How to handle mouse tracking outside Figma plugin interface boundaries?

[FlyingEagle]

I’m working on a custom control system that I’ve been using successfully in regular web applications. The mouse tracking works perfectly in Chrome and other browsers, but when I implement it in a Figma plugin interface, I run into issues.

function initializeControl(element, w, h) {
    element.width = w;
    element.height = h;
    element.style.display = 'block';
    
    element.changeEvent = new Event('valueChanged');
    
    element.addEventListener('mousedown', function(event) {
        const evt = window.event || event;
        
        if (evt.button === 0) {
            evt.preventDefault();
            
            if (element.setCapture)
                element.setCapture();
            
            element.isDragging = true;
            element.startX = evt.clientX;
            element.initialValue = element.value;
        }
    });
    
    element.addEventListener('losecapture', function() {
        element.isDragging = false;
    });
    
    document.addEventListener('mouseup', function(evt) {
        const e = window.event || evt;
        
        if (e.button === 0 && element.isDragging)
            element.isDragging = false;
    }, true);
    
    (element.setCapture ? element : document).addEventListener('mousemove', function(evt) {
        if (element.isDragging) {
            const deltaX = element.startX - evt.clientX;
            const multiplier = 8 * Math.pow(Math.abs(deltaX), element.sensitivity);
            
            element.value = Math.min(Math.max(element.minimum, element.initialValue - deltaX * element.factor * multiplier), element.maximum);
            element.render();
            element.dispatchEvent(element.changeEvent);
        }
    }, true);
    
    element.onwheel = function(evt) {
        evt.preventDefault();
        const target = evt.target;
        target.value = Math.min(Math.max(target.minimum, target.value + (evt.deltaY < 0 ? 1 : -1) * target.factor), target.maximum);
        target.dispatchEvent(target.changeEvent);
        target.render();
    };
    
    element.render = function() {
        // rendering logic here
    };
    
    element.render();
}

The problem is that mouse capture gets lost immediately when the cursor moves outside the plugin window boundaries. Has anyone found a workaround for this limitation in Figma plugins?

[CreatingStone]

yeah, this is a known figma plugin limitation. i switched to pointer events instead of mouse events - worked better for tracking. also set up a buffer zone near the plugin edges with higher sensitivity so users don’t have to drag as far outside.

[Ethan_19Chess]

Yeah, this is a browser security thing that hits all iframe environments, not just Figma plugins. I hit the same wall porting desktop app controls to web plugins. Here’s what worked for me: I built a distance-based system that multiplies mouse movements based on how close you get to the plugin edges. When the cursor hits the boundary, I reset it to the center while keeping track of the accumulated movement. Makes it feel continuous even though you’re stuck in that box. Also throw in some visual feedback - show the current value during drags since users can’t rely on normal cursor positioning like they would in desktop apps.

[Finn_Mystery]

I encountered a similar challenge when transitioning my web controls to Figma plugins. The issue with mouse capture is indeed frustrating since it won’t work outside the plugin’s sandbox due to iframe limitations. To tackle this, I adjusted my mouse tracking logic to be more responsive within the confines of the plugin space. I modified my handler to not only consider current mouse positions but also anticipate where the mouse was likely intended to go based on velocity. Furthermore, I incorporated keyboard shortcuts, allowing users to hold down keys like shift or alt during dragging to switch sensitivity levels. This adjustment provided flexibility and improved the user experience significantly.