Use ANSI color codes if SupportsVirtualTerminal #447

dahlbyk · 2017-03-01T05:51:51Z

See #304 for detail and much conversation. For now I have just rebased on develop, resolved all the conflicts, and updated the new default prompt.

Closes #282 and Jaykul/PowerLine#1.

dahlbyk · 2017-03-01T06:36:11Z

Collect Git prompt in ArrayList instead of strings

Not sure if this is a good optimization or not. Thoughts, @lzybkr?

More generally, I wonder if this is Close Enough™ for now to merge, giving basic support and a fixed point from which to iterate on how exactly ANSI colors work. In addition to the actual ANSI implementation (dedicated module?), colors play a key role in prompt customization (cc #340 #345).

rkeithhill · 2017-03-01T15:53:36Z

src/ConsoleMode.ps1

@@ -0,0 +1,103 @@
+# Hack! https://gist.github.com/lzybkr/f2059cb2ee8d0c13c65ab933b75e998c
+
+if ($IsWindows -eq $false) {


For non-cross-platform PowerShell Core, we should test $PSVersionTable.PSVersion.Major -ge 6 -and $IsWindows. As that variable is only defined in PowerShell Core. We can assume a major version of -lt 6 is Windows only.

Thought is that $IsWindows will be $null for PS -lt 6, and $null -ne $false. Net result is that we'll only create NativeConsoleMethods if we're not explicitly on not-Windows.

Or are you thinking that we shouldn't create NativeConsoleMethods for older versions of PS?

I guess I find the logic a bit cryptic. Maybe this is worth a helper function IsWindows to encapsulate the logic. RE NativeConsoleMethods no need to create these if they are not used and we won't use them except on Windows w/ANSI support, right?

I wonder if the native console methods have an impact on ConEmu and other console hosts? Do they even exist on Windows pre-10?

What was the initial impetus for this? PowerShell sets the console mode to enable ANSI seqs. Or was there a version (5.0) that didn't do this?

The api exists on all versions of Windows - but the flag we need is not recognized universally - just Win10 Anniversary and later I think. The api call will fail (I think harmlessly) if it doesn't recognize the flag.

The workaround should not be needed in V6 - I fixed it in PowerShell: PowerShell/PowerShell#2991

rkeithhill · 2017-03-01T15:58:10Z

src/GitPrompt.ps1

@@ -97,6 +97,8 @@ $global:GitPromptSettings = [pscustomobject]@{

    EnableWindowTitle                           = 'posh~git ~ '

+    AnsiConsole                                 = $Host.UI.SupportsVirtualTerminal -or ($Env:ConEmuANSI -eq "ON")


I believe the SupportsVirtualTerminal property was added in PS 5.1. I have started a prototype for ANSI stuff based on v5 classes. In it, I have a PromptRenderer class that has a HostSupportsAnsi method. That method returns $false for version less than 5.1. It returns false for Windows version less than 10.0.10586.0 (which is the build that support conhost ANSI seqs). Finally, it returns the value of $Host.UI.SupportsVirtualTerminal.

I'm not sure there's a practical difference, is there? If SupportsVirtualTerminal isn't set, it's falsey.

You're probably right. I carry some baggage having written scripts back in the early PS days that were affected by users setting Set-StrictMode -Version Latest in their global session. Fortunately that does not impact modules. That and I still cling to statically typed notions and referring to a property that may or may not exist just feels wrong. ;-)

That and I still cling to statically typed notions and referring to a property that may or may not exist just feels wrong. ;-)

Understood. I'll try to help you get over it. 😀

rkeithhill · 2017-03-01T16:02:06Z

src/GitPrompt.ps1

@@ -128,11 +130,18 @@ if (Get-Module NuGet) {
 }

 function Write-Prompt($Object, $ForegroundColor, $BackgroundColor = -1) {
+    if ($GitPromptSettings.AnsiConsole) {


So in the PromptRenderer class I was working on, the idea was that it maintained an internal StringBuilder (for ANSI hosts) and it uses Write-Host for non-ANSI. Currently it takes an array of TextSpan objs (text, fg, bg in a class) but I was thinking it might be better to have a BeginWrite/Write/EndWrite set of methods where the Write method takes a TextSpan object.

Begin/EndWrite for non-ANSI would be a no-op but for ANSI BeginWrite would init StringBuilder and EndWrite would return contents of StringBuider. For non-ANSI, EndWrite would return the requisite single space to get rid of PS> showing up.

rkeithhill · 2017-03-01T16:03:14Z

src/GitPrompt.ps1

+        $e = [char]27 + "["
+        $f = Get-ForegroundVirtualTerminalSequence $ForegroundColor
+        $b = Get-BackgroundVirtualTerminalSequence $BackgroundColor
+        return "${f}${b}${Object}${e}0m"


We need to be able to handle terms that support 24-bit color like the upcoming Windows 10 CU drop. See my Twitter post on that - https://twitter.com/r_keith_hill/statuses/835556870697930753 This was something I was encapsulating in a Color class in my prototype.

$ForegroundColor and $BackgroundColor are explicitly untyped, so in theory there's no reason Get-ForegroundVirtualTerminalSequence and Get-BackgroundVirtualTerminalSequence couldn't emit valid escape sequences given a variety of input types ("#rrggbb", System.Drawing.Color, etc).

(Not that a Color class couldn't have equivalent support.)

rkeithhill · 2017-03-01T16:07:57Z

Give me a day or so and I can commit my (very) prototype branch that uses v5 classes. It is missing stuff you have like the setting the console mode and conversion from console colors to ANSI seq indices. Maybe we can meld the two?

lzybkr · 2017-03-01T18:22:51Z

I'm not sure about ArrayList w/ -join versus += on a string - my intuition says it won't matter - the strings are short anyway.

In general, use of StringBuilder would be a better optimization because you'll allocate fewer objects.

dahlbyk · 2017-03-01T20:59:49Z

A quick benchmark confirms that it really doesn't matter for small strings, but for larger strings StringBuilder is an order of magnitude faster than ArrayList, which is maybe 25% faster than string concatenation.

We may end up wanting a StringBuilder, but I'm content to leave it for now.

Give me a day or so and I can commit my (very) prototype branch that uses v5 classes. It is missing stuff you have like the setting the console mode and conversion from console colors to ANSI seq indices. Maybe we can meld the two?

I guess my question is if this branch is a reasonable enough starting point for people to 1) test it out, if they want, and 2) serve as a base for iterating on how we handle ANSI (your PromptRenderer or otherwise). Thoughts?

rkeithhill · 2017-03-01T21:11:47Z

src/Utils.ps1

+function Get-BackgroundVirtualTerminalSequence($Color) {
+    return Get-VirtualTerminalSequence $Color 10
+}
+
 function dbg($Message, [Diagnostics.Stopwatch]$Stopwatch) {


Eventually we might to put these into an Ansi.ps1 or AnsiUtils.ps1 file but that can wait.

rkeithhill · 2017-03-01T21:12:26Z

I guess my question is if this branch is a reasonable enough starting point

Good point. Go ahead and merge it. I have an Ubuntu VM I work on everyday for embedded Linux development work. I could take it for a spin there.

@lzybkr

Hat tip to @lzybkr

- Make Set-ConsoleMode a no-op on non-Windows - Suppress a lint warning - Remove unused functions

Semantics are still quite strange... - If -Builder is specified (piped in), it will be returned, but only modified if -AnsiConsole is also specified - If -AnsiConsole is specified, a string with ANSI color escape sequences is returned. - Otherwise, an empty string is returned.

dahlbyk · 2017-03-02T17:33:31Z

Just rewrote the world:

ANSI stuff moved to separate file
Squashed a few fixup-y commits
Added a spike using StringBuilder just for fun... Write-Prompt semantics are now even more odd

rkeithhill · 2017-03-02T19:18:57Z

src/AnsiUtils.ps1

@@ -0,0 +1,36 @@
+# Color codes from https://msdn.microsoft.com/en-us/library/windows/desktop/mt638032(v=vs.85).aspx


Hehe, that is exactly the filename I'm using in my classes prototype branch. Did some work on that last night but not quite ready yet for evaluation.

dahlbyk force-pushed the SupportsVirtualTerminal branch from c86fdb2 to 30a0566 Compare March 1, 2017 05:58

dahlbyk added this to the v1.0 milestone Mar 1, 2017

dahlbyk requested a review from rkeithhill March 1, 2017 06:53

rkeithhill reviewed Mar 1, 2017

View reviewed changes

dahlbyk added 5 commits March 2, 2017 11:30

Use ANSI color codes if SupportsVirtualTerminal

cc5af78

Reset console mode on Write-VcsStatus

ef44e2b

Hat tip to @lzybkr

Collect Git prompt in ArrayList instead of strings

3c4ba08

Clean up ConsoleMode

76256bc

- Make Set-ConsoleMode a no-op on non-Windows - Suppress a lint warning - Remove unused functions

dahlbyk force-pushed the SupportsVirtualTerminal branch from 5eebe44 to d3f4ca2 Compare March 2, 2017 17:31

rkeithhill reviewed Mar 2, 2017

View reviewed changes

dahlbyk merged commit d42d7a7 into develop Mar 3, 2017

dahlbyk deleted the SupportsVirtualTerminal branch March 3, 2017 06:14

This was referenced Mar 4, 2017

Write-Prompt with $null colors, plus respecting DefaultForegroundColor #454

Merged

ANSI 256-color and 24-bit color support #455

Merged

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Use ANSI color codes if SupportsVirtualTerminal #447

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rkeithhill Mar 2, 2017

		@@ -0,0 +1,103 @@
		# Hack! https://gist.github.com/lzybkr/f2059cb2ee8d0c13c65ab933b75e998c

		if ($IsWindows -eq $false) {

		@@ -97,6 +97,8 @@ $global:GitPromptSettings = [pscustomobject]@{

		EnableWindowTitle = 'posh~git ~ '

		AnsiConsole = $Host.UI.SupportsVirtualTerminal -or ($Env:ConEmuANSI -eq "ON")

		@@ -0,0 +1,36 @@
		# Color codes from https://msdn.microsoft.com/en-us/library/windows/desktop/mt638032(v=vs.85).aspx

Use ANSI color codes if SupportsVirtualTerminal #447

Use ANSI color codes if SupportsVirtualTerminal #447

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