javascript - 如何将 SVG 文件拖放到 Fabricjs Canvas 上？

Question

我正在尝试将 Canvas 外部的 svg img 拖放到 Canvas 本身，它确实适用于简单图像(png、jpg、gif)，但不适用于 svg 文件，因为我是 FabricJS 的新手，所以我我想知道如何配置它以便它也可以与 SVG 一起使用。我不想从 SVG 创建 Fabric.Image 对象，我想将它们作为 Fabric.PathGroup 删除，以便它们保留矢量信息和编辑功能。

您可以通过此链接发现该项目:

http://jsfiddle.net/w8kkc/309/

HTML

<div id="images">
    <img draggable="true" src="http://i.imgur.com/8rmMZI3.jpg" width="100" height="100">
    <object draggable="true" type="image/svg+xml" data="http://fabricjs.com/assets/1.svg" width="100" height="100"></object>
</div>

<div id="canvas-container">
    <canvas id="canvas" width="400" height="250"></canvas>
</div>

<小时/>

Javascript (FabricJS)

var canvas = new fabric.Canvas('canvas');

function handleDragStart(e) {
    [].forEach.call(images, function (img) {
        img.classList.remove('img_dragging');
    });
    this.classList.add('img_dragging');
}

function handleDragOver(e) {
    if (e.preventDefault) {
        e.preventDefault(); // Necessary. Allows us to drop.
    }

    e.dataTransfer.dropEffect = 'copy'; // See the section on the DataTransfer object.
    // NOTE: comment above refers to the article (see top) -natchiketa

    return false;
}

function handleDragEnter(e) {
    // this / e.target is the current hover target.
    this.classList.add('over');
}

function handleDragLeave(e) {
    this.classList.remove('over'); // this / e.target is previous target element.
}

function handleDrop(e) {
    if (e.preventDefault) {
      e.preventDefault(); 
    }

    if (e.stopPropagation) {
        e.stopPropagation(); // stops the browser from redirecting.
    }

    var img = document.querySelector('#images img.img_dragging');

    // console.log('event: ', e);

    var newImage = new fabric.Image(img, {
        width: img.width,
        height: img.height,
        // Set the center of the new object based on the event coordinates relative
        // to the canvas container.
        left: e.layerX,
        top: e.layerY
    });
    canvas.add(newImage);

    return false;
}

function handleDragEnd(e) {
    // this/e.target is the source node.
    [].forEach.call(images, function (img) {
        img.classList.remove('img_dragging');
    });
}

if (Modernizr.draganddrop) {
    // Browser supports HTML5 DnD.

    // Bind the event listeners for the image elements
    var images = document.querySelectorAll('#images img');
    [].forEach.call(images, function (img) {
        img.addEventListener('dragstart', handleDragStart, false);
        img.addEventListener('dragend', handleDragEnd, false);
    });
    // Bind the event listeners for the canvas
    var canvasContainer = document.getElementById('canvas-container');
    canvasContainer.addEventListener('dragenter', handleDragEnter, false);
    canvasContainer.addEventListener('dragover', handleDragOver, false);
    canvasContainer.addEventListener('dragleave', handleDragLeave, false);
    canvasContainer.addEventListener('drop', handleDrop, false);
} else {
    // Replace with a fallback to a library solution.
    alert("This browser doesn't support the HTML5 Drag and Drop API.");
}

关于如何接受将 SVG 拖放到 Canvas 中，有什么建议吗？

Answer 1

http://jsfiddle.net/w8kkc/336/更新了 fiddle

JavaScript

var canvas = new fabric.Canvas('canvas');
var currentlyDragging;

function handleDragStart(e) {
    [].forEach.call(images, function (img) {
        img.classList.remove('img_dragging');
    });
    this.classList.add('img_dragging');
    currentlyDragging = e.target;
}

function handleDragOver(e) {
    if (e.preventDefault) {
        e.preventDefault(); // Necessary. Allows us to drop.
    }

    e.dataTransfer.dropEffect = 'copy'; // See the section on the DataTransfer object.
    // NOTE: comment above refers to the article (see top) -natchiketa

    return false;
}

function handleDragEnter(e) {
    // this / e.target is the current hover target.
    this.classList.add('over');
}

function handleDragLeave(e) {
    this.classList.remove('over'); // this / e.target is previous target element.
}

function handleDrop(e) {
    if (e.preventDefault) {
      e.preventDefault(); 
    }
    
    if (e.stopPropagation) {
        e.stopPropagation(); // stops the browser from redirecting.
    }

 
        
    // console.log('event: ', e);
    var ext = currentlyDragging.src.substr(-3);
    if (ext === 'svg') {
      fabric.loadSVGFromURL(currentlyDragging.src, function(objects, options) {
        var svg = fabric.util.groupSVGElements(objects, options);
        svg.left = e.layerX;
        svg.top = e.layerY;
        canvas.add(svg); 
      });
    } else {
       var newImage = new fabric.Image(currentlyDragging, {
          width: currentlyDragging.width,
          height: currentlyDragging.height,
          // Set the center of the new object based on the event coordinates relative
          // to the canvas container.
          left: e.layerX,
          top: e.layerY
      });
      canvas.add(newImage);
    }
    return false;
}

function handleDragEnd(e) {
    // this/e.target is the source node.
    [].forEach.call(images, function (img) {
        img.classList.remove('img_dragging');
    });
}

if (Modernizr.draganddrop) {
    // Browser supports HTML5 DnD.

    // Bind the event listeners for the image elements
    var images = document.querySelectorAll('#images img');
    var objects = document.querySelectorAll('#images object');
    [].forEach.call(images, function (img) {
        img.addEventListener('dragstart', handleDragStart, false);
        img.addEventListener('dragend', handleDragEnd, false);
    });
    [].forEach.call(objects, function (obj) {
        obj.addEventListener('dragstart', handleDragStart, false);
        obj.addEventListener('dragend', handleDragEnd, false);
    });
    // Bind the event listeners for the canvas
    var canvasContainer = document.getElementById('canvas-container');
    canvasContainer.addEventListener('dragenter', handleDragEnter, false);
    canvasContainer.addEventListener('dragover', handleDragOver, false);
    canvasContainer.addEventListener('dragleave', handleDragLeave, false);
    canvasContainer.addEventListener('drop', handleDrop, false);
} else {
    // Replace with a fallback to a library solution.
    alert("This browser doesn't support the HTML5 Drag and Drop API.");
}