# ProgressBar for Elixir
## Usage
You can render regular ("determinate") progress bars, or "indeterminate" ones that animate but don't indicate the current progress.
Do you have a use case not listed below? Please open an issue or pull request!
### Determinate progress bars
Specify the current value and the total value, and a bar will be rendered to STDOUT.
``` elixir
ProgressBar.render(2, 3)
```
Output:
|================================== | 67%
(Shortened to fit GitHub's layout. The bar will really be 100 characters wide.)
Call the function again and it will overwrite the previous bar with the new value:
``` elixir
ProgressBar.render(2, 3)
ProgressBar.render(3, 3)
```
Output:
|==================================================| 100%
This basically works by printing "\r[===…" each time, without a newline. The text cursor will return to the beginning of the line and overwrite the previous value.
When the bar becomes full, a newline is automatically printed, so any subsequent output gets its own line.
It's up to you to re-render the bar when something changes. Here's a trivial example of an animated progress bar:
``` elixir
Enum.each 1..100, fn (i) ->
ProgressBar.render(i, 100)
:timer.sleep 25
end
```
#### Customize format
Replace the `bar`, `blank`, `left` or `right` characters.
``` elixir
format = [
bar: "X", # default: "="
blank: ".", # default: " "
left: "(", # default: "|"
right: ")", # default: "|"
]
ProgressBar.render(97, 100, format)
```
Output:
…XXXXXXXXX...) 97%
You can provide empty-string values to remove `left` and `right` entirely.
#### Customize color
Specify [IO.ANSI values](http://elixir-lang.org/docs/v1.0/elixir/IO.ANSI.html) as `bar_color` or `blank_color`. Use lists for multiple values.
``` elixir
format = [
bar_color: [IO.ANSI.white, IO.ANSI.green_background],
blank_color: IO.ANSI.red_background,
]
ProgressBar.render(97, 100, format)
```
#### `percent: false`
Hides the percentage shown after the bar.
``` elixir
ProgressBar.render(1, 1, percent: false)
```
Output:
…============|
Instead of:
…============| 100%
#### `bytes: true`
This option causes the values to be treated as bytes of data, showing those amounts next to the bar.
``` elixir
ProgressBar.render(2_034_237, 2_097_152, bytes: true)
```
Output:
…========= | 97% (1.94/2.0 MB)
This is great with [progressive downloads](https://gist.github.com/henrik/108e5fc23b66131fc3aa).
### Indeterminate progress bars
Indeterminate progress bars will animate on their own, once you start them off. It's up to you to terminate them when done.
Don't output anything else while this bar is animating, as it will keep rewriting the current output line.
``` elixir
# Start it.
ProgressBar.render_indeterminate
# Do something for an indeterminate amount of time…
:timer.sleep 2000
# Show the progress bar as done.
ProgressBar.terminate
```
It will alternate between four forms by default:
|=---=---=---=---=---=---=---=---=---=---=---…
|-=---=---=---=---=---=---=---=---=---=---=--…
|--=---=---=---=---=---=---=---=---=---=---=-…
|---=---=---=---=---=---=---=---=---=---=---=…
And show as done when you terminate it:
|==========================================…
#### Customize format
You can customize the forms it alternates between, as well as the done state, and the `left` and `right` bookends.
``` elixir
ProgressBar.render_indeterminate(
bars: [ "Oo", "oO" ],
done: "X",
left: "",
right: "",
)
```
The `bars` list can be any length. Each string in that list is a "frame" in the animation.
Each string in that list can be any length and will repeat into a 100 character bar.
The bar will alternate between these strings, and then start over.
#### Customize color
You can customize the color of the bar, and of the completed state.
``` elixir
ProgressBar.render_indeterminate(
bars_color: IO.ANSI.yellow,
done_color: IO.ANSI.green,
)
```
You can pass multiple `IO.ANSI` values, just as with a regular progress bar. The indeterminate bar intentionally doesn't alternate between colors, so as not to trigger epileptic seizures…
#### Interval
You can customize the millisecond interval at which it alternates. The default is 500 milliseconds.
``` elixir
ProgressBar.render_indeterminate(interval: 10)
```
## Examples
To see these bad boys in action, clone this repo and run the example scripts:
# Run all examples.
mix run examples/all.exs
# See what's available.
ls examples
# Run a single example.
mix run examples/default.exs
Or to see them in a real project, try [Sipper](https://github.com/henrik/sipper).
## Installation
Add the dependency to your project's `mix.exs`:
``` elixir
defp deps do
[
{:progress_bar, "> 0.0.0"},
]
end
```
Then fetch it:
mix deps.get
## Tests
mix test
## Credits and license
By Henrik Nyh 2015-09-19 under the MIT license.
