Slide Editor | Shapes, Pictures & Tables

The slide editor adds three kinds of object, and highlights text. All of it is on the shared SlideEditorController, and all of it is already wired into SlideEditorView’s toolbar on both hosts.

var c = editor.Controller!;

c.AddShape(ShapeGeometry.Hexagon, slideX, slideY, width: 240, height: 180);
c.AddPicture(bytes, "image/png", slideX, slideY, width: 400);
c.AddTable(rows: 3, columns: 4, slideX, slideY, width: 480, height: 200);
c.AddTextBox(slideX, slideY);

All four place in slide coordinates and select what they added, so the next gesture is a drag of the new object rather than a hunt for it. The toolbar centres them on the slide: an object inserted at the origin lands under the title placeholder, where it is both invisible and awkward to grab.

Shapes

Twenty preset geometries, in Shiny.Controls.Office.Shapes:

Rectangle, RoundedRectangle, Ellipse, Triangle, RightTriangle, Diamond, Line, RightArrow, LeftArrow, UpArrow, DownArrow, Pentagon, Hexagon, Star5, Chevron, Parallelogram, Trapezoid, Plus, Can, Cloud.

The same enum and the same path builder the document editor uses — the shape you draw in a deck and the one you drop into a document are the same shape.

AddShape writes a real drawn shape, not a text box: TextBox is deliberately left off the non-visual properties, which is what makes PowerPoint give it the theme’s fill by default, let it be recoloured from the shape gallery, and report itself as a rectangle rather than as text. It still gets an empty text body, so double-clicking it puts a caret inside exactly as a shape drawn in PowerPoint does.

Once added, a shape is an ordinary editable shape: select it to move or resize it with its eight handles, double-click to type in it.

Pictures

c.AddPicture(bytes, "image/png", slideX, slideY, width: 400);

The bytes go in as they arrived — never re-encoded. Re-encoding would mean choosing a quality on the user’s behalf, and a deck is where people put screenshots they intend to stay legible.

The image part is added to the slide, not the presentation: that is where a picture’s r:embed is resolved from, and a relationship on the presentation part is invisible to the slide that needs it. Every insertion gets its own part, even for bytes already in the package — de-duplicating would mean hashing every existing image on every drop, and two references to one part is a lifetime rule nothing else here needs.

Tables

c.AddTable(rows: 3, columns: 4, slideX, slideY, width: 480, height: 200);

A table on a slide is not a shape. It is a p:graphicFrame whose a:graphicData holds an a:tbl, with its position on the frame and its size split between the frame’s extent and the grid inside. Both have to agree: a frame sized differently from its grid renders at the frame’s size with the columns still laid out for the grid’s, so the table overhangs its own border.

It comes out with a built-in table style applied. Without one PowerPoint draws no fill and no rules at all, which reads as a failed insert rather than as a plain table.

⚠️ A table can be added, and moved or resized as a whole. Typing into its cells is not supported yet — table cells are rendered but not selectable.

Dropping image files in

Dragging an image file onto a slide inserts it centred on the point it landed, sized to at most half the slide so a photograph dropped at full resolution does not arrive many times larger than the deck it is in. On by default.

<SlideEditorView Deck="deck"
                 AllowFileDrop="true"
                 DropRejected="OnRejected" />

Editor.DropRejected += (_, e) => Toast(e.Reason);   // MAUI

Where it works, what is accepted, and what DropRejected reports are identical to the document editor — see Shapes, Pictures & Tables there for the platform table and the format list. In short: Blazor everywhere; on MAUI, Windows, iOS/iPadOS and Mac Catalyst, with the toolbar’s picture button as the gesture elsewhere.

Highlighting

c.SetHighlight(new ArgbColor(255, 255, 255, 0));   // null clears it
c.ToggleHighlight(color);
c.CaretFormat.Highlight;

DrawingML’s a:highlight wraps a real a:srgbClr, so unlike Word’s closed list of names nothing is approximated here — the colour goes in exactly as asked.

The picker still offers HighlightPalette.Swatches, the same sixteen the document editor uses. Offering two different palettes would be the honest reading of the two formats and the wrong thing for a user, who sees one highlight button and expects the same swatches behind it in a document and in a deck.

Note

a:rPr’s children are a sequence, not a set. a:highlight has a fixed slot — after the effect list, before the underline fills — and appending it after a:latin produces a file PowerPoint refuses to open rather than offering to repair.

Strikethrough (c.ToggleStrikethrough()) is likewise read, painted and editable on both sides.