title: $:/plugins/tiddlywiki/dynaview/readme

! Dynaview

This plugin makes it possible to build user interfaces that dynamically respond to changes in the browser viewport via scrolling or zooming:

* CSS classes that allow rendering to be deferred until the output is scrolled into view
* CSS classes that allow the opacity of DOM elements to vary according to the current zoom level
* A daemon that can dynamically update a pair of state tiddlers with the current dimensions of the browser viewport
* A daemon that can dynamically adjust the size of text to yield a particular number of characters per line

Some points to note about the zoom features:

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* The zoom level currently only works on Safari, both on Mac OS and on the iPhone/iPad
* The zoom level tracked by the plugin is the pinch-zoom level, and not the text-zoom level
* Rather than being progressively rendered as needed, hidden item are rendered with zero opacity. Which means that they can still be interacted with

This is really just a proof of concept to allow the user experience to be evaluated. A production version would need to work in all browsers, which would mean adopting a polyfill such as [[Hammer.js|http://hammerjs.github.io/]] to give us manual pan and zoom support. It would also allow deeper levels of zoom.

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