Test-BufferBox 2.0 by Joel Bennett 3 years ago
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A tech demo: a scrolling buffer where you can type while it’s scrolling…
- ## Test-BufferBox 2.0
- ####################################################################################################
- ## This script is just a demonstration of some of the things you can do with the buffer
- ## in the default PowerShell host... it serves as a reminder of how much work remains on
- ## PoshConsole, and as an inspirations to anyone who is thinking about trying to create
- ## "interactive" PowerShell applications.
- ##
- ## Imagine it's a chat window: you can type, but the whole time, the ongoing conversation in the
- ## chat room you have joined is going on in the background.
- ##
- ## NOTE: because this is a "chat" demo, we treat your input as text, and to execute script in-line
- ## you have to enclose it inside $() braces.
- ##
- ####################################################################################################
- PARAM( $title = "PowerShell Interactive Buffer Demo" )
- $global:fore = $Host.UI.RawUI.ForegroundColor
- $global:back = $Host.UI.RawUI.BackgroundColor
- Function New-Box ($Height, $Width, $Title="") {
- $box = &{ "¯¯$Title$('¯'*($Width-($Title.Length+2)))";
- 1..($Height - 2) | % {(' ' * $Width)};
- ('_' * $Width);
- 1..2 | % {(' ' * $Width)};
- }
- $boxBuffer = $Host.UI.RawUI.NewBufferCellArray($box,'Green','Black')
- ,$boxBuffer
- }
- Function Scroll-Buffer ($origin,$Width,$Height,$Scroll=-1){
- $re = new-object $RECT $origin.x, $origin.y, ($origin.x + $width-2), ($origin.y + $height)
- $origin.Y += $Scroll
- $Host.UI.RawUI.ScrollBufferContents($re, $origin, $re, $blank)
- }
- Function Out-Buffer {
- PARAM ($Message, $Foreground = 'White',$Background = 'Black',[switch]$noscroll)
- BEGIN {
- if($Message) {
- $Message | Out-Buffer -Fore $Foreground -Back $Background -NoScript:$NoScroll
- }
- }
- PROCESS { if($_){$Message = $_
- if ( -not $NoScroll) {
- Scroll-Buffer $ContentPos ($WindowSize.Width -2) ($WindowSize.Height - 4)
- }
- # "{0},{1} {2},{3} -{4}" -f $script:pos.X, $script:pos.Y, $MessagePos.X, $MessagePos.Y, $message
- $host.ui.rawui.SetBufferContents(
- $MessagePos,
- $Host.UI.RawUI.NewBufferCellArray(
- @($message.PadRight($WindowSize.Width)),
- $Foreground,
- $Background)
- )
- }}}
- Function Clear-Prompt () {
- $Host.UI.RawUI.SetBufferContents( $PromptPos, $prompt )
- $Host.UI.RawUI.CursorPosition = $CursorPos
- }
- ###################################################################################################
- ##### Initialize a lot of settings
- ###################################################################################################
- $RECT = "system.management.automation.host.rectangle"
- $blank = new-object System.Management.Automation.Host.BufferCell(' ','Gray','Black','complete')
- $WindowSize = $Host.UI.RawUI.WindowSize;
- "`n" * $WindowSize.Height
- $ContentPos = $Host.UI.RawUI.WindowPosition;
- $Host.UI.RawUI.ForegroundColor = "Yellow"
- $Host.UI.RawUI.BackgroundColor = "Black"
- $ContentPos.Y += 1 # Keep the title in the top row
- $ContentPos.X += 2 # 2 cell left padding on output
- # The Message is written into the very last line of the ContentBox
- $MessagePos = $ContentPos
- $MessagePos.Y += ($WindowSize.Height - 4)
- $PromptPos = $ContentPos
- $PromptPos.X = 0
- $PromptPos.Y += $WindowSize.Height - 2
- $prompt = $Host.UI.RawUI.NewBufferCellArray( @(&{"> "+(" " * ($WindowSize.Width-3))}), "Yellow", "Black")
- $CursorPos = $PromptPos
- $CursorPos.X += 2
- ###################################################################################################
- ##### We only need this for the purposes of the demo...
- ##### In a real script you would, presumably, be getting stuff from somewhere else to display
- $noise = Get-Content ($MyInvocation.MyCommand.Path)
- $index = 0;
- $random = New-Object "Random"
- ###################################################################################################
- ##### The loop starts by clearing the screen ...
- $Host.UI.RawUI.SetBufferContents($Host.UI.RawUI.WindowPosition, (New-Box ($WindowSize.Height - 1) $WindowSize.Width $title))
- ##### Printing a "How to Exit" message
- Out-Buffer " " -Fore DarkGray -Back Cyan
- Out-Buffer " This is just a demo. " -Fore Black -Back Cyan
- Out-Buffer " We will stream in the source code of this script ... " -Fore Black -Back Cyan
- Out-Buffer " And you can type at the bottom while it's running. " -Fore Black -Back Cyan
- Out-Buffer " Imagine this as an n-way chat application like IRC, except that " -Fore Black -Back Cyan
- Out-Buffer " FOR THIS PERFORMANCE ONLY: " -Fore Black -Back Cyan
- Out-Buffer " The part of your chatting friends is played by my source code. " -Fore DarkGray -Back Cyan
- Out-Buffer " " -Fore DarkGray -Back Cyan
- Out-Buffer " Press ESC to exit, or enter 'exit' and hit Enter" -Fore Black -Back Cyan
- Out-Buffer " " -Fore DarkGray -Back Cyan
- ##### Setting the prompt
- Clear-Prompt
- ##### And initializing our two variables ...
- $line=""
- $exit = $false
- while(!$exit){
- while(!$exit -and $Host.UI.RawUI.KeyAvailable) {
- $char = $Host.UI.RawUI.ReadKey("IncludeKeyUp,IncludeKeyDown,NoEcho");
- # we don't want the key up events, but we do want to get rid of them
- if($char.KeyDown) {
- switch([int]$char.Character) {
- 13 { # Enter
- if($line.Trim() -eq "exit") { $exit = $true; break; }
- ###################################################################################################
- ###################################################################################################
- ############# WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING #############
- ############# This executes the user input! #############
- ############# Don't use this on, say, content you got from a web page or chat room #############
- iex "Out-Buffer `"$line`" -Fore Red"; #############
- ###################################################################################################
- ###################################################################################################
- $line = "";
- Clear-Prompt
- }
- 27 { # Esc
- $exit = $true; break;
- }
- 8 { # Backspace
- if($line.Length -gt 0) {
- $line = $line.SubString(0,$($line.Length-1))
- }
- # $pos = $Host.UI.RawUI.CursorPosition
- $Host.UI.RawUI.SetBufferContents( $PromptPos, $Host.UI.RawUI.NewBufferCellArray( @(&{ "> $($line)$(' ' * ($WindowSize.Width-3-$line.Length))"}), "Yellow", "Black") )
- }
- 0 { # Not actually a key
- # Out-Buffer $($Char | Out-String)
- }
- default {
- $line += $char.Character
- $Host.UI.RawUI.SetBufferContents( $PromptPos, $Host.UI.RawUI.NewBufferCellArray( @(&{ "> $($line)$(' ' * ($WindowSize.Width-3-$line.Length))"}), "Yellow", "Black") )
- }
- }
- }
- }
- # Simulate doing useful things 25% of the time
- if($random.NextDouble() -gt 0.75) {
- $noise[($index)..($index++)] | Out-Buffer
- if($index -ge $noise.Length){$index = 0}
- }
- sleep -milli 100
- }
- # set the colors back ...
- $Host.UI.RawUI.ForegroundColor = $fore
- $Host.UI.RawUI.BackgroundColor = $back
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