javascript - 当 'user-scalable' 设置为 yes 时检测双指缩放

Question

当 meta name="viewport" 设置为 user-scalable=yes 时，如何检测缩放的缩放比例(或缩放距离)？

我已经在 Android 上测试过，但如果 meta name="viewport" 设置为 user-scalable=yes，则无法检测到双指缩放。如果 meta name="viewport" 设置为 user-scalable=no 则可以检测到缩放，但我无法放大文档。

这是我在 jsFiddle 上的测试:

锤子.js: http://jsfiddle.net/pE42S/

var pziW = "test";
var viewport_width = $(window).innerWidth();
var zoom = 0;

var hammer = new Hammer(document.getElementById("touchme"));

hammer.ontransformstart = function(ev) {
    console.log("ontransformstart");
    console.log(ev);
    //pziW = $(window).innerWidth() / 2 * ev.scale;
    zoom = ev.scale;
    var msg = "ontransformstart " + pziW + " scale " + zoom;
    log(msg);
};
hammer.ontransform = function(ev) {
    console.log("ontransform");
    console.log(ev);
    zoom -= ev.scale;
    viewport_width+=viewport_width*zoom;
    zoom = ev.scale;
    pziW=viewport_width;
    //pziW = $(window).innerWidth() / 2 * ev.scale;
    jqUpdateSize();
    var msg = "ontransform " + pziW + " scale " + zoom;
    log(msg);
};
hammer.ontransformend = function(ev) {
    console.log("ontransformend");
    console.log(ev);
    var msg = "ontransformend " + pziW + " scale " + zoom;
    log(msg);
};

触摸滑动: http://jsfiddle.net/pE42S/1/

$(function() {      
    $("#touchme").swipe( {
        pinchStatus:function(event, phase, direction, distance , duration , fingerCount, pinchZoom) {
            console.log("pinchStatus");
            console.log(event);
            pziW=viewport_width - distance;
            $("#log").text(pziW);
            jqUpdateSize();
        },
        fingers:2,  
        pinchThreshold:0  
    });
});

有人有答案吗？

Answer 1

现在您可以为此使用 Visual Viewport API(并非适用于所有浏览器)。只需检查 window.visualViewport.scale > 1。