# ReactOS Font Engine Implementation

DevFeed: [ReactOS Font Engine Implementation](<https://devfeed.tech/articles/newsletter-55-32921.md>)

Original publisher: [Read original article](<https://reactos.org/blogs/newsletter-55/>)

Published: 2009-03-16T00:00:00Z

Content type: article

Language: en

Sources: [Front Page on ReactOS Website](<https://devfeed.tech/sources/front-page-on-reactos-website.md>)

Topics: [ReactOS](<https://devfeed.tech/topics/reactos.md>), [Font](<https://devfeed.tech/topics/font.md>), [Kernel](<https://devfeed.tech/topics/kernel.md>)

Tags: [free](<https://devfeed.tech/tags/free.md>), [kernel](<https://devfeed.tech/tags/kernel.md>), [memory](<https://devfeed.tech/tags/memory.md>), [open-source](<https://devfeed.tech/tags/open-source.md>), [os](<https://devfeed.tech/tags/os.md>), [react](<https://devfeed.tech/tags/react.md>), [reactos](<https://devfeed.tech/tags/reactos.md>), [win32](<https://devfeed.tech/tags/win32.md>), [winapi](<https://devfeed.tech/tags/winapi.md>)

## AI overview

The article examines ReactOS text rendering and explains that its apparently correct output relied on an incorrect implementation path and a buffer-checking bug. It describes the intended use of GreExtTextOutW and glyph data structures before text is sent to display functions.

## Source excerpt

Font Engine There is a difference between functional correctness and implementation correctness, a distinction one always has to keep in mind when saying something works in ReactOS. In the case of text rendering, while the output may for the most part look correct, the underlying implementation is nothing like how it should be. The abbreviated function call chain for displaying text is TextOutA/W, NtGdiExtTextOutW, and GreExtTextOutW. There are a few variations but the above provides a general idea of the path down to the Gre function.