsent("Normal", () => BlendMode.clear);
    blendModeMap.putIfAbsent("Color Burn", () => BlendMode.colorBurn);
    blendModeMap.putIfAbsent("Color Dodge", () => BlendMode.colorDodge);
    blendModeMap.putIfAbsent("Saturation", () => BlendMode.saturation);
    blendModeMap.putIfAbsent("Hue", () => BlendMode.hue);
    blendModeMap.putIfAbsent("Soft light", () => BlendMode.softLight);
    blendModeMap.putIfAbsent("Overlay", () => BlendMode.overlay);
    blendModeMap.putIfAbsent("Multiply", () => BlendMode.multiply);
    blendModeMap.putIfAbsent("Luminosity", () => BlendMode.luminosity);
    blendModeMap.putIfAbsent("Plus", () => BlendMode.plus);
    blendModeMap.putIfAbsent("Exclusion", () => BlendMode.exclusion);
    blendModeMap.putIfAbsent("Hard Light", () => BlendMode.hardLight);
    blendModeMap.putIfAbsent("Lighten", () => BlendMode.lighten);
    blendModeMap.putIfAbsent("Screen", () => BlendMode.screen);
    blendModeMap.putIfAbsent("Modulate", () => BlendMode.modulate);
    blendModeMap.putIfAbsent("Difference", () => BlendMode.difference);
    blendModeMap.putIfAbsent("Darken", () => BlendMode.darken);
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false,
      home: Scaffold(
        body: Stack(
          children: <Widget>[
            Image.asset(
              "images/background_bg.jpg",
              height: double.maxFinite,
              width: double.maxFinite,
              fit: BoxFit.fitHeight,
              color: selectedBlendModeIndex == 0 ? null : Colors.red,
              colorBlendMode: selectedBlendModeIndex == 0
                  ? null
                  : blendModeMap.values.elementAt(selectedBlendModeIndex),
            ),
            Positioned(
              left: 0.0,
              bottom: 0.0,
              height: 100.0,
              right: 0.0,
              child: Container(
                color: Colors.black.withOpacity(0.5),
                child: Center(
                  child: Container(
                    margin: EdgeInsets.only(bottom: 20.0),
                    height: 40.0,
                    child: ListView.builder(
                      padding: EdgeInsets.symmetric(horizontal: 8.0),
                      shrinkWrap: true,
                      scrollDirection: Axis.horizontal,
                      itemCount: blendModeMap.keys.length,
                      itemBuilder: (context, index) {
                        return Container(
                          padding: EdgeInsets.all(4.0),
                          child: ChoiceChip(
                              padding: EdgeInsets.symmetric(
                                  horizontal: 8.0, vertical: 0.0),
                              labelStyle: TextStyle(
                                  color: Colors.white,
                                  fontSize: (selectedBlendModeIndex == index)
                                      ? 15.0
                                      : 13.0,
                                  fontWeight: (selectedBlendModeIndex == index)
                                      ? FontWeight.bold
                                      : FontWeight.normal),
                              backgroundColor: Colors.black.withOpacity(0.8),
                              selectedColor: Colors.blue,
                              label: Center(
                                child: Text(blendModeMap.keys.elementAt(index)),
                              ),
                              selected: selectedBlendModeIndex == index,
                              onSelected: (bool selected) {
                                setState(() {
                                  selectedBlendModeIndex =
                                      selected ? index : null;
                                });
                              }),
                        );
                      },
                    ),
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}