js-viewpane

Viewpane

simple, feelgood, pan and zoomable image or HTML container

Viewpane enables an image or any HTML Container to be pan- and zoomable within a given parent container. In some way this is a subset of iScroll or comparable script, but it offers a smoother scrolling experience and a more natural (iOS) rubberband. Additional, viewpane toys with being in 3D space, enabling perspective experiments with css or js.

bower install viewpane

You can checkout the demos page to get an impression what it does.

usage

 
    #camera {
        position: relative;
        width: 100%;
        height: 100%;
        overflow: hidden;    
    }
 
    #viewpane {
        position: absolute;
        transform-style: preserve-3d
    }

 
    <div id="camera">
        <div id="viewpane"></div>
    </div>

 
    var viewpane = new Viewpane("camera", "viewpane", options);
 

options

    {
        // friction used on animation to stop user input. Values [0, 1[
        friction: 0.91,             
        // type of valid positions. May also be "fitBothDimensions"
        // Also `Viewpane.FOCUS_TYPE.BOTH` or `Viewpane.FOCUS_TYPE.LARGEST`
        typeOfFocus: "fitLargestDimension",     
        // The area to focus camera (bound, rubberband)
        // Default: viewpane-element dimensions
        focus: {x: 2048, y: 1024},
        // perspective of camera. Values [0, Infinity[. Default 1000  
        perspective: 1000,      
        // perspective origin. Values [0, 1]. Default (0.5, 0.5)    
        origin: {x: 0.5, y: 0.5},
        // enable rubberband on z-axis. Default true
        rubberZ: true
    }

events

Event names are also accessible view Viewpane.EVENT_*

    
    var viewpane = new Viewpane("camera", "viewpane", options);
 
    viewpane.addObserver("onClick", function (event, clickOrigin) {
        // viewpane has been clicked
    });
 
    viewpane.addObserver("onRender", function (position) {
        // viewpane has updated visually
    });
 
    viewpane.addObserver("onUpdate", function (position) {
        // viewpane has updated calculations
    });
 
    viewpane.addObserver("onInputStart", function () {
        // user input starts
    });
 
    viewpane.addObserver("onInputStop", function () {
        // user input has ended
    });
 
    viewpane.addObserver("onEnd", function () {
        // all animations and input has stopped
    });
 

api

viewpane

method	description
activate()	activate userinteraction (default)
deactivate()	deactivate user interaction
fit()	centers the contents (position, scale) to the viewport
addObserver(eventName, callback)	add an event listener (@see events)
repaint()	redraws viewpane
addEntity(Viewpane.Entity)	adds another entity which is translated by the viewpane (camera)

requirements

• support of 3d transforms

exported utilities

for details see the corresponding sourcefiles.

    // viewpane entity (renderable)
    Viewpane.Entity
    // animation loop
    Viewpane.Loop
    // vector class
    Viewpane.Vector
    // types of viewpane bounds
    Viewpane.FOCUS_TYPE

performance

• ensure images are a multiple of 2 (i.e. use 2048x1024, but NOT 2048x1025). Especially on iOS

known bugs

• sometimes zoomIn does not trigger rubberband animation

• Browserbugs

  • iOS 9.0.x, transform-style: preserve-3d flickering 3d layers

    • Currently there is no css workaround @see Stackoverflow. The attribute overflow: hidden does not work with the transform-style: preserve3d options.

    • for the viewpane, the only workaround is to use js entities instead of css. See the demos page for details.