OfficeIMO.MarkdownRenderer 0.2.0

OfficeIMO.MarkdownRenderer — WebView-Friendly Markdown Rendering for .NET

OfficeIMO.MarkdownRenderer is a host-oriented companion package for OfficeIMO.Markdown. It builds full HTML shells, renders safe HTML fragments, and produces incremental update scripts for WebView2 and browser-based chat/document surfaces.

• Targets: netstandard2.0, net472, net8.0, net10.0
• License: MIT
• NuGet: OfficeIMO.MarkdownRenderer
• Dependencies: OfficeIMO.Markdown, System.Text.Json

AOT / Trimming Notes

• The renderer itself stays lightweight and mostly composes OfficeIMO.Markdown.
• Optional runtime features such as Mermaid, charts, and math are exposed through HTML shell assets rather than heavy managed dependencies.
• For minimal hosts, use the strict minimal presets to disable optional client-side renderers.

Install

dotnet add package OfficeIMO.MarkdownRenderer

Hello, Renderer

using OfficeIMO.MarkdownRenderer;

var options = MarkdownRendererPresets.CreateStrict();

var shellHtml = MarkdownRenderer.BuildShellHtml("Markdown", options);
var bodyHtml = MarkdownRenderer.RenderBodyHtml("""
# Hello

This is rendered through OfficeIMO.MarkdownRenderer.
""", options);

Common Tasks by Example

WebView2 shell + update flow

using OfficeIMO.MarkdownRenderer;

var options = MarkdownRendererPresets.CreateStrict();

webView.NavigateToString(MarkdownRenderer.BuildShellHtml("Markdown", options));
await webView.ExecuteScriptAsync(MarkdownRenderer.RenderUpdateScript(markdownText, options));

Streaming-friendly update path

var options = MarkdownRendererPresets.CreateStrict();

webView.NavigateToString(MarkdownRenderer.BuildShellHtml("Markdown", options));

var bodyHtml = MarkdownRenderer.RenderBodyHtml(markdownText, options);
webView.CoreWebView2.PostWebMessageAsString(bodyHtml);

Optional chat bubble wrappers

var options = MarkdownRendererPresets.CreateChatStrict();
var bubbleHtml = MarkdownRenderer.RenderChatBubbleBodyHtml(markdownText, ChatMessageRole.Assistant, options);

webView.CoreWebView2.PostWebMessageAsString(bubbleHtml);

Generic-first chat composition

var options = MarkdownRendererPresets.CreateStrictMinimal();
MarkdownRendererPresets.ApplyChatPresentation(options, enableCopyButtons: false);
MarkdownRendererIntelligenceXAdapter.Apply(options);

Use this as the preferred composition path for downstream hosts. The CreateChatStrict* helpers remain available as compatibility wrappers.

Strict vs portable presets

var strict = MarkdownRendererPresets.CreateStrict();
var strictPortable = MarkdownRendererPresets.CreateStrictPortable();
var minimal = MarkdownRendererPresets.CreateStrictMinimal();
var minimalPortable = MarkdownRendererPresets.CreateStrictMinimalPortable();
var relaxed = MarkdownRendererPresets.CreateRelaxed();

var chatStrict = MarkdownRendererPresets.CreateChatStrict();
var chatMinimal = MarkdownRendererPresets.CreateChatStrictMinimal();

• CreateStrict(...): neutral untrusted-content defaults for generic markdown hosting
• CreateStrictPortable(...): same neutral defaults, but uses the portable markdown reader profile
• CreateStrictMinimal(...): neutral strict preset with Mermaid, charts, math, Prism, and copy buttons disabled
• CreateStrictMinimalPortable(...): combines minimal shell behavior with the portable reader profile
• CreateRelaxed(...): trusted-content preset that allows HTML parsing and sanitizes raw HTML conservatively
• ApplyChatPresentation(...): composes chat presentation/chrome onto any existing preset without changing its security profile
• CreateChatStrict(...): compatibility wrapper built on top of the strict preset family
• CreateChatStrictPortable(...): portable chat wrapper
• CreateChatStrictMinimal(...): minimal chat wrapper
• CreateChatStrictMinimalPortable(...): minimal portable chat wrapper
• CreateChatRelaxed(...): relaxed chat wrapper

Generic presets register neutral fenced block languages such as chart, network, visnetwork, and dataview. Chat presets additionally apply the MarkdownRendererIntelligenceXAdapter, which registers the IntelligenceX-oriented aliases ix-chart, ix-network, and ix-dataview.

IntelligenceX alias adapter

var options = MarkdownRendererPresets.CreateStrict();
MarkdownRendererIntelligenceXAdapter.Apply(options);

Use this when you want the generic strict/relaxed presets but still need the IntelligenceX alias fence contract.

Offline assets

using OfficeIMO.Markdown;
using OfficeIMO.MarkdownRenderer;

var options = MarkdownRendererPresets.CreateStrict();
options.HtmlOptions.AssetMode = AssetMode.Offline;

options.Mermaid.ScriptUrl = @"C:\app\assets\mermaid.min.js";
options.Chart.ScriptUrl = @"C:\app\assets\chart.umd.min.js";
options.Math.CssUrl = @"C:\app\assets\katex.min.css";
options.Math.ScriptUrl = @"C:\app\assets\katex.min.js";
options.Math.AutoRenderScriptUrl = @"C:\app\assets\auto-render.min.js";

Shell CSS overrides

var options = MarkdownRendererPresets.CreateChatStrict();
options.ShellCss = """
.omd-chat-bubble { border-radius: 18px; }
.omd-chat-row.omd-role-user .omd-chat-bubble { background: rgba(0, 120, 212, .18); }
""";

Feature Highlights

• Full shell HTML builder for WebView/browser hosts
• Body fragment renderer for incremental updates
• Neutral and chat-specific strict, portable, minimal, and relaxed presets
• Optional Mermaid, Chart.js, vis-network, and math shell integration
• Chat bubble helpers and copy-button UX
• Host-friendly message contract and data attributes for native integration
• Shared markdown normalization story through OfficeIMO.Markdown

Host Contract Highlights

Primary APIs

• BuildShellHtml(...)
• RenderBodyHtml(...)
• BuildUpdateScript(...)
• RenderUpdateScript(...)
• RenderChatBubbleBodyHtml(...)

WebView2 message contract

Host to web:

• PostWebMessageAsString(bodyHtml)
• PostWebMessageAsJson({ type: "omd.update", bodyHtml: "..." })

Web to host:

• { type: "omd.copy", text: "..." }

Shared visual metadata contract

Built-in visual renderers emit shared data-omd-* attributes:

• data-omd-visual-kind
• data-omd-fence-language
• data-omd-visual-hash
• data-omd-visual-contract
• data-omd-config-format
• data-omd-config-encoding
• data-omd-config-b64

That keeps host integrations stable even when new visual types are added later. Chart, network, and dataview built-ins now all flow through the same shared metadata builder, so future visual types can reuse the same contract instead of hand-assembling attributes per renderer.

You can also emit the same metadata contract directly from host code through MarkdownVisualContract.CreatePayload(...) and MarkdownVisualContract.BuildElementHtml(...) when you need custom visual blocks outside the built-in renderer list.

Security Defaults

The strict presets are biased toward untrusted chat-style content:

• raw HTML parsing disabled
• raw HTML blocks stripped at render time
• restricted URL schemes
• file: URLs blocked
• data: URLs blocked by default
• external HTTP images blocked unless explicitly allowed
• external links hardened with noopener noreferrer nofollow ugc

Use the relaxed preset only for trusted or controlled content.

Built-In Styling and Hooks

• Shell root: #omdRoot
• Default content wrapper: article.markdown-body
• Bubble wrappers: .omd-chat-row, .omd-chat-bubble
• Bubble roles: .omd-role-user, .omd-role-assistant, .omd-role-system
• Helper classes: .omd-image-blocked, .omd-chart, .omd-math

Themes come from OfficeIMO.Markdown HTML styles, and the chat presets default to HtmlStyle.ChatAuto.

Normalization and Reader Behavior

The renderer uses OfficeIMO.Markdown reader options and normalization behavior underneath.

• strict presets enable the chat-output normalization helpers
• portable presets switch the underlying reader to MarkdownReaderOptions.CreatePortableProfile()
• if you need the same parsing behavior outside the renderer, use MarkdownReaderOptions and MarkdownInputNormalizationPresets directly in OfficeIMO.Markdown

Built-In Visuals

Fenced code blocks can be converted into shell-native visuals:

• Mermaid
• Chart.js
• vis-network
• dataview tables
• math rendering

Generic dataview fences accept both array-row and object-row payloads. The built-in parser recognizes neutral aliases such as headers/items, caption/description, and callId, while ix-dataview continues to mirror the legacy data-ix-* attributes for IntelligenceX hosts.

These features are optional and can be disabled entirely in the minimal presets.

Dependencies & Versions

• OfficeIMO.Markdown
• System.Text.Json 8.x
• Targets: netstandard2.0, net472, net8.0, net10.0
• License: MIT

Package Family

• OfficeIMO.Markdown: markdown builder, typed reader/AST, and HTML rendering
• OfficeIMO.MarkdownRenderer: host/WebView rendering shell and incremental update helpers
• OfficeIMO.Word.Markdown: Word conversion layer that can sit above the markdown family

Notes on Versioning

• Minor releases may add presets, host hooks, and optional visual integrations.
• Patch releases focus on host compatibility, rendering correctness, and shell behavior hardening.

Notes

• Designed for chat surfaces, docs viewers, and embedded reporting experiences
• WebView2 is a first-class scenario, but the generated HTML works in standard browser hosts too
• Keep the renderer preset and the host trust model aligned; use strict defaults unless you intentionally need relaxed HTML handling