How to Prevent Fixed Elements from Resizing During Touchscreen Zooming?

Preventing Element Resizing During Touchscreen Zooming

In the realm of web development, fixed elements provide an anchor for important content, remaining stationary amidst the scrolling motion. However, when viewed on touchscreen devices, these elements often succumb to the pinch-to-zoom gesture, inadvertently scaling up alongside other content.

To address this dilemma, it is crucial to prevent specific elements from resizing during zooming while maintaining their original dimensions. Here's how to achieve this:

Recalculate Zoom Factor and Apply Transform:

1. Implement a scroll event listener to track user interactions.
2. Calculate the zoom factor using the ratio of innerWidth to clientWidth. This value represents the extent of zooming.
3. Set the "transform" CSS property of the targeted element to "scale(zoomFactor)." This rescales the element to counteract the browser's zoom.

Adjust Element Position:

1. Since zooming alters the element's position, new values for its "left" and "bottom" properties need to be set.

2. For example, for an absolutely positioned element within a 100% height parent, use these values:

   • "left": window.pageXOffset 'px'
   • "bottom": document.documentElement.clientHeight - (window.pageYOffset window.innerHeight) 'px'

Consider Transform-Origin:

1. The "transform-origin" property determines the anchor point for scaling.
2. Experiment with different values to achieve the desired alignment effect during zooming.

By implementing these steps, you can effectively prevent fixed elements from resizing during zooming, ensuring optimal user experience and a visually consistent web application.

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