Slide Editor

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Frameworks

.NET MAUI

Blazor

Two controls, on both hosts:

Control	What it is
SlideEditor	the lone editing surface — canvas, selection, caret, typing. No chrome.
SlideEditorView	SlideEditor plus an editing toolbar and a status line

Same packages as the viewers (Shiny.Maui.Controls.Office / Shiny.Blazor.Controls.Office), same constraints: MAUI needs UseSkiaSharp(), Blazor is WASM-only, and on Blazor the container needs an explicit height.

Open a deck for editing

using var deck = await SlideDeck.OpenAsync("deck.pptx", editable: true);

Without editable: true the deck opens read-only and Execute throws — the same shape as the document editor.

Blazor

<div style="height:560px">
    <SlideEditorView Deck="deck" @bind-SlideIndex="index" DeckChanged="OnChanged" />
</div>

MAUI

<office:SlideEditorView Deck="{Binding Deck}" SlideIndex="{Binding Index}" />

Two gestures, and the distinction is the whole design

Shape mode — a single click (tap) selects a shape and draws a dashed frame with eight resize handles. Drag the body to move it, a handle to resize it.

Text mode — a double-click (double-tap) puts a caret inside that shape’s text and the frame turns solid. That is the same split PowerPoint uses, and the frame is the only cue telling a user where their next keystroke will go.

A single click while in text mode moves the caret; a click outside the shape leaves text mode.

What can be selected

Only shapes the slide itself owns. Shapes painted from the layout or master are skipped by hit testing, because they belong to every slide using that layout — letting a click grab one would let a user drag the company logo off the whole deck at once. Shapes flattened out of a group are likewise not editable: their position is the group’s coordinate space collapsed into the slide’s, so writing a new one back would put them somewhere else entirely.

Editing

	What it does
Type	inserts at the caret, replacing the text selection
Enter	splits the paragraph, keeping its level and bullet
Backspace at offset 0	joins the paragraph onto the one above
Tab / Shift+Tab	indents / outdents the bullet’s outline level
Ctrl/Cmd+B, I, U	bold, italic, underline over the selection
Delete (shape mode)	removes the selected shape
Ctrl/Cmd+Z	undo — a whole drag is one step, not one per pointer sample

Font family, size, colour and alignment are on the controller and wired into both toolbars. AddTextBox drops an empty text box onto the slide and selects it.

Edits are surgical on the runs

A run is split only where an edit genuinely needs a boundary and is never re-created, because an a:rPr carries language, hyperlinks, effects and theme-derived fills the model does not represent. Formatting is expressed as a mutation of the run’s properties rather than a finished style, so turning on bold leaves the font, size, colour and italics exactly as they were.

⚠️ DrawingML is fussier than WordprocessingML about child order: a:rPr’s children are a sequence, not a set, and PowerPoint refuses to open a file whose run properties are out of order rather than repairing it. The editor inserts them at their schema position.

What a save rewrites

Opening a deck and saving it without editing produces a byte-identical file. That is the promise, and it is asserted by hashing every ZIP entry before and after.

Once an edit happens, the picture is more honest: the SDK’s only public flush re-serialises every part whose DOM has been materialised, and reading a deck materialises every slide, layout, master, theme and notes part it had to walk. Those round-trip through the same object model, so nothing is lost — a reopened deck reads back identically, including the slides you never touched — but their bytes move. Nothing is ever added to or removed from the package.

Keyboard input

Blazor: complete. Typing goes through beforeinput, so IME composition, autocorrect, dictation and paste all work. Arrows, Home/End, Tab, Escape, Delete and the shortcuts above are wired.

MAUI: typing works — a hidden Entry gives the platform keyboard and IME somewhere to send text. Physical keys do not, because MAUI exposes no portable key-down event. Route them yourself:

Editor.HandleKey(EditorKey.Left, shift: true);
Editor.HandleKey(EditorKey.Undo, control: true);

Tapping, dragging, typing and every toolbar command work without it.

Not implemented

• Soft line breaks (a:br). They are read and rendered, but the caret cannot be placed on one and Shift+Enter does not insert one — a break contributes no characters to the offset space.
• Editing table cells and grouped shapes; both are rendered but not selectable.
• Adding, removing or reordering slides.
• Rotation handles. A rotated shape renders rotated and can still be moved and resized, but the drag works in unrotated slide coordinates.
• Everything the viewer does not render is still not rendered — see Viewers.

Screenshots

Shape mode draws a dashed frame with eight handles; text mode turns it solid and shows a caret. That contrast is the only cue telling a user where their next keystroke will go.

MAUI — shape selected	MAUI — editing text

Blazor — shape selected	Blazor — editing text