ProText 0.1.0

ProText

High-performance Avalonia 12 text controls powered by PretextSharp.

ProText is a focused text rendering toolkit for Avalonia applications that need fast measurement, predictable caching, rich inline display, editable text presentation, and TextBox-like input surfaces without routing text rendering through Avalonia TextBlock fallbacks.

The repository, library project, package id, assembly name, and CLR namespace are now ProText because the scope covers display, presenter, and editable text controls.

The controls are mapped into Avalonia's XML namespace through assembly-level XmlnsDefinition metadata, so they can be used directly in normal Avalonia XAML once the package or project reference is present.

Packages

Package	Version	Downloads	Purpose
ProText			ProText control library with ProTextBlock, ProTextPresenter, ProTextBox, Fluent theme resources, XML documentation, README metadata, and symbol packages.

Install the package with:

dotnet add package ProText

Or reference it directly from a project file:

<PackageReference Include="ProText" Version="0.1.0" />

For local development inside this repository, reference the project directly:

<ProjectReference Include="../../src/ProText/ProText.csproj" />

Package metadata:

• Package id: ProText
• Package title: ProText
• Description: High-performance Avalonia 12 text controls powered by PretextSharp.
• License: MIT
• Repository: https://github.com/wieslawsoltes/ProText
• Dependencies: Avalonia, Avalonia Skia rendering support, Pretext, and Pretext Skia rendering support
• Artifacts: .nupkg, .snupkg, XML documentation, and the root README.md

Only src/ProText/ProText.csproj is packable. Samples, tests, and benchmark projects are explicitly marked as non-packable.

Controls

ProTextBlock

ProTextBlock is a high-performance display control intended for TextBlock-like scenarios: labels, dense rows, document fragments, diagnostics, search results, preview text, telemetry panels, and other text-heavy read-only UI.

It mirrors the public text-related TextBlock surface where practical, including:

• Text and Inlines
• Background, Padding, and Foreground
• FontFamily, FontSize, FontStyle, FontWeight, FontStretch, and FontFeatures
• TextAlignment, TextWrapping, TextTrimming, TextDecorations, LetterSpacing, LineHeight, LineSpacing, MaxLines, and BaselineOffset
• attached property helpers for TextBlock-compatible layout properties
• ProText-specific properties such as UseGlobalCache, UsePretextRendering, PretextWhiteSpace, PretextWordBreak, and PretextLineHeightMultiplier

Plain text and supported inline content are prepared through PretextSharp, measured through the shared ProText layout layer, and rendered through Skia custom drawing.

ProTextPresenter

ProTextPresenter is the reusable presenter layer for custom editable or selectable text controls. It uses the same rich content preparation, layout snapshots, cache identity, font fallback, and Skia renderer as ProTextBlock, while exposing presenter-style caret, selection, preedit, password, measurement, and hit-test APIs.

Notable features include:

• Text and display-oriented Inlines
• PreeditText and PreeditTextCursorPosition for IME composition display
• CaretIndex, SelectionStart, SelectionEnd, ShowSelectionHighlight, SelectionBrush, SelectionForegroundBrush, CaretBrush, and CaretBlinkInterval
• PasswordChar and RevealPassword
• ShowCaret(), HideCaret(), MoveCaretToTextPosition(int), MoveCaretToPoint(Point), MoveCaretHorizontal(LogicalDirection), and MoveCaretVertical(LogicalDirection)
• GetNextCharacterHit(LogicalDirection), GetCharacterIndex(Point), GetCaretBounds(int), GetLineCount(), GetLineBounds(int), and MeasureText(double)
• CaretBoundsChanged event

Use ProTextPresenter when building a custom editor, search box, command surface, code-like text host, or any control that needs text presentation primitives but owns its own editing behavior.

ProTextBox

ProTextBox is a lightweight TextBox-like control that hosts ProTextPresenter in its template. It is designed for ProText-backed editable text scenarios where you want a ready-to-use control rather than building a presenter host yourself.

It provides a focused TextBox-style API:

• two-way Text
• AcceptsReturn, AcceptsTab, and NewLine
• IsReadOnly, MaxLength, MinLines, MaxLines, IsUndoEnabled, UndoLimit, CanUndo, CanRedo, Undo(), and Redo()
• CaretIndex, SelectionStart, SelectionEnd, SelectedText, SelectAll(), and ClearSelection()
• mouse drag selection, shift-click extension, double-click word selection, triple-click line selection, and keyboard word/line navigation
• clipboard-oriented state such as CanCut, CanCopy, and CanPaste
• text and clipboard routed events such as TextChanging, TextChanged, CopyingToClipboard, CuttingToClipboard, and PastingFromClipboard
• PasswordChar, RevealPassword, placeholder/watermark text aliases, floating placeholder/watermark aliases, and placeholder/watermark foreground aliases
• InnerLeftContent and InnerRightContent
• TextAlignment, TextWrapping, TextDecorations, LineHeight, content alignment, selection brushes, caret brush, and caret blink interval
• GetLineCount() and ScrollToLine(int) backed by ProTextPresenter layout data
• UseGlobalCache, UsePretextRendering, and PretextLineHeightMultiplier

Avalonia's built-in TextBox expects Avalonia's own TextPresenter template part, so ProTextPresenter is not a drop-in replacement for the built-in TextBox template. ProTextBox exists as the ProText-backed editable host.

Rendering Model

ProText keeps text on the Pretext-powered path from preparation through rendering:

• plain text is prepared and segmented through PretextSharp
• rich inline text is flattened into immutable ProText value data, then prepared through Pretext rich inline APIs
• layout snapshots are local to each control and keyed by width
• global prepared-content cache keys exclude viewport width so prepared text can be reused across controls
• layout and render fingerprints are tracked separately
• render operations snapshot brushes, decorations, and selection styles into immutable value data
• Skia drawing is performed through Avalonia custom draw operations using ISkiaSharpApiLeaseFeature

Supported inline text content includes Run, Span, Bold, Italic, Underline, and LineBreak. InlineUIContainer is skipped because it is visual content rather than text content; ProText does not create an internal Avalonia fallback visual for it.

Foreground brushes support solid colors and gradient brushes where practical. Multilingual text remains on the Pretext path and uses the ProText Skia font resolver for font fallback.

Cache And Diagnostics

Global prepared-text caching is enabled by default and can be disabled per control with UseGlobalCache="False".

ProTextCache exposes process-wide cache controls:

• MaxEntryCount bounds the shared prepared-text and rich-inline cache
• Clear() clears ProText and PretextSharp internal layout caches
• GetSnapshot() returns Count, MaxEntryCount, Hits, and Misses for diagnostics, sample UI, and benchmarks

Quick Start

Reference the package or project, then use the controls from the standard Avalonia XAML namespace.

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        x:Class="MyApp.MainWindow">
    <ProTextBlock Text="High-volume text rendered through PretextSharp"
                  TextWrapping="Wrap"
                  TextTrimming="CharacterEllipsis"
                  UseGlobalCache="True" />
</Window>

Display Text

<ProTextBlock Text="High-volume text rendered through PretextSharp"
              TextWrapping="Wrap"
              TextTrimming="CharacterEllipsis"
              UseGlobalCache="True" />

Rich Inline Text

<ProTextBlock TextWrapping="Wrap"
              xmlns:docs="clr-namespace:Avalonia.Controls.Documents;assembly=Avalonia.Controls">
    <docs:Run Text="Inline content: " />
    <docs:Bold>bold</docs:Bold>
    <docs:Run Text=", " />
    <docs:Italic>italic</docs:Italic>
    <docs:Run Text=", and " />
    <docs:Underline>underlined</docs:Underline>
</ProTextBlock>

Presenter Surface

<ProTextPresenter Text="Selectable text presented through ProText"
                  TextWrapping="Wrap"
                  CaretIndex="24"
                  SelectionStart="9"
                  SelectionEnd="16"
                  SelectionBrush="#663B82F6"
                  SelectionForegroundBrush="#FFFFFF" />

Editable TextBox-Like Control

<ProTextBox Text="Editable text presented through ProTextPresenter"
            TextWrapping="Wrap"
            PlaceholderText="Search"
            SelectionStart="9"
            SelectionEnd="22" />

To use the Fluent ProTextBox theme, merge the ProText theme after Avalonia's Fluent theme:

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceInclude Source="avares://ProText/Themes/Fluent.axaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>

Sample App

The sample project demonstrates the current control set and comparison scenarios:

• Avalonia TextBlock beside ProTextBlock
• equivalent inline text rendered by Avalonia and ProText
• ProTextPresenter selection, caret, password, preedit, and rich-inline presentation
• Avalonia TextBox beside ProTextBox
• dense scrolling text content with cache diagnostics
• zoomable, pannable canvas tabs with 1000 absolute-positioned Avalonia TextBox controls and 1000 absolute-positioned ProTextBox controls

Run it with:

dotnet run --project samples/ProText.Sample/ProText.Sample.csproj

Performance Snapshot

Results below were generated on 2026-05-04 with BenchmarkDotNet 0.15.8 on Apple M3 Pro, macOS Tahoe 26.4.1, .NET SDK 10.0.201, and .NET runtime 10.0.5. ProText.Benchmarks and ProText.InlineBenchmarks use BenchmarkDotNet's default job; ProText.PresenterBenchmarks and ProText.TextBoxBenchmarks use ShortRun as configured in the benchmark projects.

Commands used for the documented run:

dotnet run -c Release --project benchmarks/ProText.Benchmarks/ProText.Benchmarks.csproj -- --filter "*"
dotnet run -c Release --project benchmarks/ProText.InlineBenchmarks/ProText.InlineBenchmarks.csproj -- --filter "*"
dotnet run -c Release --project benchmarks/ProText.PresenterBenchmarks/ProText.PresenterBenchmarks.csproj -- --filter "*"
dotnet run -c Release --project benchmarks/ProText.TextBoxBenchmarks/ProText.TextBoxBenchmarks.csproj -- --filter "*"

TextBlock Layout And Cache

TextBlock Headless Render

Inline Layout

Presenter Operations

TextBox Layout

The TextBox benchmark suite applies Avalonia's Fluent TextBox theme and the ProText Fluent theme before measuring. Setup validates that Avalonia TextPresenter and ProText ProTextPresenter are present in the visual tree. Layout benchmarks alternate width constraints to avoid cached no-op timings.

TextBox Headless Render

Frame benchmarks use one explicit headless render tick plus GetLastRenderedFrame() rather than CaptureRenderedFrame()'s stabilization loop.

Project Layout

• src/ProText - ProText control library, themes, shared layout, cache, and Skia renderer
• samples/ProText.Sample - desktop comparison and stress sample app
• tests/ProText.Tests - unit tests and Avalonia headless rendering tests
• benchmarks/ProText.Benchmarks - TextBlock, layout, cache, and render benchmarks
• benchmarks/ProText.InlineBenchmarks - rich-inline layout benchmarks
• benchmarks/ProText.PresenterBenchmarks - presenter measurement, hit-test, caret, selection, and render benchmarks
• benchmarks/ProText.TextBoxBenchmarks - Avalonia TextBox versus ProTextBox benchmarks
• plan - technical specification and implementation plan

Verification

dotnet build ProText.slnx
dotnet test tests/ProText.Tests/ProText.Tests.csproj
dotnet run -c Release --project benchmarks/ProText.Benchmarks/ProText.Benchmarks.csproj -- --list flat
dotnet run -c Release --project benchmarks/ProText.InlineBenchmarks/ProText.InlineBenchmarks.csproj -- --list flat
dotnet run -c Release --project benchmarks/ProText.PresenterBenchmarks/ProText.PresenterBenchmarks.csproj -- --list flat
dotnet run -c Release --project benchmarks/ProText.TextBoxBenchmarks/ProText.TextBoxBenchmarks.csproj -- --list flat

Design Principles

• Keep text measurement, layout, and rendering on the Pretext path.
• Keep prepared-text caching global by default, bounded, and diagnosable.
• Keep viewport-width-dependent layout snapshots local to each control.
• Snapshot mutable Avalonia brushes and text decorations before rendering.
• Share inline flattening, layout, selection, and render-style code between display and editable controls.
• Avoid internal Avalonia TextBlock fallbacks inside ProText controls.