Document & Slide Viewers

DocumentView renders .docx. SlideView renders .pptx. Both are read-only — editing those two formats is a later phase — and both ship in the same packages as the Spreadsheet.

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Frameworks

.NET MAUI

Blazor

Same two constraints as the Spreadsheet

MAUI requires UseSkiaSharp() in MauiProgram, or the canvas never renders. Blazor is WebAssembly only, and the container needs an explicit height or the canvas collapses to zero.

Fonts

Shiny.Blazor.Controls.Office bundles Carlito and Caladea — metric-compatible with Calibri and Cambria respectively — as eight faces under SIL OFL 1.1, about 1 MB compressed. They load automatically on the first render of any Office view, once per browser session, and are HTTP-cached afterwards.

This is not cosmetic. SkiaSharp on WebAssembly has no access to system fonts at all — there is no fontconfig and no CoreText in the browser — and SKTypeface.FromFamilyName returns a wrong-but-non-null fallback rather than failing. Without the bundle, every document renders in one monospace face and any glyph outside that face’s coverage draws as a tofu box, with no error anywhere.

Metric-compatible means the glyph advance widths match the original, so a document laid out against Calibri breaks its lines in exactly the same places against Carlito. A merely similar-looking font would render legibly and paginate differently.

To add a face the bundle does not cover:

OfficeFonts.Register(await http.GetByteArrayAsync("fonts/MyFont.ttf"));

On MAUI no bundle is needed: the platform’s own fonts are available, with the same substitution table layered on top.

Word — reflow, not pagination

using var document = await WordDocument.OpenAsync("/path/report.docx");

<office:DocumentView Document="{Binding Document}" Zoom="1.0" />

<div style="height:520px">
    <DocumentView Document="document" Theme="DocumentTheme.Dark" />
</div>

Content is laid out as one continuous column at the control’s width. There are no page breaks, no headers and no footers.

That is a deliberate choice rather than an omission. Pagination needs widow and orphan control, footnote placement, floating-object collision and repeating table headers; a partial implementation puts page boundaries in the wrong places, and a page break in the wrong place reads as a rendering bug rather than a missing feature. WordDocument.Page reports the authored page size and margins so the view can pick a sensible measure — it is not a promise of pages.

What it resolves

The full style chain: document defaults, then the named style with its entire basedOn ancestry applied outermost-first, then direct formatting on the paragraph and run. Skipping the ancestry is the usual shortcut, and it is why documents built on custom styles render in the wrong font — a style that only overrides colour inherits everything else from its parent.

Beyond that: bold, italic, underline, strike, colour, highlight, superscript and subscript; alignment and justification; indents and hanging indents; line and paragraph spacing; numbered and bulleted lists with running counters resolved from numbering.xml; tables with column spans, vertical merges and cell shading; inline images; and hyperlink colouring.

Outline and navigation

foreach (var (level, text) in document.Outline())
    Console.WriteLine(new string(' ', level * 2) + text);

view.Controller?.ScrollToHeading(index);   // index into Outline()
view.Controller!.Zoom = 1.25;
document.PlainText;

PowerPoint — scale, not reflow

using var deck = await SlideDeck.OpenAsync("/path/deck.pptx");

<office:SlideView Deck="{Binding Deck}" Mode="Single" SlideChanged="OnSlideChanged" />

<div style="height:460px">
    <SlideView Deck="deck" @bind-SlideIndex="index" @bind-Mode="mode" />
</div>

A slide is a fixed-size artboard, so the view fits and letterboxes it rather than re-laying it out. Text keeps exactly the proportions it was authored at, at any size.

SlideViewMode.Single fits one slide. SlideViewMode.Grid is a scrolling thumbnail wall where clicking a thumbnail opens that slide.

Placeholders are resolved for you

Shapes come back already resolved through slide → layout → master. This matters more than it sounds: a title placeholder on a slide routinely carries text and nothing else — no position, no size, no font — because all of that lives on the layout it came from, and on the master behind that. Reading only the slide produces a deck of correctly-worded shapes stacked in the top-left corner.

Decorative (non-placeholder) shapes from the layout and master are included, because they are content every slide inherits. Their placeholders are not, because those are templates the slide fills in rather than things to draw.

What it draws

Preset geometry for around twenty common shapes — rectangle, rounded rectangle, ellipse, triangle, diamond, line, the four arrows, pentagon, hexagon, star, chevron, parallelogram, trapezoid, plus, can and cloud. Anything else falls back to its bounding rectangle and is reported.

Solid and linear-gradient fills; outlines including dashes; theme colours with their lumMod, lumOff, shade, tint and alpha modifiers applied — “Accent 1, Lighter 40%” is a modifier, not a colour, and ignoring it renders every themed shape at full saturation; text bodies with per-level formatting from the layout’s list style; bullets; alignment and vertical anchoring; PowerPoint’s recorded autofit shrink; pictures; and tables.

deck.SlideWidth;          // 1280 for a 16:9 deck at 96dpi
deck.AspectRatio;
deck.Slides[0].Title;
deck.Slides[0].Notes;

Finding out what was skipped

Both viewers preserve the whole package and report what they could not draw:

var collector = new UnsupportedFeatureCollector();
using var document = await WordDocument.OpenAsync(path, collector);

foreach (var feature in collector.Features)
    Console.WriteLine($"{feature.Part}: {feature.Feature} ({feature.Severity})");

A viewer never reports Lossy — it does not write. Opening and saving produces a byte-identical file.

Not implemented

• Editing. Both formats are read-only for now.
• Pagination, headers, footers, footnotes, endnotes and comments in Word. Tracked insertions render as normal text; deletions are hidden.
• Text wrapping around floating images, and tab stops — a tab becomes four spaces.
• Charts, SmartArt, embedded OLE objects and animations in PowerPoint: reported, not drawn.
• Custom and freeform geometry, drawn as the bounding rectangle.
• Group shapes are flattened, which is wrong if a group has been scaled relative to its children.

Screenshots

MAUI — DocumentView	Blazor — DocumentView	Blazor — SlideView