WIP: add image and custom view rendering

[sirily11]

Summary

Validation

OSS readiness

• No secrets, internal URLs, private identifiers, or product-only service names were added.
• Public docs, fixtures, or notices were updated if behavior or dependencies changed.
• Third-party dependency changes (adds, removes, version bumps) are intentional and reviewed.
• Streaming/incomplete markdown behavior remains covered by fixtures or tests.

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[Copilot]

Pull request overview

Adds first-class rendering support for Markdown images and swift-markdown block directives, plus an app-provided SwiftUI hook (MarkdownCustomViewBuilder) to override rendering for those payloads. This extends the library’s renderable model (MarkdownRenderable) and updates conversion/rendering so these new elements flow through RenderableDocument → DocumentView.

Changes:

• Introduces MarkdownImage / MarkdownCustomBlock models and adds .image / .customView cases to MarkdownRenderable, including paragraph splitting around inline images.
• Adds MarkdownCustomViewBuilder to MarkdownRenderConfig and wires it into new MarkdownImageView / MarkdownCustomBlockView SwiftUI renderers.
• Adds unit + snapshot tests and updates the sample app (fixtures + demo builder) to showcase custom rendering.

Reviewed changes

Copilot reviewed 25 out of 34 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
Tests/MarkdownTextTests/ImageAndCustomViewTests.swift	Unit tests for image renderables, paragraph splitting, directive parsing, and config builders.
Tests/MarkdownTextTests/ImageAndCustomViewSnapshotTests.swift	Snapshot coverage for custom view builder rendering of images and directives.
Sources/MarkdownText/UI/MarkdownImageView.swift	New SwiftUI view to render .image (default rendering + custom builder hook).
Sources/MarkdownText/UI/MarkdownCustomBlockView.swift	New SwiftUI view to render .customView with fallback to directive content.
Sources/MarkdownText/UI/BlockView.swift	Wires .image and .customView into the main block rendering switch.
Sources/MarkdownText/Parser/MarkdownParserImpl.swift	Adds swift-markdown ParseOptions toggling for block directives.
Sources/MarkdownText/Parser/MarkdownParser.swift	Updates parse(text:config:) to enable directive parsing based on config.
Sources/MarkdownText/Parser/MarkdownParseOption.swift	Adds parseBlockDirectives to parsing options.
Sources/MarkdownText/Models/RenderableDocument.swift	Ensures .customView contributes fallback content to extracted attributed strings.
Sources/MarkdownText/Models/MarkdownRenderConfig+Builders.swift	Updates builder methods to preserve citationConfig + customViewBuilder; adds new builder helpers.
Sources/MarkdownText/Models/MarkdownRenderConfig.swift	Adds customViewBuilder to the public render config.
Sources/MarkdownText/Models/MarkdownRenderable.swift	Adds .image / .customView cases and IDs.
Sources/MarkdownText/Models/MarkdownImage.swift	New model representing parsed images.
Sources/MarkdownText/Models/MarkdownCustomView.swift	New custom view payload types and type-erased builder.
Sources/MarkdownText/Inline/Markdown+InlineConvertible.swift	Adds Markdown.Image inline conversion (fallback text) and MarkdownImage extraction.
Sources/MarkdownText/Block/UnorderedList+.swift	Uses blockRenderables to allow list items to contain split paragraphs/images/directives.
Sources/MarkdownText/Block/Paragraph+.swift	Splits paragraphs into multiple renderables when they contain inline images; refactors inline-appending helper.
Sources/MarkdownText/Block/OrderedList+.swift	Uses blockRenderables for list item children.
Sources/MarkdownText/Block/Document+.swift	Uses blockRenderables to support top-level images/directives in document conversion.
Sources/MarkdownText/Block/BlockDirective+.swift	Converts parsed block directives into .customView renderables with fallback content.
Sources/MarkdownText/Block/BlockConvertible.swift	Adds blockRenderables(...) to centralize paragraph/directive special-casing.
Examples/SwiftStreamingMarkdownSample/SwiftStreamingMarkdownSample/SampleMarkdownTheme.swift	Passes demonstration custom view builder into render config.
Examples/SwiftStreamingMarkdownSample/SwiftStreamingMarkdownSample/Resources/Fixtures/kitchen-sink.md	Updates fixture to include image + directive examples.
Examples/SwiftStreamingMarkdownSample/SwiftStreamingMarkdownSample/Resources/Assets.xcassets/StreamingMarkdownSample.imageset/streaming-markdown.svg	Adds sample SVG asset for image rendering demo.
Examples/SwiftStreamingMarkdownSample/SwiftStreamingMarkdownSample/Resources/Assets.xcassets/StreamingMarkdownSample.imageset/Contents.json	Asset catalog metadata for the sample SVG.
Examples/SwiftStreamingMarkdownSample/SwiftStreamingMarkdownSample/Demonstrations.swift	Adds sample customViewBuilder + demo views for image/callout rendering.

[Jun Yan (junyan72)]

sirily11 Thanks for contributing! Could you please create an issue to elaborate the ask and requirements? Thanks.

[sirily11]

sirily11 Thanks for contributing! Could you please create an issue to elaborate the ask and requirements? Thanks.

Thanks. I have created one issue in the issues tab already

[Ramon Ferreira (ramonfsk)]

thanks for tackling this, sirily11 — image support is something I'd really like to see land, and this is a strong start.

a few notes from reading through, in case they're useful:

1. macOS / AppKit build. MarkdownImageView imports UIKit and uses UIImage directly, so it won't compile on AppKit/macOS. The rest of the library stays cross-platform via the MDImage typealias (Sources/MarkdownText/Utilities/MDImage.swift) and #if canImport(UIKit) / #elseif canImport(AppKit) guards, and there's active macOS work in flight (the macOS BlockMathView, plus Add macOS support with dedicated NSTextView-based paragraph rendering #92 / Add AppKit paragraph rendering layer with full iOS parity #106) — so it'd be worth following that pattern here.

2. remote loading by default. the default view falls through to AsyncImage for any http(s) source, so remote images are fetched automatically. since this library renders LLM-produced Markdown, auto-loading arbitrary URLs straight from the model output can be a privacy/security concern (tracking pixels, client-IP leakage, SSRF-style requests to internal hosts). It might be worth making remote loading opt-in (e.g. a config flag) rather than the default, and leaving network policy (caching, pinning, allowlisting) to the host app — curious how you and the maintainers see it.

3. scope / sequencing. this PR bundles image rendering together with the more general custom-view-builder + block-directive support. since images are already on the roadmap while the custom-view direction is still being discussed in Feature request: Image rendering support and custom view support #89, would it make sense to land the image part as a focused, self-contained change first? It would also clear most of the current merge conflicts — the MarkdownRenderConfig / MarkdownRenderConfig+Builders conflicts come entirely from the customViewBuilder addition, leaving just Block/Paragraph+.swift.

happy to help with the image piece if that's useful — e.g. a focused, cross-platform image-rendering PR with a safe default — whatever best fits how you and the maintainers want to sequence things.

[sirily11]

thanks for tackling this, sirily11 — image support is something I'd really like to see land, and this is a strong start.

a few notes from reading through, in case they're useful:

1. macOS / AppKit build. MarkdownImageView imports UIKit and uses UIImage directly, so it won't compile on AppKit/macOS. The rest of the library stays cross-platform via the MDImage typealias (Sources/MarkdownText/Utilities/MDImage.swift) and #if canImport(UIKit) / #elseif canImport(AppKit) guards, and there's active macOS work in flight (the macOS BlockMathView, plus Add macOS support with dedicated NSTextView-based paragraph rendering #92 / Add AppKit paragraph rendering layer with full iOS parity #106) — so it'd be worth following that pattern here.
2. remote loading by default. the default view falls through to AsyncImage for any http(s) source, so remote images are fetched automatically. since this library renders LLM-produced Markdown, auto-loading arbitrary URLs straight from the model output can be a privacy/security concern (tracking pixels, client-IP leakage, SSRF-style requests to internal hosts). It might be worth making remote loading opt-in (e.g. a config flag) rather than the default, and leaving network policy (caching, pinning, allowlisting) to the host app — curious how you and the maintainers see it.
3. scope / sequencing. this PR bundles image rendering together with the more general custom-view-builder + block-directive support. since images are already on the roadmap while the custom-view direction is still being discussed in Feature request: Image rendering support and custom view support #89, would it make sense to land the image part as a focused, self-contained change first? It would also clear most of the current merge conflicts — the MarkdownRenderConfig / MarkdownRenderConfig+Builders conflicts come entirely from the customViewBuilder addition, leaving just Block/Paragraph+.swift.

happy to help with the image piece if that's useful — e.g. a focused, cross-platform image-rendering PR with a safe default — whatever best fits how you and the maintainers want to sequence things.

Yeah. I would love to split this PR into much more smaller one and only focus on the Image for now. Thanks for the suggestions!