TelegramCharts

This app maked for Telegram March and April contests

My telegram account: @AlexanderStef

My telegram content account: https://contest.dev/chart-ios/entry45

I consume time:

• Around 40 hours for Stage1 (March) during two weeks.
• And 55 hours for Stage2 (April) during one weeks.
• All this in parallel with the main work.

In both cases I took the 4th place.

March Contests

Goal

Build simple (only line) charts based on input data Telegram had provided.

Description

For look this version need move to tag v7. The version was written by fan without a goal to win.

You can find two directories:

Main - Сontains code table with 5 chart cells and cells for change column visible.

Charts - Contains code for show chart and interval selector.

Code use CALayer with UIBezierPath and not optimized for old devices - can lags.

April Contests

Goal

Build five (All different) charts based on input data Telegram had provided.

An additional goal was also proposed, but I initially decided not to do it.

Description

For look this version need move to tag v11 or current commit. The version was written to get the prize.

I specifically retain CALayer and UIBezierPath despite a lot of experience in OpenGL.

But wrote more optimization for smooth work:

• CallFrequenceLimiter - to not recalculate often. Need only for offload CPU and battery ;)
• Cache charts to image in background thread - for smooth scrolling
• Cache UILabels and text size - for smooth transition interval and visible
• Improve UIBezierPath calculations - draw only visible interval
• Improve mathematical component - for quick calculations (but there is something to improve)

You can find two directories:

Main - Constains code table with 6 chart cells and cells for change column visible.

Charts - Contains code for show chart and interval selector.

More detail about Charts directory:

• ChartProvider.swift - for load Chart data from json
• ChartStyle.swift - color configs for charts
• Configs.swift - animation time configs for charts
• CallFrequenceLimiter.swift - limits the number of calls per second
• Models directory - contains all models:
• -- Charts.swift and Column.swift - model from provider
• -- AABB.swift - limiting the area
• -- ColumnViewModel.swift and ChartViewModel.swift - public view models for saving charts/columns state.
• -- ColumnUIModel.swift and ChartUIModel.swift - internal models to display chart.
• Views directory - contains all views. First level has public views other internal.
• Views\Internal directory - contains base subviews: Hint, interval, chart, dates, axis views.
• Views\Internal\ColumnsView directory - contains code for render Columns.

ColumnsView directory:

• ColumnsView.swift - container containing all columns.
• ColumnViewLayerWrapper.swift - base class for render columns. Contains more methods for animation and support cache.
• PolyLineLayerWrapper.swift - contains code for generate line points by ColumnUIModel.
• BarLayerWrapper.swift - contains code for generate bars points by ColumnUIModel.
• AreaViewLayerWrapper.swift - contains code for generate fill line points by ColumnUIModel.

Finally

This code is not complete - it is stable but not perfect. Use for commercial purposes - does not make sense.