Hey everyone, I’m pretty new to Flutter development and need help with something.
I want to create a canvas-like interface where users can scroll in all directions - up, down, left, right, and even diagonally. Think about how design applications work where you have this infinite workspace that you can navigate around.
I’m not looking for complete code solutions, just need someone to point me toward the right widgets or approach. What’s the best way to handle this kind of multi-directional scrolling behavior? Should I be looking at specific scroll controllers or maybe custom gesture detectors?
I haven’t started coding yet because I’m not sure which direction to take. Any suggestions on the proper Flutter widgets or techniques would be really helpful.
Back when I was working on a whiteboard application, I went through several iterations before settling on what worked best. The approach that gave me the smoothest results was using a SingleChildScrollView nested inside another SingleChildScrollView with perpendicular scroll directions. Set the outer one to scroll horizontally and the inner one vertically. This gives you that natural two-dimensional scrolling behavior without fighting against Flutter’s built-in scroll physics. The trick is setting a large enough child size to create your virtual canvas space and managing the scroll controllers properly to prevent conflicts. Performance was surprisingly good even with complex canvas content, and you get all the native scroll behaviors like momentum and bounce effects for free. Much more predictable than custom gesture handling in my experience.
I actually built something similar for a floor plan editor app last year. The key is using InteractiveViewer widget - it handles pan and zoom gestures out of the box without needing custom gesture detectors. You wrap your canvas content inside InteractiveViewer and it automatically gives you that infinite workspace feeling. The widget manages transformation matrices internally so you don’t have to worry about the math. One thing I learned the hard way is to set proper boundary constraints using boundaryMargin and constrained properties, otherwise users can scroll way too far into empty space. Also consider using a TransformationController if you need programmatic control over the viewport position later. Much cleaner approach than trying to combine multiple SingleChildScrollViews or building custom gesture handling.
From my experience building a diagram editor, you’ll want to start with InteractiveViewer but be prepared for some gotchas. The main issue I encountered was coordinate transformation when handling tap events on canvas elements - you need to convert screen coordinates to canvas coordinates using the transformation matrix. What really helped was wrapping my canvas content in a Container with a fixed large size (like 10000x10000) to define your workspace boundaries. This prevents weird edge cases where users can pan into negative coordinate space. Also worth noting that InteractiveViewer can conflict with other gesture recognizers in your widget tree, so you might need to tune the gesture arena behavior. The panEnabled and scaleEnabled properties give you good control over which interactions to allow. Performance-wise, make sure to implement efficient viewport culling since only visible elements need to be rendered during pan operations.
honestly just use a simple Stack widget inside a Container and handle the panning yourself with GestureDetector. i did this for my drawing app and its way less overhead than InteractiveViewer. just track the offset values and use Transform.translate to move your canvas content around. works perfectly for basic 2d scrolling without all the extra complexity.
What worked well for me when I tackled this was combining CustomScrollView with a custom RenderObject approach. While InteractiveViewer is solid for basic cases, I found it limiting when you need precise control over scroll physics or want to implement features like snap-to-grid functionality. The CustomScrollView route gives you more flexibility with scroll behavior customization. I ended up creating a custom widget that uses GestureDetector to capture pan gestures and manually updates the scroll positions of nested scrollable widgets. Yes, it requires more boilerplate code, but you get fine-grained control over acceleration curves, boundary handling, and momentum scrolling. Start simple with InteractiveViewer first to prototype your concept, then consider the custom approach if you hit limitations. The transformation calculations aren’t too complex once you understand the coordinate system conversions.