The History of Everything

The History of Everything is a vertical timeline that allows you to navigate, explore, and compare events from the Big Bang to the birth of the Internet. Events are beautifully illustrated and animated.

The concept for this app was inspired by the Kurzgesagt video, Time: The History & Future of Everything.

The app was built with Flutter by 2Dimensions and it's available on Android and iOS.

Usage

Make sure you have Flutter installed on your local machine. For more instructions on how to install flutter, look here.

git clone https://github.com/2d-inc/HistoryOfEverything.git
cd HistoryOfEverything/app
git submodule init
git submodule update
flutter run

Overview

The app consists of three main views:

Main Menu - /app/lib/main_menu
This is the initial view for the app when it opens up. It shows a search bar on top, three menu sections for each major time era, and three buttons on the bottom for accessing favorites, sharing a link to the store, and the about page.
Timeline - /app/lib/timeline
This view is displayed when an item from the menu is selected: the user is presented with a vertical timeline. It can be scrolled up and down, zoomed in and out.
When an event is in view, a bubble will be shown on screen with a custom animated widget right next to it. By tapping on either, the user can access the ArticlePage.
ArticlePage - /app/lib/article
The ArticlePage displays the event animation, together with a full description of the event.

Animated Widgets

This relies heavily on the animations built on 2dimensions and they are seamlessly integrated with Flutter by using the Flare and Nima libraries.

One of Flutter's biggest strengths is its flexibility, because it exposes the architecture of its components, which can be built entirely from scratch: it's possible to create custom widgets out of the SDK's most basic elements.

An example can be found in /app/lib/article/timeline_entry_widget.dart
This file contains two classes:

TimelineEntryWidget that extends LeafRenderObjectWidget
VignetteRenderObject that extends RenderBox

LeafRenderObjectWidget

This class (docs) is a Widget: it can be inserted in any widget tree without any other default component:

Container(
  child: TimelineEntryWidget(
        isActive: true,
        timelineEntry: widget.article,
        interactOffset: _interactOffset
    )
)

This snippet is used in /app/lib/article/article_widget.dart

The LeafRenderObjectWidget is responsible for having a constructor and encapsulating the values that the RenderObject needs.

The following two overrides are also fundamental:

createRenderObject()
Instantiates the actual RenderObject in the Widget Tree;
updateRenderObject()
Any change to the parameters that are passed to the Widget can be reflected also on the UI, if needed. Updating a RenderObject will cause the object to redraw.

RenderObject

As specified in the docs, this is an object in the render tree, and it defines what and how its creator Widget will paint on the screen.

The key override here is paint():
the current PaintingContext exposes the canvas, and this class can draw, taking full advantage of the exposed API.
The Flare library, granted access to the canvas, draws the animation.
To have the animation reproduce correctly, it's also necessary to call advance(elapsed) on the current FlutterActor each frame. Moreover, the current ActorAnimation requires that the function apply(time) is called on it to display it's correct interpolated values.
This is all made possible by relying on Flutter's SchedulerBinding.scheduleFrameCallback().

This is just a brief overview of how the Flare widgets can be customized for every experience.

sinyu1012 / HistoryOfEverything