Installation

Install the package set that matches the layer and backend you need.

Core engine

dotnet add package Pretext

Then import the core namespace:

using Pretext;

Add Pretext plus one or more backends when you want to:

prepare text once and reuse it across many width probes
compute line counts or line strings in a custom control
drive your own native or SkiaSharp drawing code
use the engine outside Uno entirely

Recommended pairings:

Host	Packages
Windows-native	`Pretext` + `Pretext.DirectWrite`
Linux-native	`Pretext` + `Pretext.FreeType`
macOS-native	`Pretext` + `Pretext.CoreText`
Generic SkiaSharp	`Pretext` + `Pretext.SkiaSharp`
Uno app	`Pretext.Uno`

First-party backend packages:

dotnet add package Pretext.DirectWrite   # Windows
dotnet add package Pretext.FreeType      # Linux
dotnet add package Pretext.CoreText      # macOS
dotnet add package Pretext.SkiaSharp     # portable fallback / Skia hosts

The core Pretext package targets:

netstandard2.0
net461
net6.0
net8.0
net10.0

Pretext.Contracts is available when you want to implement a custom measurement backend instead of using one of the first-party backends.

Platform-neutral helper package

dotnet add package Pretext.Layout

Import the helper namespace when you want the wrap-metric and obstacle-layout utilities without any Uno dependency:

using Pretext.Layout;

Use Pretext.Layout when you want:

PreparedTextMetrics
ColumnFlowLayout
ObstacleLayoutHelper
geometry primitives such as RectObstacle, CircleObstacle, and Interval

Uno companion

dotnet add package Pretext.Uno

Pretext.Uno depends on Pretext, Pretext.Layout, and the first-party backend packages, so the core engine, helper layer, and host-native/portable backend set are brought in transitively. The companion package itself remains net10.0-desktop. Backend discovery then prefers the native backend for the current OS and falls back to Pretext.SkiaSharp when needed. Import the core namespace and whichever companion namespaces you want:

using Pretext;
using Pretext.Layout;
using Pretext.Uno.Controls;

Use the companion package when you want the reusable Uno-side controls from this repository:

StretchScrollHost
UiRenderScheduler

Font string format

Every preparation entry point accepts a font string. First-party backends share the same CSS-like parser from Pretext.Contracts:

a size in px, for example 16px
an optional weight, for example 700 16px Inter
optional italic or oblique
a family list, where only the first family is used

Examples:

"16px Inter"
"italic 16px Georgia"
"700 18px \"IBM Plex Sans\""
"600 15px system-ui"

Line height is not read from the font string. Pass it separately to Layout or LayoutWithLines.

Build the repo

dotnet build PretextSamples.slnx
dotnet test tests/Pretext.Uno.Tests/Pretext.Uno.Tests.csproj
bash ./pack-packages.sh

Sample app

The repository now ships two sample hosts plus a shared sample layer:

samples/PretextSamples.Shared for shared sample data, assets, and models
samples/PretextSamples.Uno for the Uno host
samples/PretextSamples.MacOS for the native AppKit host using Pretext.CoreText