Fully offline PlantUML
Open .puml, .plantuml, .iuml, or .pu documents, start from a sequence template, and export SVG, vector PDF, or PNG on device.
What's New · 1.6.18
SourceCanvas
Let your AI draw. See the real diagram on Mac.
Version 1.6.18 adds fully offline PlantUML documents, templates, safety diagnostics, Agent Preview, and MCP workflows.
- Works with popular MCP AI hosts
- Local preview without document uploads
- 20 Mermaid types plus more formats
What's New in SourceCanvas 1.6.18
Ask Codex, ChatGPT, Gemini CLI, Qwen Code, or another AI to turn a process, system, or idea into Mermaid, PlantUML, Graphviz, or SVG. SourceCanvas receives it through local MCP, validates it, shows the result live, and keeps it editable and exportable.
macOS MCP Agent
Use the new signed local Agent Service with seven diagram tools, Resources, Prompts, and native AI Preview windows.
Connect popular AI hosts
Detect and configure ChatGPT/Codex, Claude Desktop, Cursor, Visual Studio Code, Gemini CLI, and Qwen Code. Other MCP-compatible hosts can use the copied connection settings.
Single-file safety
PlantUML include/import directives and URL or file images are blocked; inline definitions, sprites, built-in themes, emoji, and OpenIconic remain available offline.
More reliable document and Agent workflows
Open or drag every supported format more reliably on Mac, including Graphviz .dot files associated with another app. Agent Service startup and Connection Diagnostic are also more robust.
Core Features
Stop moving between an AI chat, an online renderer, and an export tool. SourceCanvas gives AI-generated diagrams one focused Mac workspace for review and delivery.
A local diagram window for AI
On Mac, Agent Service lets an AI validate, render, and keep diagrams updated in one native preview window as work progresses.
From a plain request to a visible result
Describe a workflow, architecture, database, or plan to the AI you already use, then immediately inspect both its diagram source and rendered result.
See many kinds of diagrams
Cover flowcharts, sequence and architecture diagrams, class, state and ER diagrams, Gantt charts, mind maps, timelines, Kanban, data charts, and more.
Easy to inspect without learning syntax
Automatic mode detects the format. Fit Screen, zoom, backgrounds, and friendly source diagnostics help anyone check labels, links, and hierarchy.
Keep it local and export it clearly
Core rendering runs on device. Save the source or export SVG, vector PDF, and PNG 1x/2x/3x for documents, presentations, and sharing.
Your AI's diagram window on Mac
SourceCanvas 1.6.18 includes a signed local MCP server on macOS. Let Codex, ChatGPT, Gemini, Qwen Code, or another AI use dedicated diagram tools, then review, edit, and export the result in a native Mac window.
Describe the process, system relationship, project plan, or knowledge structure you need. The AI drafts PlantUML, Mermaid, Graphviz, or SVG while SourceCanvas validates and displays it locally. During long coding tasks, the AI can refresh architecture, state, or progress diagrams so one Preview ID keeps showing the current state.
Detect and configure ChatGPT/Codex, Claude, Cursor, Visual Studio Code, Gemini, and Qwen Code directly; use copied connection settings for other MCP hosts.
Enable the local service
Enable Agent Service in Settings > MCP & Agent, then run Connection Diagnostic. The service stays on this Mac.
Connect the AI you use
Add sourcecanvas to ChatGPT/Codex, Claude Desktop, Cursor, Visual Studio Code, Gemini CLI, or Qwen Code. For another MCP host, paste the copied MCP connection settings.
Validate, preview, and export
Seven MCP tools detect, validate, render, inspect, and export SVG, Mermaid, Graphviz, and PlantUML. A stable Preview ID keeps one native AI Preview window updated, including live diagrams for long-running work.
SourceCanvas changes only its MCP entry and keeps local backups. It never enables Host trust or automatic tool approval. MCP uses local stdio/XPC, and Agent Service is not exposed outside macOS.
Fully offline
PlantUML is now supported in SourceCanvas 1.6.18
Open or paste PlantUML sequence, class, and activity diagrams. The official runtime is bundled in the app, so rendering needs no server, Java, or external Graphviz. A single-file safety model blocks include/import directives and external images.
View on the App Store
Mermaid Diagrams You Can Write
SourceCanvas focuses on turning readable code into useful diagrams. Start with common chart names, then learn more diagram styles as your documents grow.
Flow and structure
- Flowchart / graph
- Sequence diagram
- Class diagram
- State diagram
- Entity relationship diagram
- Requirement diagram
- C4 context diagram
- Architecture diagram
- Block diagram
Planning and knowledge
- Gantt chart
- Mind map
- Timeline
- Git graph
- User journey
- Kanban
Data and analysis
- Pie chart
- Quadrant chart
- Sankey chart
- XY chart
Specialized diagrams
- Packet diagram
Some newer diagram styles may evolve over time; flowcharts, sequence diagrams, Gantt charts, and mind maps are good places to start learning.
Code Drawing Tutorial
Write diagram code, choose the diagram mode, inspect the result, then save or export in four steps. Select any step below.
Write diagram code or open a local file
Write PlantUML, Mermaid, or Graphviz DOT in the editor, or open .svg, .mmd, .mermaid, .dot, .gv, .puml, .plantuml, .iuml, and .pu files directly.
- Good for learning Mermaid diagrams from examples.
- Good for maintaining documentation flowcharts and architecture diagrams.
- macOS supports drag and drop; iOS, iPadOS, and visionOS use the system file entry point.
Use Automatic and the renderer menu
Automatic detects the type from content and extension. To force a renderer, choose SVG, Mermaid, Graphviz, or PlantUML from the data-driven menu.
- Automatic handles most pasted or opened source.
- All four formats use local renderers.
- PlantUML uses the bundled official runtime with no server, Java, or external Graphviz.
Inspect source and result together
The preview area reports render state. Zoom in or out to inspect details, and use two-finger pinch zoom directly on iPhone and iPad.
- Check fine strokes, nodes, and labels with buttons or touch gestures.
- Open find and replace with Cmd+F or the editor button.
- Invalid input shows line/column diagnostics and a source marker.
Save source or export the preview
After the graphic looks right, save its source or export the final rendering as SVG, vector PDF, or PNG 1x/2x/3x.
- SVG, Mermaid, Graphviz, and PlantUML can all export final SVG.
- PDF keeps paths and text sharp at any zoom.
- On iOS, system file panels retain the current graphic and background.
Supported Platforms
One preview flow adapts to desktop, touch screens, and spatial computing, with layouts tuned for each screen size.
Mac: keyboard-first wide workspace
Wide screens keep source and preview side by side for quick checks across code, docs, and design tools.
iPad: side-by-side source workspace
With the left tool column removed, the top command area and side-by-side editor/preview layout make landscape checks faster for SVG icons and Mermaid diagrams.
iPhone: system document bar and two control rows
Source and preview stack on narrow screens; the system document bar owns files while two app rows provide mode, background, zoom, and Fit Screen.
Apple Vision Pro: large diagram review in spatial windows
Place diagrams and documents in a larger workspace, especially for complex Mermaid charts.
Built Around Everyday AI Diagram Needs
Searches such as AI diagram generator, AI flowchart generator, text to diagram, Mermaid editor, and diagram viewer all point to the same need: turn an AI answer into a diagram you can trust and use.
AI flowcharts
Give an AI your business steps, approval path, or instructions, then use SourceCanvas to verify every node, decision, and connection.
Systems and architecture
Review AI-generated sequence, component, service architecture, class, state, and database ER diagrams.
Plans and knowledge
Organize projects, lessons, research, or personal plans with Gantt charts, timelines, mind maps, user journeys, and Kanban.
Mermaid and UML preview
Open Mermaid, PlantUML, Graphviz DOT, SVG, or matching Markdown code blocks from an AI and render them immediately on device.
Docs and presentation export
Export an approved diagram as SVG, PNG, or vector PDF for reports, slides, requirements, tutorials, and sharing.
FAQ
Quick answers about SVG, Mermaid, Graphviz, PlantUML, file formats, privacy, and export.
Is SourceCanvas free?
This website presents the capabilities of the lightweight local preview tool. Actual pricing and availability should be checked on the App Store page.
Does SourceCanvas upload my files?
No. Core SVG, Mermaid, Graphviz, and PlantUML rendering stays on your device. Only after you enable secure remote resources does the app connect directly to HTTPS or local resource hosts named by the SVG.
Which file formats are supported?
SourceCanvas supports .svg, .mmd, .mermaid, Graphviz .dot/.gv, PlantUML .puml/.plantuml/.iuml/.pu, and matching Markdown code blocks.
Can I drag files in from Finder?
Yes. The Mac app accepts every registered source format. A .dot file still opens as Graphviz source when another app owns that extension. iPhone, iPad, and Apple Vision Pro use the system document browser.
Why can Mermaid backgrounds be changed?
Different documents and design contexts use different backgrounds. Transparent, white, paper, mist, and dark backgrounds help catch contrast and edge issues earlier.
When should I export SVG, PNG, or PDF?
SVG and vector PDF suit lossless scaling in documents and reviews. PNG 1x/2x/3x suits tickets, chat, and raster workflows.
What changed in iOS save and export?
System documents autosave source and use the document browser for names and locations. Preview export remains separate with PNG 1x, PNG 2x, PNG 3x, and PDF.
Does SourceCanvas run its own AI model?
No. Keep using your chosen Codex, ChatGPT, Gemini, Qwen Code, or another AI. SourceCanvas is the local Mac tool that receives, validates, displays, edits, and exports the diagram.
Which AI systems can SourceCanvas connect to?
On macOS, Settings directly configures ChatGPT/Codex, Claude Desktop, Cursor, Visual Studio Code, Gemini CLI, and Qwen Code. Other local stdio MCP hosts can use the copied connection settings. SourceCanvas never enables automatic approval.