如何获取 canvas 中的图像 ID

How to get Id of image in canvas

我正在尝试在 canvas 中拖放图像,并且我在 canvas 中获得了该图像的完美坐标。但我想要当前被拖放的图像的 Id。 我们如何获取当前拖放到 canvas.

中的图像的 Id

这是我的代码:

<!DOCTYPE html>
<!--
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and open the template in the editor.
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<html>
    <head>
        <title>Test</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script>
        <script src="http://d3lp1msu2r81bx.cloudfront.net/kjs/js/lib/kinetic-v4.7.2.min.js"></script>
        <script src="http://code.jquery.com/ui/1.9.2/jquery-ui.min.js"></script>
        <style>
            body{padding:20px;}
            #container{
                border:solid 1px #ccc;
                margin-top: 10px;
                width:350px;
                height:350px;
            }
            #toolbar{
                width:350px;
                height:35px;
                border:solid 1px blue;
            }
            #buttons > input {
                padding: 10px;
                display: block;
                margin-top: 5px;
            }
            #buttons {
                position: absolute;
                top: 5px;
                left: 10px;
            </style>
        </head>
        <body>
            <script>window.tableIndex = 0;
                window.tablePositionList = [[], []];
            </script>

            <h4>Drag from  onto canvas. Then drag around canvas.</h4>
            <div id="toolbar">
                <img id="house2" class="tool" width=32 height=32 src="https://dl.dropboxusercontent.com/u/139992952/Whosebug/house204-1.jpg"><input type="hidden" id="house2_hidden" value="">
                <img id="house" class="tool" width=32 height=32 src="https://dl.dropboxusercontent.com/u/139992952/multple/4top.png"><input type="hidden" id="house_hidden" value="">
                <img id="house6" class="tool" width=32 height=32 src="https://dl.dropboxusercontent.com/u/139992952/Whosebug/house204-2.jpg"><input type="hidden" id="house6_hidden" value="">
                <br>
            </div>
            <div id="container"></div>
            <div id="buttons">
                <input type="button" id="clear" value="Clear">
                <input type="button" id="submit"  value="Submit" >
            </div>

            <script>
//                var $tools = $(".tool");
                //global variable
//                var imageId;
//                imageId = document.getElementById('house2_hidden').value = "house2";
//                imageId = document.getElementById('house_hidden').value = "house";
//                imageId = document.getElementById('house6_hidden').value = "house6";
                var global_image;
                // get a reference to the house icon in the toolbar
                // hide the icon until its image has loaded
                var $house = $("#house");
                $house.hide();

                var $house2 = $("#house2");
                $house2.hide();

                var $house6 = $("#house6");
                $house6.hide()


                // get the offset position of the kinetic container
                var $stageContainer = $("#container");
                var stageOffset = $stageContainer.offset();
                var offsetX = stageOffset.left;
                var offsetY = stageOffset.top;
                // create the Kinetic.Stage and layer
                var stage = new Kinetic.Stage({
                    container: 'container',
                    width: 350,
                    height: 350
                });
                var layer = new Kinetic.Layer();
                stage.add(layer);
                // start loading the image used in the draggable toolbar element
                // this image will be used in a new Kinetic.Image
                var image1 = new Image();
                image1.onload = function () {
                    $house.show();
                };
                var image2 = new Image();
                image2.onload = function () {
                    $house2.show();
                };
                var image3 = new Image();
                image3.onload = function () {
                    $house6.show();
                };
                image1.src = "https://dl.dropboxusercontent.com/u/139992952/multple/4top.png";
                image2.src = "https://dl.dropboxusercontent.com/u/139992952/Whosebug/house204-1.jpg";
                image3.src = "https://dl.dropboxusercontent.com/u/139992952/Whosebug/house204-2.jpg";
                // make the toolbar image draggable
                $("#house").draggable({
                    helper: 'clone',
                    obstacle: "#house",
                    preventCollision: true,
                    containment: 'container'
                });
                $("#house2").draggable({
                    helper: 'clone',
                    obstacle: "#house2",
                    preventCollision: true,
                    containment: 'container'
                });
                $("#house6").draggable({
                    helper: 'clone',
                    obstacle: "#house6",
                    preventCollision: true,
                    containment: 'container'
                });
                // set the data payload
                $house.data("url", "house.png"); // key-value pair
                $house.data("width", "32"); // key-value pair
                $house.data("height", "33"); // key-value pair
                $house.data("image", image1); // key-value pair

                $house2.data("url", "house204-1.jpg"); // key-value pair
                $house2.data("width", "32"); // key-value pair
                $house2.data("height", "33"); // key-value pair
                $house2.data("image", image2); // key-value pair

                $house6.data("url", "house204-1.jpg"); // key-value pair
                $house6.data("width", "32"); // key-value pair
                $house6.data("height", "33"); // key-value pair
                $house6.data("image", image3); // key-value pair

                // make the Kinetic Container a dropzone
                $stageContainer.droppable({
                    tolerance: 'fit',
                    drop: dragDrop
                });

                // handle a drop into the Kinetic container
                function dragDrop(e, ui) {
                    var x = parseInt(ui.offset.left - offsetX);
                    var y = parseInt(ui.offset.top - offsetY);



                    console.log(x);
                    console.log(y);
                    // get the drop payload (here the payload is the image)
                    var element = ui.draggable;
                    var data = element.data("url");
                    var theImage = element.data("image");
                    // create a new Kinetic.Image at the drop point
                    // be sure to adjust for any border width (here border==1)
                    var image = new Kinetic.Image({
                        name: data,
                        x: x,
                        y: y,
                        image: theImage,
                        draggable: true
                    });
                    var x = parseInt(ui.offset.left - offsetX);
                    var y = parseInt(ui.offset.top - offsetY);

                    global_image = image;
                    //
                    layer.add(image);
                    layer.draw();
                    $("#clear").click(function () {

                    });
                    document.getElementById('clear').addEventListener('click', function () {

                    });

                    var x = parseInt(ui.offset.left - offsetX);
                    var y = parseInt(ui.offset.top - offsetY);


                    window.tablePositionList[tableIndex] = [x, y];
                    window.tableIndex++;

                }


            </script>
            <div style="height: 20px;width: 20px;background-color: red;" onclick="getImageValue();">
            </div>
            <script>
                document.getElementById('submit').addEventListener('click', function () {

                    console.log(tablePositionList)
                });
                function getImageValue()
                {
                    console.log("global_image.data");
//                        console.log(tableIndex);
                    global_image.destroy();
                    layer.draw();
//                        var backindex = tableIndex - 1;
//                    window.tablePositionList.remove(tableIndex, 1);
                    window.tablePositionList.pop();
                    window.tableIndex--;

                }
//                function clear() {
//                    console.log("global_image.data");
//                    global_image.destroy();
//                    layer.draw();
//                }
            </script>
        </body>

    </html>

在您的 dragDrop 函数中,您可以访问包含被拖动元素的 element 变量。 您可以访问其 ID 属性,例如:

element[0].id

或 jQuery:

$(element).attr('id')

在您的 dragDrop 函数中使用 ui.draggable.attr('id'); 来获取拖动图像的 ID。

简单的解决方案,让您获得拖动项目的 id。

var draggedElementID = ui.draggable.attr('id');

这是您可以访问它的代码。

function dragDrop(e, ui) {
    var x = parseInt(ui.offset.left - offsetX);
    var y = parseInt(ui.offset.top - offsetY);


    // Below line gives you the id of the image that is dragged.
    var draggedElementID = ui.draggable.attr('id');



    console.log(x);
    console.log(y);
    // get the drop payload (here the payload is the image)
    var element = ui.draggable;
    var data = element.data("url");
    var theImage = element.data("image");
    // create a new Kinetic.Image at the drop point
    // be sure to adjust for any border width (here border==1)
    var image = new Kinetic.Image({
        name: data,
        x: x,
        y: y,
        image: theImage,
        draggable: true
    });
    var x = parseInt(ui.offset.left - offsetX);
    var y = parseInt(ui.offset.top - offsetY);

    global_image = image;
    //
    layer.add(image);
    layer.draw();
    $("#clear").click(function () {

    });
    document.getElementById('clear').addEventListener('click', function () {

    });

    var x = parseInt(ui.offset.left - offsetX);
    var y = parseInt(ui.offset.top - offsetY);


    window.tablePositionList[tableIndex] = [x, y];
    window.tableIndex++;

}

添加此脚本以捕获 dragstop 事件。

$('.tool.ui-draggable').on('dragstop', function(e){ var imgid = $(e.target).attr('id'); console.log(imgid);});

您也可以捕获 dragstart / drag 事件。