excalidraw

# Excalidraw Diagram Generator Generate beautiful hand-drawn style diagrams rendered as PNG images. ## Workflow 1. **Generate JSON** — Write Excalidraw element array based on what the user wants 2. **Save to file** — Write JSON to `/tmp/<name>.excalidraw` 3. **Render** — `node <skill_dir>/scripts/render.js /tmp/<name>.excalidraw /tmp/<name>.png` 4. **Send** — Send the PNG via message tool with `filePath` ## Quick Reference ```bash node <skill_dir>/scripts/render.js input.excalidraw output.png ``` ## Element Types | Type | Shape | Key Props | |------|-------|-----------| | `rectangle` | Box | x, y, width, height | | `ellipse` | Oval | x, y, width, height | | `diamond` | Decision | x, y, width, height | | `arrow` | Arrow | connects shapes (see Arrow Binding below) | | `line` | Line | x, y, points: [[0,0],[dx,dy]] | | `text` | Label | x, y, text, fontSize, fontFamily (1=hand, 2=sans, 3=code) | ### Styling (all shapes) ```json { "strokeColor": "#1e1e1e", "backgroundColor": "#a5d8ff", "fillStyle": "hachure", "strokeWidth": 2, "roughness": 1, "strokeStyle": "solid" } ``` **fillStyle**: `hachure` (diagonal lines), `cross-hatch`, `solid` **roughness**: 0=clean, 1=hand-drawn (default), 2=very sketchy ## Arrow Binding (IMPORTANT) **Always use `from`/`to` bindings for arrows.** The renderer auto-calculates edge intersection points — no manual coordinate math needed. ### Simple arrow (straight, between two shapes) ```json {"type":"arrow","id":"a1","from":"box1","to":"box2","strokeColor":"#1e1e1e","strokeWidth":2,"roughness":1} ``` That's it. No x, y, or points needed. The renderer computes start/end at shape edges. ### Multi-segment arrow (routed path with waypoints) For arrows that need to go around obstacles, use `absolutePoints` with intermediate waypoints: ```json { "type":"arrow","id":"a2","from":"box3","to":"box1", "absolutePoints": true, "points": [[375,500],[30,500],[30,127],[60,127]], "strokeColor":"#1e1e1e","strokeWidth":2,"roughness":1 } ``` - First point = near source shape edge (will snap to actual edge) - Last point = near target shape edge (will snap to actual edge) - Middle points = absolute waypoint coordinates for routing ### Arrow labels Place a separate text element near the arrow midpoint: ```json {"type":"text","id":"label","x":215,"y":98,"width":85,"height":16,"text":"sends data","fontSize":10,"fontFamily":1,"strokeColor":"#868e96"} ``` ### Arrow styles - `"strokeStyle":"dashed"` — dashed line - `"startArrowhead": true` — bidirectional arrow ## Template: Flowchart with Bindings ```json { "type": "excalidraw", "version": 2, "elements": [ {"type":"rectangle","id":"start","x":150,"y":50,"width":180,"height":60,"strokeColor":"#1e1e1e","backgroundColor":"#b2f2bb","fillStyle":"hachure","strokeWidth":2,"roughness":1}, {"type":"text","id":"t1","x":200,"y":65,"width":80,"height":30,"text":"Start","fontSize":20,"fontFamily":1,"strokeColor":"#1e1e1e"}, {"type":"arrow","id":"a1","from":"start","to":"decision","strokeColor":"#1e1e1e","strokeWidth":2,"roughness":1}, {"type":"diamond","id":"decision","x":140,"y":170,"width":200,"height":120,"strokeColor":"#1e1e1e","backgroundColor":"#ffec99","fillStyle":"hachure","strokeWidth":2,"roughness":1}, {"type":"text","id":"t2","x":185,"y":215,"width":110,"height":30,"text":"Condition?","fontSize":18,"fontFamily":1,"strokeColor":"#1e1e1e","textAlign":"center"}, {"type":"arrow","id":"a2","from":"decision","to":"process","strokeColor":"#1e1e1e","strokeWidth":2,"roughness":1}, {"type":"rectangle","id":"process","x":150,"y":350,"width":180,"height":60,"strokeColor":"#1e1e1e","backgroundColor":"#a5d8ff","fillStyle":"hachure","strokeWidth":2,"roughness":1}, {"type":"text","id":"t3","x":190,"y":365,"width":100,"height":30,"text":"Process","fontSize":20,"fontFamily":1,"strokeColor":"#1e1e1e"} ] } ``` ## Layout Guidelines - **Node size**: 140-200 × 50-70 px - **Diamond**: 180-200 × 100-120 px (taller for text) - **Vertical spacing**: 60-100 px between nodes - **Horizontal spacing**: 80-120 px between nodes - **Text**: Position inside shape manually (offset ~15-30px from top-left of shape) - **Arrow labels**: Place as separate text elements near midpoint of arrow path ## Color Palette **Fills**: `#a5d8ff` (blue), `#b2f2bb` (green), `#ffec99` (yellow), `#ffc9c9` (red), `#d0bfff` (purple), `#f3d9fa` (pink), `#fff4e6` (cream) **Strokes**: `#1e1e1e` (dark), `#1971c2` (blue), `#2f9e44` (green), `#e8590c` (orange), `#862e9c` (purple) **Labels**: `#868e96` (gray, for annotations) ## Tips - Every element needs a unique `id` (required for binding!) - Use `from`/`to` on arrows — don't calculate coordinates manually - `roughness:0` for clean diagrams, `1` for sketchy feel - Text `fontFamily:1` for hand-drawn, `3` for code - Group related elements spatially, color-code by type - For nested layouts, use a large background rectangle as a container