fabric.js ライブラリを使用して、ドラッグ アンド ドロップのムードボード クリエーターを作成しています。画像をキャンバスにドラッグ アンド ドロップするときの Firefox を除いて、すべてが完璧に機能します。画像を追加しますが、img URL にリダイレクトします。リダイレクト後、戻るボタンをクリックすると前のページに戻り、画像がキャンバスに表示されます。
私は今、あらゆる種類のことを試して、数時間検索して読んでいます。私のコードの何かが「e.stopPropagation();」を妨げているようです。または「e.preventDefault()」が正しく機能しません。グレムリンしか見つからない。
どんな助けでも素晴らしいでしょう。ありがとう！
更新: JSFiddle を追加しました。
これが私のコードのjsfiddleです：
http://jsfiddle.net/bQxMu/
更新 2:
問題を修正しました。修正した部分は次のとおりです。
function handleDrop(e) {
// this / e.target is current target element.
/*
if (e.stopPropagation) {
e.stopPropagation(); // stops the browser from redirecting.
}
*/
e.stopPropagation(); // Stops some browsers from redirecting.
e.preventDefault(); // Stops some browsers 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;
}
すべての助けをありがとう:)
window.onload=function(){
var canvas = new fabric.Canvas('canvas');
canvas.backgroundColor = '#ffffff';
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';
return false;
}
function handleDragEnter(e) {
// this / e.target is the current hover target.
this.classList.add('over');
}
function handleDragLeave(e) {
e.stopPropagation();
this.classList.remove('over'); // this / e.target is previous target element.
}
function handleDrop(e) {
// this / e.target is current target element.
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');
});
}
var removeSelectedEl = document.getElementById('remove-selected');
removeSelectedEl.onclick = function() {
var activeObject = canvas.getActiveObject(),
activeGroup = canvas.getActiveGroup();
if (activeGroup) {
var objectsInGroup = activeGroup.getObjects();
canvas.discardActiveGroup();
objectsInGroup.forEach(function(object) {
canvas.remove(object);
});
}
else if (activeObject) {
canvas.remove(activeObject);
$("#imageControl").fadeOut('slow');
}
};
var sendBackwardsEl = document.getElementById('send-backwards');
sendBackwardsEl.onclick = function() {
var activeObject = canvas.getActiveObject();
if (activeObject) {
canvas.sendBackwards(activeObject);
}
};
var sendToBackEl = document.getElementById('send-to-back');
sendToBackEl.onclick = function() {
var activeObject = canvas.getActiveObject();
if (activeObject) {
canvas.sendToBack(activeObject);
}
};
var bringForwardEl = document.getElementById('bring-forward');
bringForwardEl.onclick = function() {
var activeObject = canvas.getActiveObject();
if (activeObject) {
canvas.bringForward(activeObject);
}
};
var bringToFrontEl = document.getElementById('bring-to-front');
bringToFrontEl.onclick = function() {
var activeObject = canvas.getActiveObject();
if (activeObject) {
canvas.bringToFront(activeObject);
}
};
document.getElementById('saveImg').onclick = function() {
if (!fabric.Canvas.supports('toDataURL')) {
alert('This browser doesn\'t provide means to serialize canvas to an image');
}
else {
canvas.deactivateAll().renderAll();
window.open(canvas.toDataURL('png'));
}
};
canvas.on('selection:cleared', function(options) {
var activeObject = canvas.getActiveObject();
if (activeObject === null) {
$("#imageControl").fadeOut('slow');
}
});
canvas.on('object:selected', function(options) {
var activeObject = canvas.getActiveObject();
if (options.target && activeObject !== null) {
$("#imageControl").show('slow');
}
});
canvas.on('selection:created', function(options) {
if (options.target) {
$("#imageControl").show('slow');
}
});
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.");
}
}
HTML:
<div id="images">
<img draggable="true" src="http://i.imgur.com/q9aLMza.png" width="70" height="90"></img>
</div>
<div id="canvas-container-controls">
<div id="imageControlWrapper">
<div id="imageControl">
<button class= "imgBtn" id="saveImg">Save Canvas</button>
<button class="imgBtn" id="remove-selected">Remove selected object/group</button>
<button id="send-backwards" class="imgBtn">Send backwards</button>
<button id="send-to-back" class="imgBtn">Send to back</button>
<button id="bring-forward" class="imgBtn">Bring forwards</button>
<button id="bring-to-front" class="imgBtn">Bring to front</button>
</div>
</div>
<div id="canvas-container">
<canvas id="canvas" width="400" height="400"></canvas>
</div>
</div>