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> A flexible progress bars drawing in terminal emulators.

**TTY::ProgressBar** provides independent progress bars component for [TTY](https://github.com/piotrmurach/tty) toolkit.

## Features

* Fully [configurable](#3-configuration)
* Extremely flexible progress display [formatting](#4-formatting)
* Includes many predefined tokens to calculate ETA, Bytes ... [tokens](#41-tokens)
* Allows to define your [custom tokens](#42-custom-formatters)
* Supports parallel multi progress bars [multi](#6-ttyprogressbarmulti-api)
* Works on all ECMA-48 compatible terminals

## Installation

Add this line to your application's Gemfile:

```ruby
gem 'tty-progressbar'
```

And then execute:

    $ bundle

Or install it yourself as:

    $ gem install tty-progressbar

## Contents

* [1. Usage](#1-usage)
* [2. TTY::ProgressBar::API](#2-ttyprogressbar-api)
  * [2.1 advance](#21-advance)
  * [2.2 iterate](#22-iterate)
  * [2.3 current=](#23-current)
  * [2.4 ratio=](#24-ratio)
  * [2.5 width=](#25-width)
  * [2.6 start](#26-start)
  * [2.7 update](#27-update)
  * [2.8 finish](#28-finish)
  * [2.9 stop](#29-stop)
  * [2.10 reset](#210-reset)
  * [2.11 complete?](#211-complete)
  * [2.12 resize](#212-resize)
  * [2.13 on](#213-on)
* [3. Configuration](#3-configuration)
  * [3.1 :head](#31-head)
  * [3.2 :frequency](#32-interval)
  * [3.3 :interval](#33-interval)
* [4. Formatting](#4-formatting)
  * [4.1 Tokens](#41-tokens)
  * [4.2 Custom Formatters](#42-custom-formatters)
  * [4.3 Custom Tokens](#43-custom-tokens)
* [5. Logging](#5-logging)
* [6. TTY::ProgressBar::Multi API](#6-ttyprogressbarmulti-api)
  * [6.1 new](#61-new)
  * [6.2 register](#62-register)
  * [6.3 advance](#63-advance)
  * [6.4 start](#64-start)
  * [6.5 finish](#65-finish)
  * [6.6 stop](#66-stop)
  * [6.7 complete?](#67-complete)
  * [6.8 on](#68-on)
  * [6.9 :style](#69-style)
* [7. Examples](#7-examples)
  * [7.1 Color](#71-color)
  * [7.2 Speed](#72-speed)

## 1. Usage

**TTY::ProgressBar** requires only format string and total number of steps to completion. Once initialized, use `advance` method to indicated the progress like so:

```ruby
bar = TTY::ProgressBar.new("downloading [:bar]", total: 30)
30.times do
  sleep(0.1)
  bar.advance(1)
end
```

This would produce animation in your terminal:

```ruby
# downloading [=======================       ]
```

Use **TTY::ProgressBar::Multi** to display multiple parallel progress bars:

```ruby
bars = TTY::ProgressBar::Multi.new("main [:bar] :percent")

bar1 = bars.register("one [:bar] :percent", total: 15)
bar2 = bars.register("two [:bar] :percent", total: 15)

bars.start

th1 = Thread.new { 15.times { sleep(0.1); bar1.advance } }
th2 = Thread.new { 15.times { sleep(0.1); bar2.advance } }

[th1, th2].each { |t| t.join }
```

which will produce:

```ruby
# ┌ main [===============               ] 50%
# ├── one [=====          ] 34%
# └── two [==========     ] 67%
```

## 2. TTY::ProgressBar API

### 2.1 advance

Once you have **TTY::ProgressBar** instance, you can progress the display by calling `advance` method. By default it will increase by `1` but you can pass any number of steps, for instance, when used to advance number of bytes of downloaded file.

```ruby
bar.advance(1000)
```

You can also pass negative steps if you wish to backtrack the progress:

```ruby
bar.advance(-1)
```

Note: If a progress bar has already finished then negative steps will not set it back to desired value.

### 2.2 iterate

To simplify progressing over an enumerable you can use `iterate` which as a first argument accepts an `Enumerable` and as a second the amount to progress the bar with.

First, create a progress bar without a total which will be dynamically handled for you:

```ruby
bar = TTY::ProgressBar.new
```

Then, either directly iterate over a collection by yielding values to a block:

```ruby
bar.iterate(30.times) { |v| ... }
```

or return an 'Enumerator':

```ruby
progress = bar.iterate(30.times)
# => #<Enumerator: #<Enumerator::Generator:0x...:each>
```

By default, progress bar is advanced by `1` but you can change it by passing second argument:

```ruby
bar.iterate(30.times, 5)
```

### 2.3 current=

**TTY::ProgressBar** allows you to set progress to a given value by calling `current=` method.

```ruby
bar.current = 50
```

Note: If a progress bar has already finished then negative steps will not set it back to desired value.

### 2.4 ratio=

In order to update overall completion of a progress bar as an exact percentage use the `ratio=` method. The method accepts values between `0` and `1` inclusive. For example, a ratio of 0.5 will attempt to set the progress bar halfway:

```ruby
bar.ratio = 0.5
```

### 2.5 width=

You can set how many terminal columns will the `:bar` actually span excluding any other tokens and/or text. For example if you need the bar to be always 20 columns wwide do:

```ruby
bar.width = 20
```

or with configuration options:

```ruby
bar = TTY::ProgressBar.new("[:bar]", width: 20)
```

### 2.6 start

By default the timer for internal time esitamation is started automatically when the `advance` method is called. However, if you require control on when the progression timer is started use `start` call:

```ruby
bar.start  # => sets timer and draws initial progress bar
```

### 2.7 update

Once the progress bar has been started you can change its configuration option(s) by calling `update`:

```ruby
bar.update(complete: '+', frequency: 10)
```

### 2.8 finish

In order to immediately stop and finish the progress call `finish`. This will finish drawing the progress and return to new line.

```ruby
bar.finish
```

### 2.9 stop

In order to immediately stop the bar in the current position and thus finish any further progress use `stop`:

```ruby
bar.stop
```

### 2.10 reset

In order to reset currently running or finished progress bar to its original configuration and initial position use `reset` like so:

```ruby
bar.reset
```

After resetting the bar if you wish to draw and start the bar and its timers use `start` call.

### 2.11 complete?

During progresion you can check if a bar is finished or not by calling `complete?`. The bar will only return `true` if the progression finished successfuly, otherwise `false` will be returned.

```ruby
bar.complete? # => false
```

### 2.12 resize

If you wish for a progress bar to change it's current width, you can use `resize` by passing in a new desired length. However, if you don't provide any width the `resize` will use terminal current width as its base for scaling.

```ruby
bar.resize      # => determine terminal width and scale accordingly
bar.resize(50)  # => will resize bar proportionately from this point onwards
```

To handle automatic resizing you can trap `:WINCH` signal:

```ruby
trap(:WINCH) { bar.resize }
```

### 2.13 on

The progress bar fires events when it is progressing, stopped or finished. You can register to listen for events using the `on` message.

Every time an `advance` is called the `:progress` event gets fired which you can listen for:

```ruby
bar.on(:progress) { ... }
```

When the progress bar finishes and completes then the `:done` event is fired. You can listen for this event:

```ruby
bar.on(:done) { ... }
```

Alternatively, when the progress bar gets stopped the `:stopped` event is fired. You can listen for this event:

```ruby
bar.on(:stopped) { ... }
```

## 3. Configuration

There are number of configuration options that can be provided:

* `:total` total number of steps to completion
* `:width` of the bars display in terminal columns excluding formatting options. Defaults to total steps
* `:complete` completion character by default `=`
* `:incomplete` incomplete character by default single space
* [:head](#21-head) the head character by default `=`
* `:output` the output stream defaulting to `stderr`
* [:frequency](#22-frequency) used to throttle the output, by default `0`
* [:interval](#23-interval) used to measure the speed, by default `1 sec`
* `:hide_cursor` to hide display cursor defaulting to `false`
* `:clear` to clear the finished bar defaulting to `false`

All the above options can be passed in as hash options or block parameters:

```ruby
TTY::ProgressBar.new "[:bar]" do |config|
  config.total = 30
  config.frequency = 10
  config.clear = true
end
```

### 3.1 :head

If you prefer for the animated bar to display a specific character for a head of progression then use `:head` option:

```ruby
bar = TTY::ProressBar.new("[:bar]", head: '>')
#
# [=======>      ]
```

### 3.2 :frequency

Each time the `advance` is called it causes the progress bar to repaint. In cases when there is a huge number of updates per second, you may need to limit the rendering process by using the `frequency` option.

The `frequency` option accepts `integer` representing number of `Hz` units, for instance, frequency of 2 will mean that the progress will be updated maximum 2 times per second.

```ruby
TTY::ProgressBar.new("[:bar]", total: 30, frequency: 10) # 10 Hz
```

### 3.3 :interval

For every call of `advance` method the **ProgressBar** takes a sample for speed measurement. By default the samples are grouped per second but you can change that by passing the `interval` option.

The `interval` option is an `integer` that represents the number of seconds, for example, interval of `60` would mean that speed is measured per 1 minute.

```ruby
TTY::ProgressBar.new(":rate/minute", total: 100, interval: 60) # 1 minute

TTY::ProgressBar.new(":rate/hour", total: 100, interval: 3600) # 1 hour
```

## 4. Formatting

Every **TTY::ProgressBar** instance requires a format string, which apart from regular characters accepts special tokens to display dynamic information. For instance, a format to measure download progress could be:

```ruby
"downloading [:bar] :elapsed :percent"
```

### 4.1 Tokens

These are the tokens that are currently supported:

* `:bar` the progress bar
* `:current` the current progress number
* `:current_byte` the current progress in bytes
* `:total` the total progress number
* `:total_byte` the total progress in bytes
* `:percent` the completion percentage
* `:elapsed` the elapsed time in seconds
* `:eta` the esitmated time to completion in seconds
* `:rate` the current rate of progression per second
* `:byte_rate` the current rate of pregression in bytes per second
* `:mean_rate` the averaged rate of progression per second
* `:mean_byte` the averaged rate of progression in bytes per second

### 4.2 Custom Formatters

If the provided tokens do not meet your needs, you can write your own formatter and instrument formatting pipeline to use a formatter you prefer. This option is preferred if you are going to rely on progress bar internal data such as `rate`, `current` etc. which will all be available on the passed in progress bar instance.

For example, begin by creating custom formatter called `TimeFormatter` that will dynamicly update `:time` token in format string. The methods that you need to specify are `initialize`, `matches?` and `format` like follows:

```ruby
class TimeFormatter
  def initialize(progress)
    @progress = progress # current progress bar instance
  end

  def matches?(value)  # specify condition to match for in display string
    value.to_s =~ /:time/
  end

  def format(value)  # specify how display string is formatted
    transformed = (Time.now - @progress.start_at).to_s
    value.gsub(/:time/, transformed)   # => :time token replacement
  end
end
```

Notice that you have access to all the configuration options inside the formatter by simply invoking them on the `@progress` instance.

Create **TTY::ProgressBar** instance with new token:

```ruby
bar = TTY::ProgressBar.new(":time", total: 30)
```

Then add `TimeFormatter` to the pipeline like so:

```ruby
bar.use TimeFormatter
```

and then invoke progression:

```ruby
bar.advance
```

### 4.3 Custom Tokens

You can define custom tokens by passing pairs `name: value` to `advance` method in order to dynamically update formatted bar. This option is useful for lightweight content replacement such as titles that doesn't depend on the internal data of progressbar. For example:

```ruby
bar = TTY::ProgressBar.new("(:current) :title", total: 4)
bar.advance(title: 'Hello Piotr!')
bar.advance(3, title: 'Bye Piotr!')
```

which outputs:

```ruby
(1) Hello Piotr!
(4) Bye Piotr!
```

## 5. Logging

If you want to print messages out to terminal along with the progress bar use the `log` method. The messages will appear above the progress bar and will continue scrolling up as more are logged out.

```ruby
bar.log('Piotrrrrr')
bar.advance
```

will result in:

```ruby
# Piotrrrrr
# downloading [=======================       ]
```

## 6. TTY::ProgressBar::Multi API

### 6.1 new

The multi progress bar can be created in two ways. If you simply want to group multiple progress bars you can create multi bar like so:

```ruby
TTY::ProgressBar::Multi.new
```


However, if you want a top level multibar that tracks all the registered progress bars then provide a formatted string:

```ruby
TTY::ProgressBar::Multi.new("main [:bar] :percent")
```

### 6.2 register

To create a `TTY::ProgressBar` under the multibar use `register` like so:

```ruby
multibar = TTY::ProgressBar::Multi.new
bar = multibar.register("[:bar]", total: 30)
```

The `register` call returns the newly created progress bar which answers all the progress bar api messages.

Please remember to specify total value for each registered progress bar, either when sending `register` message or when using `update` to dynamicaly assign the total value.

### 6.3 advance

Once multi progress bar has been created you can advance each registered progress bar individually, either by executing them one after the other synchronously or by placing them in separate threads thus progressing each bar asynchronously. The multi bar handles synchronization and display of all bars as they continue their respective rendering.

For example, to display two bars async, first register them with the multi bar:

```ruby
bar1 = multibar.register("one [:bar]", total: 20)
bar2 = multibar.register("two [:bar]", total: 30)
```

Next place the progress behaviour in separate process or thread:

```ruby
th1 = Thread.new { 20.times { expensive_work(); bar1.advance } }
th2 = Thread.new { 30.times { expensive_work(); bar2.advance } }
```

Finally, wait for the threads to finish:

```ruby
[th1, th2].each { |t| t.join }
```

### 6.4 start

By default the top level multi bar will be rendered as the first bar and have its timer started when on of the regsitered bars advances. However, if you wish to start timers and draw the top level multi bar do:

```ruby
multibar.start  # => sets timer and draws top level multi progress bar
```

### 6.5 finish

In order to finish all progress bars call `finish`. This will finish the top level progress bar, if it exists, all any registered progress bars still in progress.

```ruby
multibar.finish
```

### 6.6 stop

Use `stop` to terminate immediately all progress bars registered with the multibar.

```ruby
multibar.stop
```

### 6.7 complete?

To check if all registered progress bars have been successfully finished use `complete?`

```ruby
multibar.complete? # => true
```

### 6.8 on

Similar to `TTY::ProgressBar` the multi bar fires events when it is progressing, stopped or finished. You can register to listen for events using the `on` message.

Every time any of the registered progress bars progresses the `:progress` event is fired which you can listen for:

```ruby
multibar.on(:progress) { ... }
```

When all the registered progress bars finish and complete then the `:done` event is fired. You can listen for this event:

```ruby
multibar.on(:done) { ... }
```

Finally, when any of the progress bars gets stopped the `:stopped` event is fired. You can listen for this event:

```ruby
multibar.on(:stopped) { ... }
```

### 6.9 :style

In addition to all [configuration options](#3-configuration) you can style multi progress bar:

```ruby
TTY::ProgressBar::Multi.new("[:bar]", style: {
  top: '. '
  middle: '|-> '
  bottom: '|__ '
})
```

## 7. Examples

This section demonstrates some of the possible uses for the **TTY::ProgressBar**, for more please see examples folder in the source directory.

### 7.1 Colors

Creating a progress bar that displays in color is as simple as coloring the `:complete` and `:incomplete` character options. In order to help with coloring you can use [pastel](https://github.com/piotrmurach/pastel) library like so:

```ruby
require 'pastel'

pastel = Pastel.new
green  = pastel.on_green(" ")
red    = pastel.on_red(" ")
```

And then pass in the colored strings as options to **TTY::ProgressBar**:

```ruby
bar = TTY::ProgressBar.new("|:bar|",
  total: 30,
  complete: green,
  incomplete: red
)
```

To see how a progress bar is reported in terminal you can do:

```ruby
30.times do
  sleep(0.1)
  bar.advance
end
```

### 7.2 Speed

Commonly a progress bar is utilized to measure download speed per second. This can be done like so:

```ruby
TTY::ProgressBar.new("[:bar] :byte_rate/s") do |config|
  config.total = 300000
  config.interval = 1     # => 1 sec
end
```

This will result in output similar to:

```ruby
# downloading [=======================       ] 4.12MB/s
```

## Contributing

1. Fork it ( https://github.com/piotrmurach/tty-progressbar/fork )
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create a new Pull Request

This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.

## Copyright

Copyright (c) 2014-2017 Piotr Murach. See LICENSE for further details.