在多个蒙版图像上单击后上传图像

Question

用户单击“蒙版图像”后，我们允许用户上传自定义图像，如果存在单个蒙版图像，则可以正常工作：https://codepen.io/kidsdial/pen/jJBVON

要求：

但是如果有多个遮罩图像，那么用户还应该能够在所有遮罩图像上上传自定义图像 [类似https://codepen.io/kidsdial/pen/rRmYPr之类的东西，但现在它仅适用于单个图片...

2张图像codepen：https://codepen.io/kidsdial/pen/xBLrjY

8张图像的数字笔：https://codepen.io/kidsdial/pen/ywMVOY

var mask;

let jsonData = {
  "path" : " newyear collage\/",
  "info" : {
    "author" : "",
    "keywords" : "",
    "file" : "newyear collage",
    "date" : "sRGB",
    "title" : "",
    "description" : "Normal",
    "generator" : "Export Kit v1.2.8"
  },
  "name" : "newyear collage",
  "layers" : [
    {
      "x" : 0,
      "height" : 612,
      "layers" : [
        {
          "x" : 0,
          "color" : "0xFFFFFF",
          "height" : 612,
          "y" : 0,
          "width" : 612,
          "shapeType" : "rectangle",
          "type" : "shape",
          "name" : "bg_rectangle"
        },
        {
          "x" : 160,
          "height" : 296,
          "layers" : [
            {
              "x" : 0,
              "height" : 296,
              "src" : "ax0HVTs.png",
              "y" : 0,
              "width" : 429,
              "type" : "image",
              "name" : "mask_image_1"
            },
            {
              "radius" : "26 \/ 27",
              "color" : "0xACACAC",
              "x" : 188,
              "y" : 122,
              "height" : 53,
              "width" : 53,
              "shapeType" : "ellipse",
              "type" : "shape",
              "name" : "useradd_ellipse1"
            }
          ],
          "y" : 291,
          "width" : 429,
          "type" : "group",
          "name" : "user_image_1"
        },
        {
          "x" : 25,
          "height" : 324,
          "layers" : [
            {
              "x" : 0,
              "height" : 324,
              "src" : "hEM2kEP.png",
              "y" : 0,
              "width" : 471,
              "type" : "image",
              "name" : "mask_image_2"
            },
            {
              "radius" : "26 \/ 27",
              "color" : "0xACACAC",
              "x" : 209,
              "y" : 136,
              "height" : 53,
              "width" : 53,
              "shapeType" : "ellipse",
              "type" : "shape",
              "name" : "useradd_ellipse_2"
            }
          ],
          "y" : 22,
          "width" : 471,
          "type" : "group",
          "name" : "user_image_2"
        }
      ],
      "y" : 0,
      "width" : 612,
      "type" : "group",
      "name" : "newyearcollage08"
    }
  ]
};

$(document).ready(function() {

    $('.container').click(function(e) {
        setTimeout(() => {
            $('#fileup').click();
        }, 20)
    });



    function getAllSrc(layers) {
        let arr = [];
        layers.forEach(layer => {
            if (layer.src) {
                arr.push({
                    src: layer.src,
                    x: layer.x,
                    y: layer.y
                });
            } else if (layer.layers) {
                let newArr = getAllSrc(layer.layers);
                if (newArr.length > 0) {
                    newArr.forEach(({
                        src,
                        x,
                        y
                    }) => {
                        arr.push({
                            src,
                            x: (layer.x + x),
                            y: (layer.y + y)
                        });
                    });
                }
            }
        });
        return arr;
    }



    function json(data)

    {
        var width = 0;
        var height = 0;
        let arr = getAllSrc(data.layers);

        let layer1 = data.layers;
        width = layer1[0].width;
        height = layer1[0].height;

        for (let {
                src,
                x,
                y
            } of arr) {
            $(".container").css('width', width + "px").css('height', height + "px").addClass('temp');

            var mask = $(".container").mask({
                maskImageUrl: 'https://i.imgur.com/' + src,
                onMaskImageCreate: function(img) {

                    img.css({
                        "position": "absolute",
                        "left": x + "px",
                        "top": y + "px"
                    });
                }
            });

            fileup.onchange = function() {
                mask.loadImage(URL.createObjectURL(fileup.files[0]));
            };
        }

    }
    json(jsonData);

}); // end of document ready

// jq plugin for mask
(function($) {
    var JQmasks = [];
    $.fn.mask = function(options) {
        // This is the easiest way to have default options.
        var settings = $.extend({
            // These are the defaults.
            maskImageUrl: undefined,
            imageUrl: undefined,
            scale: 1,
            id: new Date().getUTCMilliseconds().toString(),
            x: 0, // image start position
            y: 0, // image start position
            onMaskImageCreate: function(div) {},
        }, options);


        var container = $(this);

        let prevX = 0,
            prevY = 0,
            draggable = false,
            img,
            canvas,
            context,
            image,
            timeout,
            initImage = false,
            startX = settings.x,
            startY = settings.y,
            div;

        container.mousePosition = function(event) {
            return {
                x: event.pageX || event.offsetX,
                y: event.pageY || event.offsetY
            };
        }

        container.selected = function(ev) {
            var pos = container.mousePosition(ev);
            var item = $(".masked-img canvas").filter(function() {
                var offset = $(this).offset()
                var x = pos.x - offset.left;
                var y = pos.y - offset.top;
                var d = this.getContext('2d').getImageData(x, y, 1, 1).data;
                return d[0] > 0
            });

            JQmasks.forEach(function(el) {
                var id = item.length > 0 ? $(item).attr("id") : "";
                if (el.id == id)
                    el.item.enable();
                else el.item.disable();
            });
        };

        container.enable = function() {
            draggable = true;
            $(canvas).attr("active", "true");
            div.css({
                "z-index": 2
            });
        }

        container.disable = function() {
            draggable = false;
            $(canvas).attr("active", "false");
            div.css({
                "z-index": 1
            });
        }

        container.onDragStart = function(evt) {
            container.selected(evt);
            prevX = evt.clientX;
            prevY = evt.clientY;
            var img = new Image();
            evt.originalEvent.dataTransfer.setDragImage(img, 10, 10);
            evt.originalEvent.dataTransfer.setData('text/plain', 'anything');
        };

        container.getImagePosition = function() {
            return {
                x: settings.x,
                y: settings.y,
                scale: settings.scale
            };
        };

        container.onDragOver = function(evt) {
            if (draggable && $(canvas).attr("active") === "true") {
                var x = settings.x + evt.clientX - prevX;
                var y = settings.y + evt.clientY - prevY;
                if (x == settings.x && y == settings.y)
                    return; // position has not changed
                settings.x += evt.clientX - prevX;
                settings.y += evt.clientY - prevY;
                prevX = evt.clientX;
                prevY = evt.clientY;
                container.updateStyle();
            }
        };

        container.updateStyle = function() {
            clearTimeout(timeout);
            timeout = setTimeout(function() {
                context.clearRect(0, 0, canvas.width, canvas.height);
                context.beginPath();
                context.globalCompositeOperation = "source-over";
                image = new Image();
                image.setAttribute('crossOrigin', 'anonymous');
                image.src = settings.maskImageUrl;
                image.onload = function() {
                    canvas.width = image.width;
                    canvas.height = image.height;
                    context.drawImage(image, 0, 0, image.width, image.height);
                    div.css({
                        "width": image.width,
                        "height": image.height
                    });
                };

                img = new Image();
                img.src = settings.imageUrl;
                img.setAttribute('crossOrigin', 'anonymous');
                img.onload = function() {
                    settings.x = settings.x == 0 && initImage ? (canvas.width - (img.width * settings.scale)) / 2 : settings.x;
                    settings.y = settings.y == 0 && initImage ? (canvas.height - (img.height * settings.scale)) / 2 : settings.y;
                    context.globalCompositeOperation = 'source-atop';
                    context.drawImage(img, settings.x, settings.y, img.width * settings.scale, img.height * settings.scale);
                    initImage = false;
                };
            }, 0);
        };

        // change the draggable image
        container.loadImage = function(imageUrl) {
            if (img)
                img.remove();
            // reset the code.
            settings.y = startY;
            settings.x = startX;
            prevX = prevY = 0;
            settings.imageUrl = imageUrl;
            initImage = true;
            container.updateStyle();
        };

        // change the masked Image
        container.loadMaskImage = function(imageUrl, from) {
            if (div)
                div.remove();
            canvas = document.createElement("canvas");
            context = canvas.getContext('2d');
            canvas.setAttribute("draggable", "true");
            canvas.setAttribute("id", settings.id);
            settings.maskImageUrl = imageUrl;
            div = $("<div/>", {
                "class": "masked-img"
            }).append(canvas);

            // div.find("canvas").on('touchstart mousedown', function(event)
            div.find("canvas").on('dragstart', function(event) {

                if (event.handled === false) return;
                event.handled = true;
                container.onDragStart(event);
            });

            div.find("canvas").on('touchend mouseup', function(event) {
                if (event.handled === false) return;
                event.handled = true;
                container.selected(event);
            });

            div.find("canvas").bind("dragover", container.onDragOver);
            container.append(div);
            if (settings.onMaskImageCreate)
                settings.onMaskImageCreate(div);
            container.loadImage(settings.imageUrl);
        };
        container.loadMaskImage(settings.maskImageUrl);
        JQmasks.push({
            item: container,
            id: settings.id
        })
        return container;
    };
}(jQuery));

.temp {
background: black;
}

.container {
	background: black;
  position: relative;
 
}

.masked-img {
	overflow: hidden;
	margin-top: 30px;
	position: relative;
}

<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>

<input id="fileup" name="fileup" type="file" style="display:none" >

<div class="container">

</div>

video link

修改

我尝试过使用静态方式：https://codepen.io/kidsdial/pen/xBLrjY，这里用于2张图像，其中包括2张<input type="file" >，对于3张图像，我可能需要添加3个输入文件，是否可以固定或的数量还有其他动态黑客技术，因此它可以用于任意数量的蒙版图像吗？

Answer 1

由于您在实际的绘图中使用的是画布元素，因此我们可以利用它：

$('.container').click(function(e) {
  var elements = document.elementsFromPoint(e.clientX, e.clientY);
  elements.some(element => {
    if(!element.getContext) return false;
    var rect = element.getBoundingClientRect();
    var x = e.pageX - rect.left;
    var y = e.pageY - rect.top;
    var pixel = element.getContext('2d').getImageData(x,y,1,1).data;
    if(pixel[3] === 255) {
      setTimeout(() => {
          $('#fileup').click();
      }, 20);
      return true;
    }
    return false;
  });
});

clientX和clientY是相对于客户区域（浏览器中当前可见的页面区域）的点击坐标。将它们与document.elementsFromPoint()一起使用可以为我们提供点击位置下方的所有元素。

然后，我们扫描所有找到的元素，检查它们是否具有属性getContext。 .some()使我们可以遍历元素数组，同时还可以根据需要选择提前终止。我们测试getContext来查看它是否是canvas元素，如果不是，我们可以跳过它。

如果是画布，我们可以继续下一步。 getContext('2d')抓取了画布的绘制上下文，我们可以通过getImageData()从中提取原始像素数据。

事件中的

pageX和pageY是相对于整个页面的点击坐标。 getBoundingClientRect()为我们提供了元素相对于页面的位置。结合使用这些，我们可以得到点击相对于元素的坐标。我们在getImageData()中使用它来获取该画布中单击位置处的画布像素数据。

像素数据是交错的红色，蓝色，绿色和Alpha（不透明度）值，每个值的范围是0到255。由于我们抓取了一个像素，因此它将有4个值，最后一个是alpha。然后，我们可以使用它来确定是否触发文件对话框。

如果我们恰巧在画布的单击位置找到不透明像素，则可以触发文件对话框，然后通过从true回调返回.some()来跳过其余元素。 / p>