ddbe370d22
This PR reimplements the VT rendering engines to do a better job of preserving the original color types when propagating attributes over ConPTY. For the 16-color renderers it provides better support for default colors and improves the efficiency of the color narrowing conversions. It also fixes problems with the ordering of character renditions that could result in attributes being dropped. Originally the base renderer would calculate the RGB color values and legacy/extended attributes up front, passing that data on to the active engine's `UpdateDrawingBrushes` method. With this new implementation, the renderer now just passes through the original `TextAttribute` along with an `IRenderData` interface, and leaves it to the engines to extract the information they need. The GDI and DirectX engines now have to lookup the RGB colors themselves (via simple `IRenderData` calls), but have no need for the other attributes. The VT engines extract the information that they need from the `TextAttribute`, instead of having to reverse engineer it from `COLORREF`s. The process for the 256-color Xterm engine starts with a check for default colors. If both foreground and background are default, it outputs a SGR 0 reset, and clears the `_lastTextAttribute` completely to make sure any reset state is reapplied. With that out the way, the foreground and background are updated (if changed) in one of 4 ways. They can either be a default value (SGR 39 and 49), a 16-color index (using ANSI or AIX sequences), a 256-color index, or a 24-bit RGB value (both using SGR 38 and 48 sequences). Then once the colors are accounted for, there is a separate step that handles the character rendition attributes (bold, italics, underline, etc.) This step must come _after_ the color sequences, in case a SGR reset is required, which would otherwise have cleared any character rendition attributes if it came last (which is what happened in the original implementation). The process for the 16-color engines is a little different. The target client in this case (Windows telnet) is incapable of setting default colors individually, so we need to output an SGR 0 reset if _either_ color has changed to default. With that out the way, we use the `TextColor::GetLegacyIndex` method to obtain an approximate 16-color index for each color, and apply the bold attribute by brightening the foreground index (setting bit 8) if the color type permits that. However, since Windows telnet only supports the 8 basic ANSI colors, the best we can do for bright colors is to output an SGR 1 attribute to get a bright foreground. There is nothing we can do about a bright background, so after that we just have to drop the high bit from the colors. If the resulting index values have changed from what they were before, we then output ANSI 8-color SGR sequences to update them. As with the 256-color engine, there is also a final step to handle the character rendition attributes. But in this case, the only supported attributes are underline and reversed video. Since the VT engines no longer depend on the active color table and default color values, there was quite a lot of code that could now be removed. This included the `IDefaultColorProvider` interface and implementations, the `Find(Nearest)TableIndex` functions, and also the associated HLS conversion and difference calculations. VALIDATION Other than simple API parameter changes, the majority of updates required in the unit tests were to correct assumptions about the way the colors should be rendered, which were the source of the narrowing bugs this PR was trying to fix. Like passing white on black to the `UpdateDrawingBrushes` API, and expecting it to output the default `SGR 0` sequence, or passing an RGB color and expecting an indexed SGR sequence. In addition to that, I've added some VT renderer tests to make sure the rendition attributes (bold, underline, etc) are correctly retained when a default color update causes an `SGR 0` sequence to be generated (the source of bug #3076). And I've extended the VT renderer color tests (both 256-color and 16-color) to make sure we're covering all of the different color types (default, RGB, and both forms of indexed colors). I've also tried to manually verify that all of the test cases in the linked bug reports (and their associated duplicates) are now fixed when this PR is applied. Closes #2661 Closes #3076 Closes #3717 Closes #5384 Closes #5864 This is only a partial fix for #293, but I suspect the remaining cases are unfixable.
Welcome to the Windows Terminal, Console and Command-Line repo
This repository contains the source code for:
- Windows Terminal
- Windows Terminal Preview
- The Windows console host (
conhost.exe) - Components shared between the two projects
- ColorTool
- Sample projects that show how to consume the Windows Console APIs
Related repositories include:
- Windows Terminal Documentation (Repo: Contribute to the docs)
- Console API Documentation
- Cascadia Code Font
Installing and running Windows Terminal
👉 Note: Windows Terminal requires Windows 10 1903 (build 18362) or later
Microsoft Store [Recommended]
Install the Windows Terminal from the Microsoft Store. This allows you to always be on the latest version when we release new builds with automatic upgrades.
This is our preferred method.
Other install methods
Via GitHub
For users who are unable to install Terminal from the Microsoft Store, Terminal builds can be manually downloaded from this repository's Releases page.
⚠ Note: If you install Terminal manually:
- Be sure to install the Desktop Bridge VC++ v14 Redistributable Package otherwise Terminal may not install and/or run and may crash at startup
- Terminal will not auto-update when new builds are released so you will need to regularly install the latest Terminal release to receive all the latest fixes and improvements!
Via Windows Package Manager CLI (aka winget)
winget users can download and install the latest Terminal release by installing the Microsoft.WindowsTerminal package:
winget install --id=Microsoft.WindowsTerminal -e
Via Chocolatey (unofficial)
Chocolatey users can download and install the latest Terminal release by installing the microsoft-windows-terminal package:
choco install microsoft-windows-terminal
To upgrade Windows Terminal using Chocolatey, run the following:
choco upgrade microsoft-windows-terminal
If you have any issues when installing/upgrading the package please go to the Windows Terminal package page and follow the Chocolatey triage process
Windows Terminal 2.0 Roadmap
The plan for delivering Windows Terminal 2.0 is described here and will be updated as the project proceeds.
Project Build Status
| Project | Build Status |
|---|---|
| Terminal | |
| ColorTool |
Terminal & Console Overview
Please take a few minutes to review the overview below before diving into the code:
Windows Terminal
Windows Terminal is a new, modern, feature-rich, productive terminal application for command-line users. It includes many of the features most frequently requested by the Windows command-line community including support for tabs, rich text, globalization, configurability, theming & styling, and more.
The Terminal will also need to meet our goals and measures to ensure it remains fast and efficient, and doesn't consume vast amounts of memory or power.
The Windows Console Host
The Windows Console host, conhost.exe, is Windows' original command-line user experience. It also hosts Windows' command-line infrastructure and the Windows Console API server, input engine, rendering engine, user preferences, etc. The console host code in this repository is the actual source from which the conhost.exe in Windows itself is built.
Since taking ownership of the Windows command-line in 2014, the team added several new features to the Console, including background transparency, line-based selection, support for ANSI / Virtual Terminal sequences, 24-bit color, a Pseudoconsole ("ConPTY"), and more.
However, because Windows Console's primary goal is to maintain backward compatibility, we have been unable to add many of the features the community (and the team) have been wanting for the last several years including tabs, unicode text, and emoji.
These limitations led us to create the new Windows Terminal.
You can read more about the evolution of the command-line in general, and the Windows command-line specifically in this accompanying series of blog posts on the Command-Line team's blog.
Shared Components
While overhauling Windows Console, we modernized its codebase considerably, cleanly separating logical entities into modules and classes, introduced some key extensibility points, replaced several old, home-grown collections and containers with safer, more efficient STL containers, and made the code simpler and safer by using Microsoft's Windows Implementation Libraries - WIL.
This overhaul resulted in several of Console's key components being available for re-use in any terminal implementation on Windows. These components include a new DirectWrite-based text layout and rendering engine, a text buffer capable of storing both UTF-16 and UTF-8, a VT parser/emitter, and more.
Creating the new Windows Terminal
When we started planning the new Windows Terminal application, we explored and evaluated several approaches and technology stacks. We ultimately decided that our goals would be best met by continuing our investment in our C++ codebase, which would allow us to reuse several of the aforementioned modernized components in both the existing Console and the new Terminal. Further, we realized that this would allow us to build much of the Terminal's core itself as a reusable UI control that others can incorporate into their own applications.
The result of this work is contained within this repo and delivered as the Windows Terminal application you can download from the Microsoft Store, or directly from this repo's releases.
Resources
For more information about Windows Terminal, you may find some of these resources useful and interesting:
- Command-Line Blog
- Command-Line Backgrounder Blog Series
- Windows Terminal Launch: Terminal "Sizzle Video"
- Windows Terminal Launch: Build 2019 Session
- Run As Radio: Show 645 - Windows Terminal with Richard Turner
- Azure Devops Podcast: Episode 54 - Kayla Cinnamon and Rich Turner on DevOps on the Windows Terminal
- Microsoft Ignite 2019 Session: The Modern Windows Command Line: Windows Terminal - BRK3321
FAQ
I built and ran the new Terminal, but it looks just like the old console
Cause: You're launching the incorrect solution in Visual Studio.
Solution: Make sure you're building & deploying the CascadiaPackage project in Visual Studio.
⚠ Note:
OpenConsole.exeis just a locally-builtconhost.exe, the classic Windows Console that hosts Windows' command-line infrastructure. OpenConsole is used by Windows Terminal to connect to and communicate with command-line applications (via ConPty).
Documentation
All project documentation is located at aka.ms/terminal-docs. If you would like to contribute to the documentation, please submit a pull request on the Windows Terminal Documentation repo.
Contributing
We are excited to work alongside you, our amazing community, to build and enhance Windows Terminal!
BEFORE you start work on a feature/fix, please read & follow our Contributor's Guide to help avoid any wasted or duplicate effort.
Communicating with the Team
The easiest way to communicate with the team is via GitHub issues.
Please file new issues, feature requests and suggestions, but DO search for similar open/closed pre-existing issues before creating a new issue.
If you would like to ask a question that you feel doesn't warrant an issue (yet), please reach out to us via Twitter:
- Kayla Cinnamon, Program Manager: @cinnamon_msft
- Dustin Howett, Engineering Lead: @dhowett
- Michael Niksa, Senior Developer: @michaelniksa
- Mike Griese, Developer: @zadjii
- Carlos Zamora, Developer: @cazamor_msft
- Leon Liang, Developer: @leonmsft
Developer Guidance
Prerequisites
- You must be running Windows 1903 (build >= 10.0.18362.0) or later to run Windows Terminal
- You must enable Developer Mode in the Windows Settings app to locally install and run Windows Terminal
- You must have the Windows 10 1903 SDK installed
- You must have at least VS 2019 installed
- You must install the following Workloads via the VS Installer. Note: Opening the solution in VS 2019 will prompt you to install missing components automatically:
- Desktop Development with C++
- Universal Windows Platform Development
- The following Individual Components
- C++ (v142) Universal Windows Platform Tools
Building the Code
This repository uses git submodules for some of its dependencies. To make sure submodules are restored or updated, be sure to run the following prior to building:
git submodule update --init --recursive
OpenConsole.sln may be built from within Visual Studio or from the command-line using a set of convenience scripts & tools in the /tools directory:
Building in PowerShell
Import-Module .\tools\OpenConsole.psm1
Set-MsBuildDevEnvironment
Invoke-OpenConsoleBuild
Building in Cmd
.\tools\razzle.cmd
bcz
Running & Debugging
To debug the Windows Terminal in VS, right click on CascadiaPackage (in the Solution Explorer) and go to properties. In the Debug menu, change "Application process" and "Background task process" to "Native Only".
You should then be able to build & debug the Terminal project by hitting F5.
👉 You will not be able to launch the Terminal directly by running the WindowsTerminal.exe. For more details on why, see #926, #4043
Coding Guidance
Please review these brief docs below about our coding practices.
👉 If you find something missing from these docs, feel free to contribute to any of our documentation files anywhere in the repository (or write some new ones!)
This is a work in progress as we learn what we'll need to provide people in order to be effective contributors to our project.
- Coding Style
- Code Organization
- Exceptions in our legacy codebase
- Helpful smart pointers and macros for interfacing with Windows in WIL
Code of Conduct
This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.