I’m pretty new to Flutter development and I’m stuck on something. I want to create a canvas-like interface where users can scroll in all directions - up, down, left, right, and even diagonally at the same time.
Think of apps like Canva or Adobe XD where you have this infinite workspace that you can navigate around freely. That’s exactly what I’m trying to build.
I don’t need someone to write the code for me, but I could really use some pointers on:
What Flutter widgets would work best for this
The general approach or logic I should follow
Any specific concepts I should research
I haven’t started coding yet because I’m not sure which direction to go. Any guidance from experienced developers would be awesome!
I built a whiteboard app and here’s what worked best: use SingleChildScrollView with both directions enabled. Wrap your canvas in one with scrollDirection: Axis.vertical, then nest another inside with scrollDirection: Axis.horizontal. You get smooth movement in all directions without the headache of custom gesture handling that InteractiveViewer brings. Key trick - make your inner container way bigger than the screen to get that infinite workspace vibe. Way more reliable than custom scroll views when you’ve got positioned widgets everywhere. Performance holds up fine until you hit 100+ interactive elements.
honestly, the scrolling widget’s not the hard part - it’s all that coord math when transforms kick in. start with a basic CustomScrollView using horz and vert scroll controllers. much easier to debug than diving straight into InteractiveViewer. get your 2-way scrolling solid first, then tackle zoom and gesture conflicts.
I built something similar for a drawing app last year. I found that using InteractiveViewer as a base works well since it handles pan and zoom gestures with minimal setup. The key is to treat your canvas as one large child widget within InteractiveViewer, and then you can position UI elements using Transform widgets or custom containers. To facilitate custom interactions on canvas elements, utilize GestureDetector. If you require more precise control over scrolling behavior, consider using CustomScrollView.
The main challenge lies not in scrolling itself, but rather in managing coordinate transformations when users interact with objects on a scaled or panned canvas, which can quickly become complex. A good place to start is with InteractiveViewer coupled with a Container for your canvas; you can always consider switching to CustomPainter later if you run into performance issues.
Sounds like you’re dealing with viewport transformation, not just scrolling. Had a similar project that needed that infinite canvas feel. What saved me tons of headaches was using Transform widget with GestureDetector for manual pan handling. You basically create a big virtual coordinate system and map screen coordinates to canvas coordinates through matrix transformations. The upside? Complete control over how elements behave when navigating. Start with a stateful widget that tracks pan offset values, then use Transform.translate to shift your canvas content. Got basic panning working? Add zoom with Transform.scale. This approach handles edge cases that pre-built scroll widgets choke on, especially when you need custom hit testing for canvas elements.