How to Use AI Canvas Tools to Edit Text & Code Interactively

Google Gemini Canvas (2026)

Gemini's Canvas workspace lets you write and edit documents or code with changes appearing in real-time on your screen .

How to use it:

• Click the Canvas button beneath the Gemini prompt bar to transition from standard chat to an interactive workspace .
• Use the floating quick editor toolbar to highlight specific text and instantly change the tone, adjust the length, or fix formatting errors.
• For coding, you can generate HTML/CSS/JS and see a live preview of your changes.

Best for: Building web apps, editing docs with live previews, and rapid prototyping.

Mistral le Chat Canvas

Mistral's Canvas is a built-in editor for creating and refining text, code, spreadsheets, and more, collaborating with the AI right inside your chat .

How to use it:

• Canvas is off by default in le Chat. To turn it on, open the Tools menu at the bottom of the chat window and check the box next to Canvas .
• Once activated, you can ask the AI to generate or modify content, and edits appear in real-time within the canvas pane.
• You can also explicitly open a Canvas by typing / in your prompt and selecting "Open a new Canvas" .

Best for: Quick content creation, spreadsheet editing, and straightforward text or code generation.

Building a Custom HTML5 Canvas Text Editor

For developers who need to build a text or code editor from scratch using the HTML5 <canvas> API, the approach is fundamentally different — you must reimplement all text-editing primitives manually because the canvas element has no native text input capabilities.

Core steps:

• Capture keyboard events on the window and write keystrokes out to the canvas .
• Implement caret (cursor) positioning and text selection rectangles . The Infinite Canvas tutorial explains that building a text editor on canvas means reimplementing caret movement, selection rectangles, and IME composition from scratch .
• Use measurement APIs like ctx.measureText() and newer Canvas Text Metrics APIs (getIndexFromOffset, getSelectionRects) to map pixel positions back to character indices . These newer APIs, proposed by Igalia, reduce the need for custom JavaScript solutions .
• Double-click on text to enter an editing state .
• Leverage libraries like Konva.js or KineticJS to simplify the process by providing layers, hit detection, and transform handles .

Alternative: For many use cases, it's easier to use HTML elements like textarea or contenteditable rather than building a full editor on canvas . The canvas approach is only necessary when you need pixel-level control over rendering (e.g., for a design tool or a custom drawing app).

Which Canvas Should You Use?

Bottom line: If you're a writer or coder, use one of the AI canvas tools. If you're building a custom application that needs precise rendering, the HTML5 canvas approach gives you full control — but be prepared for the extra development effort.