javascript - canvas - 由 fabricjs 和 angularjs 使用捏缩放

Question

我正在尝试使用 FabricJs 在 Canvas 上缩放。但我对此一无所知。

而且我还从谷歌搜索了一些代码。但不工作。任何人都不会为使用 fabric 的缩放选项写一篇文章。

请如果你对此有任何想法。请让我知道......

我试过了

....

canvas.on('touch:gesture', function (e) {
                isGestureEvent = true;
                // /* Just use the scale of the touch event to determine zoom in or zoom out. */
                var lPinchScale = e.self.scale;
                var type = e.e.type;
                if (type == "touchstart") {

                    //console.log("touchstart");
                    aGestureTouchStartTouches = e.e.touches;
                    aGestureScale.push(lPinchScale);
                    //console.log("scale:" + lPinchScale);

                } else if (type == "touchmove") {
                    console.log("touchmove");


                    //var modCheck = 5;
                    //if(aGestureScale.length % modCheck == 0) {

                    // canvasScale is current scale
                    // lPinchScale is what we want to set it to, relative to what it is now
                    // ie if canvasScale == 2.7
                    // var newScale = canvasScale * lPinchScale
                    // newScale is where we want canvasScale to end up
                    // 

                    // Get the last pinch scale;
                    var lastScale = aGestureScale[aGestureScale.length - 1];

                    // if scaleDiff negative then pinch in (zoom out), positive it is pinch out (zoom in)
                    var scaleDiff = lPinchScale - lastScale;
                    if (scaleDiff < 0) {

                        scaleDiff = lastScale - lPinchScale;
                        scaleDiff = 1 + scaleDiff;
                        fnZoomOutByFactor(scaleDiff);
                    }
                    else {

                        scaleDiff = 1 + scaleDiff;
                        fnZoomInByFactor(scaleDiff);
                    }

                    //console.log("scale:" + lPinchScale);
                    //}

                    // add new scale
                    aGestureScale.push(lPinchScale);

                } else {
                    console.log("gesture that is not move or start")
                }
            });

....

这就像一个示例代码。我不能把我所有的代码。 bcs 这是非常大的代码..请为我提供一些示例..

谢谢!!

我已经下载了最新版本:https://github.com/kangax/fabric.js/tags

但不工作。 :(

Answer 1

我稍微改变了一下，它起作用了

var canvas = new fabric.CanvasWithViewport('canvas');
canvas.on('touch:gesture',function(event){
    isGestureEvent = true;      
    var lPinchScale = event.self.scale;  
    var scaleDiff = (lPinchScale -1)/10 + 1;  // Slow down zoom speed    
    canvas.setZoom(canvas.viewport.zoom*scaleDiff);   

});