# Official draw.io Style Reference Mirror

- Source URL: https://github.com/jgraph/drawio-mcp/blob/main/shared/style-reference.md
- Upstream repository: https://github.com/jgraph/drawio-mcp
- Mirrored on: 2026-04-04
- Sync method: copy the upstream file into this directory, then keep this header and preserve the upstream body below unchanged unless a local note is absolutely required

---

# draw.io Style Reference for AI File Generation

This document is a companion to [`mxfile.xsd`](https://github.com/jgraph/drawio-mcp/blob/main/shared/mxfile.xsd) and provides all information
needed to programmatically generate valid draw.io (.drawio) files. All data
was extracted from the draw.io source code.

See also: [Generate and validate draw.io diagrams with AI](https://www.drawio.com/doc/faq/ai-drawio-generation)

---

## 1. File Structure Overview

A minimal valid draw.io file:

```xml
<mxfile>
  <diagram id="page-1" name="Page-1">
    <mxGraphModel dx="0" dy="0" grid="1" gridSize="10" guides="1"
                  tooltips="1" connect="1" arrows="1" fold="1"
                  page="1" pageScale="1" pageWidth="850" pageHeight="1100"
                  math="0" shadow="0">
      <root>
        <!-- Root container (always required, always id="0") -->
        <mxCell id="0" />
        <!-- Default layer (always required, always id="1", parent="0") -->
        <mxCell id="1" parent="0" />
        <!-- Diagram elements go here with parent="1" -->
      </root>
    </mxGraphModel>
  </diagram>
</mxfile>
```

### Critical Rules

1. **The first two mxCell elements are mandatory structural cells:**
   - `id="0"` — root container, no parent attribute
   - `id="1"` with `parent="0"` — default layer
2. **All diagram elements must have `parent="1"`** (or the id of a group/layer).
3. **IDs must be unique** within the diagram. Use any string (e.g. "2", "node-1", "abc123").
4. **Vertices need `vertex="1"`**, edges need `edge="1"`** — these are mutually exclusive.
5. **Edges should reference source and target** via cell IDs. Edges without connections need explicit mxPoint sourcePoint/targetPoint.
6. **Always use uncompressed XML** (no `compressed="true"`). AI should not generate compressed content.
7. **Style strings end with semicolon.** Example: `"rounded=1;whiteSpace=wrap;html=1;"`
8. **Coordinates: origin (0,0) is top-left**, x increases rightward, y increases downward.

---

## 2. Style String Format

The `style` attribute on mxCell is a **semicolon-separated list of key=value pairs**:

```
key1=value1;key2=value2;key3=value3;
```

A **style class name** or **shape name** can appear as a bare token (without `=`):

```
ellipse;whiteSpace=wrap;html=1;fillColor=#DAE8FC;
```

Here `ellipse` sets the shape. Multiple bare tokens are possible for style class inheritance:

```
text;html=1;align=left;
```

### Rules
- Keys and values are **case-sensitive**
- **No spaces** around `=` or `;`
- Boolean values use `0` and `1` (not true/false)
- Colors use `#RRGGBB` hex format (with `#`), `none`, or `default`
- The trailing `;` is conventional but not strictly required
- Unknown keys are silently ignored

---

## 3. Shape Types

### 3.1 Core mxGraph Shapes

These shapes are defined in the mxGraph core library:

| shape= value | Description | Notes |
|---|---|---|
| `rectangle` | Rectangle (default) | Also the default if no shape specified |
| `ellipse` | Oval / ellipse | Use `aspect=fixed` for circle |
| `rhombus` | Diamond | Use `perimeter=rhombusPerimeter` |
| `triangle` | Triangle | Use `perimeter=trianglePerimeter` |
| `hexagon` | Hexagon | Use `perimeter=hexagonPerimeter2` |
| `cloud` | Cloud | |
| `cylinder` | 3D Cylinder | |
| `line` | Horizontal line | |
| `arrow` | Block arrow | |
| `arrowConnector` | Arrow-shaped connector | |
| `doubleEllipse` | Double-bordered ellipse | |
| `image` | Image container | Requires `image=<url>` |
| `label` | Rectangle with icon area | Default vertex shape |
| `swimlane` | Container with header bar | Use `startSize` for header height |
| `actor` | Actor (stick figure outline) | |
| `connector` | Edge connector | Default edge shape |

### 3.2 Extended Shapes (draw.io Shapes.js)

These are registered via `mxCellRenderer.registerShape()`:

| shape= value | Description |
|---|---|
| `cube` | 3D cube |
| `isoCube` | Isometric cube |
| `isoCube2` | Isometric cube (variant 2) |
| `isoRectangle` | Isometric rectangle |
| `cylinder2` | Cylinder (variant 2, configurable) |
| `cylinder3` | Cylinder (variant 3) |
| `datastore` | Cylindrical data store |
| `note` | Sticky note |
| `note2` | Note (variant 2) |
| `document` | Document page with curled bottom |
| `folder` | Folder icon |
| `card` | Card with cut corner |
| `tape` | Punched tape |
| `tapeData` | Tape data storage |
| `process` | Process box (double-sided borders) |
| `process2` | Same as process |
| `step` | Step/chevron arrow |
| `plus` | Plus sign |
| `ext` | Extended rectangle (supports `double=1`) |
| `callout` | Speech bubble |
| `parallelogram` | Parallelogram (use `perimeter=parallelogramPerimeter`) |
| `trapezoid` | Trapezoid (use `perimeter=trapezoidPerimeter`) |
| `curlyBracket` | Curly bracket |
| `switch` | Networking switch shape |
| `transparent` | Invisible shape |
| `message` | Envelope/message |
| `corner` | L-shaped corner |
| `crossbar` | Cross bar |
| `tee` | T-shaped connector |
| `singleArrow` | Single arrow |
| `doubleArrow` | Double-headed arrow |
| `flexArrow` | Flexible arrow |
| `wire` | Wire connector |
| `waypoint` | Waypoint marker |
| `manualInput` | Manual input (flowchart) |
| `internalStorage` | Internal storage (flowchart) |
| `dataStorage` | Data storage (flowchart) |
| `loopLimit` | Loop limit (flowchart) |
| `offPageConnector` | Off-page connector |
| `delay` | Delay shape |
| `display` | Display device |
| `or` | OR gate |
| `orEllipse` | OR ellipse |
| `xor` | XOR gate |
| `sumEllipse` | Sum/sigma ellipse |
| `sortShape` | Sort shape |
| `collate` | Collate shape |
| `cross` | Cross / X shape |
| `dimension` | Dimension line |
| `partialRectangle` | Rectangle with configurable borders |
| `lineEllipse` | Line with ellipse |
| `link` | Link / chain shape |
| `pipe` | Pipe connector |
| `zigzag` | Zigzag connector |
| `filledEdge` | Filled edge connector |
| `table` | Table container |
| `tableRow` | Table row |
| `tableLine` | Table line |
| `rect2` | Alternative rectangle |

### 3.3 UML Shapes

| shape= value | Description |
|---|---|
| `umlActor` | UML stick figure |
| `umlBoundary` | UML boundary |
| `umlEntity` | UML entity |
| `umlDestroy` | UML destruction mark |
| `umlControl` | UML control |
| `umlLifeline` | UML lifeline |
| `umlFrame` | UML frame |
| `umlState` | UML state (use `perimeter=mxPerimeter.StatePerimeter`) |
| `lollipop` | UML provided interface |
| `requires` | UML required interface |
| `requiredInterface` | UML required interface (arc) |
| `providedRequiredInterface` | UML assembly connector |
| `module` | UML module |
| `component` | UML component |
| `associativeEntity` | ER associative entity |
| `endState` | State diagram end state |
| `startState` | State diagram start state |

### 3.4 Stencil Libraries

Additional shapes are available via stencil libraries in the `stencils/` directory.
Use with: `shape=stencil(<library>.<shape>)` or `shape=mxgraph.<library>.<shape>`.

Major libraries:
- `mxgraph.flowchart.*` — Flowchart shapes
- `mxgraph.bpmn.*` — BPMN shapes
- `mxgraph.aws4.*` — AWS architecture icons
- `mxgraph.azure.*` — Azure architecture icons
- `mxgraph.gcp.*` / `mxgraph.gcp2.*` — Google Cloud icons
- `mxgraph.cisco.*` / `mxgraph.cisco19.*` — Cisco networking
- `mxgraph.kubernetes.*` — Kubernetes icons
- `mxgraph.uml.*` — UML shapes
- `mxgraph.er.*` — Entity-relationship shapes
- `mxgraph.electrical.*` — Electrical engineering symbols
- `mxgraph.pid.*` — Piping and instrumentation
- `mxgraph.mockup.*` — UI wireframe components
- `mxgraph.lean_mapping.*` — Lean mapping
- `mxgraph.eip.*` — Enterprise integration patterns

---

## 4. Style Properties Reference

### 4.1 Fill and Stroke

| Property | Values | Default | Description |
|---|---|---|---|
| `fillColor` | `#RRGGBB`, `none`, `default` | `default` | Shape fill color |
| `gradientColor` | `#RRGGBB`, `none` | none | Gradient end color (gradient from fillColor to gradientColor) |
| `gradientDirection` | `north`, `south`, `east`, `west` | `south` | Gradient direction |
| `strokeColor` | `#RRGGBB`, `none`, `default` | `default` | Border/stroke color |
| `strokeWidth` | number | `1` | Border width in pixels |
| `dashed` | `0`, `1` | `0` | Dashed stroke |
| `dashPattern` | string | — | Dash pattern, e.g. `"1 3"` (1px dash, 3px gap), `"8 8"` |
| `opacity` | `0`–`100` | `100` | Overall opacity (0=transparent, 100=opaque) |
| `fillOpacity` | `0`–`100` | `100` | Fill opacity only |
| `strokeOpacity` | `0`–`100` | `100` | Stroke opacity only |
| `glass` | `0`, `1` | `0` | Glass/shine overlay effect |
| `shadow` | `0`, `1` | `0` | Drop shadow (also controlled globally on mxGraphModel) |

### 4.2 Shape Geometry

| Property | Values | Default | Description |
|---|---|---|---|
| `shape` | see Shape Types above | `label` | Shape type |
| `perimeter` | see Perimeters below | `rectanglePerimeter` | Connection point calculation |
| `rounded` | `0`, `1` | `0` | Round rectangle corners |
| `arcSize` | number | — | Corner radius for rounded shapes (0–50, as percentage) |
| `aspect` | `variable`, `fixed` | `variable` | `fixed` preserves width/height ratio |
| `direction` | `north`, `south`, `east`, `west` | — | Rotate shape by 90° increments |
| `flipH` | `0`, `1` | `0` | Flip horizontally |
| `flipV` | `0`, `1` | `0` | Flip vertically |
| `rotation` | number (degrees) | `0` | Free rotation angle (0–360) |
| `fixedSize` | `0`, `1` | `0` | Shape keeps size independent of label |

### 4.3 Text and Labels

| Property | Values | Default | Description |
|---|---|---|---|
| `html` | `0`, `1` | `1` | Enable HTML label rendering |
| `whiteSpace` | `wrap`, `nowrap` | — | Text wrapping mode. Use `wrap` for most shapes |
| `fontSize` | number | `12` | Font size in pixels |
| `fontFamily` | string | `Helvetica` | Font family name |
| `fontColor` | `#RRGGBB`, `default` | `default` | Text color |
| `fontStyle` | bitmask | `0` | Font style: 0=normal, 1=bold, 2=italic, 4=underline (combine by adding: 3=bold+italic) |
| `align` | `left`, `center`, `right` | `center` | Horizontal text alignment |
| `verticalAlign` | `top`, `middle`, `bottom` | `middle` | Vertical text alignment |
| `labelPosition` | `left`, `center`, `right` | `center` | Horizontal label position relative to shape |
| `verticalLabelPosition` | `top`, `middle`, `bottom` | `middle` | Vertical label position relative to shape |
| `overflow` | `visible`, `hidden`, `fill`, `width` | — | Text overflow handling |
| `spacing` | number | `2` | General padding in pixels |
| `spacingTop` | number | `0` | Top padding |
| `spacingBottom` | number | `0` | Bottom padding |
| `spacingLeft` | number | `0` | Left padding |
| `spacingRight` | number | `0` | Right padding |
| `textOpacity` | `0`–`100` | `100` | Text opacity |
| `labelBackgroundColor` | `#RRGGBB`, `none`, `default` | — | Background behind text (useful for edge labels) |
| `labelBorderColor` | `#RRGGBB`, `none` | — | Border around label |
| `labelWidth` | number | — | Fixed label width |
| `textDirection` | `default`, `ltr`, `rtl` | `default` | Text direction |
| `horizontal` | `0`, `1` | `1` | `0` for vertical text |

### 4.4 Edge / Connector Properties

| Property | Values | Default | Description |
|---|---|---|---|
| `edgeStyle` | see Edge Styles below | — | Routing algorithm |
| `curved` | `0`, `1` | `0` | Curved edge path |
| `rounded` | `0`, `1` | `1` | Round edge corners (for orthogonal) |
| `jettySize` | `auto`, number | `auto` | Spacing from port for orthogonal edges |
| `sourceJettySize` | number | — | Source-side jetty override |
| `targetJettySize` | number | — | Target-side jetty override |
| `orthogonalLoop` | `0`, `1` | `1` | Self-loop routing style |
| `elbow` | `horizontal`, `vertical` | — | Elbow edge direction |
| `jumpStyle` | `arc`, `gap`, `sharp` | — | Line crossing visualization |
| `jumpSize` | number | `6` | Jump width at crossings |

### 4.5 Arrow Markers

| Property | Values | Default | Description |
|---|---|---|---|
| `startArrow` | arrow type | `none` | Marker at edge start |
| `endArrow` | arrow type | `classic` | Marker at edge end |
| `startSize` | number | — | Start marker size |
| `endSize` | number | — | End marker size |
| `startFill` | `0`, `1` | `1` | Fill start marker |
| `endFill` | `0`, `1` | `1` | Fill end marker |

**Arrow type values:**

| Value | Description |
|---|---|
| `none` | No arrow |
| `classic` | Standard filled triangle |
| `classicThin` | Thin triangle |
| `block` | Filled block |
| `blockThin` | Thin block |
| `open` | Open (unfilled) triangle |
| `openThin` | Thin open triangle |
| `oval` | Circle/oval |
| `diamond` | Diamond |
| `diamondThin` | Thin diamond |
| `box` | Square box |
| `halfCircle` | Half circle |
| `circle` | Circle |
| `circlePlus` | Circle with plus |
| `cross` | Cross mark |
| `baseDash` | Perpendicular dash |
| `doubleBlock` | Double filled block |
| `dash` | Short dash |
| `async` | Asynchronous (half-arrow) |
| `openAsync` | Open asynchronous arrow |
| `manyOptional` | ER many-optional (crow's foot) |

**Fill behavior:** `startFill=0`/`endFill=0` renders the marker as an outline only. This is important for UML and ER diagram conventions (e.g., open diamond = aggregation, filled diamond = composition).

### 4.6 Connection Points

| Property | Values | Default | Description |
|---|---|---|---|
| `exitX` | `0.0`–`1.0` | — | Relative x of exit point (0=left, 0.5=center, 1=right) |
| `exitY` | `0.0`–`1.0` | — | Relative y of exit point (0=top, 0.5=middle, 1=bottom) |
| `exitDx` | number | — | Absolute x offset from exit point |
| `exitDy` | number | — | Absolute y offset from exit point |
| `exitPerimeter` | `0`, `1` | `1` | Use perimeter for exit point |
| `entryX` | `0.0`–`1.0` | — | Relative x of entry point |
| `entryY` | `0.0`–`1.0` | — | Relative y of entry point |
| `entryDx` | number | — | Absolute x offset from entry point |
| `entryDy` | number | — | Absolute y offset from entry point |
| `entryPerimeter` | `0`, `1` | `1` | Use perimeter for entry point |
| `portConstraint` | `eastwest`, `northsouth`, `perimeter`, `fixed` | — | Port constraint |

### 4.7 Container / Swimlane Properties

| Property | Values | Default | Description |
|---|---|---|---|
| `container` | `0`, `1` | `0` | Cell is a container (children can be placed inside) |
| `collapsible` | `0`, `1` | `1` | Container can be collapsed |
| `recursiveResize` | `0`, `1` | `1` | Resize children when container resizes |
| `swimlaneFillColor` | `#RRGGBB` | — | Swimlane header fill color |
| `startSize` | number | `23` | Swimlane header height in pixels |
| `horizontal` | `0`, `1` | `1` | Swimlane orientation (1=header on top, 0=header on left) |
| `childLayout` | `stackLayout`, `treeLayout`, `flowLayout` | — | Auto-layout for children |
| `resizeParent` | `0`, `1` | — | Parent resizes to fit children |
| `resizeParentMax` | `0`, `1` | — | Limit parent resize |
| `resizeLast` | `0`, `1` | — | Last child fills remaining space |
| `horizontalStack` | `0`, `1` | — | Stack direction (1=horizontal, 0=vertical) |
| `marginBottom` | number | — | Bottom margin for stack layout |

### 4.8 Image Properties

| Property | Values | Default | Description |
|---|---|---|---|
| `image` | URL string | — | Image URL (data: URIs also supported) |
| `imageWidth` | number | `42` | Image width |
| `imageHeight` | number | `42` | Image height |
| `imageAlign` | `left`, `center`, `right` | — | Image horizontal alignment |
| `imageVerticalAlign` | `top`, `middle`, `bottom` | — | Image vertical alignment |
| `imageAspect` | `0`, `1` | `1` | Preserve image aspect ratio |

### 4.9 Sketch / Hand-Drawn Style

| Property | Values | Default | Description |
|---|---|---|---|
| `sketch` | `0`, `1` | `0` | Enable hand-drawn/sketch style (uses rough.js) |
| `comic` | `0`, `1` | `0` | Comic book style |
| `fillStyle` | `solid`, `hachure`, `cross-hatch`, `dots` | — | Fill pattern for sketch mode |
| `fillWeight` | number | — | Hatch line weight (negative = thinner) |
| `hachureGap` | number | — | Gap between hatch lines in pixels |
| `hachureAngle` | number (degrees) | — | Angle of hatch lines |
| `jiggle` | number | — | Hand-drawn jiggle amount |
| `curveFitting` | `0`–`1` | — | Curve fitting quality |
| `simplification` | `0`–`1` | — | Path simplification |
| `disableMultiStroke` | `0`, `1` | — | Disable double-stroke effect |
| `disableMultiStrokeFill` | `0`, `1` | — | Disable double-stroke fill |

### 4.10 Behavior Properties

| Property | Values | Default | Description |
|---|---|---|---|
| `movable` | `0`, `1` | `1` | Allow moving |
| `resizable` | `0`, `1` | `1` | Allow resizing |
| `rotatable` | `0`, `1` | `1` | Allow rotation |
| `bendable` | `0`, `1` | `1` | Allow bending edges |
| `editable` | `0`, `1` | `1` | Allow label editing |
| `deletable` | `0`, `1` | `1` | Allow deletion |
| `cloneable` | `0`, `1` | `1` | Allow cloning |
| `foldable` | `0`, `1` | — | Allow fold/collapse |
| `connectable` | `0`, `1` | `1` | Allow connections |
| `pointerEvents` | `0`, `1` | `1` | Enable mouse events |
| `autosize` | `0`, `1` | `0` | Auto-size to fit content |

---

## 5. Edge Styles (Routing Algorithms)

| edgeStyle= value | Description |
|---|---|
| `orthogonalEdgeStyle` | Routes with right-angle turns (most common) |
| `segmentEdgeStyle` | Manual segments with horizontal/vertical segments |
| `elbowEdgeStyle` | Single elbow (one bend). Combine with `elbow=horizontal` or `elbow=vertical` |
| `entityRelationEdgeStyle` | Entity-relationship style (perpendicular exits) |
| `isometricEdgeStyle` | Isometric diagram routing |
| `loopEdgeStyle` | Self-referencing loop |
| `sideToSideEdgeStyle` | Side-to-side connection |
| `topToBottomEdgeStyle` | Top-to-bottom connection |
| (empty/none) | Straight line, no routing |

**Common edge style combinations:**

```
edgeStyle=orthogonalEdgeStyle;rounded=1;         # Rounded orthogonal (default-like)
edgeStyle=orthogonalEdgeStyle;curved=1;           # Curved orthogonal
edgeStyle=elbowEdgeStyle;elbow=horizontal;        # Horizontal elbow
edgeStyle=entityRelationEdgeStyle;                # ER-style connections
edgeStyle=none;                                    # Straight line
```

---

## 6. Perimeter Types

The perimeter determines how connection points are calculated on a shape's border:

| perimeter= value | Use with |
|---|---|
| `rectanglePerimeter` | Rectangles (default) |
| `ellipsePerimeter` | Ellipses, circles |
| `rhombusPerimeter` | Diamond shapes |
| `trianglePerimeter` | Triangles |
| `hexagonPerimeter2` | Hexagons |
| `parallelogramPerimeter` | Parallelograms |
| `trapezoidPerimeter` | Trapezoids |
| `calloutPerimeter` | Callout/speech bubbles |
| `backbonePerimeter` | Backbone/bus shapes |
| `centerPerimeter` | Single center point |
| `stepPerimeter` | Step/chevron shapes |

**Important:** When using non-rectangular shapes, always set the matching perimeter. Otherwise edges will connect to the rectangular bounding box instead of the visible shape border.

---

## 7. Predefined Style Classes

These class names can be used as bare tokens in the style string. They set multiple style properties at once:

| Class | Sets |
|---|---|
| `text` | No fill, no stroke, left-aligned, top-aligned |
| `edgeLabel` | Extends text, adds label background, font size 11 |
| `label` | Bold, left-aligned, with image area (42x42), rounded |
| `icon` | Extends label, centered image above text |
| `swimlane` | Swimlane shape, bold, header size 23 |
| `group` | No fill, no stroke, transparent container |
| `ellipse` | Ellipse shape with ellipsePerimeter |
| `rhombus` | Diamond shape with rhombusPerimeter |
| `triangle` | Triangle shape with trianglePerimeter |
| `line` | Line shape, strokeWidth=4 |
| `image` | Image shape with label below |
| `arrow` | Arrow shape, no edge routing |

### Color Theme Classes

Each sets `fillColor`, `gradientColor`, `strokeColor`, plus `shadow=1` and `glass=1`:

| Class | fillColor | gradientColor | strokeColor |
|---|---|---|---|
| `blue` | #DAE8FC | #7EA6E0 | #6C8EBF |
| `green` | #D5E8D4 | #97D077 | #82B366 |
| `yellow` | #FFF2CC | #FFD966 | #D6B656 |
| `orange` | #FFCD28 | #FFA500 | #D79B00 |
| `red` | #F8CECC | #EA6B66 | #B85450 |
| `pink` | #E6D0DE | #B5739D | #996185 |
| `purple` | #E1D5E7 | #8C6C9C | #9673A6 |
| `gray` | #F5F5F5 | #B3B3B3 | #666666 |
| `turquoise` | #D5E8D4 | #67AB9F | #6A9153 |

`plain-*` variants (e.g. `plain-blue`) set the same colors without shadow and glass.

---

## 8. Common Color Palettes

### Standard draw.io Colors

These are commonly used in the draw.io UI:

**Fill colors (light):**
- `#DAE8FC` (light blue)
- `#D5E8D4` (light green)
- `#FFF2CC` (light yellow)
- `#F8CECC` (light red)
- `#E1D5E7` (light purple)
- `#E6D0DE` (light pink)
- `#F5F5F5` (light gray)
- `#FFCD28` (orange)
- `#FFE6CC` (light orange)

**Stroke colors (matching):**
- `#6C8EBF` (blue)
- `#82B366` (green)
- `#D6B656` (yellow/gold)
- `#B85450` (red)
- `#9673A6` (purple)
- `#996185` (pink)
- `#666666` (gray)
- `#D79B00` (orange)

**Font/accent colors:**
- `#000000` (black)
- `#FFFFFF` (white)
- `#333333` (dark gray)
- `#0000EE` (link blue)

### Special Color Values

- `none` — transparent / no color (removes fill or stroke)
- `default` — uses the current theme's default (resolves at render time)

---

## 9. HTML Labels

When `html=1` is set in the style, the cell's `value` attribute can contain HTML:

### Supported HTML Elements
- `<b>`, `<i>`, `<u>`, `<s>` — text formatting
- `<br>` / `<br/>` — line break
- `<p>`, `<div>`, `<span>` — block/inline containers
- `<font>` — font attributes (face, size, color)
- `<table>`, `<tr>`, `<td>`, `<th>` — tables
- `<ul>`, `<ol>`, `<li>` — lists
- `<hr>` — horizontal rule
- `<img>` — inline images (with src attribute)
- `<a>` — links (href attribute)
- `<sub>`, `<sup>` — subscript/superscript

### HTML in Attributes

HTML in the `value` attribute must be **XML-escaped**:
- `<` → `&lt;`
- `>` → `&gt;`
- `&` → `&amp;`
- `"` → `&quot;`

Example:
```xml
<mxCell value="&lt;b&gt;Title&lt;/b&gt;&lt;br&gt;Description"
        style="rounded=1;whiteSpace=wrap;html=1;" vertex="1" parent="1">
```

### Common HTML Patterns

**Bold title with description:**
```
&lt;b&gt;Title&lt;/b&gt;&lt;br&gt;Description text
```

**UML class box (within table container):**
```
&lt;p style=&quot;margin:0px;margin-top:4px;text-align:center;&quot;&gt;&lt;b&gt;ClassName&lt;/b&gt;&lt;/p&gt;
&lt;hr size=&quot;1&quot;/&gt;
&lt;p style=&quot;margin:0px;margin-left:4px;&quot;&gt;+ field: Type&lt;/p&gt;
&lt;hr size=&quot;1&quot;/&gt;
&lt;p style=&quot;margin:0px;margin-left:4px;&quot;&gt;+ method(): ReturnType&lt;/p&gt;
```

**Colored text:**
```
&lt;font color=&quot;#FF0000&quot;&gt;Red text&lt;/font&gt;
```

---

## 10. Layers

Layers are additional mxCell elements with `parent="0"`:

```xml
<root>
  <mxCell id="0" />
  <mxCell id="1" parent="0" />               <!-- Default layer -->
  <mxCell id="layer2" value="Background" parent="0" />  <!-- Additional layer -->

  <!-- Elements on default layer -->
  <mxCell id="2" ... parent="1" />

  <!-- Elements on "Background" layer -->
  <mxCell id="3" ... parent="layer2" />
</root>
```

To hide a layer: add `visible="0"` to the layer cell.

---

## 11. Groups and Containers

A group/container is a vertex that other cells reference as their parent:

```xml
<!-- Group container -->
<mxCell id="group1" value="Group" style="group;" vertex="1" parent="1">
  <mxGeometry x="100" y="100" width="300" height="200" as="geometry" />
</mxCell>

<!-- Children reference the group as parent -->
<mxCell id="child1" value="Inside" style="rounded=1;html=1;" vertex="1" parent="group1">
  <mxGeometry x="10" y="10" width="100" height="40" as="geometry" />
</mxCell>
```

**Key points:**
- Child coordinates are **relative to the parent container**
- Use `style="group;"` for invisible containers
- Use `style="swimlane;startSize=30;"` for containers with a visible header
- Add `container=1;` to any style to make it act as a container
- `collapsible=0;` prevents the collapse/expand button

### Collapsible Containers and Alternate Bounds

When a container (e.g. swimlane) is collapsible, draw.io stores alternate bounds
in an `mxRectangle` child element inside `mxGeometry`. When the container is
collapsed/expanded, the geometry swaps between the normal and alternate bounds:

```xml
<mxCell id="class1" value="ClassName" style="swimlane;fontStyle=1;childLayout=stackLayout;startSize=26;collapsible=1;" vertex="1" parent="1">
  <mxGeometry x="100" y="100" width="200" height="150" as="geometry">
    <mxRectangle x="100" y="100" width="200" height="26" as="alternateBounds" />
  </mxGeometry>
</mxCell>
```

The `alternateBounds` typically has the same x/y but a smaller height (just the header).
AI generators generally do not need to produce `mxRectangle` elements — draw.io adds
them automatically when the user collapses a container.

---

## 12. Edge Geometry and Labels

### Basic Connected Edge

```xml
<mxCell id="e1" value="" style="endArrow=classic;html=1;"
        edge="1" parent="1" source="v1" target="v2">
  <mxGeometry relative="1" as="geometry" />
</mxCell>
```

### Edge with Waypoints

```xml
<mxCell id="e2" value="" style="edgeStyle=orthogonalEdgeStyle;html=1;"
        edge="1" parent="1" source="v1" target="v2">
  <mxGeometry relative="1" as="geometry">
    <Array as="points">
      <mxPoint x="300" y="150" />
      <mxPoint x="300" y="250" />
    </Array>
  </mxGeometry>
</mxCell>
```

### Edge with Label

Edge labels are usually encoded in the edge cell's `value`. The label position is controlled by the geometry:

```xml
<mxCell id="e3" value="label text" style="endArrow=classic;html=1;"
        edge="1" parent="1" source="v1" target="v2">
  <mxGeometry x="-0.5" y="0" relative="1" as="geometry">
    <mxPoint as="offset" />
  </mxGeometry>
</mxCell>
```

- `x` on geometry: position along edge (-1 to 1, where 0 = center, -1 = near source, 1 = near target)
- `y` on geometry: perpendicular offset in pixels

### Unconnected Edge (Floating)

```xml
<mxCell id="e4" value="" style="endArrow=classic;html=1;"
        edge="1" parent="1">
  <mxGeometry relative="1" as="geometry">
    <mxPoint x="100" y="200" as="sourcePoint" />
    <mxPoint x="300" y="100" as="targetPoint" />
  </mxGeometry>
</mxCell>
```

---

## 13. Complete Examples

### Example 1: Simple Flowchart

```xml
<mxfile>
  <diagram id="flowchart" name="Flowchart">
    <mxGraphModel dx="0" dy="0" grid="1" gridSize="10" guides="1"
                  tooltips="1" connect="1" arrows="1" fold="1"
                  page="1" pageScale="1" pageWidth="850" pageHeight="1100">
      <root>
        <mxCell id="0" />
        <mxCell id="1" parent="0" />

        <!-- Start -->
        <mxCell id="start" value="Start" style="ellipse;whiteSpace=wrap;html=1;fillColor=#D5E8D4;strokeColor=#82B366;" vertex="1" parent="1">
          <mxGeometry x="340" y="40" width="120" height="60" as="geometry" />
        </mxCell>

        <!-- Decision -->
        <mxCell id="decision" value="Condition?" style="rhombus;whiteSpace=wrap;html=1;fillColor=#FFF2CC;strokeColor=#D6B656;" vertex="1" parent="1">
          <mxGeometry x="320" y="150" width="160" height="80" as="geometry" />
        </mxCell>

        <!-- Process A -->
        <mxCell id="procA" value="Process A" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#DAE8FC;strokeColor=#6C8EBF;" vertex="1" parent="1">
          <mxGeometry x="160" y="290" width="120" height="60" as="geometry" />
        </mxCell>

        <!-- Process B -->
        <mxCell id="procB" value="Process B" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#DAE8FC;strokeColor=#6C8EBF;" vertex="1" parent="1">
          <mxGeometry x="520" y="290" width="120" height="60" as="geometry" />
        </mxCell>

        <!-- End -->
        <mxCell id="end" value="End" style="ellipse;whiteSpace=wrap;html=1;fillColor=#F8CECC;strokeColor=#B85450;" vertex="1" parent="1">
          <mxGeometry x="340" y="420" width="120" height="60" as="geometry" />
        </mxCell>

        <!-- Edges -->
        <mxCell id="e1" style="endArrow=classic;html=1;" edge="1" parent="1" source="start" target="decision">
          <mxGeometry relative="1" as="geometry" />
        </mxCell>
        <mxCell id="e2" value="Yes" style="endArrow=classic;html=1;" edge="1" parent="1" source="decision" target="procA">
          <mxGeometry relative="1" as="geometry" />
        </mxCell>
        <mxCell id="e3" value="No" style="endArrow=classic;html=1;" edge="1" parent="1" source="decision" target="procB">
          <mxGeometry relative="1" as="geometry" />
        </mxCell>
        <mxCell id="e4" style="endArrow=classic;html=1;" edge="1" parent="1" source="procA" target="end">
          <mxGeometry relative="1" as="geometry" />
        </mxCell>
        <mxCell id="e5" style="endArrow=classic;html=1;" edge="1" parent="1" source="procB" target="end">
          <mxGeometry relative="1" as="geometry" />
        </mxCell>
      </root>
    </mxGraphModel>
  </diagram>
</mxfile>
```

### Example 2: UML Class Diagram

```xml
<mxfile>
  <diagram id="uml" name="Classes">
    <mxGraphModel dx="0" dy="0" grid="1" gridSize="10" guides="1"
                  tooltips="1" connect="1" arrows="1" fold="1"
                  page="1" pageScale="1" pageWidth="850" pageHeight="1100">
      <root>
        <mxCell id="0" />
        <mxCell id="1" parent="0" />

        <!-- Class: Animal -->
        <mxCell id="animal" value="&lt;p style=&quot;margin:0px;margin-top:4px;text-align:center;&quot;&gt;&lt;i&gt;&amp;lt;&amp;lt;abstract&amp;gt;&amp;gt;&lt;/i&gt;&lt;br&gt;&lt;b&gt;Animal&lt;/b&gt;&lt;/p&gt;&lt;hr size=&quot;1&quot;/&gt;&lt;p style=&quot;margin:0px;margin-left:4px;&quot;&gt;+ name: String&lt;br&gt;+ age: int&lt;/p&gt;&lt;hr size=&quot;1&quot;/&gt;&lt;p style=&quot;margin:0px;margin-left:4px;&quot;&gt;+ speak(): void&lt;br&gt;+ move(): void&lt;/p&gt;" style="verticalAlign=top;align=left;overflow=fill;fontSize=12;fontFamily=Helvetica;html=1;whiteSpace=wrap;" vertex="1" parent="1">
          <mxGeometry x="300" y="40" width="200" height="140" as="geometry" />
        </mxCell>

        <!-- Class: Dog -->
        <mxCell id="dog" value="&lt;p style=&quot;margin:0px;margin-top:4px;text-align:center;&quot;&gt;&lt;b&gt;Dog&lt;/b&gt;&lt;/p&gt;&lt;hr size=&quot;1&quot;/&gt;&lt;p style=&quot;margin:0px;margin-left:4px;&quot;&gt;+ breed: String&lt;/p&gt;&lt;hr size=&quot;1&quot;/&gt;&lt;p style=&quot;margin:0px;margin-left:4px;&quot;&gt;+ fetch(): void&lt;/p&gt;" style="verticalAlign=top;align=left;overflow=fill;fontSize=12;fontFamily=Helvetica;html=1;whiteSpace=wrap;" vertex="1" parent="1">
          <mxGeometry x="180" y="260" width="160" height="120" as="geometry" />
        </mxCell>

        <!-- Class: Cat -->
        <mxCell id="cat" value="&lt;p style=&quot;margin:0px;margin-top:4px;text-align:center;&quot;&gt;&lt;b&gt;Cat&lt;/b&gt;&lt;/p&gt;&lt;hr size=&quot;1&quot;/&gt;&lt;p style=&quot;margin:0px;margin-left:4px;&quot;&gt;+ indoor: boolean&lt;/p&gt;&lt;hr size=&quot;1&quot;/&gt;&lt;p style=&quot;margin:0px;margin-left:4px;&quot;&gt;+ purr(): void&lt;/p&gt;" style="verticalAlign=top;align=left;overflow=fill;fontSize=12;fontFamily=Helvetica;html=1;whiteSpace=wrap;" vertex="1" parent="1">
          <mxGeometry x="460" y="260" width="160" height="120" as="geometry" />
        </mxCell>

        <!-- Inheritance: Dog extends Animal -->
        <mxCell id="e1" style="endArrow=block;endFill=0;html=1;" edge="1" parent="1" source="dog" target="animal">
          <mxGeometry relative="1" as="geometry" />
        </mxCell>

        <!-- Inheritance: Cat extends Animal -->
        <mxCell id="e2" style="endArrow=block;endFill=0;html=1;" edge="1" parent="1" source="cat" target="animal">
          <mxGeometry relative="1" as="geometry" />
        </mxCell>
      </root>
    </mxGraphModel>
  </diagram>
</mxfile>
```

### Example 3: Network Diagram with Groups

```xml
<mxfile>
  <diagram id="network" name="Network">
    <mxGraphModel dx="0" dy="0" grid="1" gridSize="10" guides="1"
                  tooltips="1" connect="1" arrows="1" fold="1"
                  page="1" pageScale="1" pageWidth="850" pageHeight="1100">
      <root>
        <mxCell id="0" />
        <mxCell id="1" parent="0" />

        <!-- DMZ Group -->
        <mxCell id="dmz" value="DMZ" style="swimlane;startSize=25;fillColor=#F5F5F5;strokeColor=#666666;fontStyle=1;html=1;" vertex="1" parent="1">
          <mxGeometry x="50" y="50" width="300" height="200" as="geometry" />
        </mxCell>

        <!-- Firewall inside DMZ -->
        <mxCell id="fw" value="Firewall" style="shape=mxgraph.cisco.firewalls.firewall;sketch=0;html=1;whiteSpace=wrap;" vertex="1" parent="dmz">
          <mxGeometry x="100" y="60" width="80" height="60" as="geometry" />
        </mxCell>

        <!-- Internal Group -->
        <mxCell id="internal" value="Internal Network" style="swimlane;startSize=25;fillColor=#DAE8FC;strokeColor=#6C8EBF;fontStyle=1;html=1;" vertex="1" parent="1">
          <mxGeometry x="450" y="50" width="300" height="200" as="geometry" />
        </mxCell>

        <!-- Server -->
        <mxCell id="srv" value="App Server" style="rounded=1;whiteSpace=wrap;html=1;fillColor=#D5E8D4;strokeColor=#82B366;" vertex="1" parent="internal">
          <mxGeometry x="90" y="60" width="120" height="60" as="geometry" />
        </mxCell>

        <!-- Connection -->
        <mxCell id="conn" style="endArrow=classic;startArrow=classic;html=1;strokeWidth=2;" edge="1" parent="1" source="fw" target="srv">
          <mxGeometry relative="1" as="geometry" />
        </mxCell>
      </root>
    </mxGraphModel>
  </diagram>
</mxfile>
```

### Example 4: Custom Metadata with UserObject

```xml
<mxfile>
  <diagram id="metadata" name="Servers">
    <mxGraphModel dx="0" dy="0" grid="1" gridSize="10" guides="1"
                  tooltips="1" connect="1" arrows="1" fold="1"
                  page="1" pageScale="1" pageWidth="850" pageHeight="1100">
      <root>
        <mxCell id="0" />
        <mxCell id="1" parent="0" />

        <!-- Server with custom attributes -->
        <UserObject id="srv1" label="Web Server" tooltip="Production web server"
                    ip="10.0.1.10" environment="production" owner="ops-team">
          <mxCell style="rounded=1;whiteSpace=wrap;html=1;fillColor=#D5E8D4;strokeColor=#82B366;" vertex="1" parent="1">
            <mxGeometry x="100" y="100" width="140" height="70" as="geometry" />
          </mxCell>
        </UserObject>

        <!-- Database with custom attributes -->
        <object id="db1" label="PostgreSQL" ip="10.0.2.20"
                environment="production" port="5432">
          <mxCell style="shape=cylinder3;whiteSpace=wrap;html=1;boundedLbl=1;backgroundOutline=1;size=15;fillColor=#DAE8FC;strokeColor=#6C8EBF;" vertex="1" parent="1">
            <mxGeometry x="350" y="90" width="100" height="90" as="geometry" />
          </mxCell>
        </object>

        <mxCell id="conn1" style="endArrow=classic;html=1;" edge="1" parent="1" source="srv1" target="db1">
          <mxGeometry relative="1" as="geometry" />
        </mxCell>
      </root>
    </mxGraphModel>
  </diagram>
</mxfile>
```

---

## 14. Additional mxGraphModel Attributes

These optional attributes on `<mxGraphModel>` are less commonly used but appear
in real-world files:

| Attribute | Values | Description |
|---|---|---|
| `adaptiveColors` | `auto`, `simple`, `none`, `default` | Controls color adaptation for light/dark mode viewing |

**adaptiveColors** example:
```xml
<mxGraphModel dx="0" dy="0" grid="1" ... adaptiveColors="auto">
```

AI generators typically do not need to set this attribute.

---

## 15. Validation Checklist for AI-Generated Files

Use this checklist to verify generated draw.io files:

1. **Valid XML**: File is well-formed XML with proper escaping
2. **Root element**: `<mxfile>` as root, contains at least one `<diagram>`
3. **Diagram IDs**: Each diagram has a unique `id` attribute
4. **Structural cells**: Root contains `<mxCell id="0"/>` and `<mxCell id="1" parent="0"/>`
5. **Unique IDs**: All cell IDs are unique within the diagram
6. **Parent references**: Every cell (except id="0") has a valid `parent` referencing an existing cell
7. **Type flags**: Each content cell has either `vertex="1"` or `edge="1"` (not both)
8. **Edge references**: Edge `source` and `target` reference existing vertex IDs
9. **Geometry**: Vertices have mxGeometry with x, y, width, height; edges have `relative="1"`
10. **Style format**: Style strings use `key=value;` format, valid keys and values
11. **Perimeter match**: Non-rectangular shapes have matching perimeter in style
12. **HTML escaping**: HTML in `value` attributes is properly XML-escaped
13. **Coordinate system**: x increases right, y increases down, no negative dimensions
14. **Group hierarchy**: Children of groups have coordinates relative to the group
