Changelog

All notable changes to this project are documented here. The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

Added

• Switching a layer off now takes its shapes out of the lists too, and out of the selection. Hiding a layer took its shapes off the canvas and left them everywhere else: listed in the Shape Tree, found by the shape search, offered by Select component under a cursor that was over a box nothing was drawn in any more — and still selected, with handles sitting on nothing, one drag away from moving a shape nobody can see. A hidden shape is now hidden in all of them, on the same reckoning the canvas draws by (every layer it carries off, or Unlayered off for a shape carrying none), and anything inside a hidden shape goes with it. The selection gives up whatever went with the layer and keeps the rest of itself. A layer's own List shapes is the exception: that question named the layer, so hidden or not, its answer is what is on it.

• The Shape Tree and the Layers sidebar now describe the drawing the same way. They used to disagree: walking down the layer rows said nothing to the tree, which went on listing the whole page whatever was marked, and picking a shape in the tree — alone among every list in the app — left the Layers sidebar marking whatever it had been marking before. Now, while the Layers sidebar is open, the tree lists what is on the marked layer: the shapes that carry it, everything inside them (a child with no membership of its own is on whatever it is inside, the rule the canvas already draws by), and the groups on the way down, unfolded so a match three deep is not hidden behind a fold. Its subtitle names the layer and counts what it is showing, so a shorter list does not read as a drawing that lost shapes. Picking a shape in the tree marks the layer that shape is on. Shutting the Layers sidebar leaves no marked layer to follow and the tree is the whole page again — as does Follow layer in the tree's own header, for wanting both panes open and the whole page listed.

• Edit an exported SVG somewhere else and bring the edits back. Exported SVGs carry the whole drawing as embedded metadata, so re-opening one always round-tripped perfectly — including round-tripping away everything you had done to it in between. Opening an edited SVG now compares the picture against the drawing inside it and offers to apply what it finds:

  • shapes you deleted — every shape's group carries its Visio id, so an id the picture no longer has is a shape that was deleted (deleting a group in Inkscape takes its children's ids with it, which reads correctly as deleting the group);
  • shapes you drew — any path, rect, circle, ellipse, line, polyline or polygon sitting outside every shape group becomes a real Visio shape, geometry, fill, stroke, dash and all. Curves come through as RelCubBezTo rows rather than being flattened, because that row is SVG's cubic C; quadratics, S/T shorthands and elliptical arcs are converted exactly (arcs to within 0.02% of their radius), and a path drawn into an Inkscape layer lands on the Visio layer of the same name;
  • shapes you changed — a shape you moved, turned or whose points you dragged. The page is re-rendered from the embedded document and compared with the file you bring back, and the difference is written as cells, not as a replacement outline: a changed transform becomes Pin/Angle/Flip, every coordinate moving together becomes a move rather than a rewrite of every row, and one dragged point becomes that row's X/Y (or a bezier's A/B/C/D) and nothing else. A row inherited from a master gains an override holding only the cell that changed, so everything else it inherits it goes on inheriting, and a coordinate Visio wrote as Width*0.6 stays a proportion — it is rewritten as Width*0.72, not replaced by the number it happened to equal. Points added to or removed from an outline, a scale or a skew, and a coordinate driven by a formula that is not a plain proportion are all reported with a reason instead of being approximated.

  Nothing is applied without being asked first, and the dialog says what it found. An SVG whose shape ids have been stripped (by an "optimised SVG" export, say) is refused outright rather than read as everything was deleted.

• Collapse all, Expand all and Collapse unselected on the Shape Tree, and Collapse unselected on the layer tree. Tidying a drawing where everything is inside a group used to be one click per group. Collapse unselected folds everything except the way down to the shape (or layer) you are working in. Fixed alongside it: the Shape Tree reopened the branch holding the selected shape on every redraw, so folding the branch you were in came undone the moment anything else changed. It now reveals a shape when you select it and leaves your folding alone after that.

• Exported SVGs have real layers. The export used to tag each shape with a data-layers attribute, which no SVG editor reads: opening the file gave one flat pile of paths and an empty layer panel. Shapes are now grouped into inkscape:groupmode="layer" containers named for the Visio layers they are on, and a layer switched off in the app comes out as a hidden group rather than a pile of individually hidden shapes — so the eye in Inkscape's layer panel is a real toggle. A Visio layer is a property of a shape while SVG's paint order is document order, so collecting a layer's shapes together can restack the drawing; that is only done where it provably cannot show (every pair of shapes that swapped has disjoint bounding boxes). Where it would, the layer is emitted as several groups in the original order — an uglier layer panel, but the picture Visio draws.

• The parser says where each geometry row came from. It used to answer only what does this shape draw: the master's rows and the shape's own rows were flattened into one effective list of numbers, which is everything the renderer needs and nothing an editor can use. Each row now also carries the Geometry section's IX, its own IX, whether it lives on the shape, on the master or is a shape row overriding a master row, which cells the shape's own row actually holds, and the formula behind each cell. That last one matters because reading only the computed value cannot tell a coordinate someone typed from the current answer to Width*0.5 — and overwriting the second kind with a number silently de-parametrises the shape, which is the whole point of a Visio master. This is groundwork for editing a path's points; nothing about what is drawn has changed, and the visual diff explicitly ignores it, so the same outline reached two different ways is still not a difference.

• A Select tool, and shapes you can actually push around. There was a pen but nothing to pick things up with: a press on a shape panned the canvas, and the only way to move anything was to edit its XML. Select now sits beside Pen in the toolbar, and the selected shape carries eight resize handles and a rotation grip:

  • drag the shape to move it (grab an unselected shape and it selects and moves in one gesture; a whole multiple selection drags together),
  • drag a handle to resize — corner handles change both axes, edge handles one, Shift keeps the proportions,
  • drag the grip to turn it, Shift snapping to 15°.

  Handles sit on the shape's own box, so a shape turned 30° gets handles turned 30° with it and resizing runs along its own axes. What follows the pointer is an outline, not the drawing: the shape is edited once, when the mouse comes up, so a drag is one durable edit that survives Save Visio rather than a hundred. Dragging a group takes its contents with it, and resizing one scales them with it. It all works on a shape nested three groups deep, because the cells are worked out through the same matrix chain the renderer walks. A connector is drawn between its endpoints rather than placed by its pin, so it says so instead of pretending to move.

• The Shape Tree walks under the arrow keys. A page is thirty rows called Shape.7, Shape.8, Shape.9, which is not a list anyone wants to hunt through with a mouse. ↑/↓ step through the rows you can see, → opens a group and then walks into it, ← closes it and then climbs back out, Home/End and PgUp/PgDn go further at once, Space shows or hides the row's shape and F2 renames it. The cursor is deliberately not the selection — moving it only draws the same box hovering a row does, so you can walk a drawing watching the canvas without disturbing what you had selected — and Enter is what commits it. The tree is a single tab stop rather than six buttons per row.

• Delete shapes. There was no way to, short of hiding them or pruning a whole layer. Select one or several and Delete appears with the other arrange actions in the right-click menu; the Delete and Backspace keys do the same, except while the pen tool has them or you are typing in a box. Deleting a group deletes what is inside it, and any connector glued to something that goes is unglued rather than left pointing at a shape that no longer exists. It is a real edit to the drawing, so it survives Save VSDX.

• The Shape Tree lists the page. It used to open on the selected shape's parent group, so selecting a shape that was not in a group gave a tree of exactly one row: every row you could click was the row already selected, which is indistinguishable from clicking rows doing nothing. It now shows every shape on the page, nested, with the selected one marked and its branches opened. Hovering a row draws a box round that shape on the canvas, its tooltip carries the shape's own text (often the only thing that tells Shape.8 from Shape.9), and right-clicking a row opens the same menu the canvas does — rename, edit XML, send to a layer, arrange, delete.

• The Layers pane splits where you want it to, not where the stylesheet said. Its width was already yours to drag; the division between the tool sections at the top and the list of layers below was not, so opening Filter, Find and Grouping at once left the list a sliver. There is now a handle between the two. Until you touch it the split is automatic, exactly as before — the tools take what they need and the list takes the rest. Drag it and the split is pinned, so folding a section open or shut no longer moves it; it cannot be dragged so far that the list has no room, nor past what the tools actually fill, and a window that shrinks re-clamps it rather than leaving no list at all. Double-click the handle to go back to automatic.

• Export at a size other programs can cope with. A drawing is rendered in its own units, 96 to the paper inch, so a large one is tens of thousands of units across. SVG is resolution independent and does not care; the software you hand the file to does — browsers give up rasterising past ~32767px, Inkscape's PDF export garbles it, and a PDF page cannot exceed 200in (14400pt) per side at all, which is a limit in the format rather than a viewer bug. Export… now opens a dialog offering Original size, Viewer-safe (longest side 19200px — the largest a PDF page can legally be), Screen (4096px), or a custom longest side. Rescaling costs nothing: only the root width/height change, the viewBox and every coordinate are left exactly as they were, so it is the same vector drawing at full precision merely labelled with a size ordinary software can handle. The presets are ceilings and never magnifiers, so a drawing already inside the limit exports untouched, and the dialog opens on Original size unless the drawing is too big for a PDF page. Exports also carry a real intrinsic size now — the on-screen SVG says width="100%", which in a file means "100% of nothing" and leaves every program to invent its own answer.

• PDF export, via jsPDF and svg2pdf.js fetched on demand and pinned by SHA-256. Writing a PDF from scratch would mean font subsetting, and half a megabyte of dependency for a feature most sessions never touch is the wrong trade for an app you can run off a USB stick — so nothing is downloaded until you choose PDF and tick Allow this download, and the bytes are checked against a digest 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 the dialog names the library and shows both digests. The libraries are held in memory only, so they are re-fetched and re-verified next session. The dialog lists the exact URLs and digests before you agree, and npm run test:pdf-live checks the pinned digests against what the CDN actually serves. The page comes out in the drawing's own orientation — jsPDF reorders format to agree with orientation, so a wide drawing asked for a portrait page would be rendered off the edge of it.

• Export a plain SVG. Embed the source Visio document is a checkbox now; untick it for a much smaller SVG that will not re-open in this app.

• Undo what you just hid. Ctrl+Z takes back the last change to which layers are shown, Ctrl+Shift+Z (or Ctrl+Y) puts it back. Hide all is one click and undoing it by hand was one click per layer, which is the wrong trade. Visibility is a small, self-contained piece of state — the set of hidden layers — so the history is a stack of those sets rather than a general command history: it covers single toggles, the bulk buttons, a group's checkbox and applying a named view, and nothing else. It is per page, because restoring one page's visibility onto another would be nonsense, and inside a text box the browser's own undo is left alone.

• A resizable Layers pane, with its tools folded away. Layer names are as long as their author made them and a fixed 240px pane truncated half of an Electrical/HV/Feeders tree, so the pane's right edge now drags (double-click it to fit the longest row). Filtering layers, finding shapes, choosing a delimiter, named views and tags are each occasional, so each is a section that starts folded and opens on its heading — the list of layers is what the pane is for. A folded heading still says what it is doing ("pump", on · /), so a filter left on is never a drawing that mysteriously lost its layers.

• One menu per layer row. A row is its name, its checkbox and its tags; everything else it can do is on its menu, which a right-click opens as does the ⋯ at its end: List shapes, Rename…, Move to group…, Edit tags…, Delete…. The strip of ⊙ ✎ 🏷 🗑 icons that used to sit on every row is gone, and the name has that width back. On a group row every entry speaks for the whole subtree, List shapes included — that lists every shape on every layer under the group, each shape once however many of those layers it is on, which is the only way to ask "what is in Electrical?" when Electrical is a naming convention rather than a layer.

• Finding a shape now says which layer it is on. Picking a shape from the search results, from a layer's object list or from Select component highlights the row for its layer in the Layers sidebar — clearing a filter and expanding any collapsed groups that were hiding that row, because a row that is not drawn cannot be pointed at. "Where is it?" has two answers and the second one is the one that says whether you can even see it.

• Rename a shape from the Shape Tree row. Every row has a ✎; the double-click that was supposed to do this never landed, because the click that selected the row redrew the tree and the second click hit a different element. Selecting a shape that is already selected no longer redraws anything, so the double-click works too.

• Group layers into a tree by a delimiter. Visio's layer model is flat, but drawings fake a hierarchy in the name — Electrical/HV, Electrical/LV. Group by delimiter in the Layers sidebar reads that convention back out and nests the rows accordingly, with a collapsible row per prefix, a collapse/expand-all button, and a per-group checkbox that shows or hides everything under it (tri-state when only part of the group is showing). The delimiter is yours to pick — /, ., ::, anything — and is matched literally rather than as a pattern; emptying the box just returns the list to flat, as does unticking the box.

  Moving a layer is renaming it, because the name is the path — nothing in the file records where a layer sits. Every row, group or layer, offers a Rename… that edits the full path it stands for: retype Electrical/HV as Plumbing/HV and the layer moves, as HV and it moves out to the top level. On a group row the same edit re-prefixes every layer beneath it, so renaming Electrical to Site/Power moves the whole subtree; only the part of each name the row accounts for is replaced, so anything nested below keeps its suffix and travels along. Merging one group into another is allowed; a rename that would leave two layers on a page sharing a full name is refused, for the same reason creating a duplicate is. A row that is both a layer and a parent — Electrical next to Electrical/HV — renames itself and its children together. With grouping off it is a plain rename, which is also the first way to rename a single layer from the sidebar rather than through the Layer Matrix's Replace all.

  No group is written to the file — the tree is derived from the layer names every time, and every layer keeps its own row and index. The settings do travel with the drawing: whether grouping is on, the delimiter, and which groups were left collapsed are stored in a visio/solutions/vsdxeditor-layer-tree.xml Solution XML part, the same channel the named views and layer tags ride, so they survive a Microsoft Visio open+save and whoever opens the file next sees the tree its author saw. A drawing that was never grouped still opens flat.

• Select several shapes, and arrange them. Ctrl-click (or shift-click) adds a shape to the selection and drops it again — on the canvas, in Select component, in the shape search results and in a layer's object list. The selected shapes are outlined, solid for the one the rest of the panels are pointed at and dashed for the others. The right-click menu grows an Arrange section acting on the whole selection: Group, Ungroup, Bring to front and Send to back.

  Z-order in Visio is the order the <Shape> elements are written in, so front and back are a move among a shape's own siblings — a shape inside a group comes to the front of that group. Group and ungroup are a move too, but a shape's PinX/PinY are written in its parent's coordinates, so re-parenting one has to rewrite them by exactly the right amount or the drawing comes apart. Each shape's new Pin, Angle and flip flags are read back out of the matrix the renderer itself composes, which is exact rather than approximate: that matrix is only ever a translation, a rotation and a reflection, never a scale or a shear. Rotated and flipped shapes, and groups nested inside groups, come out where they went in.

  Two cases are refused rather than done badly. A connector is drawn in its parent's coordinates instead of its own, so grouping one would move it. And a group that came from a master cannot be dissolved: its parts read their size and geometry from that master through the group, and pulling them out would leave empty shapes behind — Visio's own ungroup breaks the master link and copies everything down, which is a much larger operation than moving elements about. Groups you made yourself have no master and ungroup fine.

• Find shapes by name, text, or ID. A Find shapes box in the Layers sidebar searches the current page — name, NameU, shape text, or #7 to search by ID on a prefix — and lists what it finds, groups and nested shapes included. Hovering a result draws a selection square around that shape on the canvas, which is the actual point: the list answers where is it? without changing anything. Clicking selects the shape and opens the Shape Tree on it, Enter takes the top match, Esc closes.

  The results share the panel a layer's own shape list already used, because both answer the same question with the same list, so opening one clears the other. Shapes on hidden layers stay listed and are marked hidden — a shape you cannot see is usually the one you are hunting for. Typing is debounced and the list stops at the first 300 matches, since re-walking a large page's shape tree on every keystroke costs more than it tells anyone.

• Rename a shape from its right-click menu. Rename… sets the shape's Visio name — its Name/NameU, the field Visio's own Shape Name dialog edits — so the Shape Tree, the Select component list and the diff report all call it Feeder cable instead of Shape.7. The prompt starts from the name it has now, and a blank answer clears it. Renaming was already possible by double-clicking a row in the Shape Tree; the canvas is where you are when you notice the name is wrong, so it is offered there too. Like every other edit, it lives in memory until you Save VSDX.

• A right-click menu on layer rows. The row buttons are deliberately faint until hovered, which is fine for the one action a row is mostly used for and poor for the rest — so right-clicking a row (layer or group) names them instead: Rename…, Move to group…, and Edit tags…. Move to group… is a rename with the layer's own name held fixed — it asks only which group to put it in, and a blank answer moves it out to the top level. On a group row every entry speaks for the whole subtree, and Add tags to N layers… adds the tags you type to each layer under the group without disturbing the tags they already carry.

• Add and remove layers. The Layers sidebar has an add-layer button, each layer row a Delete… on its menu, and a shape's right-click menu can create a layer and file the shape onto it in one step — the common case after drawing something with the pen. Deleting a layer never deletes its drawing: shapes on it stay, and any left on no layer at all show up under the editor-only Unlayered row, where Send Object To Layer can file them again. The confirm prompt says how many shapes are involved before you commit.

  A layer only exists as a Row in the page's Layer section, and a shape's membership is that row's index, so indexes are never reused or shuffled: a new layer takes one past the highest (including past the unnamed placeholder rows Visio leaves behind when it deletes a layer), and deleting one leaves its index unused rather than renumbering the survivors and silently moving every shape. Clearing a shape's membership writes Visio's explicit empty LayerMember rather than dropping the cell, because dropping it lets the shape inherit its master's layers and land straight back where it was.

• A Pan tool — a hand for getting about a crowded drawing. The canvas has always panned from a press on empty space, which is no use on a drawing whose shapes cover it — and on a big one they cover nearly all of it. With ✋ Pan out, a drag anywhere moves the page, shapes included, and nothing on it is picked or moved by mistake; the handles step aside while it is out. It is a way of looking at a drawing rather than of changing one, so it works on a read-only file too. Select takes the canvas back.

• Pen tool — draw new paths onto a drawing. Click to place a corner, drag to pull a bezier handle out of the point you just placed (mirrored on both sides, like Illustrator's smooth point). Enter or a double-click finishes the path, clicking the first anchor closes it, Backspace drops the last point, Esc discards it. Fill and stroke — colour, weight in points, line pattern, fill colour and opacity — are set from a bar above the canvas and previewed live while you draw.

  The path is written as real Visio geometry, not an approximation: Visio's RelCubBezTo row is SVG's cubic C command, with cells A,B and C,D holding the two control points, so an exported curve is the curve you drew. Straight runs stay plain MoveTo/LineTo rows. Because Visio has no absolute cubic — every curve is a fraction of the shape's Width/Height — a path is committed as a whole once its bounding box is known, and a path with no extent on one axis (a perfectly horizontal drag) gets that axis floored and is centred in the box rather than collapsing to a point.

• Finding a shape: "Select component" and per-layer object lists. Right-clicking now lists every shape whose box covers that point, topmost first and groups included, so a shape buried under another one is reachable — and each layer in the sidebar offers a List shapes that lists every shape on it, nested shapes included. Hovering a row in either list draws a selection square around that shape on the canvas; clicking selects it. Hidden shapes stay listed and are marked as hidden, since a shape you cannot see is usually the one you are hunting for.

  The boxes come from a new shape-picker module that reproduces the renderer's own transform chain, so a shape nested three groups deep is hit-tested exactly where it is drawn. 1-D connectors are special-cased the way the renderer does it — they are drawn straight in page coordinates and their group carries no transform at all — with the rule exported from svg-renderer rather than guessed at twice. A test composes the transform off the rendered SVG and checks the picker against it, shape by shape, across four real drawings (487 groups, 408 of them nested).

• Esc lets the selection go. Clicking bare canvas was the only way to drop a selection, and a drawing whose shapes cover the page has no bare canvas to click — nor does a click clear anything with the hand out. Esc typed into a box still belongs to the box, and while the pen is out it still belongs to the pen, which uses it to take back the path being drawn.

• addVsdxShapeToPage in the parser: adds a top-level shape to a page, assigning the next free shape ID. The counterpart to replaceVsdxShapeXmlSnippet, which deliberately refuses any ID that does not already exist.

Changed

• Hairlines are drawn at their true size by default. The viewer used to open with a floor under every line — nothing thinner than one screen pixel at the zoom the page was drawn for. That keeps fine detail readable on a plan shrunk to fit a window, but it is not what the drawing says: on anything viewed at or near full size it made every hairline heavier than Visio, an export or a print would draw it. Hairlines: fit zoom is still in the toolbar, one click away.

Fixed

• Clicking a shape that is on no layer marked no row at all. The sidebar has a row for exactly that — the editor-only Unlayered one — but the click looked for a layer tag on the shape, and a shape on no layer carries none, so it gave up before it got as far as answering. Clicking such a shape, or the text drawn on it, now marks Unlayered, the same as picking it from the shape search or a layer's object list already did. Clicking empty canvas still marks nothing.

• Clicking a shape pointed the Layers sidebar at a row that was folded away. Picking a shape on the canvas opens the sidebar and marks the layer it is on — and with layer names grouped into a tree, that row may be inside a collapsed group, where there is no row to mark. The pane opened on a tree with every group shut and nothing highlighted anywhere in it. A click now unfolds its way down to the layer, every group on the path and no others, which is what the shape-search and List shapes rows already did.

• Resizing a shape did not resize the shape. The handles moved, the dashed outline followed the pointer, the pin and the Width landed where they should — and the drawing was redrawn at exactly the size it already was, sitting inside a box that had grown around it.

  A Visio outline is stored one of two ways. RelMoveTo/RelLineTo and their kin hold fractions of Width and Height, so they follow the box for nothing; MoveTo/LineTo/ArcTo/NURBSTo hold inches, and in a real file those inches come with a formula — Width*0.5 — that Visio re-evaluates whenever Width changes. This app has no formula engine: it reads the number the formula last produced. Nothing re-evaluated it, so nothing moved. Every fixture in the repo happens to be drawn in fractions, which is how a resize that plainly did not resize sat behind 1,551 passing checks.

  A resize now scales the geometry rows themselves, by the rule a missing formula engine can still follow: the outline scales with the box. For the Width*k cell that is the answer Visio would have computed, to the last decimal. The formula is written back untouched beside the new number, so Visio still works the exact value out for the cells that need more than a proportion, and a shape that was parametrised stays parametrised. Rows drawn in fractions are left alone — they were never the problem. The arithmetic is per row type, since not everything in a row is a length: an arc's bulge is measured at right angles to its chord and has to be re-measured against the chord an uneven scale leaves behind, an elliptical arc's axis angle and ratio describe a different ellipse afterwards, and a spline's knots and a NURBS weight are not distances at all and do not move.

  Resizing a group also reaches all the way down now, not just to its children. A grandchild is placed in its parent's inches and inherits no scale from above, so a nested group used to keep its inner picture the size it was while the outer one grew around it.

• Letting go of a dragged shape cost what the file costs rather than what the shape costs. Moving, resizing or turning a shape was committed by rewriting the whole .vsdx, parsing it back and drawing every shape on the page from the result — on a 20 MB drawing of 8,470 shapes, 172 s of frozen tab in our headless harness to change six numbers on one shape. It threw away the selection, the folded rows of the Shape Tree and the scroll position on the way past, too.

  Group, ungroup, z-order and delete change the shape of the document — which element lives inside which, and in what order — so they still go that way. A placement does not. It changes at most six cells on a handful of shapes, and every one of them is already in memory and already on the canvas. So the model is given the numbers, the shapes that moved are drawn again and nothing else is, and the package is rewritten later — whenever something next wants the bytes (Save, Export, Compare, the shape XML editor, or an edit that does go through the package). Letting go of that shape went from 172 s to 0.09 s.

  Nor is the shape that moved drawn again. A shape's paths, its text and — for a group — everything inside it are in the shape's own coordinates: they say what the shape looks like, never where it is. Where it is, is one attribute on its group. So a move, a turn or a flip writes that attribute and stops, however much is inside the shape, and dragging a group of a thousand children costs what dragging one rectangle costs. Only a resize draws a shape again, because Width and Height scale its geometry, re-wrap its text and rescale a group's contents. The numbers the drawing is given are rounded exactly the way the writer rounds them, so what is on screen is what the file gives back: the tests drag a shape, a group, a shape nested inside a group and two shapes at once, then save, re-open and compare the transforms character for character.

• Large drawings were slow to open, slow to click and stuttered when dragging. Four things, measured on a 20 MB drawing of 8,470 shapes:

  • Three quarters of the canvas was invisible. Every shape was rendered with its Shape Data and user cells as v:custProps / v:userDefs elements — 66,734 of the page's 99,519 SVG elements — and not one of them is ever painted, or read back off the canvas. They are there for fidelity with Visio's own SVG export, so they now go on at export time instead: the canvas is 32,785 elements, a third of what it was, and renders 40% faster. Exported files are unchanged, character for character.
  • Dragging a shape re-derived the whole page, twice, per mouse event. Working out where a dragged shape would land needs the page flattened to boxes, and that was rebuilt from scratch on every event: 39 ms of arithmetic per mouse move, on a mouse that reports far faster than the screen redraws. It is built once when the drag starts — nothing in the drawing moves until the drag is let go — and the planning happens once per frame with wherever the pointer got to. That is 39 ms an event down to 0.03 ms a frame.
  • Clicking a shape re-drew the whole drawing. A selection is painted over the page — the shapes are identical whether or not one of them is selected — but selecting one rebuilt all 32,785 SVG elements, re-walked every group to reapply layer and shape visibility, and rebuilt the Shape Tree's 67,760 rows, to move one mark. It now moves the mark: the overlay is redrawn, and only the rows and groups that were marked or should be are touched. Selecting a shape went from 2.0 s to 0.2 s of work in our headless harness. The page underneath is left exactly as it was, so a selection no longer quietly re-renders at whatever zoom you had reached.
  • Opening a file spent most of its time looking for cells. Reading a shape asks for dozens of its cells by name, and each ask scanned all of that shape's children — so reading one shape scanned it dozens of times over. Each shape is indexed by cell name the first time it is asked. Opening the 20 MB drawing went from 34.5 s to 17.9 s.

• There was no way to scroll the canvas, and no scrollbars. The drawing is placed by a CSS transform rather than by scrolling — that is what keeps the vectors crisp at any zoom — and the cost of it was that the viewport was not a scrollable box: the browser drew no scrollbars, the wheel only ever zoomed, and the arrow keys did nothing. Dragging was the only way to move, and a drag went as far as the hand did, so a drawing could be flung right out of the window with nothing left on screen to say which way it had gone. So:

  • the wheel scrolls, Shift+wheel scrolls sideways, and Ctrl/⌘+wheel (and a trackpad pinch) zooms about the pointer — what Visio does, and what the browser does;
  • the arrow keys pan a step and Shift+arrow a bigger one, Page Up / Page Down move a screenful, and Home / End jump to the corners. Pressing on the canvas focuses it, so the keys reach it;
  • scrollbars are drawn at the right and bottom edges, from the same pan the drag uses. They appear only when part of the drawing is off screen; the thumb is as long as the share of the drawing you can see, and its track can be clicked to jump;
  • the drawing can no longer be lost: a pan stops when the drawing's edge meets the window's, and one smaller than the window stays inside it. A drag that runs into the edge and comes back still follows the hand rather than creeping, because it is anchored to where the press was.

  + and − now zoom about the middle of the window rather than the top-left corner, which used to walk the drawing out of view a step at a time.

• Dragging the canvas felt heavy on a large drawing. A mouse delivers moves faster than the screen refreshes, and each one wrote a transform — on a page of 8,470 shapes and 99,519 SVG elements, that is a lot of layout work thrown away unseen. Moves are now accumulated and written once on the next animation frame, and the drawing is put on its own compositor layer while a gesture is in flight so a pan moves it rather than repainting it.

• A large drawing could not be zoomed out far enough to see. Fixing the zoom blur had a consequence nobody wanted: the SVG used to be laid out at width: 100% with its natural size as a maximum, so the browser quietly shrank a big drawing to the window and "100%" meant "as big as fits". Sizing the SVG in layout made 100% mean 100% — and a Visio drawing is not necessarily a sheet of paper. A site plan in this repo is 3962 × 2618 inches, which is 380,372 renderer pixels across and fits a window at 0.32%; against a zoom floor of 10% it simply could not be pulled back far enough, and − stopped doing anything. So the floor is now 0.02%, opening a page genuinely fits it to the window (rather than fitting by accident), Fit actually fits — including magnifying a drawing smaller than the window, which it never did — and the readout no longer rounds every one of those zooms to 0%.

• Zooming blurred the whole drawing until you moved. Zoom was a scale() on the container, and scaling a composited layer does not redraw it — the compositor stretches the pixels it already has, which is why the picture went soft the moment the wheel moved and snapped back the moment you panned (a pan is what finally invalidated the layer). The scale now goes into the SVG's own layout size as soon as the gesture settles, so the browser draws the vectors at the size they are shown at. Vectors have no business being blurry at any zoom. Panning is still a transform, since a translate resamples nothing.

• The export dialog showed options that did not apply. It was hiding them — with the hidden attribute — but they were laid out with display: flex, and an author rule beats the browser's own rule for hidden. So every row the dialog thought it had folded away was on screen and fully usable: Longest side while you were exporting at original size or fit-to-screen, the SVG embed the source document checkbox while you were exporting a PDF (which cannot carry it), and the PDF library download consent while you were exporting an SVG (which downloads nothing).

• Selecting a shape behind another one looked like it had not worked. The selection was drawn as an outline on the shape's own group, and an outline is painted where the shape is painted — so picking a buried shape out of Select component or the Shape Tree drew a marker the shape in front covered up. You moved the pointer off the row, the hover box went with it, and nothing appeared to be selected. The marker is now its own overlay, drawn last, so it is on top of the drawing whatever it is selecting.

• The selection box was drawn round the shape's geometry, not round the shape. A shape's box is where its geometry lives, and the ink is not confined to it: put a 50pt stroke on a short path and most of the shape ends up outside the box that is supposed to contain it. The box now comes from where the browser actually drew the shape — stroke and all — and falls back to the geometric box only where there is nothing laid out to measure.

• The Shape Tree's ✕ did not delete anything. It removed the shape from the page held in memory, which looks identical on screen, and then Save VSDX patches the original package and skips shapes it no longer knows about — so the shape came back in the saved file. It goes through the package now, like every other edit. The row the tree opened on is deletable too; it was exempt only because the old in-memory version had nowhere to put a tree with no root.

• "Select component" missed shapes that were behind the one you clicked. The list was built from one question — which shapes' bounding boxes cover this point — asked in page inches. That leans on the app's own screen→page transform being right, and on a box standing in for the shape, which it is not once a piece is rotated or L-shaped. When it came up short there was nothing to do but send the shape on top to the back and pick what was underneath, which is a workaround for a list that failed to offer it. The browser already knows the answer for what it drew: elementsFromPoint returns the whole stack at a point, completely covered entries included, hit-tested against the real outline with none of our arithmetic in the way. Both questions are now asked and the answers merged, deduplicated and put back in paint order. Where the browser has no such API, the box test still answers on its own, exactly as before.

• Shapes on a background page could be seen but not picked. A page that names a background page is drawn as that page's shapes with its own on top — the renderer has always merged the two. Everything that answered "what is under the cursor", though, asked the foreground page alone, so a title block or frame living on the backdrop was a shape you could see, right-click straight through, and never reach: Select component offered the shapes in front of it and nothing behind. The hit test now runs against the page as drawn. Backdrop shapes are listed and marked background, hover highlights them and clicking selects them; the rest of the menu then says the shape belongs to the background page instead of offering it one of this page's layers, whose numbering means nothing to it.

• Closed sheet tabs came back when you pruned the drawing. Remove Non-selected and Remove Non-visible pruned the file bytes as they were last parsed, then re-read the result — so every page you had closed, every sheet you had renamed or reordered, and any tag colours or named views you had not saved came back with it. Both now prune the package with your pending edits already written into it, the same step the pen, arrange and XML-edit paths already took.

• Hand-editing a shape's XML no longer resets the layers. Applying a shape edit rebuilds the package and re-parses it, and the sidebar is rebuilt from the result — but layer visibility toggles, renames, tags and per-shape layer moves live only in memory until something writes them out, so the edit was applied to the file as opened and the re-parse reverted them. Those pending edits are now folded into the package first (the same step the prune paths already did for themselves), and the editor-only "Unlayered" row — which has nowhere to live in the file — is carried across the re-parse by hand.

• Hairlines no longer vanish on scaled drawings. Visio's LineWeight 0 (hairline) was floored at a constant 0.5 units, which is meaningless in a scaled drawing's coordinate space — on a 1:100 plan that is 1/19200 of an inch, so whole layers drawn with hairlines (raised-floor grids, construction lines) rendered as nothing. The floor is now Visio's own 0.25 pt, scaled with the drawing.

• Hatch fills are drawn as hatches. FillPattern 2–24 were painted as an opaque solid in the fill's foreground colour, turning stippled squares into black blocks and flooding shaded areas. They are now emitted as vector SVG <pattern> definitions (Visio's 6 pt tile, 8×8 cells), honouring the fill's background colour and both transparencies. Patterns 2–7, 11 and 24 match a Visio 16 export cell for cell.

• Dashed lines are dashed. getDashArray only knew LinePattern 1–5 and drew everything else solid; all 23 built-in patterns are now defined, with dash runs measured in line weights as Visio does, and a round cap so dash-dot patterns show their dots.

Added

• Hairlines toolbar control — choose between Fit zoom (no line thinner than a screen pixel at the rendered zoom, the default) and True size (real Visio weights), plus an ⟳ Update button that re-renders the page for the current zoom. The minimum is baked into the SVG, so it is applied on demand rather than on every wheel tick; the button highlights when the view has been zoomed away from the render.
• Layer tags — assign free-form, comma-separated tags to layers from the Layers sidebar (🏷 on a layer row) or the new Tags column in the Layer Matrix. Tags are per page, trimmed, and de-duplicated case-insensitively.
• Tag colours — each tag gets a document-wide colour (derived from its name until you pick one) shown on the sidebar chips; recolour it from the swatch in the Tags legend of the sidebar or the Layer Matrix.
• Filter by tag — the layer search box now matches tags as well as layer names, and tag:<name> restricts matching to tags, so Select filter / Deselect filter can show or hide everything carrying a tag at once. Clicking a tag in the legend fills the box.
• Tags and their colours are stored inside the drawing in Visio's Solution XML store, the channel that survives a Microsoft Visio open+save (see docs/visio-roundtrip.md), keyed by layer name so they outlive layer renumbering. Every save path (save, prune, SVG export) carries them along.

[0.0.4] - 2026-08-03

Fixed

• Referenced unnamed layer rows are shown as muted italic Layer <index> entries instead of being discarded with unused Visio placeholders, so bulk layer hiding also affects their shapes.
• Added an editor-only Unlayered layer for controlling shapes without Visio layer membership. Its settings can be captured in named views without adding a synthetic layer to the Visio document.
• Layers hidden in the original Visio file can now be revealed immediately in the live viewer; clearing the runtime CSS state also removes the SVG display="none" presentation attribute created during initial rendering.

0.0.3 — 2026-08-01

Added

• Additional Visio formats — open drawings (.vsdx, .vsdm, .vsd), templates (.vstx, .vstm, .vst), and stencils (.vssx, .vssm, .vss). XML stencil masters and binary stencil masters where available are exposed as read-only sheets. XML drawings and templates remain editable, retain macro/package contents, and keep their original extension when saved or embedded in an SVG export.
• Layer Matrix page filter — the matrix can now be narrowed to a single page (or shown across all pages); Replace all respects the filter.
• The Named views section of the layers sidebar now explains where views are stored (inside the .vsdx on Save VSDX).
• Named views in the Layer Matrix — create, apply, update, and delete view presets without returning to the Layers sidebar.
• Sheet tab controls — delete sheets with the tab's ×, drag tabs to reorder sheets, and right-click for rename, close-left, close-right, close-others, and close-this actions.

Changed

• Search discovery metadata — the GitHub Pages site now publishes canonical URLs, page-specific descriptions, social metadata, SoftwareApplication structured data, and an XML sitemap.
• Named views now preserve complete layer state, including visibility, print, active, lock, snap, and glue settings. Existing visibility-only views remain compatible.
• Sheet renames, ordering, and deletions are persisted into saved/exported VSDX documents, including relationship and named-view cleanup.
• Website / front page on GitHub Pages: a landing page (index.html) with a features overview and links, plus rendered How-to, Changelog, and Download pages sharing a common nav. The app itself moved to app.html.
• Portable offline downloads for Windows and Linux: npm run package:portable inlines the whole app into a single self-contained vsdxeditor.html and zips it per platform with a launcher (scripts/build-portable.mjs).
• Release workflow — pushing a v* tag builds the portable zips and publishes them to a GitHub Release automatically (.github/workflows/release.yml).

Changed

• The live app URL is now …/app.html; the site root is the new landing page.
• git vsdxdiff / the difftool server now serves the app from app.html.

0.0.2 — 2026-07-03

Added

• git vsdxdiff — a git difftool that opens the browser visual diff (overlay + side-by-side) for two revisions of a .vsdx, serving the app and both versions from a throwaway localhost server (scripts/git-difftool-serve.mjs).
• App auto-loads a comparison from URL query params (?base=…&head=… / ?file=…), used by the difftool.
• vsdx:install-difftool now also registers the difftool and the git vsdxdiff alias (moved into scripts/install-git-integration.mjs).

0.0.1 — 2026-07-03

First tagged release.

Added

• Browser-based viewer for Visio .vsdx and legacy .vsd files, rendering each page to SVG with multi-page tabs, zoom (in/out/fit), and pan.
• Layers: visibility sidebar with search/filter, and a full Layer Visibility Matrix for bulk toggling and layer renaming (Replace all).
• Shape Tree panel showing a shape's group hierarchy and inherited style.
• Per-shape XML editing and Send Object To Layer via a shape context menu.
• Document pruning: Remove Non-visible and Remove Non-selected shapes.
• Export SVG of a page and Save VSDX with edits applied.
• Visual compare of two .vsdx files (overlay + side-by-side diff) highlighting added/removed/moved/modified shapes and layer changes.
• git toolchain for .vsdx: deterministic canonical serialization, a git diff textconv driver (readable XML instead of "Binary files differ"), and a real 3-way git merge driver, with a Zip Slip guard.
• .vsdx CLI: vsdx:unpack, vsdx:pack, vsdx:verify.
• Test suites for the diff engine and diff view (npm test).
• Automatic GitHub Pages deployment.