Usage guide

A tour of the VSDX Viewer UI. The app runs entirely in your browser — nothing is uploaded. Open the live app or run it locally with npm run dev.

Opening a file

• Click Open in the toolbar and choose a supported Visio file, or drag it onto the drop zone.

Supported formats are .vsdx, .vsdm, .vstx, .vstm, .vssx, .vssm, .vsd, .vst, and .vss. XML stencils are displayed as read-only master sheets; XML drawings and templates can be edited and saved in their original format.

An .svg this app exported can be opened too: it carries the source drawing as embedded metadata, and if you have edited the picture in another editor since, you are asked whether to bring those edits back — see Editing the SVG somewhere else.

The file name appears in the toolbar and the first page renders as SVG. Multi-page documents show one tab per page beneath the toolbar — click a tab to switch pages.

Navigating the drawing

The arrow keys act on the canvas once it has the focus, which pressing on it gives it.

Zoom is applied to the SVG's own size rather than as a transform on top of it, so the drawing is re-drawn at every zoom instead of magnified as pixels — no soft edges while you wheel, and none left behind afterwards. The flip side is that the drawing is placed by a transform too, so the browser has no scrollable box here and would draw no scrollbars of its own: the ones at the right and bottom edges are drawn from the same pan the drag uses. They appear only when part of the drawing is off screen, and the drawing itself can no longer be flung out of the window — a drag stops when its edge reaches the window's.

A page opens showing all of itself. A Visio drawing is not necessarily a sheet of paper: a site plan or a floor layout is measured at full size, and one that is 3962 × 2618 inches is 380,372 renderer pixels across — it fits a 1200-pixel window at 0.32%. So opening a page fits it to the window, Fit returns you there at any time, and zoom goes down to 0.02% for the drawings that need it. Below 10% the readout switches to decimals, because 0% tells you nothing about whether − did anything.

Thin lines (hairlines)

Visio stores a LineWeight of 0 as a hairline: the thinnest line the output device can draw. On a scaled drawing — a 1:100 floor plan, say — that is a fraction of a millimetre on paper, so it can disappear entirely when the page is scaled down to fit a window. The Hairlines control in the toolbar decides what happens to those lines:

The minimum is baked into the SVG when the page is drawn, so changing the zoom does not change it — following the zoom live would mean re-rendering the whole drawing on every wheel tick. Instead, ⟳ Update re-renders the page for the current zoom, and lights up once you have zoomed away from the zoom the drawing on screen was rendered for. Export… exports what is on screen, so switch back to True size first if you have been using Fit zoom and want an export with untouched line weights.

Layers

Click Layers to open the layers sidebar. Each layer has a visibility toggle; turning one off hides its shapes in the rendered page.

The pane resizes both ways. Drag its right-hand edge to make it wider — long layer names need the room — and drag the line between the tool sections and the list of layers to decide how the height is split between them. Until you drag it the split is automatic: the tools take what they need and the list takes the rest. Once you drag it, it stays put even as you fold sections open and shut. Double-click the handle to hand the split back to the layout.

A layer's row is its name, its checkbox and its tags — nothing else. Everything else a row can do is on its menu, which a right-click on the row opens, as does the ⋯ at its end:

• List shapes — every shape on that layer, in the panel above the list. Hovering a row draws a square around that shape on the canvas.
• Rename… and Move to group… — see grouping.
• Edit tags… — see layer tags.
• Delete… — see adding and removing layers.

On a group row every entry speaks for the whole subtree: List shapes lists every shape on every layer under it (each shape once, however many of those layers it is on), and Delete asks once for the lot.

The pane itself

Layer names are as long as their author made them, and the tools for working with them are each occasional, so:

• Drag the pane's right edge to make it wider; double-click that edge to fit it to the longest row.
• The tools are folded away by default — Filter layers, Find shapes, Grouping, Named views, Tags — each opening on its heading. A heading says what it is doing while folded, so a filter left on ("pump") is never a drawing that mysteriously lost its layers.
• + in the pane's header adds a layer.

Showing and hiding

• A layer's checkbox, or a click anywhere on its row, toggles it.
• Under Filter layers: a Search layers box with a filter mode (Contains, Equals, Starts with, Ends with, Doesn't contain), then Show matches / Hide matches for what the filter caught, and Show all / Hide all for the whole page.
• Ctrl+Z takes back the last change to what is shown — Hide all is one click and undoing it by hand is one click per layer. Ctrl+Shift+Z (or Ctrl+Y) puts it back. The history is per page and covers single toggles, the bulk buttons, a group's checkbox, and applying a named view; it is about visibility only, not about edits to the drawing.

Grouping layers by a delimiter

Visio has no layer hierarchy — a page carries one flat list. What drawings do instead is put the hierarchy in the name: Electrical/HV, Electrical/LV, Plumbing/Cold. Open Grouping in the Layers sidebar and tick Group by delimiter to read that convention back out and nest the rows accordingly.

• The box below it is the delimiter, and it is yours to choose — /, ., ::, anything. It is matched literally, not as a pattern. Emptying it returns the list to flat, as does unticking the box.
• ▾ / ▸ collapses or expands a group; Collapse all / Expand all does the lot, and Collapse unselected folds everything except the way down to the layer you last picked.
• A group's checkbox shows or hides every layer under it, and reads as half-ticked when only part of the group is showing. Its count (2/3) says how many.
• A layer with no delimiter in its name stays where it is, at the top level. A layer that is also a parent — Electrical alongside Electrical/HV — keeps its own row and gains a twisty for its children.
• Picking a shape — on the canvas, or from Select component, the shape search or a layer's object list — unfolds its way down to the layer that shape is on and marks the row. Only the groups on the way there open; the rest of the tree stays as you folded it. A shape that is on no layer marks the Unlayered row, because that is the answer for it.

No group is ever written to the document: the tree is derived from the layer names every time, and every layer keeps its own row and index. What is saved is the setting itself — whether grouping is on, your delimiter, and which groups you left collapsed — because a drawing whose layers are named Electrical/HV is grouped by / for everybody, not just for you. It rides the same channel as named views and layer tags, so it survives a round-trip through the real Visio, and whoever opens the file next sees the tree you saw. A drawing that was never grouped opens flat, as before.

Moving and renaming — the name is the path

Nothing in a .vsdx records where a layer sits, because nothing in Visio has a place to sit: the tree is derived from the names and nothing else. So moving a layer is renaming it. Give a layer another group's prefix and that is where it appears.

Every row — group or layer — offers Rename… on its menu (right-click the row, or use its ⋯), which edits the full path the row stands for, prefilled so you can retype just the part you want to change:

Only the part of each name the row accounts for is replaced, so everything nested below keeps its own suffix and travels along: moving the group Electrical moves Electrical/HV and Electrical/LV with it, and layers outside it are untouched. A row that is both a layer and a parent — Electrical next to Electrical/HV — renames itself and its children together.

Moving a group onto another group's name merges the two. That is only a clash if it would leave two layers on the page with the same full name, which is refused for the same reason a duplicate new layer is.

With grouping switched off the same entry just renames — there is no path on show — but typing a delimiter into the name still files the layer into a group; you simply won't see it as one until you tick Group by delimiter.

Renames are ordinary layer renames, so — like the Layer Matrix's Replace all — they live in memory until you Save VSDX, and a named view that referred to a layer by its old name no longer matches it.

The row menu

Right-click any row — layer or group — or click its ⋯:

Move to group… is the same edit as a rename with the last segment held fixed — useful when the name is long and only its home is wrong. It works with grouping switched off too, where it simply prefixes the name.

Adding and removing layers

• + in the sidebar's header adds a layer to the page you are on. Names have to be unique on the page — tags and named views identify layers by name, so two layers sharing one would be indistinguishable to both.
• Delete… on a row's menu deletes that layer, after telling you how many shapes are on it. On a group row it deletes every layer under the group, asking once for the lot.
• + New layer… in a shape's right-click menu creates a layer and files that shape onto it — handy right after drawing something with the pen, which lands unlayered.

Deleting a layer is not deleting its drawing. Its shapes stay exactly where they are; a shape that was also on another layer simply loses this one, and a shape left on no layer at all appears under the editor-only Unlayered row, from where Send Object To Layer can file it somewhere else.

Both need an editable Visio XML package — a read-only binary .vsd or a stencil has nowhere to write a layer to — and, like every other edit, they only change the in-memory document until you Save VSDX.

A layer exists in the file as a numbered row, and every shape records its layers by number, so the numbers are never reused or shuffled: a new layer takes one past the highest already present, and deleting a layer leaves its number unused rather than renumbering the others (which would move every shape on them). Layer creation is a per-page action, so it lives in the sidebar rather than the cross-page Layer Matrix.

Layer tags

Layers can carry free-form tags — "electrical", "draft", "as-built" — so a drawing can be sliced by concern rather than by layer name.

• Tag a layer: pick Edit tags… from its row menu in the Layers sidebar (right-click the row, or use its ⋯) and type a comma-separated list, or type into the Tags column of the Layer Matrix. Tags are trimmed and de-duplicated case-insensitively, and each page keeps its own tagging.
• Colours: every tag gets a colour — derived from its name until you pick one. Click a tag's swatch in the Tags legend (sidebar or matrix) to recolour it; the colour is document-wide, so a tag looks the same everywhere.
• Filter by tag: the layer search box matches tag names as well as layer names, and tag:electrical restricts the match to tags only. Combine it with Select filter / Deselect filter to show or hide everything carrying a tag in one click. Clicking a tag in the legend fills the box for you.
• The editor-only Unlayered row can't be tagged — it isn't a real Visio layer, so there'd be nowhere to store it.

Visio's layer object model has no tag field, so tags and their colours are stored in the drawing's Solution XML store — the same channel as named views, proven to survive a Microsoft Visio open+save (see visio-roundtrip.md). Layers are matched by name, so tags stay attached even if Visio renumbers layers. Like every other edit they live in memory until you Save Visio (or Export…).

Sheet tabs

• Click a sheet name to open it or its × to delete it.
• Right-click a sheet to rename it, delete it, delete sheets to either side, or delete every other sheet.
• Drag sheets left or right to reorder them.

At least one foreground sheet is always retained. Deletions and sorting are written into the document when you Save Visio or Export….

Layer Visibility Matrix

Click Layer Matrix for a grid of every layer across every page. From here you can:

• Toggle any layer/page cell.
• Search matrix (Ctrl+F) to jump to a layer.
• Rename layers: type into Replace layer names with and click Replace all to rename matching layers in bulk.
• Edit the Tags column (comma-separated) for any layer on any page; the search box matches tags too.
• Create, apply, update, and delete Named views without leaving the matrix.

Named views (layer presets)

The Named views controls in the Layers sidebar and Layer Matrix let you save the current layer configuration under a name, so a shared drawing can flip between the layer sets different teams care about — e.g. a "Network" view and an "Electrical" view of the same diagram.

• Save view… — captures a per-page snapshot of each layer's visibility, print, active, lock, snap, and glue settings under a name you choose. Saving again with an existing name overwrites it.
• Select a view from the dropdown to apply it — every page's layers are set to that view's recorded settings. (Layers are matched by name, so a view keeps working after layers are reordered.) Ctrl+Z takes the change back on the page you are on if it was not what you wanted.
• Update overwrites the selected view with the current layer settings; Delete removes it.

Views are stored inside the .vsdx (in Visio's Solution XML store), so they travel with the file: anyone you share it with sees the same named views. Like every other edit, they're in memory until you Save Visio (or Export…), which bakes them into the downloaded file. They also survive being opened and re-saved in the real Microsoft Visio desktop app — see visio-roundtrip.md.

Inspecting shapes

• Shape Tree sidebar: select a shape and the tree opens on the whole page — every shape, nested inside its group, with the selected one marked and the branches leading to it opened. Hovering a row draws a selection square around that shape on the canvas, and the row's tooltip shows the text the shape holds, which is often the only thing that tells Shape.8 from Shape.9. Clicking a row selects that shape; right-clicking a row opens the same menu the canvas does, so rename, Edit XML, Send Object To Layer, the arrange actions and Delete are all on a row. Each row also carries a ✎ that renames the shape in place (double-clicking the name does the same once the row is the selected one; Enter commits, Esc leaves it alone, a blank answer clears it) and a × that deletes it from the drawing.

• The tree follows the marked layer. The two panes describe the same drawing, so they agree about it. While the Layers sidebar is open, the tree lists what is on the layer marked there — the shapes that carry it, everything inside them, and the groups on the way down — and walking the layer rows walks the tree with you; the subtitle names the layer and counts what it is showing. Picking a shape in the tree does the reverse and marks the layer that shape is on, the same as picking it anywhere else. Shut the Layers sidebar and there is no marked layer to follow, so the tree is the whole page again; Follow layer in the tree's header does the same with both panes open.

• A layer switched off takes its shapes out of the lists. Not just off the canvas: a shape you cannot see is not offered by the Shape Tree, by the shape search, or by Select component under the cursor — and anything inside it goes with it, the same way hiding a group on the canvas hides what is in it. If it was selected, the selection gives it up, because handles sitting on nothing are handles you can drag. The one list that still shows them is a layer's own List shapes: that question named the layer, and hidden or not, this is what is on it.

• Folding the tree. A drawing where everything is inside a group is a tree nobody can read at a glance, so three buttons act on the lot: Collapse all, Expand all, and Collapse unselected — which folds everything except the way down to the shape you are working in. Selecting a shape opens the branches leading to it, and then leaves your folding alone; folding a branch you are inside stays folded.

• Walking the tree from the keyboard. Tab into the tree (or click a row) and the arrows take over. The cursor is not the selection: moving it only points at a shape — it draws the same box hovering a row does — so you can walk a drawing watching the canvas without disturbing what you already had selected, and Enter is what commits it.

  Key	What it does
  ↑ / ↓	step through the rows you can see
  PgUp / PgDn	ten rows at a time
  Home / End	first / last row
  →	open the group under the cursor; again to step into it
  ←	close the group under the cursor; again to climb out to its parent
  Enter	select the shape the cursor is on
  Space	show/hide it — the row's checkbox
  F2	rename it in place

  The whole tree is one tab stop: the buttons on a row are reached by pointer, not by tabbing thirty times to get past them.

• Right-click a shape to open its context menu:

  • Rename… — set the shape's Visio name (its Name/NameU, the same field Visio's own Shape Name dialog edits). It is what the Shape Tree, the Select component list and the diff report call the shape, so naming the ones you care about — Feeder cable rather than Shape.7 — is worth doing before a drawing gets big. The prompt starts from the name it has now; leaving it blank clears the name and the shape falls back to its text or its Type.ID. The same rename is on every row of the Shape Tree.
  • Edit XML — open the shape's raw XML in an editor; Apply XML to commit your change or Cancel to discard.
  • Select component — everything that passes through the point you clicked, topmost first, so you can reach a shape sitting underneath another one or pick the group instead of the part inside it. You should never have to send a shape to the back to get at what is behind it. The list is the union of two answers: every shape whose bounding box covers the point, and every shape the browser itself reports at that point — which includes ones that are completely covered up, and which is hit-tested against the real drawn outline rather than a box. Hovering a row draws a selection square around that shape on the canvas; clicking selects it and points the rest of the menu at it. Nesting is shown with › markers, and shapes currently hidden are marked hidden — they stay listed, because a shape you cannot see is often the one you are looking for. If the page has a background page, its shapes are drawn underneath this page's, so they are listed too and marked background. You can highlight and select one; the rest of the menu then says it belongs to the background page, because its layers are that page's and assigning it one of this page's would be wrong.
  • Arrange, including Delete — see below.
  • Send Object To Layer — move the shape onto a different layer (filter the layer list with the search box), or + New layer… to create one and file the shape onto it at the same time.

Moving, resizing and turning shapes (Select)

Select is what the canvas does whenever neither of the other two tools — Pen and Pan — is out. Click a shape to pick it, and it grows eight square handles and a round grip above it:

The handles sit on the shape's own box, not on the upright box that contains it, so a shape turned 30° gets handles turned 30° with it and dragging one resizes along the shape's own axes. The corner opposite the one you are dragging stays exactly where it was.

The drawing follows the box: a resize scales the shape's outline, everything inside a group, and the outlines of those too. Visio stores half of an outline as fractions of the shape's width and height and half of it as inches worked out from a formula — Width*0.5 — that Visio re-evaluates every time the width changes. This app scales the second kind rather than evaluating it, which is the same answer for a plain proportion and a close one otherwise; the formula itself is left alone, so Visio still works the exact value out and a shape drawn to be resizable stays resizable.

What follows the pointer is a dashed outline, not the drawing. The shape is edited once, when you let go — so a drag is one durable change to the file rather than a hundred, and it survives Save Visio like every other edit. Pressing anywhere that is not a selected shape still pans the canvas — and on a drawing whose shapes leave no empty canvas to press, Pan in the toolbar makes every press a pan until you click Select again.

Letting go moves the shapes that moved and nothing else. A move, a turn or a flip does not change what a shape looks like — only where it is — so it is written as exactly that: the shape stays on the canvas and is placed somewhere else, however much is inside it, and a group of a thousand children costs the same as a single rectangle. Only a resize draws a shape again, because that scales its geometry, re-wraps its text and rescales a group's contents — all the way down, so a group inside a group grows too rather than keeping its old picture inside a bigger box. Either way the rest of the page is left alone — as are your selection, the folded rows of the Shape Tree and where you had scrolled to. The .vsdx itself is rewritten the next time anything needs it, which on a large drawing is the slow part and is not something to make you wait for at the moment you let go of the mouse: Save Visio, Export…, Compare…, the shape XML editor and any edit that does change the structure of the document (group, ungroup, z-order, delete) all fold your moves in first. Nothing leaves the app without them.

Dragging a group takes everything inside it, and resizing one scales its contents with it, the way Visio does. All of it works on a shape nested several groups deep: the cells are worked out through the same matrix chain the renderer walks, so a shape's position inside its parent is rewritten correctly however deep it sits.

Two things it will not do:

• Move a connector. A connector is drawn between its endpoints rather than placed by its pin, so moving the pin would move nothing. It says so rather than appearing to do nothing.
• Skew a shape. Visio's shape transform is a pin, a size, an angle and two flip flags — there is no skew in it. Slanting a shape means rewriting its geometry, which is a different operation from moving the shape about.

Editing the individual anchor points of a path (the SVG node-editing idea) is not built yet either; the pen writes geometry but nothing edits it afterwards except Edit XML.

Selecting several shapes, and arranging them

Ctrl-click (⌘-click on a Mac) or shift-click a shape to add it to the selection, and again to drop it; a plain click selects just that one. Selected shapes get a marked box on the canvas — solid for the one the Shape Tree and the Send Object To Layer list are pointed at, dashed for the rest. The box is drawn on top of the whole drawing, so selecting a shape that is buried under another one still shows, and it is measured from where the shape was actually drawn rather than from its geometry — a shape with a very thick stroke is contained by its own selection box rather than spilling out of it. The same ctrl-click works on the rows in Select component, the shape search results and a layer's object list — and picking a shape from any of them points the Layers sidebar at the layer that shape is on. Right-clicking a shape that is already selected keeps the whole selection; right-clicking anything else selects that shape instead.

Esc lets the whole selection go, handles and all. Clicking bare canvas does the same, but a drawing whose shapes cover the page may not have any bare canvas to click, and with the ✋ hand out a click does not clear it either. Esc typed into a box belongs to the box, and while the ✎ pen is out it belongs to the pen.

The Arrange section of the right-click menu then acts on everything selected:

Z-order in Visio is the order the shapes are written in, so front and back move a shape among its own siblings — a shape inside a group is brought to the front of that group, not of the page.

Two things are deliberately refused rather than done badly:

• Grouping a connector. A connector is drawn in its parent's coordinates rather than its own, so moving one into a group would move it on the page.
• Ungrouping a group that came from a master. Its parts read their size and geometry from that master through the group; pulling them out would leave empty shapes behind. Groups you made yourself have no master and ungroup fine. (The button is greyed out with the reason in its tooltip.)

Grouping and ungrouping rewrite the drawing itself, so like every other edit they take effect immediately in the editor and land in the file when you Save VSDX.

Searching for a shape

The Find shapes box — open that section in the Layers sidebar — searches the current page: type part of a shape's name or its text and the results appear right below, including shapes nested inside groups. Hovering a result draws a selection square around that shape on the canvas, which is the point of the list: it answers where is it? without changing anything. Clicking a result selects the shape, opens the Shape Tree on it, and highlights the layer it is on in the list below — clearing a filter and expanding any groups that were hiding that row, since a row that is not drawn cannot be pointed at. Enter takes the top match.

• Matching is case-insensitive and matches anywhere in the name or the text.
• #7 searches by shape ID instead, on a prefix, so the list narrows as you type.
• Shapes on hidden layers are still listed, marked hidden — a shape you cannot see is often the one you are hunting for.
• Esc or clearing the box closes the results. Searching is per page; the box clears when you switch pages.
• Long lists stop at the first 300 matches (the title says so) — type more of the name rather than scrolling.

Listing every shape on a layer

List shapes on a row's menu in the Layers sidebar (right-click the row, or use its ⋯) opens the list of every shape on that layer, including shapes nested inside groups. On a group row it lists every shape on every layer under the group, each shape once however many of them it is on.

Hovering a row draws the same selection square on the canvas; clicking selects the shape and points the sidebar at its layer. Asking again closes the list, and opening it never changes the layer's visibility. The list and the search results share one panel, so opening a layer's objects clears the search box and vice versa.

Drawing new shapes (Pen)

Click ✎ Pen to draw a path onto the current page. The button is only available for editable Visio XML packages — drawing writes back into the file, which the read-only binary .vsd formats cannot do.

• Click places a corner point.
• Click and drag places a point and pulls a bezier handle out of it. The handle is mirrored on both sides, so the curve runs smoothly through the point — the same behaviour as Illustrator's pen.
• Enter, double-click, or Finish commits the path.
• Clicking the first anchor (highlighted once the path has three points) closes the path and commits it.
• Backspace or Undo point removes the last point; Esc or Cancel discards the whole path. Pressing Esc with nothing drawn leaves the tool.

The bar above the canvas sets what the path is drawn with, and the live preview uses those settings so you can see the result before committing:

Curves are stored as Visio's RelCubBezTo rows, which map one for one onto SVG's cubic C command (cells A,B and C,D are the two control points), and straight runs stay plain MoveTo/LineTo. Nothing is fitted or approximated.

Because Visio has no absolute cubic — every curve is a fraction of the shape's Width/Height — the path becomes a shape only when you commit it, which is when its bounding box is finally known. The new shape lands on the page unlayered; right-click it and use Send Object To Layer, or + New layer… if it should go somewhere that does not exist yet.

Drawing edits the in-memory document; use Save Visio to persist them.

Pruning

• Remove Non-visible — drop shapes on hidden layers from the document.
• Remove Non-selected — keep only the currently selected shapes.

These edit the in-memory document; use Save VSDX to persist the result. Pruning rebuilds the whole package and re-reads it, so it takes everything else you have changed but not yet saved with it — closed sheet tabs included, which stay closed.

Comparing two files

1. Load a base file.
2. Click Compare… and pick a second .vsdx.
3. The diff view highlights changes:
   • shapes that were added, removed, moved, or modified,
   • layer changes (added/removed/visibility),
   • shown both as an overlay and side-by-side.

Exporting

Export… opens a small dialog: pick a format, pick a size, done.

Format

• SVG — the current page as an .svg. The source .vsdx (with your layer edits applied) is embedded as base64 <metadata>, so an exported .svg can be dropped back into the app — or handed to someone else — and opened again as the full drawing, losslessly. Untick Embed the source Visio document for a plain, much smaller SVG that will not re-open here. Shapes come out grouped into real SVG layers — see Layers in the exported SVG. Each shape also carries its Shape Data and user cells as the v:custProps / v:userDefs elements Visio's own SVG export writes; those are added on the way out rather than drawn on the canvas, because on a large drawing they are three quarters of the document and nothing paints them.
• PDF — see PDF export below.
• Save Visio (on the toolbar, not in this dialog) — download an XML drawing or template with all your edits (layer changes, shape XML edits, pruning) applied.

Size

The drawing is rendered in its own units — 96 to the paper inch — so a large engineering drawing is tens of thousands of units across. SVG is resolution independent and does not care, but the programs you hand the file to very much do: browsers get sluggish or refuse to rasterise past ~32767px, Inkscape's PDF export garbles it, and a PDF page cannot exceed 200in (14400pt) per side at all — that is a hard limit in the format, not a viewer bug.

So the dialog lets you say how big the file should claim to be:

The presets are ceilings, never magnifiers: a drawing already inside the limit exports untouched. Longest side is only asked for by Custom, and only appears then — the same goes for the rest of the dialog: the SVG embed checkbox is there for SVG and gone for PDF (a PDF cannot carry the source document), and the PDF library consent is there for PDF and gone for SVG (which downloads nothing).

Rescaling costs you nothing. Only the root width/height change; the viewBox and every coordinate in the file are left exactly as they were. The result is the same vector drawing at full precision, just labelled with a size that ordinary software can handle. The dialog opens on Viewer-safe for a drawing too big for a PDF page, and on Original size for everything else.

Layers in the exported SVG

A Visio layer is a property of a shape — the page is a flat list of shapes, each naming the layers it is on. SVG has no layer concept at all, but every editor that pretends to have one reads the same convention, so the export writes it: each Visio layer becomes a <g inkscape:groupmode="layer"> labelled with the layer's name, and Inkscape (or Boxy, or Affinity) opens the file with a working layer panel instead of one flat pile of paths. Layers you have switched off in the app come out as a hidden group, not as a pile of individually hidden shapes, so the eye icon in the layer panel actually toggles them back on.

One caveat, and it is Visio's rather than the app's. SVG's paint order is document order, while Visio's z-order is independent of its layers — a drawing can perfectly well stack wall, door, wall, door. Collecting every wall into one group therefore moves shapes past each other, and where they overlap that changes the picture. So the export only merges a layer's shapes into one group when it can show the reordering is invisible: every pair of shapes that swapped has to have disjoint bounding boxes. Where it cannot, that layer is emitted as several groups following the original order — you get Walls, Walls (2), Walls (3) in the panel instead of one Walls, and the drawing looks exactly as Visio draws it. Tidier XML is not worth a silently restacked drawing.

Editing the SVG somewhere else and bringing it back

An exported SVG carries the whole drawing inside it, so re-opening one gives you the drawing back — which for a long time meant that anything you had done to the picture in between was silently discarded. It is not any more.

Open an exported .svg in Inkscape, delete things, draw things, save, and drop the file back on the app. It compares the picture against the drawing embedded in it, tells you what it found, and asks before applying anything:

Cancel and the drawing opens exactly as it was exported, edits ignored.

Changes to an existing shape are written as cells, never as a replacement outline. This matters more than it sounds. A shape's rendered path is a lossy view of its Visio geometry: rows inherited from a master, coordinates driven by formulas, an outline expressed as fractions of the shape's own Width. Importing the drawn path wholesale would flatten a parametric shape into a dumb one that happens to look the same today and stops resizing properly tomorrow. So:

• a row your shape inherits from a master gains an override holding only the cell that changed — everything else it inherits, it goes on inheriting;
• a coordinate Visio wrote as Width*0.6 stays a proportion. Drag it and it becomes Width*0.72, not the number that happened to equal today;
• anything else formula-driven is refused with a reason, because replacing a formula with its current answer looks like nothing changed and quietly breaks the shape.

And three kinds of edit are reported rather than guessed at, because there is no honest cell to write them to:

• points added to or removed from an outline — there is no geometry row to attribute them to;
• scaling or skewing a shape — Visio's shape transform is a pin, an angle and two flip flags; it has no scale and no skew. Resize it here instead;
• an outline drawn from arcs, splines or NURBS, where a single number on the page does not come from a single cell.

Two more things it declines to convert rather than get wrong:

• <text>, <image> and <use> are reported as skipped rather than imported. Text belongs on a Visio shape, not in geometry.
• An SVG whose shape ids have been stripped — by Inkscape's Optimised SVG output, say, or by an SVG minifier — is refused outright. With no ids there is no way to tell a deletion from a file that simply never had them, and the wrong answer deletes the drawing. You get told why, and the embedded drawing opens untouched.

PDF export

PDF needs two libraries this app does not bundle — writing a PDF by hand would mean font subsetting, and half a megabyte of dependency for a feature most sessions never touch would be a poor trade for something you can run off a USB stick. So they are fetched only when you ask for a PDF, and only after you tick Allow this download:

• jsPDF 4.2.1
• svg2pdf.js 2.7.0

Both come from cdn.jsdelivr.net, and the bytes are checked against a SHA-256 digest pinned in the source before a single line of them runs. A CDN that is compromised, MITM'd, typosquatted, or that quietly republishes a version fails the check, nothing executes, and you get told which library failed along with both digests. The libraries are held in memory only, so they are re-fetched (and re-verified) next session.

The dialog shows the exact URLs and digests before you agree. If you would rather not download anything, export an SVG and convert it yourself — and if you are converting through Inkscape, set the size here first, because that is the step that usually produces the garbage.

Offline or air-gapped? PDF export will simply fail to download; everything else in the app is self-contained as always.