70867df077
## Summary of the Pull Request Identifies and scales glyphs in the box and line drawing ranges U+2500-U+259F to fit their cells. ## PR Checklist * [x] Closes #455 * [x] I work here. * [x] Manual tests. This is all graphical. * [x] Metric ton of comments * [x] Math spreadsheet included in PR. * [x] Double check RTL glyphs. * [x] Why is there the extra pixel? * [x] Scrolling the mouse wheel check is done. * [x] Not drawing outline? * [x] Am core contributor. Roar. * [x] Try suppressing negative scale factors and see if that gets rid of weird shading. ## Detailed Description of the Pull Request / Additional comments ### Background - We want the Terminal to be fast at drawing. To be fast at drawing, we perform differential drawing, or only drawing what is different from the previous frame. We use DXGI's `Present1` method to help us with this as it helps us compose only the deltas onto the previous frame at drawing time and assists us in scrolling regions from the previous frame without intervention. However, it only works on strictly integer pixel row heights. - Most of the hit testing and size-calculation logic in both the `conhost` and the Terminal products are based on the size of an individual cell. Historically, a cell was always dictated in a `COORD` structure, or two `SHORT` values... which are integers. As such, when we specify the space for any individual glyph to be displayed inside our terminal drawing region, we want it to fall perfectly inside of an integer box to ensure all these other algorithms work correctly and continue to do so. - Finally, we want the Terminal to have font fallback and locate glyphs that aren't in the primary selected font from any other font it can find on the system that contains the glyph, per DirectWrite's font fallback mechanisms. These glyphs won't necessarily have the same font or glyph metrics as the base font, but we need them to fit inside the same cell dimensions as if they did because the hit testing and other algorithms aren't aware of which particular font is sourcing each glyph, just the dimensions of the bounding box per cell. ### How does Terminal deal with this? - When we select a font, we perform some calculations using the design metrics of the font and glyphs to determine how we could fit them inside a cell with integer dimensions. Our process here is that we take the requested font size (which is generally a proxy for height), find the matching glyph width for that height then round it to an integer. We back convert from that now integer width to a height value which is almost certainly now a floating point number. But because we need an integer box value, we add line padding above and below the glyphs to ensure that the height is an integer as well as the width. Finally, we don't add the padding strictly equally. We attempt to align the English baseline of the glyph box directly onto an integer pixel multiple so most characters sit crisply on a line when displayed. - Note that fonts and their glyphs have a prescribed baseline, line gap, and advance values. We use those as guidelines to get us started, but then to meet our requirements, we pad out from those. This results in fonts that should be properly authored showing gaps. It also results in fonts that are improperly authored looking even worse than they normally would. ### Now how does block and line drawing come in? - Block and Line drawing glyphs are generally authored so they will look fine when the font and glyph metrics are followed exactly as prescribed by the font. (For some fonts, this still isn't true and we want them to look fine anyway.) - When we add additional padding or rounding to make glyphs fit inside of a cell, we can be adding more space than was prescribed around these glyphs. This can cause a gap to be visible. - Additionally, when we move things like baselines to land on a perfect integer pixel, we may be drawing a glyph lower in the bounding box than was prescribed originally. ### And how do we solve it? - We identify all glyphs in the line and block drawing ranges. - We find the bounding boxes of both the cell and the glyph. - We compare the height of the glyph to the height of the cell to see if we need to scale. We prescribe a scale transform if the glyph wouldn't be tall enough to fit the box. (We leave it alone otherwise as some glyphs intentionally overscan the box and scaling them can cause banding effects.) - We inspect the overhang/underhang above and below the boxes and translate transform them (slide them) so they cover the entire cell area. - We repeat the previous two steps but in the horizontal direction. ## Validation Steps Performed - See these commments: - https://github.com/microsoft/terminal/issues/455#issuecomment-620248375 - https://github.com/microsoft/terminal/issues/455#issuecomment-621533916 - https://github.com/microsoft/terminal/issues/455#issuecomment-622585453 Also see the below one with more screenshots: - https://github.com/microsoft/terminal/pull/5743#issuecomment-624940567 |
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README.md
Welcome to the Windows Terminal, Console and Command-Line repo
This repository contains the source code for:
- Windows Terminal
- 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:
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 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
Project Build Status
| Project | Build Status |
|---|---|
| Terminal | |
| ColorTool |
Windows Terminal v1.0 Roadmap
The plan for delivering Windows Terminal v1.0 is described here, and will be updated as the project proceeds.
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 in the ./doc folder. If you would like to contribute to the documentation, please submit a pull request.
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.