Terminal live output

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• Quickstart
• Feature details
• Live text
• Spinner
• Progress bar

ITGlobal CLI contains a “live output” feature, which allows you to create:

• lines of text,
• spinners,
• progress bars

and to update them in-place.

Quickstart

1. At first you need to create an instance of ILiveOutputManager. This object is responsible for creating and maitaining all live items.

   var liveOutput = LiveOutputManager.Create();
   

   LiveOutputManager.Create() method has parameters to override rendering of spinners and progress bar:

   var spinnerRenderer = SpinnerRenderer.BouncingBall();
   var progressBarRenderer = ProgressBarRenderer.Arrow();
   
   var liveOutput = LiveOutputManager.Create(
       spinnerRenderer: spinnerRenderer,
       progressBarRenderer: progressBarRenderer
   );
   

2. Then you may create all live output items you need:

   var text = liveOutput.CreateText("An updatable text");
   var spinner = liveOutput.CreateSpinner("A spinner");
   var progressBar = liveOutput.CreateProgressBar("A progress bar");
   

   Note that you may create new items when you need. It’s not necessary to create all of them right after creation of ILiveOutputManager.

3. Then you may update live output items as (and when) you need to”

   text.Write("This text has been updated");
   spinner.Write("Still spinning");
   progressBar.Write(33, "In progress...");
   

   All live output objects are thread-safe and can be updated from another thread.

   While a live output is on, you still may write anything to console using standard System.Console class. This will not break live output behaviour since ILiveOutputManager` handles conflicting output gracefully.

4. When you don’t need live output items anymore, you may destroy all of them by dispoing an ILiveOutputManager:

   liveOutput.Dispose();
   

   It’s strongly recommended to use using() or try-finally operators.

Feature details

Live text

Live text is a most simple live output item - it’s just a line of colored text that can be updated in place.

A live output text is created using a CreateText() method of ILiveOutputManager. It provides the following method to update it:

• Write() method updates text.

• WipeAfter() method enables or disabled a “wipe-after” mode.

  If it’s enabled, a line of text will be cleared from screen then ILiveOutputManager is disposed. Otherwise it will stay on screen in its latest state.

  By default this mode is disabled.

using (var liveOutput = LiveOutputManager.Create())
{
    var text = liveOutput.CreateText("Processing items: 1/3...");
    text.WipeAfter();
    Thread.Sleep(1000);
    text.Write("Processing items: 2/3...");
    Thread.Sleep(1000);
    text.Write("Processing items: 3/3...");
    Thread.Sleep(1000);
}

Console.WriteLine("Processing is completed");

Spinner

Spinner is a more complicated version of live text item - it’s a line of colored text that can be updated in place plus an animated spinner.

A spinner is created using a CreateSpinner() method of ILiveOutputManager. It provides the following method to update it:

• Write() method updates text.

• WipeAfter() method enables or disabled a “wipe-after” mode.

  If it’s enabled, a line of text will be cleared from screen then ILiveOutputManager is disposed. Otherwise it will stay on screen in its latest state.

  By default this mode is disabled.

using (var liveOutput = LiveOutputManager.Create())
{
    var spinner = liveOutput.CreateSpinner("Processing items: 1/3...");
    spinner.WipeAfter();
    Thread.Sleep(1000);
    spinner.Write("Processing items: 2/3...");
    Thread.Sleep(1000);
    spinner.Write("Processing items: 3/3...");
    Thread.Sleep(1000);
}

Console.WriteLine("Processing is completed");

Spinner rendering is configured via SpinnerRenderer which is passed to LiveOutputManager.Create() method.

By default a SpinnerRenderer.Default renderer is used, which is a RotatingBar renderer unless overriden. The following built-in spinner renderers are available:

• SpinnerRenderer.RotatingBar()
• SpinnerRenderer.RotatingAngle()
• SpinnerRenderer.Arrow()
• SpinnerRenderer.BouncingBall()

All of them are configurable - you may override:

• spinner colors
• spinner location (at the end of line or in beginning of it)
• a whitespace between spinner and text

Progress bar

Progress bar is a line of colored text that can be updated in place plus a bar that displays progress.

A progress bar is created using a CreateProgressBar() method of ILiveOutputManager. It provides the following method to update it:

• Write() method updates text and/or progress value.

  Progress value should lie in range from 0 to 100, where 0 means an empty bar and 100 means a full bar.

• WipeAfter() method enables or disabled a “wipe-after” mode.

  If it’s enabled, a line of text will be cleared from screen then ILiveOutputManager is disposed. Otherwise it will stay on screen in its latest state.

  By default this mode is disabled.

• Complete() method updates text and disabled bar rendering, only text will be rendered.

  This might come in handy when you have few simultaneous operations and you need to display that some of operations are fully completed.

using (var liveOutput = LiveOutputManager.Create())
{
    var progressBar = liveOutput.CreateProgressBar("Processing items...");
    progressBar.WipeAfter();
    for (var i = 0; i < 100; i += 10)
    {
        progressBar.Write(i);
        Thread.Sleep(500);
    }
}

Console.WriteLine("Processing is completed");

Progress bar rendering is configured via ProgressBarRenderer which is passed to LiveOutputManager.Create() method.

By default a ProgressBarRenderer.Default renderer is used, which is a Arrow renderer unless overriden. The following built-in progress bar renderers are available:

• ProgressBarRenderer.Arrow()
• ProgressBarRenderer.HashSign()
• ProgressBarRenderer.Legacy()
• ProgressBarRenderer.Shades()

All of them are configurable - you may override:

• progress bar colors
• progress bar location (at the end of line or in beginning of it)
• progress bar size
• a whitespace between spinner and text